[ARC5] Lopsided modulation

[Tim]

Yep Richard - you are right.  Antenna High Q at these freqs could not cause
anything like that.  But at VLF, that's another matter - audio modulation
would be a significant fraction of the operating freq...!

Tim
N6CC

On Sat, Feb 24, 2018 at 5:02 PM, Richard Knoppow <1oldlens1 at ix.netcom.com>
wrote:

>     It depends on whether its FM-or PM- ing the oscillator. If it is its
> causing the asymmetrical sidebands. You should hear it on the oscillator
> signal. Try receiving it as a PM or NBFM signal, that is, slope detect it.
>     Its not your antenna.
>
> On 2/24/2018 4:09 PM, AKLDGUY . wrote:
>
>> You may be onto something with the B+ kicking downward on modulation. I
>> notice that the dynamotor voltage does kick down significantly. This drop
>> may be causing the plate voltage to bottom out, or even go negative!, on
>> modulation peaks.
>>
>> The MD7 modulator schematic doesn't show significant capacitance
>> decoupling the bottom of the mod tranny feed to the 1625 final stage -
>> about 1.2 uF IIRC, and I followed that when building my own modulator. I
>> suspect it may not be sufficient decoupling.
>>
>> But even if the final plate voltage is bottoming out or going negative,
>> where is the literature that says this causes lopsided modulation?
>>
>> Neil ZL1ANM
>>
>
>
> --
> Richard Knoppow
> 1oldlens1 at ix.netcom.com
> WB6KBL
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