Re: [Repeater-Builder] Sinclair Q 202G Tuning Problem
Jim - W5ZIT wrote: I am trying to move a Q 202 G from the 170 mHz range down to the 147 mHz range and have run into a problem on the notch tuning. The high pass tuning works like a charm and has a good pass and notch characteristic. The low pass side is another story. The pass tuning works fine, but I can't get a notch. With the tuning rods all the way in, it is starting to notch, but only about 20 db. Eric - WB5FLY wrote: Jim, Sinclair makes two harness assemblies for that duplexer. The jumpers are about two inches longer in the low-range harness, and that makes a world of difference. You can order the low-split harness directly from Sinclair. Go to: www.sinctech.com Make it very clear that you want the low range harness, as some of the Sinclair sales folk seemed to be unaware of its availability, the last time I called them. A year or so ago, that harness cost about $145. It's all in one piece, with crimped connections. As I recall, the low range was for 136-150 MHz, and the high range was for 150-174 MHz. Most Bp/Br cavities will have one notch above and one notch below the pass frequency. I have tuned several Sinclair duplexers of this design, and they all tuned up perfectly once the correct harness was installed. 73, Eric Lemmon WB6FLY Eric - I took your advice and built up a couple of jumpers to go from the cans back to the tee in the harness on the low pass side and made them 2 inches longer than the old ones as you suggested and presto - nice deep null with the tuning rods. Thanks to all for the feedback, and thanks to the list for helping to solve this problem. 73 - Jim W5ZIT Yahoo! Groups Links * To visit your group on the web, go to: http://groups.yahoo.com/group/Repeater-Builder/ * To unsubscribe from this group, send an email to: [EMAIL PROTECTED] * Your use of Yahoo! Groups is subject to: http://docs.yahoo.com/info/terms/
RE: [Repeater-Builder] Sinclair Q 202G Tuning Problem
Jim, Sinclair makes two harness assemblies for that duplexer. The jumpers are about two inches longer in the low-range harness, and that makes a world of difference. You can order the low-split harness directly from Sinclair. Go to: www.sinctech.com Make it very clear that you want the low range harness, as some of the Sinclair sales folk seemed to be unaware of its availability, the last time I called them. A year or so ago, that harness cost about $145. It's all in one piece, with crimped connections. As I recall, the low range was for 136-150 MHz, and the high range was for 150-174 MHz. Most Bp/Br cavities will have one notch above and one notch below the pass frequency. I have tuned several Sinclair duplexers of this design, and they all tuned up perfectly once the correct harness was installed. 73, Eric Lemmon WB6FLY -Original Message- From: Repeater-Builder@yahoogroups.com [mailto:[EMAIL PROTECTED] On Behalf Of Jim Brown Sent: Saturday, April 22, 2006 2:10 PM To: Repeater-Builder@yahoogroups.com Subject: [Repeater-Builder] Sinclair Q 202G Tuning Problem I am trying to move a Q-202G from the 170 MHz range down to the 147 MHz range and have run into a problem on the notch tuning. The high pass tuning works like a charm and has a good pass and notch characteristic. The low pass side is another story. The pass tuning works fine, but I can't get a notch. With the tuning rods all the way in, it is starting to notch, but only about 20 db. Here is the strange thing - I took the coupling loop out of the high pass side and compared it to the low pass side, and they are identical. The tuning rod varies the capacitance across the single loop connector and there is no inductance in the circuit for either high pass or low pass side. How does the same hookup work to allow a notch on the low side as well as the high side? I am tempted to add a small fixed capacitance across the loop to see if that helps the tuning for the low pass side.. Any comments on which way to go? 73 - Jim W5ZIT Yahoo! Groups Links Yahoo! Groups Links * To visit your group on the web, go to: http://groups.yahoo.com/group/Repeater-Builder/ * To unsubscribe from this group, send an email to: [EMAIL PROTECTED] * Your use of Yahoo! Groups is subject to: http://docs.yahoo.com/info/terms/
Re: [Repeater-Builder] Sinclair Q 202G Tuning Problem
What you are experiencing is the symptioms of insufficient capacity to pull the notch down low enough on the low pass side. The capacity range of those tuning stubs is determined by the length of the center rod inside the plastic stub. They are 3/16 (I think) diameter brass rod with a threaded end. Sinclair had several lengths available, the longest one being about 6in long. There is probably nobody left at Sinclair that even remembers that part as that design dates back to the 1950s or 60s and was superseded by the Johanson trimmer design in the late 1960s. You should be able to get a local machinist to make you a longer one using the one you have as an example. Burt VE2BMQ Jim Brown wrote: I am trying to move a Q 202 G from the 170 mHz range down to the 147 mHz range and have run into a problem on the notch tuning. The high pass tuning works like a charm and has a good pass and notch characteristic. The low pass side is another story. The pass tuning works fine, but I can't get a notch. With the tuning rods all the way in, it is starting to notch, but only about 20 db. Here is the strange thing - I took the coupling loop out of the high pass side and compared it to the low pass side, and they are identical. The tuning rod varies the capacitance across the single loop connector and there is no inductance in the circuit for either high pass or low pass side. How does the same hookup work to allow a notch on the low side as well as the high side? I am tempted to add a small fixed capacitance across the loop to see if that helps the tuning for the low pass side.. Any comments on which way to go? 73 - Jim W5ZIT Yahoo! Groups Links Yahoo! Groups Links * To visit your group on the web, go to: http://groups.yahoo.com/group/Repeater-Builder/ * To unsubscribe from this group, send an email to: [EMAIL PROTECTED] * Your use of Yahoo! Groups is subject to: http://docs.yahoo.com/info/terms/
[Repeater-Builder] Sinclair Q-202G
Has anyone had luck using the Q-202G duplexers in the 145-148 range? What needs to be done with them for use in the ham band? Just different cables? What sort of isolation figure is possible? Thanks. Paul Yahoo! Groups Links * To visit your group on the web, go to: http://groups.yahoo.com/group/Repeater-Builder/ * To unsubscribe from this group, send an email to: [EMAIL PROTECTED] * Your use of Yahoo! Groups is subject to: http://docs.yahoo.com/info/terms/
Re: [Repeater-Builder] Sinclair Q-202G
Paul, I have tuned three Q-202G duplexers in the past six months, and all wound up with nearly identical performance. The only difference between a Q-202G duplexer for the 2m band and one for the 150-174 MHz band is the length of the jumper cables. The factory-made harness for the commercial band measures 12 between the cavities and between the inside cavities and the antenna tee connector. The 2m harness measures 14 for these four sections. The measurements are between the centers of each tee connector. The physical size of the cans and the coupling loops are the same for both splits. Using a network analyzer and great care to match the return loss between cavities, I was able to achieve at least 86 dB of isolation at 1.5 dB insertion loss. This is barely adequate for a solid-state 35W repeater that has 0.35 uV sensitivity at 12 dB SINAD. If you're willing to accept some impairment due to desense, you can run more power- especially if you have a tube PA. A 100W repeater normally requires 100 dB of isolation for zero desense, and that usually calls for six cavities. However, I have used a Q-202G duplexer with two added bandpass cavities on the receive side, and it had zero desense with a 100W PA. 73, Eric Lemmon WB6FLY Paul Holm wrote: Has anyone had luck using the Q-202G duplexers in the 145-148 range? What needs to be done with them for use in the ham band? Just different cables? What sort of isolation figure is possible? Thanks. Paul Yahoo! Groups Links Yahoo! Groups Links * To visit your group on the web, go to: http://groups.yahoo.com/group/Repeater-Builder/ * To unsubscribe from this group, send an email to: [EMAIL PROTECTED] * Your use of Yahoo! Groups is subject to: http://docs.yahoo.com/info/terms/
Re: [Repeater-Builder] Sinclair Q-202G
Yes! and they work well. You need different cable lengths and different length rods on the tubular caps,or convert to trimmers. 73,Lee Paul Holm wrote: Has anyone had luck using the Q-202G duplexers in the 145-148 range? What needs to be done with them for use in the ham band? Just different cables? What sort of isolation figure is possible? Thanks. Paul Yahoo! Groups Links Yahoo! Groups Links * To visit your group on the web, go to: http://groups.yahoo.com/group/Repeater-Builder/ * To unsubscribe from this group, send an email to: [EMAIL PROTECTED] * Your use of Yahoo! Groups is subject to: http://docs.yahoo.com/info/terms/
Re: [Repeater-Builder] Sinclair Q-202G
Hi Paul, Paul Holm wrote: Has anyone had luck using the Q-202G duplexers in the 145-148 range? Yes, there are 4 repeaters close by my area that use them. What needs to be done with them for use in the ham band? Just different cables? Right, considering they may be fairly far from the destination frequency. It's accepted that a move of 3% or less of where the factory built them is okay without cable replacement, more than that, its usually a necessity. What sort of isolation figure is possible? At 600 kHz, you will see a typical notch depth of between 85 and 92 dB depending on how good the harness matches. The *sides* of this duplexer seem to interact more so than others I have tuned, so, you need to make sure both sides are fairly close in tuning before spending time making them perfect. Here is a document that will help you tune and understand them: http://www.repeater-builder.com/sinclair/cm-1008.pdf We have Micor repeaters on the 4 installations I spoke of earlier. Most are running solid state 110 watt PA's running full power and the receivers include the Micor helical resonator preamp that gives 12 dB sinad sensitivity at -122 dBm (.2 uV) or slightly better. These repeaters have no desense, but likely have very little reserve isolation as well. One thing that can be done to add more reserve isolation is to use better than average equipment. If you have a GE Mastr II two meter or highband repeater that has inadequate duplexer isolation, change out the exciter to a PLL type and take advantage of the 20+ dB less transmitter side-band noise. Another thing is to consider using a tube type PA deck, like the GE 4EF5A1, with a typical 'multiplier' exciter. This could allow power levels in excess of 200 watts or more without suffering from inadequate transmitter side-band noise suppression. Kevin Custer Yahoo! Groups Links * To visit your group on the web, go to: http://groups.yahoo.com/group/Repeater-Builder/ * To unsubscribe from this group, send an email to: [EMAIL PROTECTED] * Your use of Yahoo! Groups is subject to: http://docs.yahoo.com/info/terms/
Re: [Repeater-Builder] Sinclair Q-202G
Hi Kevin, Just a quick question regarding your earlier email - I thought crystal oscillators were cleaner (as far as noise sidebands are concerned ) than PLL types. Is this not the case in the GE Mastr II you mention below, as you indicate the PLL type of exciter is better? Is this particular to this design? Don't get me wrong here Kevin- I'm not trying to poke holes in what you are suggesting, I just thought xtals would be cleaner? Great info about the duplexers though. 73, Matt - Original Message - From: Kevin Custer [EMAIL PROTECTED] To: Repeater-Builder@yahoogroups.com Sent: Saturday, December 18, 2004 10:59 PM Subject: Re: [Repeater-Builder] Sinclair Q-202G Hi Paul, Paul Holm wrote: Has anyone had luck using the Q-202G duplexers in the 145-148 range? Yes, there are 4 repeaters close by my area that use them. What needs to be done with them for use in the ham band? Just different cables? Right, considering they may be fairly far from the destination frequency. It's accepted that a move of 3% or less of where the factory built them is okay without cable replacement, more than that, its usually a necessity. What sort of isolation figure is possible? At 600 kHz, you will see a typical notch depth of between 85 and 92 dB depending on how good the harness matches. The *sides* of this duplexer seem to interact more so than others I have tuned, so, you need to make sure both sides are fairly close in tuning before spending time making them perfect. Here is a document that will help you tune and understand them: http://www.repeater-builder.com/sinclair/cm-1008.pdf We have Micor repeaters on the 4 installations I spoke of earlier. Most are running solid state 110 watt PA's running full power and the receivers include the Micor helical resonator preamp that gives 12 dB sinad sensitivity at -122 dBm (.2 uV) or slightly better. These repeaters have no desense, but likely have very little reserve isolation as well. One thing that can be done to add more reserve isolation is to use better than average equipment. If you have a GE Mastr II two meter or highband repeater that has inadequate duplexer isolation, change out the exciter to a PLL type and take advantage of the 20+ dB less transmitter side-band noise. Another thing is to consider using a tube type PA deck, like the GE 4EF5A1, with a typical 'multiplier' exciter. This could allow power levels in excess of 200 watts or more without suffering from inadequate transmitter side-band noise suppression. Kevin Custer Yahoo! Groups Links Yahoo! Groups Links * To visit your group on the web, go to: http://groups.yahoo.com/group/Repeater-Builder/ * To unsubscribe from this group, send an email to: [EMAIL PROTECTED] * Your use of Yahoo! Groups is subject to: http://docs.yahoo.com/info/terms/
