[ARC5] Off topic help...

[Kenneth G. Gordon]

On 11 Jun 2018 at 14:41, Glen Zook wrote:

> 
> Unfortunately, as far as I know, the Collins Radio design team, for the 30L-1, 
> have all passed.  Warren Bruene died over a year ago and I believe that he was 
> the last one.
> 
> Remember, the 30L-1 was designed to work continuously from 3.4 MHz all the 
> way to 30.0 MHz.  The original design required the 20.5-foot long RG-58/U cable 
> for best IMD, etc.  However, reportedly, Art Collins told Warren Bruene to "fix" the 
> problem and the result was that such an exact length of input cable was no longer 
> required.
> 
> For decades, people have been trying to "second guess" the Collins designs and, 
> with a very few exceptions, the "proof has been in the pudding" in that the Collins 
> equipment just works!  The only thing is that the 30L-1 can be "touchy" on the 
> 10-meter band but definitely not on 80-meters and 40-meters.

And who needs an amp on 10 meters anyway?

Thank you, Glenn. I also received a reply on this issue from Don Jackson W5QN who writes 
for the Collins' "Signal Magazine". His analysis of the circuit is something I have not seen 
before, and appears to be excellent, In any case, I am no longer going to worry about the 
"size" of L-8.

FYI, the value of the inductance of the filament choke in the Heathkit SB-200 IS too low to 
prevent loss of excitation to the amp on 80 meters. After I doubled the value of that choke in 
one of my own SB-200s (which I have loaned to a local ham), it became far easier to drive 
the amp to full power output (600 watts: I don't believe in hammering anything) on 80 
meters. In fact, that amp now requires about 50 watts drive for full power output whereas 
before the change, it required at least 90 watts. The amp seems to be a bit more stable too.

Ken W7EKB

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