[Repeater-Builder] Re: duplexer tuning question
---Is it even possible to tune within a +/- 15 Khz window? OK, maybe possible but practical? Ken I would tend to agree with Ken. Almost certainly, you cannot tune the passes any closer. The only adjustments that could change by moving 15kc are the notches. With a TXRX 28-37-02 here, we have successfully used the receive side to feed both a 147.66 and .56 receiver. Its a stretch but it worked fine. In the instant case, we're only talking 15kc. My vote is try it. I'll bet it works fine. Laryn K8TVZ 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] Re: duplexer tuning question
Retuning is required if you wan't it to work. --- In Repeater-Builder@yahoogroups.com, doug [EMAIL PROTECTED] wrote: ok guys - a question... and i am sure i'll get both sides of this one. i have a set of factory tuned tx/rx cans for a 2m machine (they are new, and not cheap) the frequency that the duplexers are tuned to could not be coordinated successfully. the freq i could get is only 15khz LOWER than the pair that the duplexer is tuned to. duplexer tuned to: 147.210 / 147.810freq to be used 147.195 / 147.795 SO Question is.. RETUNE...or leave them alone... doug 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] Re: duplexer tuning question
Good Luck! Do you have any equipment to tune it with after you build it? Any how, Have you done a search for 2 meter duplexer construction from your favorite search engine? If not try it. You will find a few good write ups including one on repeater-builder dot com site there is even one out there on building a set of BpBr from I think 8 inch copper pipe with color photos that really works. 73 --- In Repeater-Builder@yahoogroups.com, DCFluX [EMAIL PROTECTED] wrote: Ok, I have some theroies, but I need confirmation from someone that is like good with math and formulas and stuff as you know I flunked my high school pre-algebra class. Anyway I want to make a 2 meter duplexer economy style as the person who is building the repeater cannot afford a trip to the Zoo let alone a set of big cans. So I wan't to build either a 6-pack or a 8 block of cavitiys, like the UHF mobile duplexers only longer. 2 - 3dB of insertion loss would be acceptable Doing some coaxial theory and using air as a di-elelctric. Will an inner conductor with a outter diameter of 3/8 and the outer conductor with an inner diameter 1 yield 70 ohms impedence? If not what would the impedence be? And what would the dimensions of the outter conductor need to be if the inner is 3/8? The present idea of mechanical construction is to use 3/8 copper solid ground rods cut to length for the inner conductor and encasing in either 1 or 1 1/4 pipe. Then there would have to be a bushing fabricated that has allen set screws to adjust the length of the center conductor. This design should be ideal for any frequency asuming the materials are big enough. I am planning for a Notch only style duplexer to keep costs down. Without design software I cannot acurately predict band pass or BpBr Q if the cavities have more than one connector. Also loop construction ideas are welcome as I currently am planning BNCs on the top with 12 ga straight down from the top and soldered to a hole in the side of the can. I am also considering a Teflon disc at the end of the tuning rod to act as a spacer for mechanical stability if the set is lied flat. On 4/22/05, Mathew Quaife [EMAIL PROTECTED] wrote: Yes I agree on that one, I locked them down and one of them moved on me, check each one indivually. Mathew Dave VanHorn [EMAIL PROTECTED] wrote: At 07:22 AM 4/22/2005, Mathew Quaife wrote: If these are like my TX/RX duplexers, the slighest movement of the tuning rods makes a huge difference, especially on the tx side. retune would be a good idea. Take them slow, they are fun to tune. Enjoy! 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] Re: duplexer tuning question
Yeah, I gots an old Motorola tube repeater with a Sensicon RX in it and a 50 watt light bulb. Just tune for maximum brightness, Right? On 4/22/05, Coy Hilton [EMAIL PROTECTED] wrote: Good Luck! Do you have any equipment to tune it with after you build it? Any how, Have you done a search for 2 meter duplexer construction from your favorite search engine? If not try it. You will find a few good write ups including one on repeater-builder dot com site there is even one out there on building a set of BpBr from I think 8 inch copper pipe with color photos that really works. 73 --- In Repeater-Builder@yahoogroups.com, DCFluX [EMAIL PROTECTED] wrote: Ok, I have some theroies, but I need confirmation from someone that is like good with math and formulas and stuff as you know I flunked my high school pre-algebra class. Anyway I want to make a 2 meter duplexer economy style as the person who is building the repeater cannot afford a trip to the Zoo let alone a set of big cans. So I wan't to build either a 6-pack or a 8 block of cavitiys, like the UHF mobile duplexers only longer. 2 - 3dB of insertion loss would be acceptable Doing some coaxial theory and using air as a di-elelctric. Will an inner conductor with a outter diameter of 3/8 and the outer conductor with an inner diameter 1 yield 70 ohms impedence? If not what would the impedence be? And what would the dimensions of the outter conductor need to be if the inner is 3/8? The present idea of mechanical construction is to use 3/8 copper solid ground rods cut to length for the inner conductor and encasing in either 1 or 1 1/4 pipe. Then there would have to be a bushing fabricated that has allen set screws to adjust the length of the center conductor. This design should be ideal for any frequency asuming the materials are big enough. I am planning for a Notch only style duplexer to keep costs down. Without design software I cannot acurately predict band pass or BpBr Q if the cavities have more than one connector. Also loop construction ideas are welcome as I currently am planning BNCs on the top with 12 ga straight down from the top and soldered to a hole in the side of the can. I am also considering a Teflon disc at the end of the tuning rod to act as a spacer for mechanical stability if the set is lied flat. On 4/22/05, Mathew Quaife [EMAIL PROTECTED] wrote: Yes I agree on that one, I locked them down and one of them moved on me, check each one indivually. Mathew Dave VanHorn [EMAIL PROTECTED] wrote: At 07:22 AM 4/22/2005, Mathew Quaife wrote: If these are like my TX/RX duplexers, the slighest movement of the tuning rods makes a huge difference, especially on the tx side. retune would be a good idea. Take them slow, they are fun to tune. Enjoy! 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/
