Duplexer Tuning
Moderator: Queue Moderator
Duplexer Tuning
I have a couple of Celwave duplexers that I have had for a year or more. I have never attempted to tune one of them, since I don't have the equipment. However, I would like to learn how to tune them in the UHF band, and learn how to use the equipment such as a signal generator or analyzer. Anyone have any suggestions or ideas on equipment that I would need to start out?
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Victor Xray
- Posts: 845
- Joined: Mon Dec 17, 2001 4:00 pm
This page on repeater-builder.com has a lot of good documents on duplexers.
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440roadrunner
- Posts: 236
- Joined: Mon Aug 16, 2004 3:47 pm
I sure wish to heck people would include more info. Saying that you have "a cellwave duplexer" is about as descriptive as saying "I have a Motorola radio" or that "I drive a Ford."
WHAT MODEL IS the duplexer?
Some types of duplexers are VERY easy to tune, such as the vast array of inexpensive compact "notch" duplexers. It actually is possible to tune some of those with nothing more than a radio, a wattmeter/dummy load, and maybe something for RF indication, like an RF voltmeter or a couple of other simple pieces of equipment. By using such homebrew devices as an "RF tap" you can even use a second receiver.
There are other duplexers that are an INCREDIBLY tough boat to row, and even having a tracking generator doesn't make some of them easy.
On top of that you have little glitches here and there. Are any of the internals damaged, like from a lightning flashover? Especially on some of the small compacts, has hi SWR and a little too much power damaged some of the tuning dielectics? Has someone had their fingers in there, and uh, "adjusted" some of the coupling loops. Are some of the tuning fingers rusted/corroded/etc?
If this is a larger duplexer, do we know that it REALLY IS a duplexer, and not a mismash of cans that some junk dealer has thrown together? Can you identify all the cans, and do they all belong to that duplexer? Does it ACTUALLY HAVE a model number? Are you positive that it can cover the tuning range you need?
These, and many more questions, will be answered..........
There are many variables, here.
WHAT MODEL IS the duplexer?
Some types of duplexers are VERY easy to tune, such as the vast array of inexpensive compact "notch" duplexers. It actually is possible to tune some of those with nothing more than a radio, a wattmeter/dummy load, and maybe something for RF indication, like an RF voltmeter or a couple of other simple pieces of equipment. By using such homebrew devices as an "RF tap" you can even use a second receiver.
There are other duplexers that are an INCREDIBLY tough boat to row, and even having a tracking generator doesn't make some of them easy.
On top of that you have little glitches here and there. Are any of the internals damaged, like from a lightning flashover? Especially on some of the small compacts, has hi SWR and a little too much power damaged some of the tuning dielectics? Has someone had their fingers in there, and uh, "adjusted" some of the coupling loops. Are some of the tuning fingers rusted/corroded/etc?
If this is a larger duplexer, do we know that it REALLY IS a duplexer, and not a mismash of cans that some junk dealer has thrown together? Can you identify all the cans, and do they all belong to that duplexer? Does it ACTUALLY HAVE a model number? Are you positive that it can cover the tuning range you need?
These, and many more questions, will be answered..........
There are many variables, here.
Duplexer tuning:
My two bits worth:
I have a tuning procedure that I originally made for a class.
I need your e mail address.
I have a tuning procedure that I originally made for a class.
I need your e mail address.
Aloha, Bernie