Re: [Repeater-Builder] Dissasembly of msr 2000 continuous duty amp. How?
radi...@aol.com wrote: Sucess! I completely cleaned and re tinned my Weller 8100 tip, added some solder, and got heat transfer to pop it up. I was not aware of the fish paper that the wires came thru. Now to troubleshoot the amp. It probably has some blown transistors as well as the cooked caps and 12 ohm resistors across some of the finals. We do have a Motorola test set, I have done component level work in the past, but this is out of my league. Kevin, I may take you up on your offer for further help. Thanks to all who responded. 73, Marty Consider obtaining a used MICOR mobile (usually can be gotten for $5 to $50) having a power amplifier board of the desired size and transplant it onto your heatsink. The PA assembly for this mobile radio is identical to the one(s) used on the continuous duty MICOR and MSR2000 power amplifiers. Or, just figure out which stage is bad and replace the transistor(s) that have failed. There is a process I use to easily see which stage is bad. Reply if you need more help. Kevin
Re: [Repeater-Builder] Dissasembly of msr 2000 continuous duty amp. How?
Tom Parker wrote: Why has no one suggested replacing the guts of this beast with a Mitrek PA? Why? Kevin
RE: [Repeater-Builder] Coax length, etc.
The cable length issue is a brother to if you don't like your VSWR, change the point along the transmission line where you're measuring it. I don't know what that's supposed to mean. The VSWR on the line is the same no matter where along the line you measure it. If you're using a meter that reads a different VSWR depending where on the line you put it, you need a new meter... --- Jeff WN3A
[Repeater-Builder] Re: Dissasembly of msr 2000 continuous duty amp. How?
Tom Parker t...@... wrote: Why has no one suggested replacing the guts of this beast with a Mitrek PA? Only if the Mitrek VHF PA is the same animal as some Micor PA's are reported to be. ... and that you can a used Mitrek (with the matching parts) as easily as you can find a used Micor parts radio. Or the converse... s.
Re: [Repeater-Builder] Thru-Line Power Sensor?
These were used with Micor stations that had the optional wattmeter kit installed. The cable connected to the remainder of the kit whch consisted of a meter, foward/reflected power switch and calibration pot(s). The element is the same one that is used with the Motorola wattmeter and the remote metering kit on the R2001 service monitor. Milt N3LTQ - Original Message - From: La Rue Communications To: Repeater-Builder@yahoogroups.com Sent: Thursday, August 05, 2010 7:39 PM Subject: [Repeater-Builder] Thru-Line Power Sensor? Trying to confirm this is what I am looking at here. Motorola P/N reads TRN5323A. Google search yields an archived thread re-posted here on R/B from another site, but its kinda sparse with details and I want to be absolutely sure that this is what it is. Band spread of this unit is 50W 500-1000 MHz. Pic attached. Thanks in advance! John Hymes La Rue Communications 10 S. Aurora Street Stockton, CA 95202 http://tinyurl.com/2dtngmn
[Repeater-Builder] TPN1185B
Just got a Motorola cabinet with the above power supply. Does anyone know the ratings of this supply, or what equipment used it? Is it worth keeping or just junk ? Henry
Re: [Repeater-Builder] Coax length, etc.
And a new perspective on transmission lines. I didn't think it was worth responding to, Jeff. AC WA9ZZU. From: Jeff DePolo j...@broadsci.com To: Repeater-Builder@yahoogroups.com Sent: Fri, August 6, 2010 8:23:09 AM Subject: RE: [Repeater-Builder] Coax length, etc. The cable length issue is a brother to if you don't like your VSWR, change the point along the transmission line where you're measuring it. I don't know what that's supposed to mean. The VSWR on the line is the same no matter where along the line you measure it. If you're using a meter that reads a different VSWR depending where on the line you put it, you need a new meter... --- Jeff WN3A
RE: [Repeater-Builder] TPN1185B
Henry, The TPN1185B is a 500 watt (35 amps at 14 volts) battery charger power supply used in 75/100/110 watt MSF5000 stations. It is a ferro-resonant unit that is reliable but rather inefficient. 73, Eric Lemmon WB6FLY -Original Message- From: Repeater-Builder@yahoogroups.com [mailto:repeater-buil...@yahoogroups.com] On Behalf Of k4...@charter.net Sent: Friday, August 06, 2010 9:18 AM To: Repeater-Builder@yahoogroups.com Subject: [Repeater-Builder] TPN1185B Just got a Motorola cabinet with the above power supply. Does anyone know the ratings of this supply, or what equipment used it? Is it worth keeping or just junk ? Henry
Re: [Repeater-Builder] Coax length, etc.
Grab your Smith chart! LOL - Original Message - From: allan crites To: Repeater-Builder@yahoogroups.com Sent: Friday, August 06, 2010 12:46 PM Subject: Re: [Repeater-Builder] Coax length, etc. And a new perspective on transmission lines. I didn't think it was worth responding to, Jeff. AC WA9ZZU. -- From: Jeff DePolo j...@broadsci.com To: Repeater-Builder@yahoogroups.com Sent: Fri, August 6, 2010 8:23:09 AM Subject: RE: [Repeater-Builder] Coax length, etc. The cable length issue is a brother to if you don't like your VSWR, change the point along the transmission line where you're measuring it. I don't know what that's supposed to mean. The VSWR on the line is the same no matter where along the line you measure it. If you're using a meter that reads a different VSWR depending where on the line you put it, you need a new meter... --- Jeff WN3A
Re: [Repeater-Builder] Coax length, etc.
Jeff was correct to question. I was vague. What I should have said was indicated reflected power, not VSWR. But good luck trying to determine an accurate VSWR based on erroneous reflected readings. Let the boo birds squawk. Keep questioning, Jeff. 73, Russ WB8ZCC On 8/6/2010 1:07 PM, Steven M Hodell wrote: Grab your Smith chart! LOL - Original Message - *From:* allan crites mailto:wa9...@arrl.net *To:* Repeater-Builder@yahoogroups.com mailto:Repeater-Builder@yahoogroups.com *Sent:* Friday, August 06, 2010 12:46 PM *Subject:* Re: [Repeater-Builder] Coax length, etc. And a new perspective on transmission lines. I didn't think it was worth responding to, Jeff. AC WA9ZZU. *From:* Jeff DePolo j...@broadsci.com mailto:j...@broadsci.com *To:* Repeater-Builder@yahoogroups.com mailto:Repeater-Builder@yahoogroups.com *Sent:* Fri, August 6, 2010 8:23:09 AM *Subject:* RE: [Repeater-Builder] Coax length, etc. The cable length issue is a brother to if you don't like your VSWR, change the point along the transmission line where you're measuring it. I don't know what that's supposed to mean. The VSWR on the line is the same no matter where along the line you measure it. If you're using a meter that reads a different VSWR depending where on the line you put it, you need a new meter... --- Jeff WN3A
Re: [Repeater-Builder] Re: 420Mhz Radio for Voter?
How about duty cycle? Do you think this set up would transmit 7x24? -- Tim :wq On Jul 28, 2010, at 7:46 PM, James Adkins wrote: I am using the Motorola CDM series of radios for 420-425 MHz links from voting sites. They make a low-split UHF split that covers 403-470 MHz out of the box, no mods needed. On the transmit sites, you will want to use a fan for cooling. We mount the RX radio and a UHF TX radio on a 1U rack shelf, use a 4 hole saw and drill a hole under the UHF TX radio, and purchase a nice Dayton 24vdc fan that is actually a ball bearing fan that you can count on for years of use, and let it go. Have not had any problems to date with these rigs over a 4 year span.
[Repeater-Builder] Measuring duplexer insertion loss
Can somebody please explain how the insertion loss of a duplexer is properly measured using a HP 8920A (with specan). I'm pretty new to this instrument as well as duplexer work but am eager to learn. Thanks. 73 Martin P.S.: Is it correct that a duplexer that has 40 dB isolation in each leg does have 80 dB overall isolation?
RE: [Repeater-Builder] Measuring duplexer insertion loss
Can somebody please explain how the insertion loss of a duplexer is properly measured using a HP 8920A (with specan). 1. Connect duplexer Tx port to duplex port on 8920. 2. Connect antenna port on duplexer to antenna port on 8920. 3. Go to spectrum analyzer screen. 4. Set center frequency = repeater tx frequency 5. Set generate mode to TRACKing 6. Set input to ANTENNA 7. Set generate port to DUPLEX 8. Set generate level to 0 dBm 9. Set the sweep span to something reasonable, like 500 kHz. 10. By default, the marker should be at the center graticule, which should be the Tx frequency you entered in #4 above (if not, go into the marker menu, and set the marker to 5.00, which is the center of the display). The difference between the marker level and the generated level is the loss, minus your cable losses. For example, if you're generating 0 dBm, and the amplitude at the marker is -2.10 dBm, and you have 0.5 dB of patch cable loss, the insertion loss through that leg of the duplexer is 1.6 dB. Repeat the same test for the Rx leg of the duplexer by moving the cable from the Tx port to the Rx port, and changing the center frequency to the Rx frequency. P.S.: Is it correct that a duplexer that has 40 dB isolation in each leg does have 80 dB overall isolation? No. --- Jeff WN3A
[Repeater-Builder] Re: Coax length, etc.
Kevin, I am using your coaxial matching section on a couple of antennas with good results. Great article on RB and not too hard to build --- In Repeater-Builder@yahoogroups.com, Kevin Custer kug...@... wrote: Russ Hines wrote: Thanks, guys, a good topic and one that always seems to come up. And it sparks more questions and comments, of course. The cable length issue is a brother to if you don't like your VSWR, change the point along the transmission line where you're measuring it. By changing the length of the line, we're creating a transmission line transformer (a good thing) but we're limited by its length (not so good). It seems to me the mentioned circulator/isolator at the output of the xmtr is a better fix, as reflections coming back from the duplexer is absorbed by the circulator's load, the xmtr is generally happy, and we're no longer limited where we can put things in a rack or elsewhere. For amateurs, coming up with usable VHF circulators seems to be difficult and usually expensive, and coax always seems to be cheaper. Has anyone had luck finding a source for reasonbly priced VHF circulators, or success in rolling their own? Also, I noted in the pamphlet Kevin referenced that the unused duplexer port was left open (Figs. 1 2). I guess if the isolation is already greater than the load's return loss, it doesn't matter, at least at the reject frequency. But it seems to me one could possibly create problems for oneself by not terminating the unused open port. Just a thought. Maybe I work better knowing there's a load there. ;-) Your comments, please. 73, Russ WB8ZCC I think we all agree that a real impedance matching device is the best approach, but hams (generally speaking) are cheap. Many will spend two days hacking on a piece of RG-214 before spending fifty or a hundred bucks on a different (better?) solution. Allan Crites and I are currently in discussion which will be used as the basis of a RB web article that will explain exactly what is happening, why it happens, and why an 'optimized' cable length can be used to transfer power ending up with the stated loss of the duplexer and have little reflected power toward the transmitter - so long as the duplexer is tuned properly and exhibits good return loss on the frequency it's designed to pass. Kevin Custer
RE: [Repeater-Builder] Measuring duplexer insertion loss
Oh, I guess I should have thrown in a couple of generally-applicable guidelines that should go without saying when using ANY sweep gear like this: - terminate the unused port on the duplexer with a high-quality 50 ohm load - it's a good idea to use 6 dB or greater pads on inputs and outputs of the test equipment - use high-quality test cables (double-shielded when you're measuring isolation) - avoid using adapters etc. etc. etc. --- Jeff WN3A -Original Message- From: Repeater-Builder@yahoogroups.com [mailto:repeater-buil...@yahoogroups.com] On Behalf Of Jeff DePolo Sent: Friday, August 06, 2010 4:21 PM To: Repeater-Builder@yahoogroups.com Subject: RE: [Repeater-Builder] Measuring duplexer insertion loss Can somebody please explain how the insertion loss of a duplexer is properly measured using a HP 8920A (with specan). 1. Connect duplexer Tx port to duplex port on 8920. 2. Connect antenna port on duplexer to antenna port on 8920. 3. Go to spectrum analyzer screen. 4. Set center frequency = repeater tx frequency 5. Set generate mode to TRACKing 6. Set input to ANTENNA 7. Set generate port to DUPLEX 8. Set generate level to 0 dBm 9. Set the sweep span to something reasonable, like 500 kHz. 10. By default, the marker should be at the center graticule, which should be the Tx frequency you entered in #4 above (if not, go into the marker menu, and set the marker to 5.00, which is the center of the display). The difference between the marker level and the generated level is the loss, minus your cable losses. For example, if you're generating 0 dBm, and the amplitude at the marker is -2.10 dBm, and you have 0.5 dB of patch cable loss, the insertion loss through that leg of the duplexer is 1.6 dB. Repeat the same test for the Rx leg of the duplexer by moving the cable from the Tx port to the Rx port, and changing the center frequency to the Rx frequency. P.S.: Is it correct that a duplexer that has 40 dB isolation in each leg does have 80 dB overall isolation? No. --- Jeff WN3A
Re: [Repeater-Builder] Measuring duplexer insertion loss
In addition to what Jeff said in his posts, I usually run a test sweep on my HP8924 connecting the two cables together with a double female of the appropriate type. The result should be a flat line sweep but will usually show some amount of loss relative to the generator level/reference level. I note the amount of loss and either increase the generator output to place the line as near as possible to 0db or just remember to subtract it from the end reading. After I do the test sweep I connect the cabling to the device to be swept and proceed with measurements and tuning. - Original Message - From: cruizzer77 atlant...@gmx.ch To: Repeater-Builder@yahoogroups.com Sent: Friday, August 06, 2010 3:35 PM Subject: [Repeater-Builder] Measuring duplexer insertion loss Can somebody please explain how the insertion loss of a duplexer is properly measured using a HP 8920A (with specan). I'm pretty new to this instrument as well as duplexer work but am eager to learn. Thanks. 73 Martin P.S.: Is it correct that a duplexer that has 40 dB isolation in each leg does have 80 dB overall isolation? Yahoo! Groups Links
[Repeater-Builder] Re: Measuring duplexer insertion loss
Can somebody please explain how the insertion loss of a Duplexer is properly measured using a HP 8920A (with Spectrum-Analyzer). Jeff DePolo j...@... wrote: 1. Connect duplexer Tx port to duplex port on 8920. 2. Connect antenna port on duplexer to antenna port on 8920. I have to think if where you apply the source and sample matters in this example and why. One should be able to apply the Duplex Output Source Signal to the antenna port and sample each outer leg (back to the antenna port). The unconnected leg/port should probably have a termination (load) on it. Might matter more or less maybe depending on where the other half of the Duplexer is tuned. Hm...? For example, if you're generating 0 dBm, and the amplitude at the marker is -2.10 dBm, and you have 0.5 dB of patch cable loss, the insertion loss through that leg of the duplexer is 1.6 dB. Another relative comparison is to insert a barrel connector in lieu of the duplexer to get a relative idea of the cable loss (with the barrel in line). s.
[Repeater-Builder] Re: Measuring duplexer insertion loss
Thanks guys I'll have another go tomorrow (it's 0.30 a.m. in my place now). Concerning the isolation question I was obviously wrong, I came up with the idea because the duplexer is a commercial tetra duplexer of which I had the factory test certificate filed and only remembered something like 80 dB. So I hooked it up (in factory condition) and only got 40 dB difference between the high point of the curve to the low when I looked at it in the spectrum analyzer with the tracking generator on (same value on both legs). My first calculation was 40 + 40... In the meantime I dug out that spec sheet and indeed there are values of Rejection (Ant - RX Port) : -80 dB Rejection (Ant - TX Port) : -80 dB Now what am I doing wrong in this case? Somewhere there are missing 40 dB each... I have to admit that I don't have double-shielded cables available at the moment, first need to get some, but that can't make such a difference can it? 73 Martin
Re: [Repeater-Builder] Re: 420Mhz Radio for Voter?
Thanks Buch, I'd like to build the link so that it transmits all the time. That minimizes key up delays and reduces intermod on the hill. So need something that can key down forever. -- Tim :wq On Aug 6, 2010, at 3:13 PM, Glenn (Butch) Kanvick wrote: Hello Tim. Yes, the CDM's probably will not do the 24/7 even with cooling as they are designed for a 5 per cent duty cycle, maybe 10 per cent if you are very lucky and it stays in an air conditioned room all of it's life. The CDM's are a mobile version plus you need two of them, one for TX and one for RX, then you need the Motoroal RICK to make them work. Have a great weekend. Butch, KE7FEL/r On Fri, Aug 6, 2010 at 3:46 PM, Tim Sawyer tisaw...@gmail.com wrote: Oh, sorry Butch. I was asking James about the CDM radios.I know the Micor's are 7x24x365. -- Tim :wq On Aug 6, 2010, at 12:30 PM, Glenn (Butch) Kanvick wrote: Hello Tim. These do not have a fan on them, but adding a fan(s) would make the air pass by the cooling fins much faster. These are the continious duty PA's with the huge heatsink on the rear of the PA. I am not sure what Motorola's duty cycle is for these PA's. Attached is a picture of the PA. On Fri, Aug 6, 2010 at 12:26 PM, Tim Sawyer tisaw...@gmail.com wrote: How about duty cycle? Do you think this set up would transmit 7x24? -- Tim :wq On Jul 28, 2010, at 7:46 PM, James Adkins wrote: I am using the Motorola CDM series of radios for 420-425 MHz links from voting sites. They make a low-split UHF split that covers 403-470 MHz out of the box, no mods needed. On the transmit sites, you will want to use a fan for cooling. We mount the RX radio and a UHF TX radio on a 1U rack shelf, use a 4 hole saw and drill a hole under the UHF TX radio, and purchase a nice Dayton 24vdc fan that is actually a ball bearing fan that you can count on for years of use, and let it go. Have not had any problems to date with these rigs over a 4 year span. 100_1894.jpg100_1895.jpg
[Repeater-Builder] Re: RE:Mastr II drift problem
Hello, Does anyone have a 5C for the PLL exciter they want to sell? This is the larger Icom. Thanks Steve --- In Repeater-Builder@yahoogroups.com, Doug Bade k...@... wrote: There are 5C elements made for that exciter. you just do not have one.. From: Repeater-Builder@yahoogroups.com [mailto:repeater-buil...@yahoogroups.com] On Behalf Of steve Sent: Thursday, August 05, 2010 1:01 PM To: Repeater-Builder@yahoogroups.com Subject: [Repeater-Builder] RE:Mastr II drift problem I was told that I should be using 5C for receive and transmit but the 5C will NOT fit on my PLL exciter. Any ideas? Steve W4SEF
Re: [Repeater-Builder] Re: Measuring duplexer insertion loss
Martin, The other 40dB is hiding in the lower regions of the sweep. I'll try to describe what to do from memory but I may be a bit off target. The bottom of the sweep should look a bit wide and ragged, not a smooth line. Drop the Reference level down to -40 or -50. You should now see the bottom of the sweep and see a smooth, well defined line on the trace. Milt N3LTQ Quoting cruizzer77 atlant...@gmx.ch: Thanks guys I'll have another go tomorrow (it's 0.30 a.m. in my place now). Concerning the isolation question I was obviously wrong, I came up with the idea because the duplexer is a commercial tetra duplexer of which I had the factory test certificate filed and only remembered something like 80 dB. So I hooked it up (in factory condition) and only got 40 dB difference between the high point of the curve to the low when I looked at it in the spectrum analyzer with the tracking generator on (same value on both legs). My first calculation was 40 + 40... In the meantime I dug out that spec sheet and indeed there are values of Rejection (Ant - RX Port) : -80 dB Rejection (Ant - TX Port) : -80 dB Now what am I doing wrong in this case? Somewhere there are missing 40 dB each... I have to admit that I don't have double-shielded cables available at the moment, first need to get some, but that can't make such a difference can it? 73 Martin Yahoo! Groups Links
Re: [Repeater-Builder] Re: RE:Mastr II drift problem
If you have a RX 5C or 2C -or- a phase 5C or 2C ICOM, you can transplant the compensation circuit into a EC PLL ICOM. There are only 3 pins involved. There is some degree of skill required as the compensator circuit is built on a ceramic/glass substrate and is somewhat fragile. Scott Scott Zimmerman Amateur Radio Call N3XCC 474 Barnett Road Boswell, PA 15531 steve wrote: Hello, Does anyone have a 5C for the PLL exciter they want to sell? This is the larger Icom. Thanks Steve --- In Repeater-Builder@yahoogroups.com, Doug Bade k...@... wrote: There are 5C elements made for that exciter. you just do not have one.. From: Repeater-Builder@yahoogroups.com [mailto:repeater-buil...@yahoogroups.com] On Behalf Of steve Sent: Thursday, August 05, 2010 1:01 PM To: Repeater-Builder@yahoogroups.com Subject: [Repeater-Builder] RE:Mastr II drift problem I was told that I should be using 5C for receive and transmit but the 5C will NOT fit on my PLL exciter. Any ideas? Steve W4SEF Yahoo! Groups Links
[Repeater-Builder] Re: Dissasembly of msr 2000 continuous duty amp. How?
There is a process I use to easily see which stage is bad. Reply if you need more help. Maybe you'd consider posting it here? Always looking for better ways to do things. Tom DGN --- In Repeater-Builder@yahoogroups.com, Kevin Custer kug...@... wrote: radi...@... wrote: Sucess! I completely cleaned and re tinned my Weller 8100 tip, added some solder, and got heat transfer to pop it up. I was not aware of the fish paper that the wires came thru. Now to troubleshoot the amp. It probably has some blown transistors as well as the cooked caps and 12 ohm resistors across some of the finals. We do have a Motorola test set, I have done component level work in the past, but this is out of my league. Kevin, I may take you up on your offer for further help. Thanks to all who responded. 73, Marty Consider obtaining a used MICOR mobile (usually can be gotten for $5 to $50) having a power amplifier board of the desired size and transplant it onto your heatsink. The PA assembly for this mobile radio is identical to the one(s) used on the continuous duty MICOR and MSR2000 power amplifiers. Or, just figure out which stage is bad and replace the transistor(s) that have failed. There is a process I use to easily see which stage is bad. Reply if you need more help. Kevin
