[Drake] 2-NT VFO Choice

[Dennis Monticelli]

Glen,

That is exactly right, Glen.

It may have been overlooked back in the 50's and 60's when harmonics were
the biggest problem, but there were sub-harmonics too in these simple MOPA
rigs, especially when fed from low frequency VFOs that made only a token
effort to filter their outputs.

Dennis AE6C

On Mon, Feb 29, 2016 at 7:46 AM, Glen Zook <gzook at yahoo.com> wrote:

> Low pass filter won't work in this case.  He is talking about signals
> lower in frequency than the desired output frequency.
>
>
>
> For example, a number of VFOs use the 160-meter range for 80-meters and
> even for 40-meters.  For a frequency of 7100 kHz the VFO operates on 1775
> kHz and there can easily be signals at 1775 kHz, 3550 kHz, 5325 kHz, and
> the desired 7100 kHz.
>
>
>
> With the VFO output in the 40-meter band, when used for 20-meters,
> 15-meters, and 10-meters, as the band goes higher in frequency there are
> additional signals.  By the time one gets to the 10-meter band, say a
> frequency of 28.100 MHz, there are signals at the VFO fundamental of 7.025
> MHz, 14.050 MHz, 21.075 MHz, and the desired 28.100 MHz.
>
>
>
> Glen, K9STH
>
> Website: http://k9sth.net
>
>
> ------------------------------
> *From:* Bry Carling <af4k at hotmail.com>
> *To:* Dennis Monticelli <dennis.monticelli at gmail.com>; "
> drake at mailman.qth.net" <drake at mailman.qth.net>
> *Sent:* Monday, February 29, 2016 7:10 AM
> *Subject:* Re: [Drake] 2-NT VFO Choice
>
> May I suggest using a B&W FL10-100 which is a very small Low Pass filter.
>
> I just happen to have one for sale for $10.00(grin)
>
>
>