[Hammarlund] Question about warm-up vs. signal strength

[rbethman]

Mike,

Just as you found changes for the good by the 6C4 shuffle, I'd try some 
shuffles for the original "Hammarlund" tubes.  I know my HQ-170A does 
better than what you are describing.  I haven't done ANYTHING to it.  It 
does NOT drop off from time of turn on.  You've either got a tube or 
two, resistor or few that IS changing in its characteristics as it sits 
there for a period of time.

One method of finding components that are changing with heat up, is to 
use some of the "Dust-Off" sprays on components to see which are 
temperature sensitive.

My $0.02 worth.

Bob - N0DGN

Mike & Coreen Smith wrote:
> Hi Gang,
>  
> I've got my new-to-me HQ-170a running pretty fair now .  Really a very 
> nice RX.  Thanks of course are due in part to the help I have rec'd 
> from the FB folks on this list.
>  
> Cleaned lots of contacts, replaced a couple tubes,. etc.  Works very 
> well.  (some of the tubes in it are marked "Hammarlund", so presumed 
> original) The inside underneath looks nearly new and there is almost 
> no rust or other damage on the face/case whatsoever) Still a few tiny 
> bugs to work out,
>  
> *One thing I have noticed is that when I first turn it on, the 
> **signal from the Xtal calibrator is (for example) s9 on 20m, but 
> after the radio is warmed up (15-30 minutes later we'll say) **the 
> signal has dropped to perhaps S6 or S7)*
> ** 
> I notice it fairly consistently right across the spectrum.. Ie: on 6m, 
> it's S3 when first turned on, holding steady back to s1 after warm up. 
> (it will be rock steady @ S1 for days, so I don't think it's the 
> onboard Xtal cal, but the RX itself.)
>  
> /*Is this pretty much indicative of a RX ~45 years old, or are there 
> components that I should be looking at swapping out?  */(ie: caps, IF 
> tubes, etc.)  I'm quite happy with its performance the way it is now, 
> but I suppose if I could make it better. . . .
>  
> I have not yet done an alignment on it.  I am working a little on my 
> old PACO signal gen to see if it will be accurate enough to use for an 
> alignment, otherwise I may not actually do one until I have a better 
> signal source.
>  
> BTW, last weekend we had an opening on 6m and I had some W9's in here 
> well over the s9 mark, so I was quite pleased about that. I am sure my 
> 2x8el yagi antennas on the end of the coax cable didn't hurt however ;-)
>  
> Cheers,
>  
> Mike VE9AA
-- 
Bob - NØDGN