Re: [amsat-bb] PROBLEM SOLVED - Need help with bad satellite signal on AO40 -SEE COMMENT ON FT847

[K5OE@xxxxxxx]

I have noticed a similar problem with my FT-100 when mobile.  If I don't leave the engine running (and charging the battery), the power supply droop will cause the transmit frequency to shift a bit.  This is most noticeable on local repeaters where it seems to be in the order of a few kHz.  Receive is unaffected down to about 10 Vdc.
73,
Jerry, K5OE

> After posting this I checked the voltage supply for the FT847.  It showed 13
> volts.  I normally operate my battery float supply at 13.8 volts and somehow
> the power supply voltage control got lowered.  I raised it to 13.8 volts and
> my problem disappeared.
> 
> Apparently the 847 supply voltage is critical on the Sub transmit vfo.
> Anyone using this rig on battery supply might want to check it out before
> going on a wilderness trip contemplating satellite operation.  I don't know
> if this problem is on my rig or the FT847 in general.  Incidently, the main
> vfo gave me no trouble on hf during this time period.
> 
> Mal, NP2L
> ----- Original Message -----
> From: Malcolm M. Preston <malnp2l@attglobal.net>
> To: <amsat-bb@amsat.org>
> Sent: Sunday, December 29, 2002 3:40 PM
> Subject: Need help with bad satellite signal on AO40
> 
> 
> > Hi all,
> >
> > Just in the last two weeks I have been plagued with a terrible cw signal
> on
> > AO40.  At first I though it was chirp but a further look shows it to be
> > something else which I can't figure out.  If the rig is key down my signal
> > sounds like with a higher tone (on the order of say 800hz) which changes
> to
> > a lower tone (say 400hz) at the end when the key is let up.  When I send
> at
> > a normal rate it sounds like a chirpy signal.
> >
> > I checked my transmitted signal on 440 in the shack with another receiver
> > and can detect nothing amiss.  KP2Z, a neighbor, listened to it also and
> it
> > sounded ok.
> >
> > The rig is an FT847 about 3 months old.
> >
> > If anyone thinks they can put some light on this I'd surely appreciate it.
> > I can provide a .WAV file of the sounds.  I'm baffled.
> >
> > Mal, NP2L
> > St. John, USVI
> >
> 
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