Build a single, double, three or four valve TRF Receiver

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Build a single, double, three or four valve TRF Receiver

	Under construction... Presented here will be circuits and full constructional details from the above N.Z Radio Constructors Guides, along with my notes and substitution data. If you think making a crystal set was fun, wait till you do a one or two tube valve set, they are even funnier! I can provide the spares should you need them. Sets like the Duodyne All-Wave One, Challenger, Out Span Five, the Air-Ace. the Economy DX Three, Tom Thumb and of course the famous Hikers One etc. Full details on the Hikers Set here Under construction <pun intended!>. In the meantime if you have a wish to build a specific set and want the parts supplied let me know .
	What is TRF? TRF = Tuned Radio Frequency. It differs from a superhet in that there is no down conversion to an intermediate frequency so no local oscillator/mixer or i.f stages are required. Of course there are cons to this design like less selectivity and sensitivity due partly to a broad tuned RF front-end. However, a TRF radio with regeneration (reflex) set just below the point of the detector breaking into oscillation proves to be very sensitive indeed. A one tube trf actually serves three functions, the two main two being a modulation detector and audio amplifier fedback through the suppressor grid leak RC path. The third operation is as a heterodyne oscillator whereby excessive pos feedback causes the tube to oscillate creating heterodyned signals for zero beat for CW and SSB reception. For home brew hobbyists it makes for simpler building and no alignment, so no spec. equipment necessary. to be continued
Update: As this facility is taking much longer than I hoped to setup, please visit my public project plan repository of 150 plus plans for tube sets and crystal sets. There are also a few circuits on this page and of course lots on the Hikers One here

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	Email: Greg Cooney or Write to: Oldradios.co.nz, P.O Box 40495, Upper Hutt 5018, Wellington, New Zealand. I can repair and refurbish that old family heirloom radio. Email for quote. "keeping them glowing" with a specialist elect. refurbish & opt. cabinet refinish. Check here for services offered.


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