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The R29 slays the R390A

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Author Topic: The R29 slays the R390A  (Read 22375 times)
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Posts: 1782

CW is just a narrower version of AM

« on: November 18, 2007, 10:51:58 PM »

The R29

Here is a neat little Regenerative Receiver that showed its stuff tonight when the going got messy - it beat my R390A on a set of weak ones under really tough 80M conditions. I was in a CW QSO with an Arizona station and he was perhaps a 339 with my beverage. We made the Q. After that I shut down the station and decided to play with my new regen - The R29. I tuned up the band and heard a station calling me. I flipped on the ART-13 and called with the Regen still inline. No problem. Then the Arizona station calls again and said that he heard I was using the regen. He sounds better than on the R390A! No problem working split.

The idea here was to build a reproduction of a 1920's receiver to match my old time station. This was a fun project and it took about 8 nights of work to complete the receiver. The tube lineup is a pair of 27's but it also runs nicely on 76's which are 6V fils. I run the fils on AC and use a 500 Ohm humbucker potentiometer. Try the fishbone grounding method which was a common technique in the 1920's. The idea is that everything which needs grounding comes off a thick buss wire that winds through the circuit like a fish spine. Ground everything! Transformer cores, metal panel, tube sockets etc.. do not leave anything floating. Modern tube substitutes? 6J5/6C5 metal, 6C4/ 6BF6 with shield.


200 kHz bandspread (full 80M coverage in 200 kHz bands)

AM and CW bias switch (The regen likes low voltage for AM)

Input swinging link on cold side of tank (ultimate regen)

Throttle Capacitor

Volume Control

600 Ohm Output for military phones etc..

Humbucker pot

2.5VAC ( or 6VAC depending on tubes) and 150VDC

Good luck! Mike WU2D

* R29frnt.jpg (141.39 KB, 1863x1182 - viewed 2487 times.)

* R29RearDetails copy.jpg (175.89 KB, 1596x1215 - viewed 2857 times.)

* R29REGEN2007.jpg (126.01 KB, 1086x559 - viewed 3105 times.)

These are the good old days of AM
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Posts: 1853

« Reply #1 on: November 19, 2007, 11:01:38 AM »

Than's a nice Old Buzzardly looking 'gennie!

Fine Business workmanship there!


73 de Ed/KB1HYS
Happiness is Hot Tubes, Cold 807's, and warm room filling AM Sound.
 "I've spent three quarters of my life trying to figure out how to do a $50 job for $.50, the rest I spent trying to come up with the $0.50" - D. Gingery
« Reply #2 on: December 10, 2007, 05:14:16 AM »

The R29

Here is a neat little Regenerative Receiver that showed its stuff tonight when the going got messy - it beat my R390A on a set of weak ones under really tough 80M conditions. I was in a CW QSO
Mike WU2D

That is a cool-looking project, and I've always understood that the re-gen sets are exceptionally "quiet."

So how does it compare on AM ?

I started putting an SP600 through such a comparison, and have found it beats the R390A for audio quality. 

That's no big surprise, since the Hammarlund uses LC circuitry rather than a mechanical filter to establish selectivity.  The mechanical filter passband looks kinda  like a square wave, and it induces a "ringing" effect that shapes the audio sort of like listening through a paper towel cardboard.

The SP600 sounds much more like the R390, which also uses LC rather than mechanical filtering.

Example of the SP600. 18Mb *wav file, uncompressed, no EQ.

Aircheck Recording
« Reply #3 on: December 10, 2007, 05:44:21 AM »

That is very Nice work.

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Posts: 768

Crystals are from the stone age

« Reply #4 on: December 08, 2015, 10:56:54 AM »

I also use a regen a lot for QSOs A good one will put even your Kenwood or what have you to shame. Sometimes they work so well you wonder why they aren't more common. It takes some experience to run one. My favourite circuit is the classic Twinplex but I use a 12sl7. I have also a Hb using a 56 and a 58 tube. It works very well and I can switch between my modern digital and that regen and lose nothing except I am on earphones. Put one on battery power and WOW! Fine for AM too. Been there done that. Have 8 regens currently running in this shack. One is a dud (twin 26 tube with throttle cap regen) but the rest work fine.

Don VE3LYX<br />Eng, DE & petite Francais
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