[Hammarlund] Re: Phasing control null on crystal filter for SP-600

[David Wise]

> -----Original Message-----
> From: hammarlund-bounces at mailman.qth.net
> [mailto:hammarlund-bounces at mailman.qth.net]On Behalf Of Bob Young
> Sent: Thursday, July 05, 2007 2:47 AM
> To: hammarlund at mailman.qth.net
> Subject: Re: [Hammarlund] Re: Phasing control null on crystal 
> filter for
> SP-600
> 
> 
> I assume to use the AC voltmeter method like the manual you 
> need to keep a 
> speaker connected to the output also?
> Also what bandwidths did they change to in issue 2? I have 
> had trouble 
> aligning mine after I changed faceplates and screwed up the setting,
> 
> Bob Young
> KB1OKL

The manual recommends you always maintain a load on the output
transformer.  I don't remember if they say why; I'd say it's to
prevent transients from punching through the insulation.  It doesn't
matter to the radio whether it's a speaker or a resistor, but
I like to listen while I tweak.

The published bandwidths did not change.  Evidently they got it
wrong at first (too wide), then fixed it.

Dave Wise
SWL in Portland Oregon