[Hammarlund] HQ-170A drift reduction progress

[Al Parker]

Hi Mitch,
     YOur latest results look great.
     Hammarlund actually installed plastic covers over the tuning caps 
in the HQ-170 & 180's, not sure if in the A's or not.  But they 
published a service note later that said to remove them, something about 
moisture I think.  I've had, and/or worked on, several rcvrs with them.  
I know  one I did for a friend a few yrs ago, had them.  I think I 
removed them, but gave them back to him.
     YOu might come across somebody that can take a pic of them, or 
measure, they fit quite tightly, abt 1/16" thk gray plastic.
73,

Al, W8UT
www.boatanchors.org
www.hammarlund.info

"There is nothing -- absolutely nothing -- half so much
worth doing as simply messing about in boats"
Ratty, to Mole


On 4/15/2011 2:32 PM, Mitch wrote:
> All,
>      Again, thanks for all the replies and help. This morning, I am trying something different. I left the receiver turned on all night long (>8hrs) with the RF and AF gains turned down to the lowest setting. This morning, I am repeating the test of last evening. The receiver is definitely much more stable. Infact, I am quite happy with it this morning.
>
> Input to receiver coax antenna connection from signal generator for all tests -- 3 microvolts
>
> 1.9mhz             No discernable drift
> 3.8mhz             No discernable drift
> 7.150mhz          No discernable drift
> 14.2mhz            No discernable drift until the house heating system kicks on. Then it shifts in frequency about 100-200 hz.


> snip