Hi all, I've been trying to receive the 2.4 ghz from AO-51 using an AIDC-3731 downconverter with a grill. Any time I plug in the wall wart that came with the unit, I get S-9 noise on my receiver. The receiver is an Alinco DR-1200. I know it's not the best. But it's what I got. From the material I got with the downconverter, it needs 24 volts. Is that fixed in stone, or can I use something less for voltage? I think I'll try a couple of 12v batteries in series. Has anyone else had the same problem? Any suggestions will be appreciated. 73 and hope to make some more contacts on AO-51. de Doug KA8QCU
It's normal. Most of these MMDS downconverters have WAY too much gain. I had better results adding a 6~12dB Radio Shack attenuator to mine. I added it to the "radio" side of the DC injector ("bias tee") so it wouldn't dissipate any of the DC power being fed up the coax. 73, Jim KQ6EA
--- On Tue, 9/9/08, Doug Kuitula ka8qcu@pasty.net wrote:
From: Doug Kuitula ka8qcu@pasty.net Subject: [amsat-bb] AIDC 3731 problem? To: amsat-bb@amsat.org Date: Tuesday, September 9, 2008, 3:33 PM Hi all, I've been trying to receive the 2.4 ghz from AO-51 using an AIDC-3731 downconverter with a grill. Any time I plug in the wall wart that came with the unit, I get S-9 noise on my receiver. The receiver is an Alinco DR-1200. I know it's not the best. But it's what I got. From the material I got with the downconverter, it needs 24 volts. Is that fixed in stone, or can I use something less for voltage? I think I'll try a couple of 12v batteries in series. Has anyone else had the same problem? Any suggestions will be appreciated. 73 and hope to make some more contacts on AO-51. de Doug KA8QCU _______________________________________________ Sent via AMSAT-BB@amsat.org. 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
On 9 Sep 2008 at 18:33, Doug Kuitula wrote:
Hi all, I've been trying to receive the 2.4 ghz from AO-51 using an AIDC-3731 downconverter with a grill. Any time I plug in the wall wart that came with the unit, I get S-9 noise on my receiver. The receiver is an Alinco DR-1200. I know it's not the best. But it's what I got. From the material I got with the downconverter, it needs 24 volts. Is that fixed in stone, or can I use something less for voltage? I think I'll try a couple of 12v batteries in series. Has anyone else had the same problem? Any suggestions will be appreciated. 73 and hope to make some more contacts on AO-51. de Doug KA8QCU _______________________________________________
I can used the 12v from the FT-847 without any noticeable change. I was told that 24v was used on mmds system to compensate for very long coaxial cable run and i think there is some kind of voltage limiter in the downconverter.
I used about 100 feet of RG-59 and i have about S1 to S3 of noise but when signal are at TCA signal peak at 40DB over S9. If you cannot get an attenuator used a coax coil this will reduced your noise signal level.
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Luc Leblanc VE2DWE Skype VE2DWE www.qsl.net/ve2dwe WAC BASIC CW PHONE SATELLITE
participants (3)
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Doug Kuitula -
Jim Jerzycke -
Luc Leblanc