[AMRadio] AM space


k0ng at inebraska.com k0ng at inebraska.com
Wed Dec 22 20:57:17 EST 2004


Hi Steve: Yes, Rothman Modulation is a sort of "clamp tube" modulation
where a tube is placed at the antenna output point and the RF is "clamped"
to look like 100% modulation. As I recall, it mainly modulates downward to
acheive modulation because there is no sideband power from the modulator
to add to the carrier. There were Rothman Modulators sold around 1950. They
were popular for a while because the CW transmitters could be changed to AM
without any modifications to the transmitter. I might try it sometime but I will
be sure to put a low pass filter after the modulator (LP on the band
selected).  

73 , Charlie,  K0NG

Quoting StephenTetorka at cs.com:

> Hello All:
> 
> It is my observation that there is a goodly amount of 'open' space from 14.3
> to 14.35 MHz. most of the time.
> 
> Conditions are not favorable as 75...but having ample 'elbow room' sure feels
> good.
> 
> Would it be worthwhile to consider an AM gathering location there?
> 
> PS: anyone familiar with Rothman AM modulation? 
> 
> Happy Holidays,
> Steve 
> WA2TAK
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