Re: [Repeater-Builder] need input on changing Mitrek oscillator crystal
Mike, I thought there was some reference to a signal generated by the oscillator crystal in one receiver getting into the other receiver and causing a problem. I have not been able to find ref to it in a search of the messages. Perhaps it is only a concern if two receivers are operating on the very same frequency as with voting. I understood there was a recommendation for using a high side crystal frequency in one receiver and a low side crystal frequency in the other. Might it have implied that the receivers might pick up the wrong input signal as interference? Hardly any repeaters up here in the boonies are set up to use PL tones. I see only one repeater in Nova Scotia is listed as requiring PL tones. Perhaps our two repeaters should be the second and third! :-) I know were do have some problems at times where one repeaters output signal causes the other to come on. But it only happens once in a while. Just wanting to cover my bases! I appreciate any advice. Bruce - Original Message - From: Mike WA6ILQ [EMAIL PROTECTED] To: Repeater-Builder@yahoogroups.com Sent: Tuesday, November 30, 2004 5:20 AM Subject: Re: [Repeater-Builder] need input on changing Mitrek oscillator crystal At 02:52 PM 11/29/04, you wrote: I have read a few comments in the past about the need for changing the crystal from one side of the operating frequency to the other in a Mitrek. I am not sure I will be wording this properly so please be patient. I will have two repeaters at the same site which are Mitrek conversions. One repeater is on 145.210 MHz (neg. offset) and the other repeater is on 147.240 (pos. offset). At present the 145.210 repeater is not a Mitrek but when I am finished the conversion it will be replaced by the second Mitrek. I would appreciate comments re experiences (ie problems) encountered if both receivers have the same frequency crystal. thanks Bruce, VE1II The standard 136-174Mhz Mitrek configuration uses high side injection, with a 10.7 MHz IF. And remember, the 147.24 repeater will be listening to 147.84, and the 145.21 repeater will be listening to 144.61 - with over 3mhz of RX to RX separation I don't see a problem at all. And if you are referring to the two repeaters being on the same channel simultaneously, well, that's what two different PL tones are for - set up repeater 1 on tone A and repeater 2 on tone B. Or am I not understanding the question? Mike WA6ILQ 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] need input on changing Mitrek oscillator crystal
Usually if the covers are in place, that won't be a problem (the Mitreks are built in a pretty tight housing) but if it is, then the solution is in my Mitrek Interfacing writeup - just bump one to the alternate 10.8mhz IF (but he will have to re-order the RX rock, or tell the rock-chippers when he orders it that it is for a MSR-2000 second RX that is using a 10.8 IF). Moving a Mitrek RX to 10.8MHz IF requires a little soldering (you swap out the crystal filters and you HAVE to use a clip-on heat sink on the leads of the new ones) but also requires one-time-access to a service monitor (or a scope and a sweep generator that covers 10.8MHz). Mike WA6ILQ At 02:37 AM 11/30/04, you wrote: I think he may mean operating on the same IF frequency, but I'm not sure. Joe M. Mike WA6ILQ wrote: At 02:52 PM 11/29/04, you wrote: I have read a few comments in the past about the need for changing the crystal from one side of the operating frequency to the other in a Mitrek. I am not sure I will be wording this properly so please be patient. I will have two repeaters at the same site which are Mitrek conversions. One repeater is on 145.210 MHz (neg. offset) and the other repeater is on 147.240 (pos. offset). At present the 145.210 repeater is not a Mitrek but when I am finished the conversion it will be replaced by the second Mitrek. I would appreciate comments re experiences (ie problems) encountered if both receivers have the same frequency crystal. thanks Bruce, VE1II The standard 136-174Mhz Mitrek configuration uses high side injection, with a 10.7 MHz IF. And remember, the 147.24 repeater will be listening to 147.84, and the 145.21 repeater will be listening to 144.61 - with over 3mhz of RX to RX separation I don't see a problem at all. And if you are referring to the two repeaters being on the same channel simultaneously, well, that's what two different PL tones are for - set up repeater 1 on tone A and repeater 2 on tone B. Or am I not understanding the question? Mike WA6ILQ 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] need input on changing Mitrek oscillator crystal
At 10:27 AM 11/30/04, you wrote: Mike, I thought there was some reference to a signal generated by the oscillator crystal in one receiver getting into the other receiver and causing a problem. Maybe you are remembering the Cactus Radio writeup on Mitreks where they mention that the 406-420 models have a problem when duplexed with the RX multiplier getting into the TX multiplier and creating spurs. I have not been able to find ref to it in a search of the messages. Perhaps it is only a concern if two receivers are operating on the very same frequency as with voting. Even then you wouldn't have two voting RXs at the same site in the same rack. The nearest situation I know of to that is one site that has two RXs in adjacent buildings - only because the hardware was lying around, already crystaled up and on channel, and all it took was the labor to install, and it cut the mobile flutter in half...) I understood there was a recommendation for using a high side crystal frequency in one receiver and a low side crystal frequency in the other. Might it have implied that the receivers might pick up the wrong input signal as interference? Don't remember that Most well designed radios don't have that much LO or injection leakage (as long as all of the shields are in place)... Hardly any repeaters up here in the boonies are set up to use PL tones. I see only one repeater in Nova Scotia is listed as requiring PL tones. Perhaps our two repeaters should be the second and third! :-) Not unless you have a problem that requires it. Try it and see. I know were do have some problems at times where one repeaters output signal causes the other to come on. But it only happens once in a while. Probably a random mix Just wanting to cover my bases! I appreciate any advice. I'm sure that the list members will contribute. Bruce Mike WA6ILQ - Original Message - From: Mike WA6ILQ [EMAIL PROTECTED] To: Repeater-Builder@yahoogroups.com Sent: Tuesday, November 30, 2004 5:20 AM Subject: Re: [Repeater-Builder] need input on changing Mitrek oscillator crystal At 02:52 PM 11/29/04, you wrote: I have read a few comments in the past about the need for changing the crystal from one side of the operating frequency to the other in a Mitrek. I am not sure I will be wording this properly so please be patient. I will have two repeaters at the same site which are Mitrek conversions. One repeater is on 145.210 MHz (neg. offset) and the other repeater is on 147.240 (pos. offset). At present the 145.210 repeater is not a Mitrek but when I am finished the conversion it will be replaced by the second Mitrek. I would appreciate comments re experiences (ie problems) encountered if both receivers have the same frequency crystal. thanks Bruce, VE1II The standard 136-174Mhz Mitrek configuration uses high side injection, with a 10.7 MHz IF. As Neil pointed out, I had it wrong... it's low side. And remember, the 147.24 repeater will be listening to 147.84, and the 145.21 repeater will be listening to 144.61 - with over 3mhz of RX to RX separation I don't see a problem at all. And if you are referring to the two repeaters being on the same channel simultaneously, well, that's what two different PL tones are for - set up repeater 1 on tone A and repeater 2 on tone B. Or am I not understanding the question? Mike WA6ILQ 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] need input on changing Mitrek oscillator crystal
I have read a few comments in the past about the need for changing the crystal from one side of the operating frequency to the other in a Mitrek. I am not sure I will be wording this properly so please be patient. I will have two repeaters at the same site which are Mitrek conversions. One repeater is on 145.210 MHz (neg. offset) and the other repeater is on 147.240 (pos. offset). At present the 145.210 repeater is not a Mitrek but when I am finished the conversion it will be replaced by the second Mitrek. I would appreciate comments re experiences (ie problems) encountered if both receivers have the same frequency crystal. thanks Bruce, VE1II 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/
