[ARC5] Lopsided modulation

[J Mcvey]

My TX dynamotor only sags about  35V between standby and transmit. Probably contributes to the "chirp" on CW, but I don't think AM modulation would drag it down that much.. I'm using a 25V 65 amp SMPS to drive it , so once it starts, there's lots of current available for steady operation. I get about 50W cw, 22 watts on AM carrier.  My SCR274 is all unmodified circuitry, though, just like they did it on the B-17.

Someone mentioned that it may be that voice has more negative spikes . This may indeed be the case. I know mine does! Take a look at it on a scope while holding  a tone. Try different octaves.  Not very symmetrical at all. The only way to test reproduction symmetry, is to use a sine wave iat say, 1 Khz and see what that looks like.
jim 

    On Saturday, February 24, 2018 3:46 PM, AKLDGUY . <neilb0627 at gmail.com> wrote:
 

 A friend and I are running Command transmitters on the local 75 meter AM net, with full plate and screen modulation. We monitor our transmissions on the local SDR receiver site which has a waterfall display. In both cases, the lower sideband shows as considerably stronger than the upper, and this has us perplexed. Our stations are the only ones affected.
I have never seen anything in the literature to explain this. Downward modulation is a problem with AM, but articles do not indicate whether lopsided modulation results.
My transmitter is the AN/ARC-5, absolutely unmodified and running 40W input due to dynamotor constraint. His is the SCR-274 modified for plate & screen modulation and running twice that.
Anyone suggest a reason for the unequal sidebands?
Neil ZL1ANM______________________________________________________________
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