Dave Richards AA7EE

May 11, 2012

A 200mW TX and Regen Receiver Make For Some Very Satisfying QSO’s

It’s been almost 10 months since I published the post on my build of N1BYT’s WBR Receiver – a regen with an unusual design that minimizes re-radiation of the local oscillator signal without the need for an RF pre-amp. It’s fairly sensitive, stable, and only draws about 12-13mA. I’m sitting here right now with this great little regen listening to Bill Crane W9ZN calling CQ in his inimitable style.  If Bill’s the guy I think he is, he was a radio DJ that went by the name of Bill “Butterball” Crane in the 1970’s, and his sending is unmistakable – especially his rhythmic and creative CQ calls.

In the time since I published the post on the WBR, it has been far and away the most popular post in this blog. Every now and again, my build of this receiver is featured on another blog or in a forum, and the page views peak for a few days. Currently the Yahoo QRP-tech group are looking for a regen receiver for one of their group builds, and the WBR is one of the designs under consideration.  I hope that at least some of the members choose to build it. Not all regen designs are created equal; I’ve read of some builders having problems with hard-to-control regeneration, or hum issues caused by the local oscillator signal being radiated by the antenna. The WBR doesn’t suffer from these issues.

As if all this attention online isn’t enough, my build of the WBR (Wheatstone Bridge Regenerative) Receiver is about to be featured, along with photographs, in a new edition of an ARRL book to be released soon.  As I mentioned in an earlier post, Daniel N1BYT is either very gratified, or thoroughly fed-up, with all the attention his design is still receiving over 10 years after the date of it’s first publication!

After building it, I spent a month or two happily listening to, and fiddling around with it, then got caught up with building a beta version of NT7S’ CC-series QRP transceivers, and then building a K2.  Since finishing it, most of my other projects, including the WBR, have been boxed away, leaving pride of place at the operating position to the K2.

Then a couple of days ago, I pulled the WBR out of storage and hooked it up. I connected it to a 2 transistor TX powered by a 9V battery that I built based on W1FB’s implementation of the Pixie 2, and this evening called CQ with a whopping 200mW coming from the plastic 2N2222A in the final.  The Reverse Beacon Network showed a 20dB spot from N7TR 180 miles away in Reno and I figured it was worth continuing to call.

Eventually, NY6G in Tracy, CA gave me a 429 and we chatted for about half an hour. Stan lives only 46 miles away from my QTH in Oakland so although it was quite gratifying to know that he was hearing the flea power signal from my little 2 transistor transmitter, the thing that was really satisfying about the QSO was more to do with the fact that it connected me to the world of amateur radio that I remembered from my boyhood in the 1970’s; a world where there seemed to be more camaraderie and gentlemanly behavior.  Stan told me that he was born and grew up in Oakland, where I currently live.  He then moved to Alameda, served in the Air Force and left the immediate area after WW2, but remembers his Mum taking him to Lake Merritt to watch the boats. (I was watching the boats on Lake Merritt just 2 days ago.)  He also remembers when the streets were lit by gas lamps, a job which was performed by a man carrying a long pole.

Sitting at my desk with a separate transmitter and receiver that I had built from schematics Manhattan-style and using them to hear about what the city I live in was like in the 1930’s from a former resident was pure magic.  Stan was getting a kick out of my home-brew separates too:

The Altoids tin on top of the receiver is the N0XAS PicoKeyer.

This is a fun little set-up. The next day, I powered the Pixie 2 TX from 12.8V which allowed it to go QRO and output 500mW. Over the next couple of evenings I worked KI6ON Joe in Santa Clara CA, KE7GKM Bob in Boise ID, W6VJJ Rex in Half Moon Bay CA, N0EK Ed in Bergen ND, KF6RMK Bill in San Rafael CA and Jerome VA7VV in Vancouver, BC

Jerome had a couple of traditional receivers in the shack on which he was having trouble copying my flea-power signal – an FT-950 and a ProIII. However, on his SDR-IQ (a state of the art SDR receiver) with the bandwidth dialed down to 75Hz, he was copying with no problem.  He said it was the first time that he had experienced such a substantial difference between copyability between conventional receivers and SDR receivers. The thought of the signals from that little 2 transistor TX being heard in Vancouver almost 800 miles away was pretty neat.

It was great to QSO with KF6RMK too. Bill lives locally and we run into each other on the air from time to time.  We exchanged e-mails after our QSO and Bill sent me a picture of an old regen that he bought as a kit from Radio Shack many moons ago. He put it into his own case and wound some coils for it to turn it into an all-bander. Neat looking regen Bill! He said that our QSO has inspired him to drag it out and see if he can get it going on 40M  (photo credit Bill KF6RMK):

It’s been fun putting the WBR and Pixie 2 TX back into service for a while.

Now what can I build next……?

6 Comments »

  1. Really enjoyed this piece of writing. A good portion of technical description but the emotion and humanity of the human side of the hobby was a real delight. Great balance — thanks for sharing.

    Comment by Danny — May 12, 2012 @ 9:46 pm | Reply

    • Thanks Danny – as I mentioned to you on Twitter – I do hope we get to QSO again soon. I’m entering another phase of home-brewing, which tends to mean not much operating, but you never know.

      I’m very much in agreement with your love of well-sent code – am hoping to get there myself one day.

      Comment by AA7EE — May 16, 2012 @ 3:05 am | Reply

  2. Hi Dave,I’ve watched your youtube vídeo on the WBR regen and was amazed with the performance of such a simple set,Unfortunately i din’t found the schematics,i’d like to build one with a little more freqquency span,so i ask you if would you please send me a schematic.I think will have to use mecanical tunning since large capacitance varicaps and multiturns pots are impossible to find here in Brazil.So Dave,congratulations for your work,very well assembled and finished set,and most of all,very nice performance for such a simple rx.73

    Paulo PY3KM
    parisantos@hotmail.com

    Comment by Paulo — May 15, 2012 @ 7:05 pm | Reply

    • Paulo – if you Google the phrase “WBR Receiver” there is a pdf of the original article that should pop up. Try if you can to find to some suitable varactors and a multi-turn pot. My concern with using a variable capacitor is that you may suffer problems with hand capacitance. That is the beauty of using this tuning scheme in a regen – the issue of hand capacitance disappears. Good luck with your build!

      Comment by AA7EE — May 15, 2012 @ 10:31 pm | Reply

      • OK Dave.i’ll try another search on Google,may i’m lucky this time.Sure i was also worry about the hand capacitance,in ther other hand,using mecanical tunning i must be carefull with mecanical rigidity of the building,backlash and etc. So,thanks for the fast reply.I think i will try to get some parts from Farnell in England or perhaps another store in USA.73,and my best wishes!!

        Comment by Paulo — May 16, 2012 @ 1:15 am

      • Paulo – Google “WBR Receiver pdf”

        Comment by AA7EE — May 16, 2012 @ 3:02 am


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