[Hammarlund] Unstable Oscillator adjustments in the HQ-180

[rbethman]

Folks,

It is unfathomable to even attempt to compare any HQ Series by 
Hammarlund with the SP Series, especially the SP-600.

The two series are so far removed from each other that it is impossible 
to draw any inference from the entire HQ Series to somehow apply it to 
the SP-600s especially.

I do indeed currently own a Northern Radio Variant Hammarlund SP-600.

I "used" to own an HQ-170A.  It was pretty much a half step from being 
an HQ-180.

The SP-600 is far beyond a much better design and better performing 
radio than the HQ-170A, and I'd wager the same applies with a comparison 
to the HQ-180.

Regards, Bob - N0DGN


On 2/12/2016 12:25 AM, Richard Knoppow wrote:
> Interesting, I have two SP-600s and have never had problems setting 
> the oscillator frequency. The trimmer is an air capacitor and pretty 
> stable. I use a plastic tool with a metallic blade that is part of a 
> military tuning tool. Setting the coils really requires a tool with a 
> blade in socket so it won't slip off the slot.  These used to be 
> common commercial parts but no more.  I have a tool from an RCA AR88 
> that is ideal and would work for the SP-600 trimmer caps too. I 
> suppose you could make one. The RCA tool has a blade on one end and a 
> socket with a recessed blade on the other end.
>     My SP-600s have a problem with microphonics that I have never been 
> able to track down. Its not the oscillator tube although the 6C4 is 
> notorious for this.  I have a rebuild job sitting on the back burner 
> and have a couple of things to try.
>
> On 2/2/2016 10:24 AM, Al Parker wrote:
>> Hi folks,
>>    I think maybe Ed & Roy have it explained.  If it's stable at all 
>> time except when making an adjustment, or getting something metallic 
>> in the area, it's pretty normal.  Ron, you said you're using it in 
>> the CX, is it working OK under normal usage?  If you want to hear 
>> something squirrelly, try setting the osc. of an SP-600, up at 6 
>> meters ;-)
>> 73,
>> Al, W8UT