[1000mp] Fw: audio distortion with amplifier.

[Pete Smith]

Peter, is it worse on some bands than others?  With the amplifier, do you 
get reports of poor transmitted audio, or is it just the monitor that 
sounds bad?

I ask because my Mark 5 has a similar problem, and has had since it was 
new.  The only correlation between any external circumstance and the 
problem is that it has always been worst on 15 meters and it seems to get 
worse after I have been transmitting a lot for a while, as during a 
contest.  If I am just listening it doesn't seem to happen -- that is, when 
I start transmitting after a long listening period the monitor audio is fine.

I suspect my problem is inside my radio.  Don't know where yours might be.

73, Pete N4ZR

At 11:42 AM 10/29/2004, you wrote:



>Hi there,
>
>my setup is a FT-1000mp DC (from 1996) with an Ameritron AL-80B.
>In a special occasion i'm using my amplifier,perhaps once or twice in year
>mostly in a contest.....
>
>I'm still suffering from probably RF feedback in to 1000mp.
>When monitoring in SSB the audio is distorted.
>it's difficult to explain,it's like sqeezing my audio with ups and downs.
>Even in CW there's a raw tone on my signal.
>
>Running my 1000mp barefoot everething is excellent,but with the amplfier
>on,it's increasing as the output power increases,the higher ALC level the 
>more
>distorted,even on 200w out it occurs.
>I'm not overdriving the amplifier mostly the rig output is around 30-50w
>controlled with the ALC on the amp.
>
>I grounded amp and radio seperately,so no ground loops.
>I put the 12V-dc cable several times through a large Amidon core.
>The ALC and PTT cable,also several times through a Ami. core.
>Ferrite clip on beads at the back with my cw key input.
>Coax feed used also several ferrite clamps and also a line isolator,
>between my coax doesn't helped at all.
>Every bead en and core is closest  placed to my chassisrig.
>
>Has somebody any idea or experience through which way the RF
>is getting in my rig.(coax,12V-dc cable,ALC-PTT calbe....??).
>So in can focus my self  on one item......???
>
>Any suggestions or experencies very mutch welcome.
>
>
>Kind regards,73's Peter ON7BJ.
>
>
>
>
>_______________________________________________
>1000mp mailing list
>1000mp at mailman.qth.net
>http://mailman.qth.net/mailman/listinfo/1000mp