[Milsurplus] RBC

[Bob Camp]

Hi

I think this is one thing that has changed a *lot* over the last 50 years. Back when this gear was the 
“low cost alternative” to fancy new stuff, a lot of people (who probably should not have) fiddled with 
stuff. Truth in lending — I was one of them !! On a radio that cost one or two weeks paper route earnings,
it made sense at the time. 

Today we have a bit different view of tube based surplus gear. Most of us (other than me … I just get 
older) are a lot more experienced. They now can better evaluate what makes sense and what simply 
isn’t going to work. They also have the skill to do it right, if it does not work the first time. 

I see a lot of stuff for sale that looks a lot like it has sat since 1965. Somebody tried something. It sort 
of worked. They lost interest. The radio went into storage. Now somebody else pulls it out and it’s on 
the market. Maybe it goes back on the market again. The fiddled radios from the “good old days” are still the 
ones you see changing hands. 

Bob


> On Jun 16, 2016, at 2:31 PM, George Babits <gbabits at custertel.net> wrote:
> 
> Ken,
> 
> I wonder what percentage of cobbed up product detectors were really an improvement?  Maybe 10%?  I have had SX-28, R-388, R-390, Super Pros, and SP-600 receivers with prodector modifications.  All were pretty dismal. Tells me that the average modifyer really didn't know what he was doing.
> 
> 73,
> George
> W7HDL
> 
> 
> ----- Original Message ----- From: "Kenneth G. Gordon" <kgordon2006 at frontier.com>
> To: "Milsurplus" <milsurplus at mailman.qth.net>
> Sent: Thursday, June 16, 2016 9:31 AM
> Subject: Re: [Milsurplus] RBC
> 
> 
>> On 16 Jun 2016 at 9:12, George Babits wrote:
>> 
>>> is now taken up with various HROs.  Every old receiver I have ever had that
>>> someone added a product detector was pretty well ruined by the addition.
>> 
>> That depends, hugely, on how it is done, George. I agree that most of those "additions"
>> were horribly bad. They were never thoroughly or well thought-out.
>> 
>> However, in my own case, after some careful study, "back in the day", I added a product
>> detector to my very first BC-779, and the result was completely astonishing to me.
>> 
>> The apparent sensitiivity was increased many-fold, the overall internally-generated noise
>> level appeared to drop very significantly, and that receiver became my very favorite receiver
>> for CW and RTTY for as long as I had it.
>> 
>> I could copy stations with that receiver I couldn't even hear with the others I had in the
>> shack.
>> 
>> Its sensitivity and "quietness" was at least equal to my RBB, and I thought at the time it was
>> better. The two RF amp stages in the '779 made a big difference, I suspect.
>> 
>> It was amazing.
>> 
>> In my opinion, there are only two areas in the design of receivers which are true
>> improvements since about 1939 or so: those are in AGC circuits, and detector circuits.
>> Otherwise, the modern stuff is simply "fooling around" with what went before.
>> 
>> The OT designers weren't stupid, and they did it all without 'pooters.
>> 
>> Ken W7EKB
>> 
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