[ARC5] Novice receivers.

[Richard Knoppow]

     I don't know the origination of the regenerative IF. I think in 
some form it long pre-dates the Hallicrafters S-38B but I think that 
receiver was the first one Hallicrafters used it in.  I think 
Hallicrafters has a patent on the S-38B circuit but would have to search 
to find it.  I think National and others used the same trick in some low 
cost receivers.  Of course one can find regenerative detectors in a 
great many receivers but the IF is slightly different since it works 
ahead of a conventional diode detector.
     I sometimes wonder what I would have done with a used receiver of 
better quality  than the S-38B.  It was bought new because I neighbor 
had one and I nagged until I got it.  Its possible we could have gotten 
something like a used S-20R for the same money but I can't find ads for 
used ones in the old magazines.
     I was also very naive and ignorant at the time.  The neighbor was 
in his teens and his interest in electronics was more because his 
parents were rich than any real fascination.  I could have used a good 
mentor.  At the time I got the S-38B there was a lot I didn't understand 
about its workings. When I was older I educated myself, partly with the 
aid of an ARRL handbook from the public library. Some years later, when 
I became a ham, I did aquire a very good mentor and it was he who helped 
me assemble a station. I got a general right away.  My first station 
consisted of the BC-779, a BC-375E modified to work with an external 
exciter, and the external exciter, home brew out of parts I was given. 
Eventually, I was given a Barker & Williamson SSB adaptor which I used 
with the BC-375E. It sounded very good on the air and I still have all 
this stuff.  My exciter used the same General Radio ECO circuit I used 
in the receiver with a buffer and a couple of doublers.  It used plug-in 
coils.  I worked a lot of CW since the transmitter put out a lot more 
power there.  I also worked some AM using an external mic pre-amp to 
drive the modulator in place of a carbon microphone. AM quality was 
quite good but I worked mostly SSB and CW.  I had to scramble for money 
so didn't get anything new until very much later.  Actually, I still 
don't own anything I bought new. I have used Drake and Kenwood stuff and 
a lot of old receivers.
     The BC-779 was excellent for CW once I tamed the oscillator pulling 
because of the patented Hammarlund crystal filter, the best of all of 
them.  This same filter, invented by Donald Orem, the chief engineer of 
Hammarlund, was introduced on the HQ-120-X and was eventually used in 
the Super-Pro. The same filter with minor changes in detail is used in 
the SP-600 series, in Collins A line and 51J receivers (not sure of the 
R-390) and is also found in the TMC GPR-90. It is the only crystal 
filter that does not detune with bandwidth or phasing control changes.


On 11/16/2015 12:22 PM, Howard Holden wrote:
> My first receiver (novice days, 1961) was a BC-348Q, which I still 
> have and use regularly.  Without the crystal filter, it's very broad, 
> but usable. The filter cuts the signal audio way down.
>
> I'm not sure when Halli started using regeneration in the IF to 
> provide BFO action, but I used a WR-600 (wood-grain case version of 
> the S-120) in Guantanamo Bay, my call KG4DF, which also had the 
> regenerative IF. Worked a ton of CW with it, and yes the IF became 
> very sensitive just before regeneration. That was a great help on 10M 
> where I ran AM phone. 10M also got some help from an Ameco 10M preamp 
> that a stateside ham was kind enough to send me. 12 watts of 
> controlled-carrier AM, the WR-600 and a curtain rod ground plane gave 
> lots of 10M action. a 15/20 dipole gave good results on CW. Modern 
> radios make it far too easy. And then you hear the guy saying he's 
> "only" running 500 watts.......
>
> Howie WB2AWQ
>
> -----Original Message----- From: Richard Knoppow
> Sent: Monday, November 16, 2015 11:12 AM
> To: arc5 at mailman.qth.net
> Subject: Re: [ARC5] Novice receivers.
>
>    My first receiver was an S-38B,
>

-- 
Richard Knoppow
1oldlens1 at ix.netcom.com
WB6KBL