[ARC5] Fwd: Re: Lopsided modulation

[AKLDGUY .]

Interesting. Makes one wonder whether low drive in the Command transmitters
is the problem. The grid resistor is 15k, whereas the value for 2x1625
(modulated) should be about 1/3 of that.


Neil ZL1ANM

On 25/02/2018 1:06 PM, "Charles" <charlesmorris800 at centurytel.net> wrote:

> My "ARC-5" transmitters do the same thing with screen (only) modulation. A
> couple of hams with spectrum analyzers have told me that one sideband is
> considerably stronger than the other.
> I've been also told it's incidental FM or PM of the oscillator. In any
> event, especially with my 4x 4-125A linear, it puts out a clean and
> intelligible signal through a low-Q off-center-fed dipole to other AM'ers :)
>
> Charles
> WB3JOK/0 since 1976
>
> -----Original Message----- On Sat, Feb 24, 2018 at 2:07 PM, AKLDGUY . <
> neilb0627 at gmail.com> wrote:
>
> FM does not seem to be present in either his signal or mine. The carriers
>> are straight lines on the waterfall display. Actually, there is one
>> operator on the net whose carrier is a fuzzy line when he speaks, but his
>> sidebands are symmetrical. I'm stumped.
>>
>> Neil ZL1ANM
>>
>> On 25/02/2018 10:30 AM, "Richard Knoppow" <1oldlens1 at ix.netcom.com>
>> wrote:
>>
>>     That affects the upward vs downward modulation but not the strength
>>> of the sidebands. A frequent cause of asymetrical sidebands is incidental
>>> FM. If the oscillator is being affected by the modulation it can be the
>>> cause.
>>>     The scope display will not show assymetry of the upper vs lower
>>> sidebands although it will certainly show assymetry of upward vs downward
>>> modulation.
>>>
>>
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