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"What's New" Reviews
MT® 2000

Please mention you saw it in Monitoring Times!

2000 Reviews: CCRadio vs. GE Superadio / Icom W32 Transceiver as a scanner / The Ramsey FM-100 Stereo Transmitter / Low Cost Hardware for GOES Reception / Nil-Jon Scanner Antennas / Ramsey Mobile RDF System / Super Select-A-TennaAOR Antennas / Protek 3201 RF Field Analyzer

Index to scanner reviews by Bob Parnass

1999 Index to review columns: Scanner Equipment, Magne Tests, Computer & Radio, And More

1998 Reviews


CCRadio vs. Superadio - How do they stack up?

Review by Bob Grove
 

Medium wave (standard AM broadcast band) DXing (long-distance listening) is a specialized hobby, separate from shortwave listening. General coverage communications receivers, perfectly acceptable for the SW listener, commonly attenuate their sensitivity in the MW band to avoid the consequences of local strong-signal overload, and loop antennas are often invoked to reject ambient electrical noise or null interference from co-channel broadcasters.

Off-the-shelf consumer radios are hardly adequate for the hard-core MW DXer; they suffer the maladies of poor sensitivity, broad selectivity, imaging, strong-signal overload, and dismal frequency accuracy. And, just for kicks, they rarely allow the use of an external antenna.

For many years a popular favorite among MW DXers was a Radio Shack receiver with TRF (tuned radio frequency) design; it was a hot receiver, and many aficionados were disappointed when the product was discontinued.

More recently, the GE series of Superadios, now in their third generation, have been accepted as the standard of comparison for medium wave broadcast listeners, primarily because of its legendary IF (intermediate frequency) filtering. Now there is a new kid on the block: the CCRadio, made by Sangean under contract with C. Crane Co. of Fortuna, CA, and reviewed in MT Feb 1999.

Is the CC hype louder than its performance, or is this newer model a serious threat to the GE’s lofty position? At nearly three times the price of the GE ($159.95 vs. $59.95), does the CC offer that much more? Let’s take a quick overview of their cosmetics and features, then a more discerning look at their relative performances under actual listening conditions.

The smaller CC (11”W x 6-3/4”H x 3-1/2”D) is finished in charcoal gray matte, while the larger GE (13”W x 9”H x 3-1/2”D) exhibits a glossier black and chrome highlighting. Both radios offer separate bass and treble tone controls, headphone jack, telescoping whip (longer on the GE), and dual AC/battery power supply. Both provide screw terminals for an external AM antenna (the GE also includes terminals for FM), a top-cabinet push/push power switch, and a right-side-mounted tuning dial. But that’s where the similarity ends.
 

Tuning Dial

The GE sports a traditional analog slide-rule dial, while the CC offers a backlighted LCD which has an alarm clock/sleep function and 20 memory channels (5 in each of 4 bands) in addition to its mandatory frequency display.

The accurate and informative LCD wins hands down over the old analog dial with its loose calibration. The GE offers automatic frequency tuning (AFC) on its FM mode, required in older variable frequency oscillator (VFO) designs to prevent tuning drift. The CC, being frequency synthesized and utilizing phase locked loop (PLL) drift cancellation, does not require such compensatory circuitry.

Like modern automotive radios, an up/down autoseek feature searches out signals at the press of a key.

While the GE offers conventional AM/FM coverage (530-1700 kHz/88-108 MHz), the CC adds seven weather channels (162.400-162.550 MHz) with severe conditions alarm, and TV audio for channels 2-13.
 

Audio Quality

This one is a little tricky. The CC is admittedly designed for talk radio, so its IF and audio filtering are contoured to favor the more limited range of voice frequencies. The GE does a much better job on music with its choice of wide/narrow filters and separate, larger woofer/tweeter speaker system in a larger enclosure.  Although the printed specifications show the CC’s audio output rated at 1.8 watts for 10% THD (total harmonic distortion) versus the GE’s 700 milliwatts (unspecified THD), both radios deliver approximately the same acoustic sound levels before going into distortion.

While the sound of the GE on music is more transparent with richer bass and crisper highs, the CC music performance is certainly listenable, but clearly favors the human voice. Both sets offer considerable tonal equalization with their bass and treble controls.
 

Sensitivity

We noticed no remarkable difference in either AM or FM sensitivity between the two sets, although other observers report slightly better weak AM signal reception on the GE. Weather band reception on the CC was roughly equivalent to that of a hand-held scanner, remarkable for a multiband portable. Reception on this range is undoubtedly helped by the frequency-resonant 16” whip antenna.
 

Selectivity

The ability of a receiver to reject interference from adjacent channels stations is critical to AM DXers. While the GE offers two selectivity choices, the wide is unjustifiably broad given the poor fidelity common on medium wave; as a result, only the stronger signals will be heard with that selection, swamping weak, adjacent-channel broadcasters. The narrow position certainly improves adjacent channel selectivity, but does not compare to the sharp skirts and ultimate attenuation of the CC’s filters.

On the other hand, using the internal AM loop antenna to null interference is much sharper on the GE, and at nighttime, image interference from 60 meter (5 MHz band) shortwave signals are quite prominent on the CCRadio using its own whip.
 

The Bottom Line

If you require a portable with good fidelity, excellent adjacent channel AM selectivity, and favor listening to distant talk radio in crowded band conditions, the CCRadio is a clear choice, and tosses in weather band and TV audio as well.

If you are looking for a more economical AM/FM radio with better-than-average performance and outstanding music quality, the GE Superadio III should prove quite satisfactory.
 

CCRadio, $159.95 plus shipping from C Crane Company, 558 10th St., Fortuna, CA 95540 2350; ph. (800) 522-8863.

GE Superadio III, available from MT advertisers including Grove Enterprises, PO Box 98, Brasstown, NC 28902; ph. (800) 438-8155 (Price $59.95 plus $5.95 shipping). 


The Icom W32A Transceiver

By Gary Webbenhurst  AB7NI
 

 Wow! This is a great scanner!

 That is the conclusion I have arrived at, after evaluating my new Icom W32A amateur transceiver. Like most ham radio operators, I keep waiting for the "perfect" handheld transceiver (HT.) Over the years, I have owned more than a dozen radios from all the major manufacturers. They all have their advantages and disadvantages. But I think I finally found one that comes very close to perfection.

 Here is my checklist of the features for the perfect HT.

1.  The alpha numeric display must be large and easy to read.
2.  Display and keypad must be brightly backlit.
3.  Audio speaker must be adequate to the task for clear, crisp sound.
4.  Display of the battery's current voltage status.
5.  A real time clock display.
6.  Good mechanical battery release button.
7.  Extended wide band receive coverage.
8.  Computer programmable.
9.  Direct keypad input.
10. Small cheatsheet and/or a summary of instructions.
11. Easy to understand programming booklet.
12. A good antenna for the intended ham bands.
13. The keypads must be large and spaced for the average fingers.
14. True dual band capabilities.
15. External power jack.
16. Standard earphone and microphone connection.

 Until now, only the Yaesu 530 came close. But, alas, my 530 has died and good used ones are impossible to come by. Thus I began a new search. Now, there have been many really good HTs. I loved one model, but it had a fatal flaw: The battery release button had a 100% duty cycle. That meant that every time I went to slide the radio unto my belt, the battery would come loose and fall to ground, usually damaging the battery pack.

 Applied to the checklist, the W32A is good for 15 out of 16. (No clock.)
 

Great scanning features

 While I was evaluating the W32A as a ham transceiver, I noticed that it had many features that would make it a very good scanner. Here are several features of the W32A that are really handy for the scanner enthusiast:

• Expanded coverage of 108-135AM, 136-199, 300-399, 400-599 and 600-999 MHz
 To enjoy these ranges, one can perform a simple keyboard modification of holding the SQL and Band buttons down, while powering on the radio. Of course, we all know that just because the radio displays a certain frequency, that is no guarantee that the radio can actually receive such a frequency. I had mixed luck in the TV audio range. Depends on the antenna and literally how you hold the radio. I could move the radio from vertical to horizontal or three feet from the previous location and now the station came in clear. Other times nothing. Reception on the aircraft and 800Mhz range (cellular blocked) was excellent. You can check the internet for the hardware modification to open the transmit frequency range.

The radio can be configured for dual display (and simultaneous scanning) of Very High Frequencies (VHF) and Ultra High Frequencies (UHF.) The choices include the following combinations:
Wx/VHF 10 preprogrammed weather channels  136-199.995
VHF/UHF 108-135.975AM 300-399.995
VHF/UHF 136-199.995  400-599.995
UHF/UHF 435-454.975  600-999.990
 This is a true dual band radio! Image the possibilities. You can scan the aircraft frequencies on one side, the ham bands or public safety on the other side. Listen to the audio of the five o'clock TV news while also listening for a ham buddy on the two meter band. Or monitor your favorite 440 MHz repeater while simultaneously scanning the fire department channels. How many scanners will do that?

Another great feature is the five programmable search ranges. These begin with memory channels M1A (lower) and M1B (upper). The others are shown below with the particular ranges I wanted on the VHF side. Of course you could program anything you wanted.

 My favorite setup for the VHF side:
M1A 145.110 M1B 147.995 Ham repeaters on two meters
M2A 118.950 M2B 128.000 Local airports
M3A 151.145 M3B 151.465 Park Rangers and forestry
M4A 153.740 M4B 154.445 local fire departments
M5A 154.650 M5B 156.150 local police departments

 UHF possibilities:
M1A 440.000 M1B 450.000 Ham repeaters on 440
M2A 406.000 M2B 412.000 Trunked military systems
M3A 412.000 M3B 419.900 Various Federal Agencies
M4A 453.050 M4B 453.975 local public safety
M5A 460.025 M5B 460.625 local police/fire departments

 To use this feature, you simply press Scan while in the Variable Frequency Oscillator (VFO) mode. It will begin searching in the first range 145.110 to 147.995. To search any of the other ranges just press 2, 3, 4 or 5. This is way too easy! Even my brother-in-law figured it out! UHF has its own five search ranges.

You can select the scan pause mode for each of the five ranges. Choices are: 15 seconds, 10, 5 or carrier activated. I prefer carrier activated so as not to lose any radio traffic.

An excellent cheatsheet and an easy to understand instruction programming booklet

CTCSS (Continuously Tone Coded Squelch System). An impressive list of 50 different PL tones. You can use the correct tone squelch to keep out the annoying intermod noise and unwanted signals. Set the radio to a frequency in VFO mode, activate Tone Squelch, then press scan and the radio will search for the correct tone. Cool!

 When set to a specific frequency and tone squelch pocket beep, it will ring like a phone (or other sounds that you can program.) This also means I can use the W32A to act as a CTCSS activated pager ? great if you are a volunteer firefighter or Emergency Medical Service (EMS) person.

100 memory channels for the VHF side and another 100 for UHF, plus the 10 memory band scan edge channels for both VHF and UHF.

A special memory channel, the Call channel. This allows one button touch access for your favorite frequency on VHF and UHF. While my ham buddies and I refer to this as the "Charlie" channel, it is in reality a two meter ham radio simplex frequency. You can program anything you desire.

A power saver feature can be activated to reduce the current drain while in manual mode.

Automatic power off at 20, 40 or 60 minutes. This is great, because I often forget to turn my radio off. No more dead batteries for this guy. This feature can also be toggled on/off.

The display backlight can be set for 5 seconds or on/off toggle. This is a great feature. If you are monitoring in poor light conditions, you can keep the backlight on continually until you decide to turn it off. The four LEDs draw minimal current from the battery. If you are using an external power source, the backlight is not an energy concern.

Keypad beep tone can be easily disabled or reactivated.
Select step size. Available in any of these kilohertz steps: 5,10, 12.5, 15, 20, 25, 30, 50!
Select LCD contrast setting.
Ten preset NOAA Weather channels.
Display can show frequency or channel number plus an eight digit alpha numeric (AN). The potential here is great. If the local police have 8 channels, I program them into the radio's Channels 1-8. On the 8 character AN label, I can use anything I want such as South, Records, SWAT, Chase, Downtown, car-2car, on-scene, white, blue etc.

 I can also use the common abbreviations such as SO for Sheriffs Office, CP for Command Post, DOT for Department of Transportation, CDF for California Division of Forest and Fire Fighting. DNR for Department of Natural Resources, HP for Highway Patrol, SP for State Police, FBI etc. Thus I end up with a display reading “CH 1 Downtown.”

• When used with the CS-W32 software and connection cable, the W32A can be programmed from a create-your-own database of frequencies. You can program the receive frequency, transmit frequency, PL tone, offset etc. You can have several databases. I have one for each of the major geographical areas I visit. I also have one just for airshows. You can trade data files on the internet. I have several to swap!

• And finally, extra cost battery pack and alkaline battery case are available.  Size and feel are good: not too big, not too small.  Belt clip and handstrap are included. It has a large and easy-to read display, and priority channel feature.
 

Disadvantages:

• The W32A does not do  trunk tracking. You can use the conventional method of locking out the 800MHz data channels.
• No 30-54 MHz low band coverage.
• There are no banks like a conventional scanner. You have a bank of 100 memory channels on each side and you can lock out (skip) any channels you desire.
• No cellular coverage, but who cares?
• The scan rate is good, but not nearly as fast as other scanners and radios.
• No clock!  Oh well.  Many agencies now give the time as part of their radio procedure. Car: "Adam 56 is 10-8"   Dispatcher: "at 10:32"

 Street price of the Icom W32A is around $300.

 Next time you are in the market for a scanner, consider an amateur radio transceiver. You don't have to be a licensed ham to buy amateur radios; just don't transmit. Ah, what the heck -- get your license.


The Ramsey Model FM-100 

Professional FM Stereo Transmitter  $249.95 Kit  Ramsey Electronics, Inc.  793 Canning Parkway  Victor, NY 14564  Phone (716) 924-4560  Fax (716) 924-4555  Web: www.ramseyelectronics.com 

  

The Ramsey FM-100 Stereo Transmitter 

Review by Thomas James Arey

If you have been following the radio press for the last year or so, you are aware that there is a boom in interest in low power broadcasting. There is growing interest in the hobby community about the practical and fun uses of unlicensed Part-15 transmitters. (FM broadcast signal with a field strength not exceeding 250 microvolts/meter measured at a distance of three meters from the transmitter (FCC rule 15.239)) 

Others are testing the limits of the existing law (broadcast pirates) and still others have supported a total revamping of broadcast law to allow low power, affordable, licenses. The FCC's recent decision to allow low power broadcasting -- consistent with its on-going move toward deregulation in all the radio services -- make these very exciting times, indeed. (See this month's Washington Whispers and American Bandscan columns.)  The folks at Ramsey Electronics have long been at the forefront of low-power transmitter development. They were revolutionary even before most people knew a low power revolution was going on. Many low power experimenters began their hobby broadcast efforts by building one of two other Ramsey offerings, the FM-10 (now called the FM-10a) or the FM25. 

While these transmitters continue to serve the needs of many hobbyists at very reasonable prices, a couple of years ago Ramsey answered the call for a more sophisticated FM transmitter to meet the needs of this growing aspect of the radio hobby. The no-compromise FM-100 provides studio quality audio signals and a level of transmitter control not found in other lower cost units, while remaining a legal Part-15 transmitter. 

The FM-100 is more than just a transmitter; it contains all the essential aspects of a complete broadcast station short of the actual the signal sources. The unit includes two line inputs and one microphone input, all with a high level of audio signal filtering and signal mixing controls. Further, the microphone line has Automatic Gain Control (AGC) to prevent overloading should you have the uncontrollable urge to start shouting like Wolfman Jack. Both channels also have LED readout audio level meters so you can see just what your signal is doing. 

All of these efforts in design serve to allow the user to produce the highest quality signal free of the distortion and noise sometimes experienced by Part-15 listeners. Properly used, the audio quality of your signal should rival that of most any commercial station. 

The 25 mW (that's milliwatt, not megawatt!) FM stereo transmitter is the response of Ramsey's years of technical experience to what their customer base wanted. 

For places outside the United States where higher power is legal, this unit can be purchased with a 1 watt RF output module. Export units connected to gain antennas have been known to cover several miles with their signal. (But don't try this at home in the US, kids...The FCC still frowns on folks tweaking their equipment beyond Part-15 standards.) 

Frequency control is state of the art, Phased Lock Loop-controlled. The output frequency is displayed on a large, easy to read, Light Emitting Diode (LED) display. Frequency adjustment is as simple as the push of a button.  Unlike many lower power transmitters that depend on "wall wart" or battery power supplies, the FM-100 has its own internal power supply. This supply benefits from filtering capacitors to reduce ripple, eliminating background audio hum. All your listeners should hear are your broadcasts. 

The unit comes in a sturdy metal case with a silk screened front panel. This goes a long way toward making the whole package look very professional. 

The whole kit and kaboodle 

The FM-100 can be purchased in a fully wired and tested version; however, I opted to break out the soldering iron and build the kit. Over the years I have built many Ramsey kits. I have always been impressed with their attention to detail, particularly where beginners are concerned. While the FM-100 could be considered a moderately advanced kit, anyone who knows which end of a soldering iron to hold and who can follow clear, step-by-step directions should be able to build a fine project. 

The Ramsey kit manuals rival the standards of the long departed Heathkit books. Complete parts inventory check lists are included along with check-as-you-go building steps. There is also a large-format parts placement guide that you can follow along as you do your work. 

The Ramsey folks also take the time to teach you about the circuit as you go through the building process. By the time you are done, you will not only have an FM broadcast station, you will also have the ability to tell people how the thing works. 

Recommended building time for a beginner is listed at 24 hours. This is about right. Since the construction is based on a series of circuit groups, it was easy to build a section or two through to completion in an evening. 

Given the attention to detail of the manual, I had no reason to be surprised when the unit fired up the first time without any problems. Ramsey seems to have anticipated many of the common problems associated with construction projects and they tend to give a lot of extra support where it's needed. 

Getting on the air 


I have had previous experience with both the FM-10a and the FM-25. While these remain great entry level units, the FM-100 is clearly head and shoulders above either of Ramsey's previous offerings. I had to let my next door neighbor know that there wasn't a new station in town. 

My most routine use for the FM-100 remains getting signals from my home stereo system out to a "boom box" by my backyard pool. The possibilities, however, go far beyond that. The FM-100 would make a great basic setup for a school radio program. The manual alludes to the fact that the unit can be used as a front end for "carrier-line" use but reminds people that they should seek a qualified engineer to make this happen. 

Before you take to the airwaves, the Ramsey manual gives complete practical comments on the proper, legal use of this transmitter under the current regulations. This includes a list of Frequently Asked Questions that show they have been keeping their ears tuned to their customers over the years. 

The world of hobby broadcasting is growing every day, but even with the newly-enacted low-power regulations the number of potential new licenses may not exceed 1,000. Why wait? Start broadcasting, legally and with the cleanest signals on the airwaves, using Ramsey's FM-100s. 


Low Cost Hardware For GOES Reception

- by Lawrence Harris -

 My backyard comprises a dish and antenna farm, but nothing stays in one place for long. One day the washing line/mast support has a vertically polarized log periodic antenna fitted at the top for monitoring satellites; the next day this may be replaced by a multi-element yagi pointing at GOES. For the last few days it has supported a VHF antenna that is pointing upwards, then westwards, now southwards (for testing polar satellite reception). Meanwhile, the dishes on the ground get moved about, dependent on test requirements.

The units that I have recently had under test comprise an active feed and a downconverter. In isolation, these components are unlikely to be of much use to anyone, but as new additions to a weather satellite (WXSAT) system, they are invaluable. This article provides the background to their use as the essential parts of a low-cost GOES WEFAX system.

 Starting from scratch

The newcomer to monitoring satellites has a bewildering choice. The cheapest systems are likely to be commercial satellite television receivers, where bulk production means lower costs. However, thanks to NOAA (the National Oceanic and Atmospheric Administration) we also have several weather satellites that provide interesting alternatives! There are two different groups of satellites (constellations) available for monitoring. I suspect that most WXSAT monitors started with the polar orbiters -- currently NOAA-14 and NOAA-15. These (as the type suggests) orbit earth in near-polar orbits, and therefore pass over every point on earth three or four times each day.

To receive signals from these WXSATs, you need a suitable 137 MHz band antenna and receiver. The units must be specifically designed for WXSAT use; general purpose utility antennas and receivers are unsuitable due to the special nature and content of WXSAT signals. Forget the discone; although these allow you to tune to the 137 MHz band, special characteristics (for example, the NOAA WXSATs provide right-hand circular polarization) mean that reliable reception may be limited to an occasional minute during high elevation passes. A crossed-dipole, turnstile or quadrifilar helix antenna are amongst the most popular choices for reception. WXSAT receivers are also highly specialized, requiring a wider-than-normal bandpass, together with tight filtering for optimum reception.

Perhaps you have a complete polar orbiting WXSAT set-up and have been monitoring NOAAs-14 and -15, in addition to Resurs 01-N4 and Meteor 3-5. What else do you need for GOES reception? Two -- maybe three -- items. Before I detail these, let us take a brief look at history.

 Compatibility

There are grounds for being grateful for decisions made decades ago. Despite their significant differences in operation, the decision was made to provide a satellite downlink of low-resolution imagery from geostationary weather satellites in a format compatible with automatic picture transmission (APT). This is the image format of the polar orbiting WXSATs. Both types (with few exceptions) provide low resolution pictures in which image data is amplitude modulated on a 2.4 kHz carrier. The image data is a signal representing the measured brightness of a small component of the scene below the satellite.

This modulated carrier then frequency modulates the main radio frequency carrier. In a visible-light image, high modulation means dark levels (sea), and low modulation means white (cloud). Land generally falls in an intermediate range of gray levels.

This unique form of signal processing is the reason that receivers of special design are essential for good reception, and means that a system that can receive and produce pictures from most polar orbiting WXSATs, can also produce them from geostationary WXSATs -- including Meteosat-7 for European users, and GOES for American users. The only compromise is that a receiver for polar orbiting WXSATs normally has an intermediate frequency (i.f.) bandwidth a little wider than that required for geostationary WXSATs -- to allow for Doppler effects. Doppler effects are not observed from geostationary satellites -- under average conditions!

 What extra equipment do you need?

These two components -- the active feed and downconverter -- cannot achieve much on their own (or even together). They are designed to be additions to a polar orbiter receiving system that will already include a 137 MHz receiver and decoding system. Such receivers sometimes include an additional connector for 137.5 MHz to take a feed from a downconverter.

You also require a suitable dish to receive the signal. Contacts tell me that supplies of old Primestar dishes are often available for the taking, due to obsolescence. Even if such a dish is unavailable, a home-made dish should not be out of the question. When I first decided to set up a receiving system for 1691 MHz back in the mid-1980s, buying a dish was impossible. Satellite television was in its infancy and such dishes were very expensive. I decided to construct my own, after realizing that at this frequency, surface accuracy was a minimal problem -- imperfections of over 1cm were acceptable! I built a 1m diameter dish using chicken wire, supported by a wooden frame. I fitted a downconverter, and immediately found a signal from METEOSAT -- Europe’s geostationary WXSAT.

Software is required to decode the telemetry. The necessary facilities are almost certainly included with your current NOAA-Meteor-Resurs program; look for a GOES option.

 Component 1 - the Active Feed

My original feed for 1691 MHz reception was passive; it consisted of a cylindrical feed fitted with a small dipole. Because of the low signal strength, I had to fit a microwave amplifier. This new "active feed" device is almost revolutionary in providing a signal suitable for direct input to a downconverter without the need for a preamp. This is indicated by its specification:

Specification

Feed gain 6.0 dBi

Preamplifier gain 14.0 dB (giving a total gain of 20 dB)

Noise figure <0.5 dB

Voltage supply 6 to 16 Vdc at 20 mA current.

The majority of system noise is added at the first stage; this active feed provides 20 dB gain with no more than 0.5 dB noise figure.

Price $89 ex postage

 Component 2 -- the Downconverter

Downconverters are commonly used in radio ham environments; this unit converts the amplified 1691 MHz signal from the active feed into a 137.50 MHz equivalent for transport to the receiver. It is a work of art! The input connector is a standard N-type plug for use at 1691 MHz; the output is an F-type socket. Little is likely to go wrong with it. It should be given protection from the elements by fitting in a small enclosure to keep out rain, especially around the connectors.

 Specification

1691 MHz input, 137.50 MHz output

Gain 33dB nominal with 2dB nominal noise figure

Power input 6 to 16V d.c. at 40mA nominal current

Power output (if selected) 50mA at the N-type socket for powering the active feed

Price $135 ex postage

 

Switch-on and locate GOES

For testing purposes, I used a small off-set dish in order to provide worse-case conditions -- those possibly met by anyone confined to using a small dish. Setting up required the routing of cable from the dish/active feed to the downconverter, and then indoors to the computer. A 5m length of cable is supplied for the feed to downconverter, and this should be used without cutting or other modification. You will need to provide cable for the 137 MHz run; the specifications provided with the system suggest that up to 100m of either 50 or 75ohm cable can be used. I fed some low-loss 50ohm cable through already-prepared feed holes leading to my computer room.

The system worked from switch-on. The dish has to be pointed at the satellite, and this can readily be achieved by monitoring audio from the WXSAT receiver. Two satellites are available -- GOES-10 is located over longitude 135 west, for west coast coverage, and GOES-8 will be found at 75 west, for the east coast. A helper can be invaluable for the process of either adjusting the dish position or monitoring the audio -- but I achieved this on my own, so help is not essential.

 Results

My backyard is in Peverell, Plymouth, UK, so I used the system on Meteosat-7 -- the equivalent of GOES-8. A look at the transmission schedule for GOES-8 and GOES-10 shows a near continuous sequence of images from not only the original GOES satellite, but also images originating from Meteosat-7, NOAA-14, and the other GOES.

The schedule ensures that formats of specific regions are transmitted at regular intervals. Because these have identical content (only the clouds have moved!) they can be animated. Software normally has an "animation" facility, and this provides the best guide to nowcasting and forecasting that can be obtained. Even using the three-hourly images from GOES-8 that are transmitted by Meteosat-7, Europeans can monitor weather changes over America. A selection of GOES images are shown here.

With all satellites, you either receive them near-perfectly, or they are of little interest. No-one wants to view noisy images, or to have to spend time using software to "clean" them. This system provided virtually noise-free images throughout the test period. One minor "hiccup" happened when a gale blew the dish a few degrees in azimuth, causing enough signal loss to suggest that the system had failed because of the rain. Close examination immediately revealed that the pointing was several degrees off. Re-adjustment corrected this and the system continued to operate flawlessly. For permanent use, it is advisable to fix the dish to the ground, rather than merely resting weights on the mount support legs as I did!

The pricing of these units brings GOES WEFAX imagery right into the domestic market. Fifteen years ago I paid the equivalent of over $200 for a downconverter, and the system also needed an expensive preamplifier. It is encouraging to see such products arriving at these prices.

 Availability

The two units (feed and converter) are manufactured by Timestep Weather Satellite Systems and retailed by Swagur Enterprises (now defunct - ed, 2004). Check-out the Timestep site at: www.Time-step.com

Prices given above were those applicable at the end of 1999; please check in case of changes.

 

Frequencies - polar

NOAA-14 transmits APT on 137.62 MHz

NOAA-15 transmits APT on 137.50 MHz

NOAAs transmit beacon data on 137.77 or 136.77 MHz

Meteor 3-5 may transmit APT on 137.30 MHz when in sunlight

Resurs 1-4 transmits APT on 137.85 MHz

Frequencies - geostationary

GOES-8 and GOES-10 use 1691 MHz for WEFAX

 


Nil-Jon Scanner Antennas

By Bob Grove

 A relative newcomer to the consumer antenna marketplace is Nil-Jon, offering several models for TV and FM broadcasting, amateur, and scanner listening. We decided to take a look at two wideband scanner antennas since the promotional literature issued by the company gives them rave reviews.

 

The Big Base  

It seemed fair to compare the big base model with two perennial favorites, the Channel Master 5094 Monitenna and the Antenna Craft Scantenna. Both of these antennas have so far been unbeaten for wide frequency coverage, excellent reception, and low cost. Their receiving performance and architecture are virtually indistinguishable.

With the Nil-Jon selling at nearly three times the cost ($129.95 vs. $49.95) of its two competitors (which include 50 feet of coax as well), it had better offer something special.

The Nil-Jon is shipped as a semi-kit, roughly a dozen element pieces, interconnect cables, splitter, boom, and a bag of nuts and bolts. Using the enclosed (old edition) directions to sort parts and then assemble the rig took about half an hour. The new manual is a vast improvement.

The competitors’ antennas come fully assembled, requiring only fanning out the elements which then latch into position. All three antennas require attaching their respective balun transformers and U-bolt brackets. Common tools (screwdriver, pliers, etc.) are required to assemble the antenna.

The marked difference between the Nil-Jon and its two competitors is its use of three independently fed elements. While the competitive antennas are essentially comprised of a single vertical element with parasitic elements hinged to it in an “X”-like configuration, the Nil-Jon’s three separate vertical dipoles are mounted on clear acrylic plates and spaced wide enough to avoid interaction which could skew the omnidirectional pattern of the antenna.

The piping used for the elements is seamless aluminum conduit (3/4”D, .035” thick) bearing the mill’s stamp; this is much larger than used in either of the competitors, and gives it an edge in the durability department. It is rather crudely cut, however, giving the ends of the tubing a ragged, home-brew look. But that doesn’t affect its performance.

The elements are off-center fed like the Grove Omni, resulting in a balanced, high-impedance feed point, matched by three conventional VHF/UHF TV balun transformers. Three lengths of F-connector-fitted RG6/U coax route the signals from the balun transformers to a three-way VHF/UHF TV splitter, connected in reverse as a signal combiner. The combined signals are then led to the receiver or scanner via the owner’s F-connector-fitted cable. We would recommend anchoring the longest of the three interconnect cables to the boom with PVC electrical tape to keep it from flapping in the wind, possibly subjecting it to premature failure.

 

So How Does it Work?

To do a fair comparison, the Nil-Jon was mounted in the same position as a Scantenna, separated by several feet to avoid incorrect readings resulting from interaction of the elements. Using an Icom R7100 receiver as the test instrument, several steady carriers were selected in the 30, 90, 120, 150, 160, 300, 420, 450, and 860 MHz bands.

After a reading was taken from the Scantenna, the coax lead-in was switched to the Nil-Jon. Just to confirm the results, the coax was then reattached to the Scantenna and signal strengths were again measured. Unexpectedly, within visual limits, every signal was identical on all frequencies!

No attempt was made to measure characteristic impedance or VSWR. Transmitting into the antenna is probably possible if the power is low, limited primarily by the small components used in the transformers and splitter.      

 

The Bottom Line

In order, the flimsiest construction is the Scantenna, although its history shows very little damage from wind and weather -- most damage is incurred from rough handling during shipping! It is made from rolled and seamed aluminum tubing of the TV antenna variety. Next, the Monitenna, which is assembled from seamless tubing and is more durable. Both antennas reflect typical assembly line construction and finishing.

Strongest of all is the Nil-Jon with its heavy-gauge tubing and heftier boom, in spite of its homemade appearance. While we noted no difference in signal reception among the three contenders, the Nil-Jon’s durable construction may give it an edge under severe wind load conditions. 

 

The Mag Mount Mobile 

This was a pleasant surprise. The appearance of the HD-V/U-Super-M mobile antenna itself is unusual, with three slightly-different-length VHF-Hi band whips all radiating upward at an angle from the base (see photo). At first glance, one might think that the purpose of the separation is to prevent interaction which might degrade a broadbanding design, similar to a dipole cluster of different lengths, each resonant at a different frequency.

But there is an added advantage to this design. At higher frequencies, as an element becomes electrically longer, the radiation and reception pattern starts to favor the ends. By angling the whips downward, this pattern is also lowered toward the horizon. Now the extra length has gain over the quarter-wave whip, providing better performance. And angled downward, the antenna cluster is less likely than a comparative single vertical element to strike overhead obstacles.

 

The Bottom Line

So does it really do this? You bet! The Super-M was compared to an 18” whip, the Grove ANT-30 Stealth, and even a cellular gain antenna, all popular favorites for scanner monitoring as well as VHF/UHF transmitting.

In every case, the Nil-Jon Super-M equaled or outperformed the contenders, sometimes by a substantial amount! And even though the manufacturer advertises it for 140-170/400-480 MHz communications, for receiving purposes, it works well past the 800 MHz band.

The antenna consists of three black-enameled and rubber-tipped elements (16” to 18-1/4”), a machined brass base, and a Larsen 3-1/2” magnetic mount. A 12-foot length of RG-58/U coax terminates in a PL-259 connector for attachment to two-way radios; an optional UHF/BNC adaptor is required for scanners.

 HD-SCAN-WB-OMNI-F base antenna, $129.05 plus shipping.  HD-V/U-Super-M mobile antenna, $64.95 plus $7.50 shipping.  From Nil-Jon Antennas, PO Box 764, Amherst, OH 44001; ph. (440) 989-2295. Web site www.nil-jonantennas.com; e-mail pfb@eriecoast.com.


Ramsey Mobile RDF System

By Bob Grove   

Radio direction finding (RDF) antennas find myriad uses in communications, from locating sources of intentional or incidental interference, to homing in on downed aircraft beacons. Amateur radio “fox hunts,” locating hidden transmitters, are a popular pastime in some radio clubs. Members often use those talents to find repeater jammers.

Classical systems use loops, Adcock arrays, Yagi (beam) antennas, and other manually rotated antennas to determine target bearings from the operator’s position. But automatic direction-sensing antennas with a compass-bearing readouts are certainly easier to use, and often more accurate.

Doppler schemes use multiple antennas, arranged in a circle and electronic sampled hundreds of times per second by a rapid switching circuit. Comparing signal arrival times at the different antennas is automatically translated into direction and displayed on a control panel as a digital bearing or, more often, as an LED in a circle representing a compass rose.

While commercial Doppler RDF systems can be very expensive (often thousands of dollars), Ramsey Electronics has recently released an inexpensive kit. The DDF-1 Doppler Direction Finder is based on a circuit published in QST magazine (April/May 1999 issue), contributed by WA2EBY.

A single Doppler RDF system can be operated over a wide frequency range, as illustrated by the advertised 130-1000 MHz span of the Ramsey. However, proper positioning of the whips at different frequencies is critical for accurate bearings, meaning that antenna lengths and separations must be changed for wide frequency excursions.

The DDF-1 display contains an array of 16 LEDs, and is capable of resolving bearings within 22.5 degrees (16 x 22.5 = 360). While this may not be accurate enough to position a rocket launcher, it is adequate for following and finding a target transmitter. And a second operator using an RDF at another location could radio his bearings as well, allowing cross-coordinates to be plotted on a map for rapid resolution of the target’s location. 

Putting it Together

A 36-page assembly/calibration manual is included with the kit. Although assembly is not particularly difficult for an experienced kit builder, calibration procedures may be rather daunting for someone unfamiliar with radio or electronics theory.

It is important to have access to an oscilloscope to verify the square wave pattern of the logic circuits; a frequency counter to measure the operating frequency of the clock oscillator; a voltmeter to assure correct operating voltage in the circuitry; and an audio generator to calibrate the signal level circuitry.

The operator will also need to secure the assistance of a confederate with a walkie-talkie or mobile rig who is willing to drive around, communicating with you to coordinate proper positioning and alignment of the rooftop array and control settings.

The DDF-1 kit contains all the parts necessary to assemble a full system, including approximately 150 circuit board components, plus miscellaneous hardware. You will need to supply the coax cable (RG58/U or RG174/U) down-lead and five-conductor cable (multi-conductor telephone or computer cable will work well) from the rooftop array to the console. You will also need to supply the DC cable with a standard power connector, and an audio cable to connect between the control box and your radio’s external speaker/earphone jack.

While the ABS plastic box utilized a professional stick-on panel, the antennas will look quite homemade. Four copper-clad steel rods anchored to small circuit boards housed in white-plastic jar lids comprise the antenna array. Plenty of unimpeded rooftop space will be needed to accommodate the four whips, spaced a yard apart

The antenna bases are “anchored” to the vehicle roof by flexible tape magnets with barely enough strength to hold them upright. The manual recommends slow driving speeds, or replacing the magnetic strips with something more substantial, like speaker magnets. Good idea unless you are satisfied taking all bearings from one position. 

In Operation

The panel consists of a central ring of red LEDs with a center green LED; two red LEDs indicating low/high audio level; a Power switch; a stop/run Scan switch; and a normal/reverse Phase switch. There are also three controls: Calibrate (used to set your initial compass bearing); Damping (used to average out flutter in the logic circuits); and Audio Level (used to balance the input level with required speaker volume).

After some fiddling with the controls, we found the system actually quite simple to use, but the newcomer will need to do considerable experimenting with known signals to feel comfortable with the variables that accompany any direction finding effort.

  The DDF-1 Doppler Direction Finder kit is available for $149.95 plus $6.95 shipping from Ramsey Electronics, 793 Canning Parkway, Victor, NY 14564; ph. (800) 446-2295. Visit their Website at www.ramseyelectronics.com


 Super Select-A-Tenna Review

By Larry Van Horn

  One of my radio hobby passions is DXing (listening for distant stations) in the AM broadcast band (525-1710 kHz). When first I started in this hobby in 1963, AM broadcast band (BCB) DXing was my main listening focus and I continue to DX these frequencies years later. I have used a plethora of bought and built equipment and antennas for AM DXing over the years to weed out weak signals in this spectrum  --  some good and some not so good.

Needless to say I was excited when given the opportunity to test Intensitronics Corporation's latest addition to their BCB antenna product line  --  the Super Select-A-Tenna. I have been using  the company's original offering, the  Select-A-Tenna (both first and second generation models), for several years now.  While it isn't my primary BCB DX antenna, it does an excellent job when matched up with two of my secondary portable receivers that I use from time to time -- the Sony ICF-2010 and GE Super Radio III.

  Evolution of an Idea

To back track a bit, the original Select-A-Tenna is a passive device that requires no wires, no batteries, no plugs, etc. It works by simply placing it next to your radio and turning the large tuning knob to the same station frequency as your radio. This antenna functions by concentrating the radio station signal energy in the near proximity of the Select-A-Tenna. If the radio you use has an internal antenna and is placed in that same near proximity, the radio and antenna share the same signal concentration and gain improvement. The manufacturer claims 30dB improvement of signal with the original Select-A-Tenna and my testing showed that is the case over most of the BCB spectrum.

Recently Intensitronics released their second generation of Select-A-Tenna (Grove ANT-21). This antenna has the same intrinsic +30dB signal strength improvement and features of the original version. In this second generation model, a jack on the front panel allows the unit to either be connected to an outside long wire and ground, or directly to a radio's antenna and ground terminals when the radio has no internal ferrite rod antenna (such as in a communications type receiver). This opens up several receiver options over the earlier version.

Users in all-metal buildings or campers where AM radio signals do not suitably penetrate will also find this unit effective, because a long wire outside antenna and ground may easily be connected directly to the Select-A-Tenna. This allows outside AM signals to be ported through the Select-A-Tenna to a ferrite-loop-only receiver.

Other users with radios having only an antenna jack and ground terminals, but who want an alternative to the long wire and ground, can connect the Select-A-Tenna directly to the radio using the external antenna and ground cable assembly that is provided with these antennas.

  The New Super Select-A-Tenna

The brand new Super Select-A-Tenna was developed for listeners who require better performance working within some very specific AM listening applications.

One of these applications involves coupling older model internal ferrite rod antennas that don't work well to this antenna to obtain good, high-Q, mutual coupling. My Sony 2010 tends to fit into this category and the Super-Select-A-Tenna did show a significant improvement over the second generation model I have been using with it.

This new model is an active device with additional controls for an internal regenerative amplifier, and it does require a 9-volt battery (not included) to operate this unit. Normally, you find regeneration circuits on top end AM-BCB air-core loop antennas such as the Kiwa. This is a very nice additional feature to and it works quite well to narrow down adjacent channel splatter when activated.

This unit has an additional variable 0dB to +10dB gain added to the intrinsic +30dB mentioned before for a useful gain up to +40dB. While this didn't really matter much on some of the clear channels station we monitored in our test (loud is still loud), it was really useful when trying to dig out a single station from hundreds on the crowded AM BCB graveyard channels of 1230, 1240, 1340, 1400, 1450 and 1490 kHz.

Gain is not what you always want on these crowded frequencies. In fact it can be a curse, depending on conditions and your local radio environment. The combination of directionality plus the ability to adjust the gain supplied by the antenna to the radio, resulted in a couple of new stations added to my logbook during our testing.

This unit has both coarse and fine tuning controls (like its more expensive brother, the Kiwa) for ease of operation at the higher gain settings. It also has the ability to effectively drive a remote ferrite probe. This is useful when using the antenna with a large case radio which may prevent effective proximity coupling and reduce the effectiveness of the Super Select-A-Tenna.

To recap, this new model may be used in any of four different modes of operation:

(1) Direct near proximity, just like the first and second generation Select-A-Tennas

(2) Ferrite probe near proximity

(3) Direct wired antenna connection, and

(4) External antenna and ground for metal-buildings when using modes 1 and 2.

The new Super model has a high-signal level and low-impedance balanced drive port for the ferrite probe. This provides the capability to not only drive the 6-foot coaxial cable and probe, which are included, but the cable may be extended to as much as 26-feet¨(not included). We found this particularly useful for remotely locating the Super Select-A-Tenna away from radio noise sources (including the human kind) or into better signal locations without having to move the radio itself. (It's hard to make an AC-only rig portable.)

  Bottom Line

I was particularly impressed with this new version of the Select-A-Tenna as an owner of both the original and second generation models. This is a significant improvement over those early antennas, and its four modes of operation will make the Select-A-Tenna of benefit to an even greater number of hobbyists.

While it couldn't hold a candle to my Kiwa (I didn't expect it to, given the price differential), it really performed quite well for an antenna in its price range. If you can't afford a Kiwa, but you want a capable, loop style antenna for the BCB frequencies, take a serious look at the new Super Select-A-Tenna. This model (Grove ANT-40) is available from Grove Enterprises (800-438-8155 or www.grove-ent.com) for $189.95 plus shipping.


 The Antenna Line from AOR

By Bob Grove

 AOR SA7000

The AOR SA7000 is a wideband (30 kHz-2000 MHz) base or transportable monitoring antenna measuring 5 feet tall (longest element), and about 4 inches wide. The two vertical elements are conjoined by an impedance matching system to provide a nominal 50 ohm unbalanced load for the receiver cable (approximately 50 feet, included). It is not intended for transmitting.

The elements are made of durable steel, and the system is easily and quickly assembled using only a Philips screwdriver, pliers, and an Allen wrench (provided).

 Our Test

We compared the AOR SA7000 with the popular Grove ScanTenna at VHF/UHF, and a GAP Titan HF vertical for 100 kHz-30 MHz measurements. While the ScanTenna outperformed the SA7000 by 6-10 dB on all our VHF/UHF test frequencies between 27 and 900 MHz, reception was quite acceptable. Similarly, at shortwave frequencies, in spite of the considerable difference in antenna length (5 feet vs. 30 feet), response of the AOR was only about 10-12 dB lower. When tuning the 100 kHz-500 kHz LF range, LORAN C and non-directional beacons came in loud and clear.

Years ago, the U.S. Coast Guard made similar short-element tests and found that an impedance-matched five-foot antenna was able to hear HF signals 100% of the time when compared to a full size antenna. This is because the main limiting factor below approximately 50 MHz is atmospheric noise, becoming increasingly disruptive the lower you tune in frequency. If an antenna is long enough to capture enough signal to overcome the receiver's internally-generated circuit noise, that's all that's required.

The net result is that the background noise is very quiet and S-meter readings will be quite low when compared to longer antennas, but the signal will be there above the noise, just as it would be when using a much longer antenna. Just turn up the volume!

 The Bottom Line

We would recommend the AOR SA7000 wideband antenna for general purpose reception throughout the 100 kHz-2000 MHz range for wide-frequency-coverage receivers like the AOR AR5000 Plus, AR7000, Icom R8500, PC100/1000, R9000L, WiNRADiO WR1000/1550/3100/8000 series, and extended-frequency coverage scanners like the Alinco DJX10T, ICOM R2/3/10, Yaesu VR500, and AOR AR8200.

It is pre-eminently useful as a rapid-deployment field antenna for emergency and tactical applications. While received signal strengths will not be as strong as experienced with larger, separate scanner/HF antennas, they are adequate for local monitoring applications and near-field surveillance and countermeasures.

The SA7000 is available for $189.95.*

 

SA3000

The SA3000 is an unconventional discone design intended for mast mounting. Essentially, it is a composite of several element lengths in an effort to extend the typical 8:1 frequency range of a discone so that it can accommodate wideband receivers over the entire 25-2000 MHz spectrum. As with the previously reviewed SA7000 antenna, signal strength measurements were compared to those received on the Grove ScanTenna. Overall reception was as good as that heard on the standard of reference.

Predictably, however, reception below 30 MHz deteriorated rapidly and substantially (although not as rapidly as on the ScanTenna). This is also characteristic of discone antennas in general, making VHF/UHF discones virtually useless for serious listening on shortwave and medium wave.

Because the elements are of various lengths, we suspect that the DA500 may be somewhat directional, and should be rotated while receiving tests are being made to find the most favorable compromise position. Directivity should be less pronounced on those frequencies in which various element lengths overlap in their frequency coverage.

The elements are made of strong, lightweight, stainless steel tubing; a sturdy connector block attaches to about 50 feet of coax cable (included) via a TNC connector. The receiver end of the coax is fitted with a BNC connector. We would suspect that the antenna could be used for transmitting as well as receiving over those frequency ranges closely impedance-matched by the antenna.

Although washers called out on our instructions were missing from our sample, we suspect that they probably weren't necessary for their intended placement. We were very impressed with this antenna, both from a standpoint of quality of manufacture and performance, and would recommend it for general purpose 25-2000 MHz receiving applications.

The SA3000 is available for $129.95.*

 

MA500

For mobile VHF/UHF monitoring applications, the MA500 magnetic-base antenna is a strong contender. The same VHF/UHF element found on the higher price SA7000 is firmly attached to a rugged, strongly magnetic base. About 16 feet of coax cable with BNC connector is included.

For this test we measured its performance against a Nil-Jon Super-M (see June MT, p.104) and an 18" whip. Although the Super-M is considerably shorter, we found it performed equally well against MA500 to perform nearly identically, given variables on the road. Both antennas outperformed the simple whip.  

 The MA500 is available for $99.95*

=============

 *Prices quoted are all from Grove Enterprises (PO Box 98, Brasstown, NC 28902; 800-438-8155; http://www.grove-ent.com/order) and do not include shipping.


 

Protek 3201 RF Field Analyzer

 

 

Three or four years ago, we reviewed a radical new test instrument produced in Korea, the Protek model 3200. Now upgraded to a model 3201, we thought it might be time to take another look at this unusual piece of equipment.

 

The 3201 is ideally suited for the installation and maintenance of paging, two-way radio, cellular telephone, cable TV, and satellite TV systems as well as antenna site maintenance.   

 

Lightweight (1.4 lbs.) and compact (4-1/4"W x 9"H x 2"D), the 3201 is intended as a hand-held, portable, multi-function, field test instrument for the radio industry, As such, it is essentially a combination spectrum analyzer, frequency counter, and data recorder with considerable flexibility, and it is extremely easy to use by simply following its on-screen menu.

 

With a frequency coverage of 100 kHz-2060 MHz, direct-entry keypad, and a versatile LCD display, the unit is designed to operate as a stand-alone instrument or to interface with a computer and a printer. Software, documentation, and an RS232C cable are provided.

 

 

The Display 

 

The backlit LCD measures 2-1/2" square  (3-1/2" diagonally), and contrast is continuously adjustable for any lighting condition.

 

 

Spectrum Analysis

 

The spectrum analyzer mode is quite user friendly, allowing a choice of sampling steps between 5 kHz and 6 MHz, with 160 total samples per sweep. This equates to spans as small as 800 kHz, to as great as 960 MHz. Unfortunately, the user cannot select resolution bandwidth.

 

 Sweep speed is quite slow, taking about 13 seconds per span, making the capture of short-term transmissions rather hit-and-miss. It is most satisfactory for continuous carriers.

 

An operating mode may be chosen which allows simultaneous sweep and audio recovery, affording the user the opportunity to sample the hits as the sweep progresses across the spectrum.

 

Automatic scanning/sweeping is user-programmable, allowing continuous spectrum sweeping, recurrent sweeping over a range, or scanning discrete memory channels. Scanning speed is 12.5 channels per second. 

 

A rotary tuning knob is provided, but its rubbery, erratic response mandates the use of an alternative set of up/down keys.

 

 

Audio Recovery

 

The 3201 does have the capability of allowing audio recovery of AM, WFM, and NFM signals; while SSB is also specified, the low injection level and apparent lack of AGC makes such signals virtually unintelligible. A tiny, one-inch speaker slot on the rear of the unit is barely adequate for quiet environments. An external earphone jack is provided (ear bud included).

 

Although sensitivity is excellent (typically 0.5 microvolts NFM), poor dynamic range prohibits serous monitoring applications. Using the rubber duckie antenna included with the set, it works reasonably well, but connecting a large, outdoor antenna invites overload and the attendant mish-mash of mixed signals.

 

An adjustable squelch level is visualized by an attendant bar graph, allowing the user to adjust audio cutoff levels, as well as choose signal thresholds to automatically stop scanning and searching sequences.

 

Additional sources of noise include a variety of self-generated spurious signals (ďspursĒ) from the instrument itself. Motorboating sounds, whines, and hisses were commonly heard at various frequency settings; bringing your hand near the LCD while monitoring AM at lower frequencies invites a loud wailing from the displayís driver circuitry.

 

However, audio monitoring is not the instrumentís purpose; it is designed for near field measurement of discrete signals, not for scanning the spectrum for listening purposes.

 

Up to 1600 memory channels including frequency, amplitude, and channel identifier, may be stored in 10 banks.

 

 

Frequency Counter

 

Seven-digit readout with +/-50 PPM accuracy may be expected from 9-2060 MHz. Sensitivity averages 100-150 millivolts, and acquisition time is a short 0.5 seconds. Up to 10 of these readings may be stored in memory for later recall.

 

 

Bar Graphs

 

For data comparison, the user may select a display of 1, 5, 10, 20, 40, 80, or 160 separate bar graphs. Two separate signal levels (such as video/sound may be compared on screen in the comparison mode, or up to 160 different signal levels may be shown.

 

A printer driver allows a permanent record to be made of the instrumentís measurements over time.

 

 

Power

 

The 3201 is powered by six internal AA NiCd cells; optionally, an external source of 12 VDC may be applied for extended periods of portable or mobile use. Battery operation is rather short, only about one-half hour with the NiCds supplied with the unit. Recharge time, though, is short -- about 1-1/2 hours. A wall adaptor is provided.

 

To conserve power, the audio section may be switched off during measurements-only use, and the instrument may be programmed to automatically shut down after 5, 10, 20, or 30 minutes of idle time.

 

 

The Bottom Line

 

We found the Protek 3201 to be a highly versatile piece of test equipment, suitable for a variety of field instrumentation applications where compactness and flexibility are of paramount importance.

 

The 3201 comes with carrying strap, canvas zipper bag, BNC/BNC coax jumper, flex whip, rechargeable NiCd cells, AC wall adaptor/charger, ear bud, PC software, computer cable, documentation, and operating manual.

 

The Protek3201 is $2100 retail from Protek, 154 Veterans Drive, Northvale, NJ 07647. Phone(888) 784-8400, fax (201) 767-7343, email hcprotek@hcprotek.com, or visit their web site at http://www.hcprotek.com

 


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