[AMRadio] New monthly AM operating event

[Rob Atkinson]

This is one of the reasons why, when I was working on my HT-20 a few
years ago, I pretty much left the audio stock.  I increased the grid
input resistor on the pre-amp to 10 meg and increased the value of the
coupling caps slightly but that was about it.  Stock military rigs
like the ART-13 with space shuttle audio may be okay on 7295 but the
upper side bands of rigs that pass full audio will probably go above
7300.
One advantage to the D104 as far as this is concerned, is its designed
roll-off at 3 kc.

73
Rob
K5UJ


On Sat, Oct 27, 2018 at 2:07 PM Donald Chester <k4kyv at charter.net> wrote:

>
> Be careful. Operating that close to the band edge on AM or USB opens the
> possibility of an FCC citation for transmitting outside the amateur band.  A
> phone signal must be especially clean to not have any audible sideband
> products beyond 4 kc/s away from the carrier frequency.  I don't often
> operate AM on the popular 7295 frequency for this reason, and when I do, I
> carefully check my frequency, switch in the narrow audio LPF and closely
> watch modulation percentage on the scope.
>
> The FCC may have cut back on their monitoring activities in recent years and
> probably don't pay as much attention to what goes on in the HF spectrum as
> they used to; they once would cite an amateur for any detectable emissions
> outside the band, even when suppression of spurious sideband products
> conformed with "good engineering practice".