Hamtronics T50 Exciter

On Coax/a/ and ftoror Cabtet minimum order is 100' and 50 ' muEspies

Prices and specrfications subject to chancy without notice. Ninety E9CH Day Limited Warrmty-All Products FOB Us Vetjas, Nevada

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Phooe

Prices and specifications subiecl to change wrttxnri notice

Robert B Grove WA4PYQ Rt 1, Box 756 Brasstown NC 23902

Those Hamtronics Kits ... How Can You Use Them?

— an in-depth look at some electronic bargains

Hamtronics Xv4

Photo A. T50 FM exciter: a high-quality VHF kit at a tow price. 130 73 Magazine • June, 1980

Through the years, many fine companies and products have come and gone in the capricious game of consumer electronics, Ham radio certainly has not escaped its share of casualties. But one company which has been around for a while is Ham-tronics, well-known for its quality kits and reasonable prices-

Recently, I decided to have an up-to-date look at their growing catalog to see for myself some of their more recent products, I was so impressed that I decided to take a closer look at some of the kits,

T50 2-Watt VHF Exciter

Designed to put out 2 Watts on any one of three bands (6, 2, or 1 % meters), this $44 95 rig will accommodate six crystal-con-

300 Watt Linear Amplifier Meter Band

Photo B. LPA2-15 linear amplifier is typical of several Harntronics power amplifiers for VHF applications.

trolled channels. Either narrow-band FM or CVV modes may be selected- Individual crystal trimmers allow precise netting for accuracy.

For voice transmission, a trimpot allows adjustment from O to 7-kHz deviation-A phase modulator includes audio shaping and filtering for maximum audio punch. Microphone gain is adjustable separately from deviation limitation.

With TVI such a constant problem, ) paid particular attention to suppression of unwanted spurious signals. The T50 shielded oscillator and multiplier coils and a three-stage harmonic filter at the output keep harmonics and spurious signals down 60 dB

The little board measures 3" x7'/j"x 2", and requires 13,6 volts dc at 400 imA for full output.

LPA2 Linear Power Amplifier

For the VHF and UHF enthusiast who needs that extra margm of power, I recommend a look at the Harntronics line of linear power amplifier kits, starting at $59,95. Requiring only 1- to 2-Watts drive (and thus fully compatible with the T50 exciter and XV2 and XV4 transmitting converters, as well as with most commercial portables), these amplifiers may be ordered for outputs from 15 to 45 Watts! And they may be used on side* band, FM, CW, AM —you name it They are available for the 50-, 144-, 220-, and 432-MHz bands.

Output transistors are fully vswr protected; they are high-gam, emitter-ballasted devices.

As with the T50, a 13 6-V dc power supply is required [but at 2 to 8 Amps, depending upon the amplifier chosen and the drive level). Heat sinks are provided with these kits.

R75 VHF FM Receiver

For the purist who wants only the best reception on two meters, the R75 singlechannel strip receiver should till the bill. Nominal i-f bandwidth is ±7 kHz, but filter cascading is available as an option to make passbands very narrow.

Selectivity options for the R75 include 4 increments, from an LC filter [±30 kHz at 60 dB down) to a ra2or-sharp 8-pole slicer (±9 kHz at 60 dB down). Prices are from $69.95 to $99.95 for these receiver kits.

l-f boards are available separately for $20 less than the full kit prices.

Sensitivitv is an extraordinary 0.2 microvolts, making the R75 a natura! for 136 MHz satellite reception of NOAA/ATS as well as for 143/149 MARS operation.

The low-noise FET front end is gate protected, and shielded double-tuned coils are featured to enhance single-signal reception The crystal oscillator is voltage regulated, and a trimmer allows tight calibration.

Built-in test points assure optimum tune-up. The 2-board receiver (rf and i f/audio) requires 1 3.b V dc at 60-150 rnilliamps and will provide 2 Watts of audio —that's enough for virtually any application!

R85 UHF Receiver

For an additional $20 over the cost of the R75, you can be the proud owner of a UHF receiver with the same excellent specifications as the VHF version.

This UHF receiver affords an excellent opportunity for those ATV experimenters who don't wish to invest in an expensive commercial ly-assem-bled UHF receiver, A matching transmitter will be described shortly.

R110 Aircraft Receiver

With the increased interest among scanner enthusiasts, it isn't surprising that someone has finally offered a VHF aircraft-band receiver The primary hitch that has prevented scanner manufacturers from including the aircraft band in their programmable scanners is the fact that while the land mobile services are all FM, aircraft still tenaciously hold on to the AM mode.

While Regency Electronics now offers their Digital Flight Scan receiver, only Bearcat has both land mobile FM and aircraft AM in one receiver (models BC-220 and BC-300).

The Harntronics R110 receiver kit is an excellent accessory for the owner of FM-only scanners. It is designed for 110-to 130-MHz reception, but can a!so be used on virtually any frequency from 26- to 220MHz

Sensitivity is 0.2 microvolts for 10 dB signal-plus-noise to noise — (5 + NjN Selectivity is not particularly a problem in the aircraft band, so the receiver has moderate selectivity.

The R110 features 2 V\ atts of audio, squelch, S-meter output, rf age circuitry, and a dual-gate MOSFET front end Itisvir-

Kit Transceiver Meter Band

Photo C. R75 VHF single-channel receiver —a hot performer.

, ¡f tually the same receiver kit as the R75, and sells for $74.95.

Preamplifier Kits

Not all receivers have the degree of sensitivity we would like. For that reason, Harntronics offers a fine series of receiving preamplifiers to bring up the apparent sensitivities of those questionable front ends. Basically, all a pre-amp needs to do is to bring a weak signal up to a level that can ride over a receiver's inherent noise, and the job is done.

For receiving applications in the 20-to-230MHz range, the P8 will probably fill the bill. It has two J-FETs in cascade, providing 20- to 25-dB gain with only 2.5 dB of noise! And it will continue to provide that gain within 6 dB with frequency excursions as much as 3% off center frequency.

One possible application of a preamp like the P8 is in the extension of frequency coverage of programmable scanner radios. It is well known that a listener can pick up images of frequencies lower than he can tune, but their signal levels are way down.

Suppose that you would like to hear the ATS satellite at 1 35.575 MHz; no programmable scanner covers that range in the FM mode. By using the P8 preamp tuned to that frequency, you would be able to pick up the image frequency (roughly 217-MHz higher) on your scanner! Simply double the i-f frequency and add that number to the received signal frequency. With Regency and Radio Shack programmables (10.7-MHz i-f), simply add 21.4 MHz (ATS would be tuned in at 156,976), For Bearcats, i-fs may be 10.8 or 10,85 MHz, so you would add 21.6 or 21,7 MHz, It's that simple.

I he only drawback from such a system is when the preamp also increases signal levels of loud VHF stations on the normal rf passband of the receiver. This can cause intermod problems, But the technique is viable in a pinch!

The P8 kit costs only $10.95; a premium P9 is available for $12.95 ($21.95 wired) which boasts lower noise and sharper passband (6 dB bandwidth within 2% center frequency).

For UHF, try the P15 preamp with 20-dB gain and 5-dB noise figure for any 10-MHz segment between 380 and 520 MHz. ($18,95 kit; $27.95 wired).

Scanner enthusiasts may wish to try the image-enhancement receiving technique using this converter to tune in the elusive 406-to 420-MHz government band. As before, add twice the i-f frequency to the desired frequency, and punch up the total on your UHF scanner.

Accessories for the Receiver

For expanding the flexibility of your receiving installation, let me call your attention to several innovative circuits from Harntronics. Their AS10 scanner adapter permits a four-channel scanning function to be added to any fixed-frequency receiver. Two adapters may be linked for 8 channels, and so on.

The P13 receiving multi-coupler allows the use of two receivers simultaneously on one antenna. Any segments of the 26- to 230-MHz range may be selected. The P13 is modeled after the P9 VHF preamp, and provides 15-dB gain in each channel.

The A3 multichannel adapter allows a singlechannel receiver or transmitter to be multichannel-ized, It accepts crystal fundamentals from 10 to 20 or 38 to 55 MHz (specify model). The A13 affords six-channel capacity.

XV4 UHF Transmitting Converter

OSCAR Phase III is a snap using this neat little $99,95 transmitting adapter with your10-meter transceiver. The XV4 requires a minimum of only 1 milliwatt of drive. (An attenuator will be necessary with most exciters). Output power is 1-1 Ya Watts on SSBr CW, or FM. Image rejection is down 60 dB.

The circuit utilizes a double-balanced mixer to assure low spurious generation and guarantee easier alignment as well Two oscillators are provided for remote switching of operating frequency ranges.

Frequency stability es good, too. Thermal drift is less than 200 Hz per hour at constant ambient temperature, or within 1 kHz for 10° F temperature change.

t Several options of another version, the model XV2 transmitting converter, are available to allow outputs on 2 or 6 meters as well as 220 MHz, They may be driven by a CB or 10-meter rig.

A novel XV28 transmitter down-converter allows a two-meter rig to serve as an exciter to drive one of the other converters. For

: .-. . ¿i example, a two-meter transceiver connected to the XV28 will now have an output in the 28-MHz region. This signal may be injected into an XV4 for 432-MHz operation.

Hams who have not yet had the experience of operating 432 have a treat in store OSCAR Phase 111, amateur fast-scan TV, UHF repeaters, and other operating modes await the newcomer to UHF ham radio. It is especially active in metropolitan areas. The Harntronics transmitting converters permit one of the most cost-effective ways I know of to get quality hands-on exposure to this interesting portion of the spectrum.

Harntronics provides an unusual opportunity for the home builder to acquire quality equipment at wholesale prices. Try to buy the parts alone for one of these kits, and you'll see what I mean!

A copy of the new 1980 catalog can be obtained by writing: Harntronics, 65F Moul Road, Hilton NY 14468, ■

Tempo

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