RAN Technology

My $18.50 homebrew boatanchor receiver

Vintage Ham Radio 0 Comments 04/28/2020 

Made of command set parts!

Posted By: Robert Nickels (ranickels)

The HW-16 had to be pushed aside while waiting for parts, creating an opening just big enough for the homebrew receiver I got recently via eBay for $18.50 - plus 2X that to ship it here.   I like saving and restoring old homebrew gear just out of respect for the amount of time and effort our forefathers put into making things from scratch, and this receiver intrigued me, as the IF transformers were from the Command Set.  

It's a 15 tube dual-conversion superhet covering 160-10 plus six meters (the 2-tube six meter converter was removed, but plugs into the sockets at the rear).   Naturally there was no documentation which only adds to the fun ;-)    I hadn't seen the underside of the chassis before it arrived but I was pleased that my assumption was correct, that anyone who went to the effort that was obvious from the top side layout would do a neat job of it.    The wiring is neat and makes uses of the 8-terminal wiring terminal blocks and 3-in-1 bypass capacitors from the command set receivers, all of which are still good.   I suspect other components are of mil surplus origin as well.

The first IF at 1415 kHz uses the transformers from the 3-6 MHz receiver  and the second conversion is to 85 kHz where those wonderfully narrow BC-453 IF transformers make the receiver very usable to copy SSB.   The only problem was the IF was misaligned enough from the BFO range that it wasn't demodulating properly until I tweaked it up, with the help of the little Dentron MLX-Mini 80 meter QRP transceiver that is being held down by a D-104, which served as my SSB signal generator.

The results are very impressive, the stability is good enough to stay tuned to a SSB signal and sensitivity is under a microvolt on 20 meters without doing any more than IF alignment.   Routine preflight stuff like cleaning and de-oxiting controls and tube pins and replacing the filter caps resulted in a totally deaf receiver until I found a couple of components leads touching that shouldn't have been that was shorting the audio.     Then two dead tubes later I had radio!   Not bad for a set that hadn't been powered up in who knows how long?

The dial is hand-calibrated but seems to be reasonably close and provides a good tuning rate.   The panel is a little rough so I'll have to think about what if anything to do about that.    The S-meter is from a Breting 12 and seems to be defective, but that's easily corrected.   The dial reminds me of the Marconi marine sets, it's just a dial cord reduction but is smooth and works well.    Obviously damp basements or garages are not the best places to store old radios!

My $54 receiver is a keeper!   While using surplus parts was common in the 50s or 60s when this was built, I applaud the builder for taking the extra time to create a full-featured ham receiver using surplus parts rather than just hacking up a couple of command sets.   Performance-wise, this receiver is in the same league as commercial offerings from Hammarlund, Hallicrafters, or National, which is pretty good for a homebrew job.

Description Comment  
Here's a short video showing the IF selectivity Here's an AM signal from K9GAS, you can get a sense for the bandwidth of the 85kHz IF as I tune across the signal. I'd guess it's about 4kHz. Narrower than most other boatanchor receivers without crystal or mechanical filters.

    Jay Miller KK5IM recently wrote an article in Electric Radio magazine about fulfilling his dream of building a homebrew "AM Kilowatt" transmitter (375 watts output by today's standards).     His crystal-controlled exciter that drive the 813 was based on his Novice transmitter, which was built by his grand-uncle back in the 1960s when Novice class hams were l...  READ MORE
- Robert Nickels (ranickels),  07/09/2020 

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Category: Technical
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- Robert Nickels (ranickels),  06/06/2020 
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- Robert Nickels (ranickels),  06/04/2020 
   What can I say, I like oddball radios!    There was already a different version of this CAI SSB-125 on my shelf but it had the remote control head, and this one was cheap, well under $100 including shipping, and I'm easily amused.   VIDEO DEMO HERECommunications Associates Inc. was a supplier of commercial, military, and marine radios based in Huntington Station, ...  READ MORE
- Robert Nickels (ranickels),  05/14/2020 
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- Robert Nickels (ranickels),  04/22/2020 

Wireless on a Train

a lesser-known radio "first"
Category: Historic
WHEN Frederick Wally stepped out of a little cubby-hole in one corner of the forward day coach on the Lackawanna Limited, west-bound, as it neared North Scranton, Pennsylvania, Tuesday, November 25, 1913, and pinned a sheet of paper on the wall, the passengers in the front seats, who had been casually wondering what caused the strange, crackling sounds that had been coming from the cubby-hole, pri...  READ MORE
- Robert Nickels (ranickels),  04/14/2020 
    The  Dentron MLX-MINII thought it would be cool to use the Dentron MLX-MINI on the Saturday Vintage Sideband Net but it's a little marginal since the rule is "no tubes, go home!".   However hybrid rigs are allowed, and Special Dispensation is given for rigs with Red LEDs.    So I thought the MLX was double-qualifed - even more so after I realized t...  READ MORE
- Robert Nickels (ranickels),  04/04/2020 

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