Another thing that may have gone is the RF sensing circuit that is probably set for 25w max. RF switched preamps are more susceptible to burn-out as they rely on fast switching of the preamp bypass circuit. Even a few milliseconds delay will allow enough RF energy to zap the delicate GasFet in the preamp. This is why we suggest using a sequencer to control RF switching before RF is generated. Its not done much by satellite operators but very common by mw and eme stations.
Some high-end radios have transmit RF delay settings available in their menu. if you radio has such, add 50-100 ms delay will provide much more protection.
You know re-reading your comments I wonder if you transmitted 440-MHz thru a 144-MHz preamp? The RF sense circuit might not detect 440 as well as 144 MHz. That is why radio with separate VHF and UHF antennas are preferred.
Best to return to ARR for repair - it is a flat rate. I have repaired many ARR P144VDG over the years.
73, Ed - KL7UW
At 12:48 PM 8/6/2011, Zachary Beougher wrote:
Thanks for the responses everyone. And Dee, no, I am not a handy tech - obviously! I transmitted probably 2-3 times through it using 35w, 1-2 second each, then it blew. Like you, Mark, I am a little surprised it blew so quickly, but oh well.
Thanks!
Zack KD8KSN (aka reckless preamp handler) =P
-----Original Message----- From: Dee Sent: Saturday, August 06, 2011 3:51 PM To: 'Zachary Beougher' ; [email protected] Subject: RE: [amsat-bb] ARR Preamp Help
You have blown it--If you are not a handy tech. - Send it back to ARR and they have a flat fee for repairs. Check with them on the internet. 73, Dee, NB2F
-----Original Message----- From: [email protected] [mailto:[email protected]] On Behalf Of Zachary Beougher Sent: Saturday, August 06, 2011 3:40 PM To: [email protected] Subject: [amsat-bb] ARR Preamp Help
Hi All,
I was monitoring some passes while mobile today, and amidst all of the confusion of messing with coax and frequencies, I accidently transmitted on 440, through the preamp, with 35w (the relay is rated at 25w). I thought I had switched the VFO back to 2m, but I guess not. It was only for a split second, but since that every time I turn the preamp on it automatically knocks out all received signal. Does anyone have any idea on what I need to do/check to see what I did to it? I have heard of this happening, I just need to know what path to take now to get it fixed.
It is worth mentioning that I can receive fine with the preamp in-line, but the minute I throw the power switch it knocks out all receive (just static, no received audio). I have not changed any of the connections, so having a coax hooked up backwards is not the issue.
Thanks,
Zack KD8KSN
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
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: 50-1.1kw?, 144-1.4kw, 432-100w, 1296-60w, 3400-? DUBUS Magazine USA Rep [email protected] ======================================