[ARC5] Radios and the Canal

[Geoff]

> Hammarlund built a very fine radio indeed, except for one thing... 
> trademark drift.  It seemed the same in the HQ-120-X, HQ-129-X, BC-779, 
> BC-794, HQ-150, HQ-170 and HQ-180... I've used them all.  Oddly enough, 
> the HQ-180 doesn't appear to be as pronounced as the 170 for some reason.
>
> In my experience with the HRO, NC-173 and NC-183-D, the National radios 
> don't have this issue to near the same degree.
>
> But as far as tube radios exclusive of Collins, the RCA AR-88 is the best 
> tube receiver I've ever used.
>
> 73
>
> Mike
> W4DSE
>


But the Hammys can be controlled to a large degree with a TC cap as done in 
the SP-400 and can be retrofitted to its predecessors. Use one cap across 
the variable to  tame the highest band and others switched in for lower 
ranges for better control.
The same works on the single conversion HQ family.

Ive managed to tame the HQ-180/180A but it is different procedure involving 
changes to the HFO which should be applicable for the 170/170A.

Out of the box Id say the best non Collins tube sets for stability are the 
RA-17, SX-73/R-274, RBB/RBC, HRO-60; and for ham band only the NC-300/303 
and SX-115. All the above are in the collection here and have been fully 
restored electronically and mechanically where needed.

The various Drakes are in their own category as they use a PTO. Some similar 
Heathkits are stable but have other problems.

As a speciality product the Clegg Zeus and Interceptor B are amazingly 
stable and after a short warmup I often work SSB stations down the band on 
6M.

My last drift taming project (2 weeks ago) was a Heath DX-100 for a 
customer.

Carl


>
>
> --- On Tue, 5/14/13, Kenneth G. Gordon <kgordon2006 at frontier.com> wrote:
>
>> From: Kenneth G. Gordon <kgordon2006 at frontier.com>
>> Subject: Re: [ARC5] Radios and the Canal
>> To: "Bill Cromwell" <wrcromwell at gmail.com>
>> Cc: Arc5 at mailman.qth.net
>> Date: Tuesday, May 14, 2013, 2:12 PM
>> On 14 May 2013 at 13:42, Bill
>> Cromwell wrote:
>>
>> > I am still biased in favor of Hammarlunds for tube
>> > receivers.
>>
>> Well, I'm on your side on that one, Bill. Me too...although
>> National runs a very, VERY close
>> second.
>>
>> Ken W7EKB
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