SW-7

[Ed Richards]

Hi Floyd;

Sounds like acoustic feedback. Some heathkits with an internal speaker
were bad for this, especially the GR-54 and GR-64. Heathkit even mounted
the tuning capacitor on rubber grommets, but if you turned the volume up
it still squealed. This is caused by the sound waves from the speaker
vibrating components in the oscillator circuit causing the IF frequency
to be modulated, which is detected and fed to the speaker where the
circle is completed. The best solution is to use an external speaker.
Good luck.

73,

Ed

On Fri, 9 Nov 2001 13:19:32 -0700 Floyd Fitzgerald
<n7wekfloyd at THERIVER.COM> writes:
> Thanks to all who volunteered suggestions for the oscillating
> problem.
>
> Not sure if I cured it, but now seems to be working as well as a
> HW-7 can.
>
> Someone in the past had installed a small speaker in the top of the
> cabinet.....when I disconnected it, the squeal went away. Used to
> work in that configuration, don't know what changed.
>
> Anyway now hearing CW and lots of foreign broadcast HI HI
>
> Thanks again,
> 73,
> Floyd
>
> -----------------------------------------------------------
> This list is a public service of the City of Tempe, Arizona
> -----------------------------------------------------------
>
> Subscription control -
> http://www.tempe.gov/lists/control.asp?list=HEATH
> To post - HEATH at LISTSERV.TEMPE.GOV
> Archives - http://interactive.tempe.gov/archives/HEATH.html

-----------------------------------------------------------
This list is a public service of the City of Tempe, Arizona
-----------------------------------------------------------

Subscription control - http://www.tempe.gov/lists/control.asp?list=HEATH
To post - HEATH at LISTSERV.TEMPE.GOV
Archives - http://interactive.tempe.gov/archives/HEATH.html