6aq5 Transmitter

50CHz CW Crystal Filter TV-502

The TV-502 transverter puts you on 2-melers the easy way. Simply plug it in to the TS-320 ior TS-520J and you're On the air Operates in the 144,0-145.7 MHz frequency range wiin a 145 0-146 0 MHz option

Si Dunn K5JRN 3607 Binkiey Dallas TX 75205

6aq5 Transmitter Qrp

ostal£iLi can do funny things to a ham. Recently, I recalled the one tube transmitter that first got me on the air as a Novice hack in 1957. And before I knew it, i was doodling a schematic and looking through my junk box for parts to build a similar rig.

My first 6AQ5 oscillator was quite a peanut whistle. It put out enough rf to hum out the flashlight bulbs I linkcoupled to the tank coil for tune-up, And that was enough power to work all states and some DX on 40.

The transmitter described in this article has several applications: (I) ¡is circuitry is simple, so many beginners and "appliance operators'* should be able to build it and get it on the air in a matter of hours; (2) its 4 to 5 Watt input is ideal Tor QRP work; and (3) it'i cheap - a good parts scrounger can build it for a few bucks at most. Even it everything has to be purchased new, the cost can be kepi below $20.

I built mine straight out of the junk box and had it on the air in five hours, including the time spent in dr illing and filing holes in the AYi x 6:S x 2 inch aluminum chassis. Parts layout is not critical, bui a beginner building his first rig might want to use a sitghtly larger chassis.

The power transformer used! in this rig is rated at 15 milliamperes continuous service. However, Tve ex-pei ienced no difficulties while drawing 20*25 milliamperes on CW. Naturally, the key shouldn't be held down for more than a lew seconds at a lime while tuning up. A transformer with a slightly higher voltage and current rating could be substituted, with a corresponding increase in input power.

My third 'CQ DE K5JRN QRP" brought a 579X report from a 500 mile daylight hop

1 a on 40 meters. Since then, this rig has given me hours of operating pleasure and manv fine QSOs. A good antenna is desirable, but my dipoles arc only 8 feet high.

While simpler transmitter* can be built, this one is just

1976 Amateur Radio

about the bare minimum: no VFQ, no meter and no bandswitch. Crystal control requires a bit more patience than VFO operation, but plenty of contacts can be made with iust a couple of "rocks." With Novices now able to use VFOs, crystals can be picked up dirt cheap at hamfests and surplus stares. Tune-up is simple. Connect the rig to a dummy load or to a 50 to 75 Ohm antenna, Temporarily slip a two turn link soldered to a 2 volt flashlight bulb over the tank coil, and tune for maxi mum brilliance. The full wave voltage doubler circuit delivers about 200 volts under load, and the 6AQ5 plate draws 20 to 25 milliamperes (four to five Watts input).

Tune-up also can be accomplished with a field strength meter, if you have one, or with the forward scale of an swr bridge. If you really want to get fancy, you can add a 0-50 or 0-100 milliarn-pere meter between RFC2 and the B plus.

The piastic form for the

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