[Elecraft] K2 FM-ing on 80 Meters

[Tom Arntzen]

This sounds like the same I'm trying to cure here also.
I did have FM-ing on 80 with dummy , but not with antenna.
My antenna is groundmounted and with radials so it's grounded.
What happens if u try the antenna with ground?
And if u set power to 50 watt on 80 meter and switch to 40 and wistle high 
tone/pitch in the mic , does your power go way up then?
I have a problem where the K2/100 forget powersetting and want regulate down 
on it self.
This happens partly on 80 also.
But a low wistle in the mic in same time as I regulate down power does work 
and it stays there until I change band again.
Can you try that?
I'm interested to hear if you have same symptom?
Good luck!
73 Tom LA1PHA

----- Original Message ----- 
From: "Don Ehrlich" <ehrlich at olypen.com>
To: <elecraft at mailman.qth.net>; <support at elecraft.com>
Sent: Thursday, October 28, 2004 6:27 PM
Subject: [Elecraft] K2 FM-ing on 80 Meters


> My just completed #4438 with SSB, DSP, 160M, and 100Watt Modules seems to 
> be working just fine .... except:
>
> .. on the low end of 80 meters (3500-3700 approximatly) the signal sounds 
> like there is a 'ringing' on it when listening to another receiver in the 
> shack.  This happens only at power levels above about 50 watts and only on 
> the low end of 80 meters.
>
> Here is what I have done:
>
> Replaced my power supply with a large lead-acid car battery to eliminate 
> any possibility of interaction with the power supply. Results the same 
> with either power source.
>
> Tried two different monitoring receivers ... same results with each.
>
> I am using a 50 ohm dummy load (Heath Cantenna).
>
>
> This is what I see:
>
> A scope looking at the RF waveform shows NO am modulation.  The envelope 
> is clean.
>
> A scope looking at the RF waveform does show a slight blurriness in the 
> horizontal axis indicating rapid but slight frequency shift.
>
> A scope monitoring the 12 volt input shows a small sinusoid waveform on 
> the 12 volt input (a hundred mV or so)  indicating that there is a 
> significant AC component of current being drawn from the battery.  The 
> frequency of this AC component of input current is about 30 hertz.
>
> I suspect ALC instability of some kind.  I could sure use some help here.
>
> Don  K7FJ
>
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