Re: [Repeater-Builder] Re: Mastr II drift problem
Sometimes troubles like this are hard to find because you can't be there when it is happening. I have found that a Radio Shack Digital Voltmeter that I have and an old laptop have been handy for such times. I bought an RS DVM with the RS-232 interface on sale a few years ago. I connected it to an old laptop that I have via the RS-232 port and run the simple program that came with the DVM. It records readings over time and stores them to a file. You can then look at the file and see if things have changed over a period of time. I've used it to record AC voltage at sites where I suspected drops in voltage levels and it was helpful to get things fixed. Definitely not lab quality equipment, but very helpful in troubleshooting. This setup could easily watch the 10 volt line or the compensation voltage line. Just thought I'd pass this idea along. 73, Joe, K1ike On 8/4/2010 8:11 AM, steve wrote: I am using a PLL exciter with a 5C Icom. I am going to check the 10 volt supply. I have a couple of 10 volt cards that I will swap out if needed. Thank you Steve
Re: [Repeater-Builder] Re: Mastr II drift problem
On 8/4/2010 9:18 AM, Joe wrote: Sometimes troubles like this are hard to find because you can't be there when it is happening. I have found that a Radio Shack Digital Voltmeter that I have and an old laptop have been handy for such times. I bought an RS DVM with the RS-232 interface on sale a few years ago. I connected it to an old laptop that I have via the RS-232 port and run the simple program that came with the DVM. It records readings over time and stores them to a file. You can then look at the file and see if things have changed over a period of time. I've used it to record AC voltage at sites where I suspected drops in voltage levels and it was helpful to get things fixed. Definitely not lab quality equipment, but very helpful in troubleshooting. This setup could easily watch the 10 volt line or the compensation voltage line. Just thought I'd pass this idea along. 73, Joe, K1ike Really??? What's the model of that DMM? We could use that here! Jim
Re: [Repeater-Builder] Re: Mastr II drift problem
Radio Shack Cat No 22-812, I don't know if they even sell them anymore. Joe On 8/4/2010 9:50 AM, wd8chl wrote: Really??? What's the model of that DMM? We could use that here! Jim
Re: [Repeater-Builder] Re: Mastr II drift problem
Is the Icom an EC model? If so you need to have at least a 5C plugged in to compensate it. Preferably a 2C on transmit. EC = External Compensation. 5C=5 ppm stability and 2C= 2 ppm. You can also check the pins on the exciter board, they have a history of being cold soldered or breaking loose. As a matter of course, I'd resolder all of them while you are in there. Bill From: Stanley Stanukinos ka5...@swbell.net To: Repeater-Builder@yahoogroups.com Sent: Tue, August 3, 2010 8:06:53 PM Subject: RE: [Repeater-Builder] Re: Mastr II drift problem Next thing look at the comp voltage going to the tcxo it comes off of the 10v reg card. Have you checked or swapped it yet? From:Repeater-Builder@yahoogroups.com [mailto:repeater-buil...@yahoogroups.com] On Behalf Of steve Sent: Tuesday, August 03, 2010 8:06 PM To: Repeater-Builder@yahoogroups.com Subject: [Repeater-Builder] Re: Mastr II drift problem Hi Stan, Yes I sent the crystals to International. I have 3 fans running full time on the heat sink. Thanks for any help! Steve --- In Repeater-Builder@yahoogroups.com, Stanley Stanukinos ka5...@... wrote: Did you just buy the crystals and insert them in the ICOMs or did you send them in to the crystal MFG to be compensated. If you did them yourself the compensation is probably now messed up. The best way to fix it is to send them in to the crystal MFG for compensation. Stan From: Repeater-Builder@yahoogroups.com [mailto:repeater-buil...@yahoogroups.com] On Behalf Of steve Sent: Tuesday, August 03, 2010 5:33 PM To: Repeater-Builder@yahoogroups.com Subject: [Repeater-Builder] Mastr II drift problem Hello all, I have having a severe drift problem on my GE Mastr II 2 meter repeater. The transmit freq will drift nearly 2 KHZ over a 5-10 minute period. I have changed exciters and used a different ICOM but no improvement. The building that I am in is not ventilated and is very very hot. I put a high/low thermometer in and one day the high temp in the building was 114 degrees. Is this the problem? Thanks for any help. Steve W4SEF
Re: [Repeater-Builder] Re: Mastr II drift problem
Thanks Doug and everyone else! THe thing that tipped me off, was the sharpie note on it as RCC UHF - up until yesterday I had never encountered one of these. The topside half of the internal workings are what made me stop and pause when I took the cover off. Quite different from the other MASTR II's I was accustomed to seeing. The 7 rows in the channel element area all squished together, as well as the ICOMs installed in there. Someone asked to check for the crystals, and they are indeed there, the RX is 454.025 but whats unusual is that the TX elements do not have the frequencies listed on them. They do not appear to have been erased by hand, or scraped off - is that commonplace for units like these? Having fun learning about this now - makes me want to fire it up and toy around with it some! John Hymes La Rue Communications 10 S. Aurora Street Stockton, CA 95202 http://tinyurl.com/2dtngmn - Original Message - From: wd8chl To: Repeater-Builder@yahoogroups.com Sent: Wednesday, August 04, 2010 6:50 AM Subject: Re: [Repeater-Builder] Re: Mastr II drift problem On 8/4/2010 9:18 AM, Joe wrote: Sometimes troubles like this are hard to find because you can't be there when it is happening. I have found that a Radio Shack Digital Voltmeter that I have and an old laptop have been handy for such times. I bought an RS DVM with the RS-232 interface on sale a few years ago. I connected it to an old laptop that I have via the RS-232 port and run the simple program that came with the DVM. It records readings over time and stores them to a file. You can then look at the file and see if things have changed over a period of time. I've used it to record AC voltage at sites where I suspected drops in voltage levels and it was helpful to get things fixed. Definitely not lab quality equipment, but very helpful in troubleshooting. This setup could easily watch the 10 volt line or the compensation voltage line. Just thought I'd pass this idea along. 73, Joe, K1ike Really??? What's the model of that DMM? We could use that here! Jim
Re: [Repeater-Builder] Re: Mastr II drift problem
Steve. Make sure you check the jumpers, if you switch the cards. Butch, KE7FEL/r On Wed, Aug 4, 2010 at 6:11 AM, steve w4...@localnet.com wrote: I am using a PLL exciter with a 5C Icom. I am going to check the 10 volt supply. I have a couple of 10 volt cards that I will swap out if needed. Thank you Steve --- In Repeater-Builder@yahoogroups.comRepeater-Builder%40yahoogroups.com, Mike Morris wa6...@... wrote: At 03:33 PM 08/03/10, you wrote: Hello all, I have having a severe drift problem on my GE Mastr II 2 meter repeater. The transmit freq will drift nearly 2 KHZ over a 5-10 minute period. I have changed exciters and used a different ICOM but no improvement. The building that I am in is not ventilated and is very very hot. I put a high/low thermometer in and one day the high temp in the building was 114 degrees. Is this the problem? Thanks for any help. Steve W4SEF Can you elaborate on the situation? Is it an FM exciter or a phase mod exciter? Is it an EC, a 5C, or 2C Icom? Have you read http://www.repeater-builder.com/ge/m2icoms.html especially the paragraph that starts with Any voltage change on the +10vDC power supply line will change the frequency on the Icom... ?? You will also what to read the page at http://www.repeater-builder.com/tech-info/temperature-compensation.html . An idea on cooled down a building before you set the frequency... I once took a couple of cheapie box fans and setting one to blow in (at floor level) and the second stacked above it to blow out (at the top of the door level), and with a piece of cardboard in between them as an air dam. The cardboard was cut from the side of a large cardboard box that was used to ship a washing machine (ask for one at any appliance store). You could do something similar for the time period needed to set the frequency - your target is 75 to 80 degrees F for about an hour. Look at page 5 of this: http://www.repeater-builder.com/ge/lbi-library/lbi-38505a.pdf Yes, it's a receiver LBI, and you have a drifting transmitter, but the temperature notes apply. Mike WA6ILQ
RE: [Repeater-Builder] Re: Mastr II drift problem
Next thing look at the comp voltage going to the tcxo it comes off of the 10v reg card. Have you checked or swapped it yet? From: Repeater-Builder@yahoogroups.com [mailto:repeater-buil...@yahoogroups.com] On Behalf Of steve Sent: Tuesday, August 03, 2010 8:06 PM To: Repeater-Builder@yahoogroups.com Subject: [Repeater-Builder] Re: Mastr II drift problem Hi Stan, Yes I sent the crystals to International. I have 3 fans running full time on the heat sink. Thanks for any help! Steve --- In Repeater-Builder@yahoogroups.com mailto:Repeater-Builder%40yahoogroups.com , Stanley Stanukinos ka5...@... wrote: Did you just buy the crystals and insert them in the ICOMs or did you send them in to the crystal MFG to be compensated. If you did them yourself the compensation is probably now messed up. The best way to fix it is to send them in to the crystal MFG for compensation. Stan From: Repeater-Builder@yahoogroups.com mailto:Repeater-Builder%40yahoogroups.com [mailto:Repeater-Builder@yahoogroups.com mailto:Repeater-Builder%40yahoogroups.com ] On Behalf Of steve Sent: Tuesday, August 03, 2010 5:33 PM To: Repeater-Builder@yahoogroups.com mailto:Repeater-Builder%40yahoogroups.com Subject: [Repeater-Builder] Mastr II drift problem Hello all, I have having a severe drift problem on my GE Mastr II 2 meter repeater. The transmit freq will drift nearly 2 KHZ over a 5-10 minute period. I have changed exciters and used a different ICOM but no improvement. The building that I am in is not ventilated and is very very hot. I put a high/low thermometer in and one day the high temp in the building was 114 degrees. Is this the problem? Thanks for any help. Steve W4SEF
