[R-390] Broadcast radio at 2 meg

[Tim Shoppa]

Murph <Murph2006 at copper.net> wrote:
> 	Why is it that I can hear broadcast stations on the 2 meg band.
> I.E. 1.250 can be heard at 2.50 etc. Twice the freq!

Harmonics, either in the transmitter or something between you and
the transmitter or in your receiver.

I have a fairly powerful transmitter (630 kc) just a mile from my
house and a weaker but still somewhat local station that I like to
listen to on 1260kc. The 390A does better than all the other
radios I have.

Just sticking a scope probe in the air in my basement shows several
volts of the 630kc signal. My 40M dipole in the backyard,
oriented on purpose against the 630kc signal, shows 10 volts or so.
Just hooking a diode and a small speaker up to the dipole I can
clearly hear the broadcasts!

Bonding the rain gutters around my house helped eliminate constant
QRM from harmonics but the harmonics are still there.

Most modern el-cheapo shortwave receivers get nothing except for the
630kc broadcaster, all and everywhere all over the dial on all bands
(including FM!)

Tim.