[Milsurplus] RBC

[Richard]

A comment on "mods."  I had a HQ-129-X wherein someone replaced the 6K8 
converter with some modern sub-miniature tube.  On 40M I was hearing 
everything from DC to daylight - very confusing.  Changed back to the 
6K8 and it became a very nice receiver.  I think the mod was to improve 
10M reception...  Yes, the designers knew what they were doing, and it's 
hard to improve on a good design.

Richard, AA1P

On 06/16/2016 04:28 PM, Bob Camp wrote:
> 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
>>>
>>> ______________________________________________________________
>>>