---------------------------------------------------------- Yak-List Digest Archive --- Total Messages Posted Tue 08/07/18: 3 ---------------------------------------------------------- Today's Message Index: ---------------------- 1. 10:48 AM - Garmin 250XL Squelch Issue (Robin Hou) 2. 11:27 AM - Garmin 250XL Squelch Issue (Bitterlich, Mark G CIV NAVAIR, WD) 3. 12:29 PM - Re: Garmin 250XL Squelch Issue (Robin Hou) ________________________________ Message 1 _____________________________________ Time: 10:48:17 AM PST US Subject: Yak-List: Garmin 250XL Squelch Issue From: "Robin Hou" I have a Garmin GNC 250XL in my CJ-6. I fly mostly in formation with others. There are 2 CJ's that I fly with which have Icom IC-A200 radio installed in them. When I fly with Icom IC-A200 equipped plane in formation, the transmission from Icom would trip my 250XL squelch which requires resetting my auto-squelch by pressing SQ button. Sometimes it is so bad that I cannot hear any transmission for the rest of the flight even after I have reset the SQ button multiple times. When the problem occurred, the 250XL continued to transmit fine but I heard no transmission. I have no problem flying formation with other planes with non-Icom radios; only the Icom radios cause this issue. Also no issue with ATC when I am flying solo. The radio has been bench checked OK. Any advise on how to pin point the issue is greatly appreciated. Thanks in advance. Read this topic online here: http://forums.matronics.com/viewtopic.php?p=482155#482155 ________________________________ Message 2 _____________________________________ Time: 11:27:36 AM PST US From: "Bitterlich, Mark G CIV NAVAIR, WD" Subject: Yak-List: Garmin 250XL Squelch Issue Are you saying that when you fly in formation with aircraft using the IC-A200 radio, that without them ever transmitting to you ... as in they are not talking or pushing the PTT button..... that as soon as you get close to these aircraft that you start to hear static in your radio? You say that the Icom would "trip my 250XL squelch". What exactly does that mean? I grasp what it PROBABLY means, but I need to know precisely what is going on. As I said, do you start to hear static noise in your headset, and that you would try to make it stop by hitting the SQ button? And that even when you got the noise in your headset to stop making noise, you then could not hear anyone else talk? Please verify this as correct. 1. Did you have the flight (as in all aircraft in formation) change to a different frequency and see if it changed what was going on? 2. When it was happening, did you try YOUR radio on a different frequency to see if you could hear anyone else? As in an ASOS transmission, tower, ground, ATC, anyone? What it sounds like ... without test data.... is that the ICOM radios have Local Oscillator leakage and they are actually radiating enough energy to impact the radio in your aircraft. The only way to know this for sure is to use a SpecAn (Spectrum Analyzer) on the offending aircraft radios (the Icom's) and see what it is for sure. It is important to know that when this happens, do you experience it only when you are on the same frequency that they are on, or can you switch to another frequency (with them staying where they were) and then your radios receiver starts working well again. Then when they switch to your new frequency, that the problem comes back. Further, that when they turn their radios completely OFF, that your receiver start working perfectly again. There are a few things that can cause this to happen but to narrow them down, you have to be very specific in exactly how this occurs, and then run tests as noted above. It is possible that if you all try a totally new frequency, well removed from the one you have been using, this problem might actually disappear. But ... it also might not... and that is also critical to know. In the end, you have stumbled on a very rare problem that will more than likely take some local expertise with the right test equipment to solve. If I could get my hands on the offending aircraft, using a SpecAn, we could nail this down very quickly ... but without that, it might prove difficult. Mark -----Original Message----- From: owner-yak-list-server@matronics.com On Behalf Of Robin Hou Sent: Tuesday, August 07, 2018 1:48 PM Subject: [Non-DoD Source] Yak-List: Garmin 250XL Squelch Issue I have a Garmin GNC 250XL in my CJ-6. I fly mostly in formation with others. There are 2 CJ's that I fly with which have Icom IC-A200 radio installed in them. When I fly with Icom IC-A200 equipped plane in formation, the transmission from Icom would trip my 250XL squelch which requires resetting my auto-squelch by pressing SQ button. Sometimes it is so bad that I cannot hear any transmission for the rest of the flight even after I have reset the SQ button multiple times. When the problem occurred, the 250XL continued to transmit fine but I heard no transmission. I have no problem flying formation with other planes with non-Icom radios; only the Icom radios cause this issue. Also no issue with ATC when I am flying solo. The radio has been bench checked OK. Any advise on how to pin point the issue is greatly appreciated. Thanks in advance. Read this topic online here: http://forums.matronics.com/viewtopic.php?p=482155#482155 ________________________________ Message 3 _____________________________________ Time: 12:29:19 PM PST US Subject: Yak-List: Re: Garmin 250XL Squelch Issue From: "Robin Hou" Hi Mark, Sorry, I should have been more clear. I say that the Icom would "trip my 250XL squelch"; what I mean is when the Icom transmits, my 250XL auto squelch function would adjust itself to a point that I can no longer hear any transmission from any radio. It occurred mostly when the Icom equipped plane is flying lead which requires transmissions lasting for a 30 seconds or so at a time. When the Icom equipped plane is not lead and stays radio silent, there was no problem. When the Icom equipped plane is not lead and only does very short transmissions (i.e. checking in), there is no problem. Interestingly, my portable radio, which has manual squelch adjustment, could receive transmission when my 250XL is silent. You ask 1. Did you have the flight (as in all aircraft in formation) change to a different frequency and see if it changed what was going on? Yes, the issue had occurred on 121.20, 123.30, 135.95 & 135.97. You ask 2. When it was happening, did you try YOUR radio on a different frequency to see if you could hear anyone else? As in an ASOS transmission, tower, ground, ATC, anyone? Yes, changing frequency on my 250XL does not restore its ability to receive transmission. When the issue occurred in the beginning of a flight, I could resolve the issue by pressing SQ; however, after about 10 to 15 minutes, pressing the SQ does nothing. Your help is greatly appreciated. Robin Read this topic online here: http://forums.matronics.com/viewtopic.php?p=482160#482160 ------------------------------------------------------------------------------------- Other Matronics Email List Services ------------------------------------------------------------------------------------- Post A New Message yak-list@matronics.com UN/SUBSCRIBE http://www.matronics.com/subscription List FAQ http://www.matronics.com/FAQ/Yak-List.htm Web Forum Interface To Lists http://forums.matronics.com Matronics List Wiki http://wiki.matronics.com Full Archive Search Engine http://www.matronics.com/search 7-Day List Browse http://www.matronics.com/browse/yak-list Browse Digests http://www.matronics.com/digest/yak-list Browse Other Lists http://www.matronics.com/browse Live Online Chat! http://www.matronics.com/chat Archive Downloading http://www.matronics.com/archives Photo Share http://www.matronics.com/photoshare Other Email Lists http://www.matronics.com/emaillists Contributions http://www.matronics.com/contribution ------------------------------------------------------------------------------------- These Email List Services are sponsored solely by Matronics and through the generous Contributions of its members.