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 VE9QRP
On Sat, Jul 31, 2010 at 4:28 PM, i8cvs [email protected] wrote:
----- Original Message ----- From: [email protected] To: "AMSAT" [email protected] 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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-- http://ve9qrp.blogspot.com _______________________________________________ Sent via [email protected]. Opinions expressed are those of the author. Not an AMSAT-NA member? Join now to support the amateur satellite program! Subscription settings: http://amsat.org/mailman/listinfo/amsat-bb
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 [email protected] ====================================== *temp