[amsat-bb] Re: AO27/TS2000

Edward R. Cole kl7uw at acsalaska.net
Sat Jul 31 13:38:35 PDT 2010

That may be because the source of the birdie is near the radio and 
not necessarily coming from the radio (e.g. nearby computers).

The FT-847 is famous for its internal birdies, but they are either 
gone or diminished when I connect my eme antenna with tower-top 
preamp.  Some do not disappear so are probably being radiated from 
the neighborhood.

A good test is to terminate the radio with a dummy load and see what 
birdies remain (most likely are internally produced in the 
radio).  Then connect the antenna with preamp and see how many go 
away or are greatly reduced.  And see how many new ones show up!  a 
preamp can generate birdies from intermodulation products or 
self-oscillation.  So saying, RF is a messy business. ;-)

When I point the 2m eme array at 70-mi distant Anchorage the noise 
floor rises (slightly).  It drops if I swing in azimuth or raise 
above 10-degrees elevation.  In character the noise is not exactly 
white noise but has a faint line-noise sound.  Cities have a lot of lines. ;-)

73, Ed
PS:  I am going to be interested to observe how many birdies my 
Elecraft K3+DEMI 144/28 xvtr combo produce compared with the FT-847 
on 144 (144-144.030 is unusable due to birdies)

At 12:11 PM 7/31/2010, Bruce Robertson wrote:
>To improve the birdie issue on the TS-2000, be sure to keep your
>antennas well away from the radio. I found the birdie less serious
>recently, now that my antennas are 100' away.
>73, Bruce
>On Sat, Jul 31, 2010 at 4:28 PM, i8cvs <domenico.i8cvs at tin.it> wrote:
> > ----- Original Message -----
> > From: <wa4hfn at comcast.net>
> > To: "AMSAT" <amsat-bb at amsat.org>
> > Sent: Saturday, July 31, 2010 8:45 PM
> > Subject: [amsat-bb] AO27/TS2000
> >>
> >>
> >> Just installed a preamp Ar2 { Advance Reciever Research) M# MSP432DG-160
> > and the birdy that the TS2000 has on AO27 recieve is now gone and 
> I was able
> > to hear the bird from start of the pass to the end.Why ,I do not know, but
> > the preamp seems to kill the birdy . Has anyone found this to be the same.
> >>
> >> WA4HFN Damon
> >> _______________________________________________
> >
> > Hi Damon, WA4HFN
> >
> > The pramplifier "seems" to kill the birdy because the preamplifier gain is
> > very high and so the birdy is belove the noise introduced by the
> > preamplifier itself.
> >
> > I guess that without any signal on the band your S meter reading is well
> > above S-9 only because of the preamplifier noise that is apparently killing
> > the birdy.
> >
> > If you reduce the gain of your preamplifier to get an S-meter 
> reading of say
> > S-1 or S-2 without any signal on the band then the birdy will appear again.
> >
> > Best 73" de
> >
> > i8CVS Domenico
> >
> >
> >
> >
> > _______________________________________________
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> >
>Sent via AMSAT-BB at amsat.org. Opinions expressed are those of the author.
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73, Ed - KL7UW, WD2XSH/45
BP40IQ   500 KHz - 10-GHz   www.kl7uw.com
EME: 144-QRT*, 432-100w, 1296-QRT*, 3400-fall 2010
DUBUS Magazine USA Rep dubususa at hotmail.com

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