subject:"\[Repeater\-Builder\] Repeater heard on Aviation Channel\! HELP"







This reminds me of an incident many years ago when Industry Canada (then
called DOC) contacted us re a ham 2 meter mobile interfering with
aircraft communications. To make a long story short, the local ham
wanted more power out of his transmitter and had physically adjusted the
low pass filter (the push and squeeze method) for more output
power. He also defeated the purpose of the filter and all kinds of
crap was getting through as well. His Watt meter showed some more
power but since it is essentially a non frequency selective device, it
didnt care what was going through.
Sad.. Very sad. :)


Which brings up another story of a tech who could not match a ¼ wave
mobile antenna to a transmitter no matter how he cut the whip.
Again the Spec A showed that the TX was badly spurious and the antenna
was showing lots of reflected power because of it. Once the PA was
tuned properly so that the spurious signals disappeared, the antenna
matched just fine. Sometimes you have to use the proper test
equipment to see what is going on.
Very very true! I spend a lot of time and money picking up test
equipment for that reason. If I can't see, I can't work.


I have been reading
these post for a couple of days now and seen in the original post that
you are loosing 110 watts in the duplexer. Maybe Im the only one that
thanks this may have something to do with the problem.

Yikes, I didn't catch that in the original read either! That is
VERY significant! 1-1.5dB maybe, but not 3dB!









  
  





  
  
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RE: [Repeater-Builder] Repeater heard on Aviation Channel! HELP

Ok, this brought up a good point. Just for sakes I took the watt meter, from the amp into a 50 ohm load, I get 140 watts out, into the duplexer's I get 70 watts out, something there has changed. With a 2.2 dB insertion loss, I should be getting right about 90 watts out if I did the math right? Anyone get anything different, if so, give me the math figures so I can check it again.

Mathew
Dave VanHorn [EMAIL PROTECTED] wrote:

This reminds me of an incident many years ago when Industry Canada (then called DOC) contacted us re a ham 2 meter mobile interfering with aircraft communications. To make a long story short, the local ham wanted more power out of his transmitter and had physically adjusted the low pass filter (the push and squeeze method) for more output power. He also defeated the purpose of the filter and all kinds of crap was getting through as well. His Watt meter showed some more power but since it is essentially a non frequency selective device, it didnt care what was going through.Sad.. Very sad. :)
Which brings up another story of a tech who could not match a ¼ wave mobile antenna to a transmitter no matter how he cut the whip. Again the Spec A showed that the TX was badly spurious and the antenna was showing lots of reflected power because of it. Once the PA was tuned properly so that the spurious signals disappeared, the antenna matched just fine. Sometimes you have to use the proper test equipment to see what is going on.Very very true! I spend a lot of time and money picking up test equipment for that reason. If I can't see, I can't work.
I have been reading these post for a couple of days now and seen in the original post that you are loosing 110 watts in the duplexer. Maybe Im the only one that thanks this may have something to do with the problem. Yikes, I didn't catch that in the original read either! That is VERY significant! 1-1.5dB maybe, but not 3dB!
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RE: [Repeater-Builder] Repeater heard on Aviation Channel! HELP

At 09:42 AM 7/8/2005, Mathew Quaife wrote:
Ok, this brought up a good point.  Just for sakes I took the watt 
meter, from the amp into a 50 ohm load, I get 140 watts out, into 
the duplexer's I get 70 watts out, something there has 
changed.  With a 2.2 dB insertion loss, I should be getting right 
about 90 watts out if I did the math right?  Anyone get anything 
different, if so, give me the math figures so I can check it again.


Is the spec on those cans that high?  I would have thought closer to 
1dB.  Still, you're loosing 3dB.
Someone kicked the can lately??






 
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RE: [Repeater-Builder] Repeater heard on Aviation Channel! HELP

At 09:42 AM 7/8/2005, Mathew Quaife wrote:
Ok, this brought up a good point.  Just for sakes I took the watt 
meter, from the amp into a 50 ohm load, I get 140 watts out, into 
the duplexer's I get 70 watts out, something there has changed.

Wait a minute!  You're saying that the amp is only DELIVERING 70W 
into the cans, or you're getting 70W OUT of the cans?

Either way I smell a rat, but I'm not sure which kind.





 
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RE: [Repeater-Builder] Repeater heard on Aviation Channel! HELP




Oops on me, 140 into the duplexer with 70 watts out and a 2.2 dB insertion loss on the cans per TXRX. 3 Cans per side. I figured it up at 140 watts in which should give me about 88.6 watts back out of the duplexer.

Mathew
Dave VanHorn [EMAIL PROTECTED] wrote:
At 09:42 AM 7/8/2005, Mathew Quaife wrote:Ok, this brought up a good point. Just for sakes I took the watt meter, from the amp into a 50 ohm load, I get 140 watts out, into the duplexer's I get 70 watts out, something there has changed. With a 2.2 dB insertion loss, I should be getting right about 90 watts out if I did the math right? Anyone get anything different, if so, give me the math figures so I can check it again.Is the spec on those cans that high? I would have thought closer to 1dB. Still, you're loosing 3dB.Someone kicked the can lately??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
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RE: [Repeater-Builder] Repeater heard on Aviation Channel! HELP

At 09:59 AM 7/8/2005, Mathew Quaife wrote:
Oops on me, 140 into the duplexer with 70 watts out and a 2.2 dB 
insertion loss on the cans per TXRX.  3 Cans per side.  I figured it 
up at 140 watts in which should give me about 88.6 watts back out of 
the duplexer.

OK, that makes more sense, and you're well within tolerance from 90W to 88.6.
The three cans is costing you there.  Do you NEED three cans on the 
output side?

Now, back to finding the spur.

Can you put a 1DB or 3DB pad in place between the TX and the 
cans?  Might be hard to find one at that power level, other than a 
long hunk of coax.  With a 3dB pad in, I would expect any reactive 
impedances on the ends to be less interactive, and if this cleans it 
up, it would have us looking at the amp for problems.

Same between the amp and exciter, though I suspect a lot easier to implement.





 
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RE: [Repeater-Builder] Repeater heard on Aviation Channel! HELP

2005-07-08 Thread Ron Wright





Mathew,

couple of things come to mind here.

If you getting less power with duplexer it could be due to duplexer not 50 Ohms giving higher SWR and PA is probably folding back. Also what type of watt meter. Hope something like a Bird. Cheap meters can give bad reading depending on load. Also if the duplexer is not tuned properly or cable lengths could cause such a problem.

I always check the SWR between duplexer and tx, not just between antenna and duplexer. I also like checking SWR with a source on rx freq on duplexer input/output portand load on rx port. Loading on the bench can give different results than the actually installation.

When I tune duplexers I also put load on all open ports such as when tuning tx side put load on rx port (don't use a receiver, but dummy load).

73, ron, n9ee/r


73, ron, n9ee/r






Ron Wright
[EMAIL PROTECTED]

Ron is the owner of Micro Computer Concepts, a manufacture of repeaters and repeater controllers since 1988.
You may see our products at http://home.earthlink.net/~mccrpt or call at 727-376-6575.
Contact me at 8849 Gum Tree Ave, New Port Richey, FL 34653 USA

Owner of the 146.64 repeater, the highest repeater, 1175 ft HAAT,
in the Tampa Bay area, Florida. The repeater also has ECHOLINK, node 79540.


Pasco County Skywarn Coordinator
Skywarn meets on 146.64 each Wednesday at 8 PM.
Skywarn nets are activated on 146.64 when the 
National Weather Service broadcast a weather alert.

see our web page at http://groups.yahoo.com/group/pascoskywarn/

All are welcome.



- Original Message - 
From: Mathew Quaife 
To: Repeater-Builder@yahoogroups.com
Sent: 7/8/2005 10:42:19 AM 
Subject: RE: [Repeater-Builder] Repeater heard on Aviation Channel! HELP

Ok, this brought up a good point. Just for sakes I took the watt meter, from the amp into a 50 ohm load, I get 140 watts out, into the duplexer's I get 70 watts out, something there has changed. With a 2.2 dB insertion loss, I should be getting right about 90 watts out if I did the math right? Anyone get anything different, if so, give me the math figures so I can check it again.

Mathew
Dave VanHorn [EMAIL PROTECTED] wrote:

This reminds me of an incident many years ago when Industry Canada (then called DOC) contacted us re a ham 2 meter mobile interfering with aircraft communications. To make a long story short, the local ham wanted more power out of his transmitter and had physically adjusted the low pass filter (the push and squeeze method) for more output power. He also defeated the purpose of the filter and all kinds of crap was getting through as well. His Watt meter showed some more power but since it is essentially a non frequency selective device, it didnt care what was going through.Sad.. Very sad. :)
Which brings up another story of a tech who could not match a ¼ wave mobile antenna to a transmitter no matter how he cut the whip. Again the Spec A showed that the TX was badly spurious and the antenna was showing lots of reflected power because of it. Once the PA was tuned properly so that the spurious signals disappeared, the antenna matched just fine. Sometimes you have to use the proper test equipment to see what is going on.Very very true! I spend a lot of time and money picking up test equipment for that reason. If I can't see, I can't work.
I have been reading these post for a couple of days now and seen in the original post that you are loosing 110 watts in the duplexer. Maybe Im the only one that thanks this may have something to do with the problem. Yikes, I didn't catch that in the original read either! That is VERY significant! 1-1.5dB maybe, but not 3dB!


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RE: [Repeater-Builder] Repeater heard on Aviation Channel! HELP

Well I just did a quick tweak on the tx duplexer, with 5 watts in I get three watts out, but then put the 140 watts in and still only get 75 watts out of the duplexer. Why would it change with higher power levels? I had asked that question once before about the 3 cans in the tx side and was told to leave it alone. Can a system be ran with 3 cans in the RX and only 2 in the TX side, or would this throw things off.

Mathew
Dave VanHorn [EMAIL PROTECTED] wrote:
At 09:59 AM 7/8/2005, Mathew Quaife wrote:Oops on me, 140 into the duplexer with 70 watts out and a 2.2 dB insertion loss on the cans per TXRX. 3 Cans per side. I figured it up at 140 watts in which should give me about 88.6 watts back out of the duplexer.OK, that makes more sense, and you're well within tolerance from 90W to 88.6.The three cans is costing you there. Do you NEED three cans on the output side?Now, back to finding the spur.Can you put a 1DB or 3DB pad in place between the TX and the cans? Might be hard to find one at that power level, other than a long hunk of coax. With a 3dB pad in, I would expect any reactive impedances on the ends to be less interactive, and if this cleans it up, it would have us looking at the amp for problems.Same between the amp and exciter, though I suspect a
lot easier to implement.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/__Do You Yahoo!?Tired of spam? Yahoo! Mail has the best spam protection around http://mail.yahoo.com

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RE: [Repeater-Builder] Repeater heard on Aviation Channel! HELP




If the duplexer is tuned at maximum power output, could the swr be out of whack still. As for the watt meter it is a Yaesu YS-500, checked against a bird watt meter just a month ago, and measures up fine with it. 

Mathew
Ron Wright [EMAIL PROTECTED] wrote:


Mathew,

couple of things come to mind here.

If you getting less power with duplexer it could be due to duplexer not 50 Ohms giving higher SWR and PA is probably folding back. Also what type of watt meter. Hope something like a Bird. Cheap meters can give bad reading depending on load. Also if the duplexer is not tuned properly or cable lengths could cause such a problem.

I always check the SWR between duplexer and tx, not just between antenna and duplexer. I also like checking SWR with a source on rx freq on duplexer input/output portand load on rx port. Loading on the bench can give different results than the actually installation.

When I tune duplexers I also put load on all open ports such as when tuning tx side put load on rx port (don't use a receiver, but dummy load).

73, ron, n9ee/r


73, ron, n9ee/r






Ron Wright
[EMAIL PROTECTED]

Ron is the owner of Micro Computer Concepts, a manufacture of repeaters and repeater controllers since 1988.
You may see our products at http://home.earthlink.net/~mccrpt or call at 727-376-6575.
Contact me at 8849 Gum Tree Ave, New Port Richey, FL 34653 USA

Owner of the 146.64 repeater, the highest repeater, 1175 ft HAAT,
in the Tampa Bay area, Florida. The repeater also has ECHOLINK, node 79540.


Pasco County Skywarn Coordinator
Skywarn meets on 146.64 each Wednesday at 8 PM.
Skywarn nets are activated on 146.64 when the 
National Weather Service broadcast a weather alert.

see our web page at http://groups.yahoo.com/group/pascoskywarn/

All are welcome.



- Original Message - 
From: Mathew Quaife 
To: Repeater-Builder@yahoogroups.com
Sent: 7/8/2005 10:42:19 AM 
Subject: RE: [Repeater-Builder] Repeater heard on Aviation Channel! HELP

Ok, this brought up a good point. Just for sakes I took the watt meter, from the amp into a 50 ohm load, I get 140 watts out, into the duplexer's I get 70 watts out, something there has changed. With a 2.2 dB insertion loss, I should be getting right about 90 watts out if I did the math right? Anyone get anything different, if so, give me the math figures so I can check it again.

Mathew
Dave VanHorn [EMAIL PROTECTED] wrote:

This reminds me of an incident many years ago when Industry Canada (then called DOC) contacted us re a ham 2 meter mobile interfering with aircraft communications. To make a long story short, the local ham wanted more power out of his transmitter and had physically adjusted the low pass filter (the push and squeeze method) for more output power. He also defeated the purpose of the filter and all kinds of crap was getting through as well. His Watt meter showed some more power but since it is essentially a non frequency selective device, it didnt care what was going through.Sad.. Very sad. :)
Which brings up another story of a tech who could not match a ¼ wave mobile antenna to a transmitter no matter how he cut the whip. Again the Spec A showed that the TX was badly spurious and the antenna was showing lots of reflected power because of it. Once the PA was tuned properly so that the spurious signals disappeared, the antenna matched just fine. Sometimes you have to use the proper test equipment to see what is going on.Very very true! I spend a lot of time and money picking up test equipment for that reason. If I can't see, I can't work.
I have been reading these post for a couple of days now and seen in the original post that you are loosing 110 watts in the duplexer. Maybe Im the only one that thanks this may have something to do with the problem. Yikes, I didn't catch that in the original read either! That is VERY significant! 1-1.5dB maybe, but not 3dB!


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RE: [Repeater-Builder] Repeater heard on Aviation Channel! HELP

At 10:16 AM 7/8/2005, Mathew Quaife wrote:
Well I just did a quick tweak on the tx duplexer, with 5 watts in I 
get three watts out, but then put the 140 watts in and still only 
get 75 watts out of the duplexer.  Why would it change with higher 
power levels?  I had asked that question once before about the 3 
cans in the tx side and was told to leave it alone.  Can a system be 
ran with 3 cans in the RX and only 2 in the TX side, or would this 
throw things off.


This tells me that a few watts coming out of the amp are not within 
the passband of the cans.

The systems I work with around here are 2 and 2, but this all depends 
on your area, and your gear.





 
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RE: [Repeater-Builder] Repeater heard on Aviation Channel! HELP




Typically to say, there is nothing in this area as far as repeaters, a few on 460 Mhz and one on VHF at 158 Mhz, other than the two cell towers more than 5 miles away, that is about it.

Mathew
Dave VanHorn [EMAIL PROTECTED] wrote:
At 10:16 AM 7/8/2005, Mathew Quaife wrote:Well I just did a quick tweak on the tx duplexer, with 5 watts in I get three watts out, but then put the 140 watts in and still only get 75 watts out of the duplexer. Why would it change with higher power levels? I had asked that question once before about the 3 cans in the tx side and was told to leave it alone. Can a system be ran with 3 cans in the RX and only 2 in the TX side, or would this throw things off.This tells me that a few watts coming out of the amp are not within the passband of the cans.The systems I work with around here are 2 and 2, but this all depends on your area, and your gear.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/
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RE: [Repeater-Builder] Repeater heard on Aviation Channel! HELP

At 10:45 AM 7/8/2005, Mathew Quaife wrote:
Typically to say, there is nothing in this area as far as repeaters, 
a few on 460 Mhz and one on VHF at 158 Mhz, other than the two cell 
towers more than 5 miles away, that is about it.

This gets into an area that I need to understand better, how do you 
know when it's good enough?

How sensitive does a repeater receiver need to be?
How much isolation do I really need?
How much power should I be running?

All of the above, relative to an antenna, feedline length, mounting 
height, and terrain..
Around here, terrain means basically flat, and sites at 100-200' typically.

Radio mobile is good at plotting coverage maps, but then you get into 
what's the actual receiver like?
An HT has a pretty lame receiver, lame antenna, and puny transmitter, 
but I haven't really looked at those numbers to see if they are all 
proportional.
IOW, is the typical HT equally sad on receive, as transmit?
What about a mobile rig?

There's no sense in being an alligator, or a fruit bat, or spending 
power and money in cans you don't actually need.

In the can side, I think the answer is, as long as you aren't getting 
desense, you've got enough isolation.
You might add cans to get around a particular interference problem, 
like a nearby transmitter or receiver that is out of band, but still 
causing problems.

At one site, we used to have a 1kW VHF paging transmitter about a 
mile away, that put a very nice signal into the receiver, right 
through the cans.
But a stub filter took him out easily, since he was pretty far away (152-ish)

   





 
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RE: [Repeater-Builder] Repeater heard on Aviation Channel! HELP

Well here is the final results of what I have done this morning, and listening to the aircraft band, I have not heard anything come back as of yet. I reduced the duplexers to 4 cans rather than 6, with 140 watts into the duplexer, I am getting 105 watts back out the antenna port. No decense that I can detect. Receiver sensitivity is right on track at .15uv @ 12dB sinad with the preamp installed. The audio out of the repeater is clean at this point. I spent almost 20 minutes on the repeater and nothing has gone wrong with it yet. I did find a few loose connections between the duplexers and the receiver, nothing in the transmit side, and not so loose they were ready to fall off, but not as tight as they should have been. I'm going to have some users work the system here this afternoon and travel about and see if I can hear it anywhere away from the repeater site.

It very well could have been a bad connection all along. I'm hoping this is the case and it won't creap back up on me.

Mathew
Dave VanHorn [EMAIL PROTECTED] wrote:
At 10:45 AM 7/8/2005, Mathew Quaife wrote:Typically to say, there is nothing in this area as far as repeaters, a few on 460 Mhz and one on VHF at 158 Mhz, other than the two cell towers more than 5 miles away, that is about it.This gets into an area that I need to understand better, "how do you know when it's "good enough"?"How sensitive does a repeater receiver need to be?How much isolation do I really need?How much power should I be running?All of the above, relative to an antenna, feedline length, mounting height, and terrain..Around here, terrain means basically flat, and sites at 100-200' typically.Radio mobile is good at plotting coverage maps, but then you get into what's the actual receiver like?An HT has a pretty lame receiver, lame antenna, and puny transmitter, but I haven't really
looked at those numbers to see if they are all proportional.IOW, is the typical HT equally sad on receive, as transmit?What about a mobile rig?There's no sense in being an alligator, or a fruit bat, or spending power and money in cans you don't actually need.In the can side, I think the answer is, as long as you aren't getting desense, you've got enough isolation.You might add cans to get around a particular interference problem, like a nearby transmitter or receiver that is out of band, but still causing problems.At one site, we used to have a 1kW VHF paging transmitter about a mile away, that put a very nice signal into the receiver, right through the cans.But a stub filter took him out easily, since he was pretty far away (152-ish)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/__Do You Yahoo!?Tired of spam? Yahoo! Mail has the best spam protection around http://mail.yahoo.com

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RE: [Repeater-Builder] Repeater heard on Aviation Channel! HELP

At 12:12 PM 7/8/2005, Mathew Quaife wrote:
Well here is the final results of what I have done this morning, and 
listening to the aircraft band, I have not heard anything come back 
as of yet.  I reduced the duplexers to 4 cans rather than 6, with 
140 watts into the duplexer, I am getting 105 watts back out the 
antenna port.  No decense that I can detect.  Receiver sensitivity 
is right on track at .15uv @ 12dB sinad with the preamp 
installed.  The audio out of the repeater is clean at this point.  I 
spent almost 20 minutes on the repeater and nothing has gone wrong 
with it yet.  I did find a few loose connections between the 
duplexers and the receiver, nothing in the transmit side, and not so 
loose they were ready to fall off, but not as tight as they should 
have been.  I'm going to have some users work the system here this 
afternoon and travel about and see if I can hear it anywhere away 
from the repeater site.

It very well could have been a bad connection all along.  I'm hoping 
this is the case and it won't creap back up on me.


Let's hope!

The output sounds a lot healthier now, and if you aren't having any 
interference or desense issues, then the extra can on the RX probably 
was hurting more than it was helping.
I'd still want to see what an SA says about the RF from each point in 
the chain, and especially the output.






 
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RE: [Repeater-Builder] Repeater heard on Aviation Channel! HELP

2005-07-08 Thread Bob Dengler

At 7/8/2005 08:08 AM, you wrote:

Can you put a 1DB or 3DB pad in place between the TX and the
cans?  Might be hard to find one at that power level, other than a
long hunk of coax.  With a 3dB pad in, I would expect any reactive
impedances on the ends to be less interactive, and if this cleans it
up, it would have us looking at the amp for problems.

...better yet, how about just an isolator on the amp output?

Bob NO6B






 
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Re: [Repeater-Builder] Repeater heard on Aviation Channel! HELP

2005-07-08 Thread Mike/k1eg






Mathew you clearly have an interesting problem and 
I believe we are all waiting to see what is causing your problem. I'm sure 
that Dave will be able to help you solve this.

Mike/K1EG


  - Original Message - 
  From: 
  Mathew Quaife 

  To: Repeater-Builder@yahoogroups.com 
  
  Sent: Friday, July 08, 2005 10:45 
AM
  Subject: RE: [Repeater-Builder] Repeater 
  heard on Aviation Channel! HELP
  
  Typically to say, there is nothing in this area as far as repeaters, a 
  few on 460 Mhz and one on VHF at 158 Mhz, other than the two cell towers more 
  than 5 miles away, that is about it.
  
  Mathew
  Dave VanHorn [EMAIL PROTECTED] 
  wrote:
  At 
10:16 AM 7/8/2005, Mathew Quaife wrote:Well I just did a quick tweak 
on the tx duplexer, with 5 watts in I get three watts out, but then 
put the 140 watts in and still only get 75 watts out of the 
duplexer. Why would it change with higher power levels? I had asked 
that question once before about the 3 cans in the tx side and was 
told to leave it alone. Can a system be ran with 3 cans in the RX 
and only 2 in the TX side, or would this throw things 
off.This tells me that a few watts coming out of the amp are 
not within the passband of the cans.The systems I work with 
around here are 2 and 2, but this all depends on your area, and your 
gear.Yahoo! Groups Links* To 
visit your group on the web, go 
to:http://groups.yahoo.com/group/Repeater-Builder/* To 
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RE: [Repeater-Builder] Repeater heard on Aviation Channel! HELP

2005-07-08 Thread Bob Dengler

At 7/8/2005 08:45 AM, you wrote:
Typically to say, there is nothing in this area as far as repeaters, a few 
on 460 Mhz and one on VHF at 158 Mhz, other than the two cell towers more 
than 5 miles away, that is about it.

The 2 vs. 3 cans on the TX side of a 2 meter duplexer has been extensively 
discussed here before.  The consensus was that you want to stick with 3 
cans because 2 will barely yield enough isolation.

Bob NO6B






 
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RE: [Repeater-Builder] Repeater heard on Aviation Channel! HELP

At 02:01 PM 7/8/2005, Bob Dengler wrote:
At 7/8/2005 08:45 AM, you wrote:
 Typically to say, there is nothing in this area as far as repeaters, a few
 on 460 Mhz and one on VHF at 158 Mhz, other than the two cell towers more
 than 5 miles away, that is about it.

The 2 vs. 3 cans on the TX side of a 2 meter duplexer has been extensively
discussed here before.  The consensus was that you want to stick with 3
cans because 2 will barely yield enough isolation.

Interesting, none of the local machines is more than four AFAIK.
But, footprints of 40 miles radius, or less are typical too, mostly 
limited by relatively low sites.






 
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Re: [Repeater-Builder] Repeater heard on Aviation Channel! HELP




Best bring the biggest hammer that you have. It's back at it. There has got to be something near here that is mixing. All morning it has been clean and now it's back to it's old tricks. 

Mathew
Dave VanHorn [EMAIL PROTECTED] wrote:
At 01:38 PM 7/8/2005, Mike/k1eg wrote:
Mathew you clearly have an interesting problem and I believe we are all waiting to see what is causing your problem. I'm sure that Dave will be able to help you solve this.I hope so! I'll try to bring a big enough hammer anyway :)
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Re: [Repeater-Builder] Repeater heard on Aviation Channel! HELP




Me Too! I think this one has gone well beyond my head. I thought I had it, but it went way out to left field again.

Mathew
Mike/k1eg [EMAIL PROTECTED] wrote:




Mathew you clearly have an interesting problem and I believe we are all waiting to see what is causing your problem. I'm sure that Dave will be able to help you solve this.

Mike/K1EG


- Original Message - 
From: Mathew Quaife 
To: Repeater-Builder@yahoogroups.com 
Sent: Friday, July 08, 2005 10:45 AM
Subject: RE: [Repeater-Builder] Repeater heard on Aviation Channel! HELP

Typically to say, there is nothing in this area as far as repeaters, a few on 460 Mhz and one on VHF at 158 Mhz, other than the two cell towers more than 5 miles away, that is about it.

Mathew
Dave VanHorn [EMAIL PROTECTED] wrote:
At 10:16 AM 7/8/2005, Mathew Quaife wrote:Well I just did a quick tweak on the tx duplexer, with 5 watts in I get three watts out, but then put the 140 watts in and still only get 75 watts out of the duplexer. Why would it change with higher power levels? I had asked that question once before about the 3 cans in the tx side and was told to leave it alone. Can a system be ran with 3 cans in the RX and only 2 in the TX side, or would this throw things off.This tells me that a few watts coming out of the amp are not within the passband of the cans.The systems I work with around here are 2 and 2, but this all depends on your area, and your gear.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/


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Re: [Repeater-Builder] Repeater heard on Aviation Channel! HELP

2005-07-08 Thread Marvin K. Hoffman







Is heat an issue? 

I recall once when I lived in the Piedmont of NC that a large
university hospital's paging transmitter would go wild with spurs in
the summer but only when someone closed the equipment room door and
upset the ventilation. 

When overheated, it would throw out spurs heard fifteen miles away on
about 20 different repeater systems. When cooled off, it was clean on
the Spectrum Analyzer.

Marv Hoffman, WA4NC
Boone, NC

Mathew Quaife wrote:

  Best bring the biggest hammer that you have. It's back at it.
There has got to be something near here that is mixing. All morning it
has been clean and now it's back to it's old tricks. 
  
  Mathew
  
  
  Dave VanHorn [EMAIL PROTECTED] wrote:
  At
01:38 PM 7/8/2005, Mike/k1eg wrote:
Mathew you clearly have an interesting problem and I believe
we are all waiting to see what is causing your problem. I'm sure that
Dave will be able to help you solve this.
  

I hope so! I'll try to bring a big enough hammer anyway :)






  
   
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Re: [Repeater-Builder] Repeater heard on Aviation Channel! HELP

2005-07-08 Thread Nate Duehr

Bob Dengler wrote:
 At 7/8/2005 08:08 AM, you wrote:
 
 
Can you put a 1DB or 3DB pad in place between the TX and the
cans?  Might be hard to find one at that power level, other than a
long hunk of coax.  With a 3dB pad in, I would expect any reactive
impedances on the ends to be less interactive, and if this cleans it
up, it would have us looking at the amp for problems.
 
 
 ...better yet, how about just an isolator on the amp output?
 
 Bob NO6B

Correct me if I'm wrong, but looking back over the thread, with all the 
speculation that the Amp is not seeing the load it wants, wouldn't Bob's 
recommendation of an isolator have fixed (well, covered up) the problem?

The Amp would have then been driving into a nice boring 50 ohm load even 
if the antenna and duplexers are somehow out of whack if the repeater 
was built properly with an isolator, wouldn't it?  Or something closer 
to 50 ohms that would have probably made it happier, anyway.

I've always thought from everything I've learned from smarter people 
than myself (definitely!) that having an isolator on things is the best 
insurance for this type of weirdness, as well as the usual reasons to 
keep RF coming down towards the PA from the outside world out of it.

Someone can unplug your antenna and your PA will sit there dumping power 
into the load on the isolator, fat dumb and happy...

It just doesn't seem wise to build repeaters without isolators on them 
at all.  Why do people do it, other than cost?  Surely the gee-whiz 
whiz-bang repeater controllers people put on such repeaters to make them 
sound like an 80's video arcade are more expensive than buying an 
isolator for the repeater??

Nate WY0X




 
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Re: [Repeater-Builder] Repeater heard on Aviation Channel! HELP

2005-07-08 Thread Bob Dengler

At 7/8/2005 12:21 PM, you wrote:
Best bring the biggest hammer that you have.  It's back at it.  There has 
got to be something near here that is mixing.  All morning it has been 
clean and now it's back to it's old tricks.

Mathew

I say throw an isolator on the amp output.  This is standard procedure for 
me anytime an intermittent spurious/noise problem shows up.  It's also 
standard procedure for all my comm site installations.

Bob NO6B






 
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Re: [Repeater-Builder] Repeater heard on Aviation Channel! HELP




Well I think with Dave's knowledge and equipment, he might be able to see what is going on. I'm certain he will find a number of my mistakes as I call them. I'm a tinker with a dangerous plan. I've talked with the EE Spectrum engineer at the aviation department, he seems to think I am riding along something as well, another frequency or something nearby. Hopefully there is an easy answer for it.

Mathew
Bob Dengler [EMAIL PROTECTED] wrote:
At 7/8/2005 12:21 PM, you wrote:Best bring the biggest hammer that you have. It's back at it. There has got to be something near here that is mixing. All morning it has been clean and now it's back to it's old tricks.MathewI say throw an isolator on the amp output. This is standard procedure for me anytime an intermittent spurious/noise problem shows up. It's also standard procedure for all my comm site installations.Bob NO6BYahoo! 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/
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Re: [Repeater-Builder] Repeater heard on Aviation Channel! HELP

2005-07-08 Thread Mike/k1eg






Hey Mathew I know it must be frustrating for you 
but you know there is something you could be doing to help Dave 
out.

1) Track the times it does this. Look for a 
pattern.

2) Record the temperature at the site, especially 
when it acts up. Both inside and outside temp and is the sun shinning on the 
antenna when it acts up.

3) Make a list of all Xmitters in a 15 mile range 
with frequency.

4) Note if this problem only shows up with one user 
or all users. Or do they have to be in a certain location for it to 
happen.

5) Make note what your old antenna was when you 
didn't have the problem vs. the new one and did you use a new connector for 
it? This checks to see if the antenna pattern has changed.

6) This maybe out in left field but is anybody 
playing with BPL in the area?

7) Nominal voltages on you supply when it doesn't 
act up and what they are when it does act up.

I can't think of anything else but I'm sure other 
people on the list will have some ideas to add also. Intermitant problems 
like this can be the hardest thing to track down so all info you can gather will 
help Dave.

73,
Mike, K1EG


  - Original Message - 
  From: 
  Mathew Quaife 

  To: Repeater-Builder@yahoogroups.com 
  
  Sent: Friday, July 08, 2005 6:19 PM
  Subject: Re: [Repeater-Builder] Repeater 
  heard on Aviation Channel! HELP
  
  Well I think with Dave's knowledge and equipment, he might be able to see 
  what is going on. I'm certain he will find a number of my mistakes as I 
  call them. I'm a tinker with a dangerous plan. I've talked with 
  the EE Spectrum engineer at the aviation department, he seems to think I am 
  riding along something as well, another frequency or something nearby. 
  Hopefully there is an easy answer for it.
  
  Mathew
  Bob Dengler [EMAIL PROTECTED] 
  wrote:
  At 
7/8/2005 12:21 PM, you wrote:Best bring the biggest hammer that you 
have. It's back at it. There has got to be something near here that 
is mixing. All morning it has been clean and now it's back to it's 
old tricks.MathewI say throw an isolator on the amp 
output. This is standard procedure for me anytime an intermittent 
spurious/noise problem shows up. It's also standard procedure for all my 
comm site installations.Bob 
NO6BYahoo! 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/
  
  
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Re: [Repeater-Builder] Repeater heard on Aviation Channel! HELP




Hi Mike, thanks for the tips, I will gather this up. I have found that if I turn the power way down, it is not as bad. Someone had mentioned to me that my power supply could be acting up, although it is only drawing 22 amps on a 70 amp power supply, I suppose there could be an issue there. As for a pattern, I have not been able to follow one as of yet, it is very sporadic at this time. I will compile as much as I can before he gets to the site. Thanks.

Mathew
Mike/k1eg [EMAIL PROTECTED] wrote:




Hey Mathew I know it must be frustrating for you but you know there is something you could be doing to help Dave out.

1) Track the times it does this. Look for a pattern.

2) Record the temperature at the site, especially when it acts up. Both inside and outside temp and is the sun shinning on the antenna when it acts up.

3) Make a list of all Xmitters in a 15 mile range with frequency.

4) Note if this problem only shows up with one user or all users. Or do they have to be in a certain location for it to happen.

5) Make note what your old antenna was when you didn't have the problem vs. the new one and did you use a new connector for it? This checks to see if the antenna pattern has changed.

6) This maybe out in left field but is anybody playing with BPL in the area?

7) Nominal voltages on you supply when it doesn't act up and what they are when it does act up.

I can't think of anything else but I'm sure other people on the list will have some ideas to add also. Intermitant problems like this can be the hardest thing to track down so all info you can gather will help Dave.

73,
Mike, K1EG


- Original Message - 
From: Mathew Quaife 
To: Repeater-Builder@yahoogroups.com 
Sent: Friday, July 08, 2005 6:19 PM
Subject: Re: [Repeater-Builder] Repeater heard on Aviation Channel! HELP

Well I think with Dave's knowledge and equipment, he might be able to see what is going on. I'm certain he will find a number of my mistakes as I call them. I'm a tinker with a dangerous plan. I've talked with the EE Spectrum engineer at the aviation department, he seems to think I am riding along something as well, another frequency or something nearby. Hopefully there is an easy answer for it.

Mathew
Bob Dengler [EMAIL PROTECTED] wrote:
At 7/8/2005 12:21 PM, you wrote:Best bring the biggest hammer that you have. It's back at it. There has got to be something near here that is mixing. All morning it has been clean and now it's back to it's old tricks.MathewI say throw an isolator on the amp output. This is standard procedure for me anytime an intermittent spurious/noise problem shows up. It's also standard procedure for all my comm site installations.Bob NO6BYahoo! 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/


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Re: [Repeater-Builder] Repeater heard on Aviation Channel! HELP

2005-07-07 Thread Mathew Quaife




HI Mike, the connectors were actually new, only been up about 6 months when we changed the antenna, but we did check the hardline before connecting the antenna and nothing showed up. I even added a short length of coax onto the end just to make sure it was not a length issue and no changes.

Mathew
Mike/k1eg [EMAIL PROTECTED] wrote:




Mathew you said this problem started when you changed the antenna. Did you cut back on the feedline and use a new connector? Awhile back there was discussion on here about problems if you don't use a new connector. Just a thought hope it helps.

73
Mike/K1EG


- Original Message - 
From: Mathew Quaife 
To: Repeater-Builder@yahoogroups.com 
Sent: Thursday, July 07, 2005 12:14 AM
Subject: Re: [Repeater-Builder] Repeater heard on Aviation Channel! HELP

It is very weird, all evening I have been working with the repeater, and what ever it is, it is very inttermittant, because it will come and go, and there is no pattern for it. I just learned of that pair, but it is the only pair that is close to me that I know of. 

Mathew
Bob Dengler [EMAIL PROTECTED] wrote:
At 7/6/2005 01:31 PM, you wrote:The repeater pair that is about 3 miles from here is, and I have not checked to see which way the offset is, but 153.920 and 158.820 is the pair given.MathewDoesn't sound like that has anything to do with the problem. If you can see the spur coming out of your exciter on the S.A., the problem lies somewhere in your system.Bob NO6BYahoo! 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/
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RE: [Repeater-Builder] Repeater heard on Aviation Channel! HELP

2005-07-07 Thread Gary Laforce











I have been reading these post for a
couple of days now and seen in the original post that you are loosing 110 watts
in the duplexer. Maybe Im the only one that thanks this may have
something to do with the problem. 




 What is the SWR between the tx
 side of the duplexer and the PA? 
 What is the SWR between the
 antenna port and the feed line to the antenna?
 When was the last time the
 duplexer tuned and how was it tuned (i.e. by the watt meter method or by a
 tracking generator and a spectrum analyzer?) 
 What is the rx signal sen thru
 the duplexer and also what is the rx sen on the antenna port of the rxer?
 




You should not be loosing 60% of your
power into the duplexer something is wrong there. On a 110 watt repeater you
should see around 70-80 watts out of the duplexer at least I have seen a little
more. 





Just my two cents 



Gary LaForce



N0PBM















  
  





  
  
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RE: [Repeater-Builder] Repeater heard on Aviation Channel! HELP

2005-07-07 Thread Tony lelieveld












Gary may
very well be on the right track. We have a repeater on 146.640 which was
being heard by, and keying up, a repeater on 146.680 (input 146.080). Someone
un-authorised had fooled around with the duplexer tuning which resulted in the
TX putting 45 Watt into the duplexer but only 3 Watt came out of it. Checking
the output on a Spectrum Analyzer revealed a Christmas tree look-a-like display
as the TX had gone spurious due to the weird impedance mismatch. After
retuning the duplexer with a Vector Network Analyzer (I am fortunate enough to
have the use of one at work) the problem disappeared and all was well again.



This reminds me of an incident many years
ago when Industry Canada
(then called DOC) contacted us re a ham 2 meter mobile interfering with
aircraft communications. To make a long story short, the local ham wanted
more power out of his transmitter and had physically adjusted the low pass
filter (the push and squeeze method) for more output power. He also defeated
the purpose of the filter and all kinds of crap was getting through as well. His
Watt meter showed some more power but since it is essentially a non frequency selective
device, it didnt care what was going through.



Which brings up another story of a tech
who could not match a  wave mobile antenna to a transmitter no matter
how he cut the whip. Again the Spec A showed that the TX was badly spurious
and the antenna was showing lots of reflected power because of it. Once
the PA was tuned properly so that the spurious signals disappeared, the antenna
matched just fine. Sometimes you have to use the proper test equipment to
see what is going on.



73,

Tony VE3DWI











From:
Repeater-Builder@yahoogroups.com
[mailto:Repeater-Builder@yahoogroups.com]
On Behalf Of Gary Laforce
Sent: July 7, 2005 12:23
To: Repeater-Builder@yahoogroups.com
Subject: RE: [Repeater-Builder]
Repeater heard on Aviation Channel! HELP





I have been reading these
post for a couple of days now and seen in the original post that you are
loosing 110 watts in the duplexer. Maybe Im the only one that thanks
this may have something to do with the problem. 




 What is the SWR between the tx side of the duplexer and the PA? 
 What is the SWR between the antenna port and the feed line to the
 antenna?
 When was the last time the duplexer tuned and how was it tuned
 (i.e. by the watt meter method or by a tracking generator and a spectrum
 analyzer?) 
 What is the rx signal sen thru the duplexer and also what is the rx
 sen on the antenna port of the rxer? 




You should not be loosing
60% of your power into the duplexer something is wrong there. On a 110 watt
repeater you should see around 70-80 watts out of the duplexer at least I have
seen a little more. 





Just my two cents 



Gary LaForce



N0PBM





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Re: [Repeater-Builder] Repeater heard on Aviation Channel! HELP

2005-07-06 Thread Mike Morris WA6ILQ

Comments mixed into the text below...

Mike WA6ILQ

At 07:58 PM 7/5/05, you wrote:

Mathew,

The Maggiore EV-1 is a very basic, crystal-controlled exciter that has none
of the filters, power control, or SWR protection features of commercial
units.  I have one that I took off the air because of its tendency to
produce spurs.  It is perhaps not a good idea to use a relatively unstable
exciter to feed a 200 watt (!) power amplifier, which itself may not have
all of the controls and protections of a commercial amplifier.  I've never
heard of Vocom, so I don't know where it falls in the quality lineup.

I find it interesting that the fundamental frequency of your exciter,
12.1175 MHz, when mixed with your output frequency of 145.410 MHz, produces
a product at 133.2925 MHz.  This product is in the aviation band and could
be slope-detected with ease by an AM aircraft radio on a nearby frequency.
I'm not suggesting that this is the cause, but it's a coincidence.

Having a look at 157.5275, which is 12.1175 above his output would be
interesting.
If there is a spur there, it would be indicative of the 133mhz spur being
produced by the same mechanism.

Matt, I'd grab a scanner that had a AM aircraft mode and program up
the 133mhz channel and then rock each exciter adjustment and see if
anything affects it.  I've seen spurs come and go with a 1/32 turn tweak
of a slug that was a 1/4 turn wide peak on a meter-type test set.

A bit of FM history (and yes, bear with me, it is relevant)

The local 146.22 / 82 repeater here in Los Angeles is W6FNO, and
is a very wide area system... it started out about 40 years ago as a single
system at a 3,800' northeast of downtown LA and later added an 8,000'
site with the original site used as a fill-in on the simulcast TX and voting
RX system.

Over 30 years ago, when Standard introduced the first japanese mobile
radios to the USA, the model 806 and 826, some of the users of the
146.82 system were being heard by the Torrance (one of the 86
communities that make up Los Angeles county) police department
dispatcher.
Fortunately, the Torrance radio tech was a user of the 82 system... it
seemed that almost every 82 user that were being heard by the Torrance
dispatcher had a brand-new Standard...

A bit of math showed where the problem was...  the Standard
design used an 8mhz crystal times 18, and the first stage was
an oscillator-tripler (base circuit at 8mhz, collector at 24mhz)

146.220 / 18 = 8.12 crystal fundamental

8.12 times 19 = 154.34, and guess where Torrance PD was...

The simple cure was to take the 8mhz rocks and trash them
and insert a 12mhz rocks.  The oscillator-tripler automagically
became an oscillator-doubler when a 12mhz rock was
selected.
The deviation in the Standard was created by a phase modulator
and while the dev was slightly reduced when running 12mhz
vs 8mhz it was not noticeable.

An agreement was worked out between Torrance and Standard,
and Standard provided the Torrance dispatcher with a Callbook
and a stack of prepaid postcards.
When the dispatcher heard a ham, they'd look up the call,
and send a postcard, which read (something like)
Your radio was heard on Torrance PD dispatch frequencies.
Standard is aware of the problem and has arranged for a free fix.
Please contact (name of local popular 2-way shop #1) at (phone
number) or (name of local 2-way shop #2) at (phone number).
Present this card to either shop and they will fix the problem
at no charge to you, and tune your radio as well.

The shop basically swapped the 146.22 rock and one other
local channel that was a potential problem, adjusted TX  and
RX frequency, and set deviation.  Standard provided the crystals
and paid for an hour of bench time per radio the shop
stapled the postcards to an invoice to Standard and they paid
the bill, no questions asked.

Now Matts radio already is using 12mhz rocks so this fix
technique is not applicable UNLESS the first stage is
an oscillator-multiplier.

You might check to see that the box containing the exciter
is tightly shielded and its power and audio leads are properly
bypassed.

If the exciter is in a box or shield of any kind... if not, maybe
it's time to box it up with a set of good quality feed through caps.

The Standard fix mentioned above took advantage of the lucky
design quirk that allowed a simple plug-in crystal swap to
eliminate the spur.
The real fix would have been adding more shielding and
a bypass cap or three.
This typical cheap design, plus the name of the current-
production Motorola radio of the time, the Motrac, is were
the (no longer politically correct) derogatory term japtrac
came from.

Check to see that all connectors are clean and tight.  Use
a spectrum analyzer to see if your PA is generating spurs.
Try running without the PA, or use a different and lower-
powered PA for comparison.

Make sure all the shields are in place. If your radio came
to you as a used radio, you might want to make sure that
there

[Repeater-Builder] Repeater heard on Aviation Channel! HELP

Ok, something new has been discovered this morning, while going back 
to the repeater for further testing.  I turned on the SM to get ready 
to check a few things, while set to 132.950 the squelch on the SM was 
open I could hear a pulsing noise.  I then went to the output of the 
repeater, I could hear the same thing.  This same noise has been heard 
on the output of the repeater on certain radios, kind of sounds like a 
warbly sound, led to always believe it was the audio delay board, so I 
ignored it, non of the users ever commented on it.  The repeater was 
not transmitting at the time.  I reached in an unplugged the delay 
board and noise is still there.  I powered down the transmitter, no 
changes, I powered down the Mastr Pro receiver, noise still there, 
only thing left was the cat controller, powered it down and noise is 
gone.  This noise was heard over a large frequency spread in the 
aircraft band on the SM.  Could it be possible that the controller 
could be the cause sending havac out the band.

Mathew







 
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Re: [Repeater-Builder] Repeater heard on Aviation Channel! HELP

2005-07-06 Thread Dave VanHorn


I powered down the Mastr Pro receiver, noise still there,
only thing left was the cat controller, powered it down and noise is
gone.  This noise was heard over a large frequency spread in the
aircraft band on the SM.  Could it be possible that the controller
could be the cause sending havac out the band.

If it's radiating enough to get out any distance, there's something 
SERIOUSLY wrong with it.
I'd consider this possible, but unlikely.

It might make it into your receiver though, if the CPU clock has the 
right harmonics.
Those oscillators are nowhere near the stability of the ones that we 
use for RF either, they will be FM'd by load, and what the processor 
is doing at the moment..

You can probably alter the xtal frequency just a bit, enough to get 
out of your receiver, but not enough to bother anything else, by 
changing one of the two caps that will be located very close to the 
crystal. 10-30pF normal value range.  MFJ had this in one or more of 
their TNCs, for the same problem.
1, 2, 4, 8, and 16 MHz are all popular uP clocks, and all have 
harmonics that end up on the bottom end of the 2M band.
In the case of 1 and 2M, the harmonics would be at 144, 146, 148, and 
144, 145, 146, 147, 148-ish, but I doubt the 1MHz rock would have 
harmonics up that high.





 
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Re: [Repeater-Builder] Repeater heard on Aviation Channel! HELP

At 7/6/2005 02:35 AM, you wrote:
Comments mixed into the text below...

Mike WA6ILQ

At 07:58 PM 7/5/05, you wrote:

 Mathew,
 
 The Maggiore EV-1 is a very basic, crystal-controlled exciter that has none
 of the filters, power control, or SWR protection features of commercial
 units.  I have one that I took off the air because of its tendency to
 produce spurs.  It is perhaps not a good idea to use a relatively unstable
 exciter to feed a 200 watt (!) power amplifier, which itself may not have
 all of the controls and protections of a commercial amplifier.  I've never
 heard of Vocom, so I don't know where it falls in the quality lineup.
 
 I find it interesting that the fundamental frequency of your exciter,
 12.1175 MHz, when mixed with your output frequency of 145.410 MHz, produces
 a product at 133.2925 MHz.  This product is in the aviation band and could
 be slope-detected with ease by an AM aircraft radio on a nearby frequency.
 I'm not suggesting that this is the cause, but it's a coincidence.

Having a look at 157.5275, which is 12.1175 above his output would be
interesting.

Right; I got my math screwed up somehow  wrote 157.87 in a previous 
message, which was incorrect.

BTW, it's too bad they don't let us listen with our HTs on airplanes, as I 
could have listened for the spur myself last Sunday flying home from MDW.

Bob NO6B






 
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Re: [Repeater-Builder] Repeater heard on Aviation Channel! HELP

At 7/6/2005 07:37 AM, you wrote:
Ok, something new has been discovered this morning, while going back
to the repeater for further testing.  I turned on the SM to get ready
to check a few things, while set to 132.950 the squelch on the SM was
open I could hear a pulsing noise.  I then went to the output of the
repeater, I could hear the same thing.  This same noise has been heard
on the output of the repeater on certain radios, kind of sounds like a
warbly sound, led to always believe it was the audio delay board, so I
ignored it, non of the users ever commented on it.  The repeater was
not transmitting at the time.  I reached in an unplugged the delay
board and noise is still there.  I powered down the transmitter, no
changes, I powered down the Mastr Pro receiver, noise still there,
only thing left was the cat controller, powered it down and noise is
gone.  This noise was heard over a large frequency spread in the
aircraft band on the SM.  Could it be possible that the controller
could be the cause sending havac out the band.

Mathew

Can you manually key your TX with the controller unpowered  check for the 
spur on the S.A.?

Bob NO6B






 
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Re: [Repeater-Builder] Repeater heard on Aviation Channel! HELP

No - 157.870 IS the correct mix to combine with 145.410 and end up on
132.950 MHz - do the math again. The difference is 12.460 MHz.

145.410 - 12.46 = 132.950
145.410 + 12.46 = 157.870

Joe M.

Bob Dengler wrote:
 
 At 7/6/2005 02:35 AM, you wrote:
 Having a look at 157.5275, which is 12.1175 above his output would be
 interesting.
 
 Right; I got my math screwed up somehow  wrote 157.87 in a previous
 message, which was incorrect.





 
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Re: [Repeater-Builder] Repeater heard on Aviation Channel! HELP

At 7/6/2005 12:26 PM, you wrote:
No - 157.870 IS the correct mix to combine with 145.410 and end up on
132.950 MHz - do the math again. The difference is 12.460 MHz.

145.410 - 12.46 = 132.950
145.410 + 12.46 = 157.870

Joe M.

OK, 12.46 is the difference between the actual spur  Mathew's output,  
12.1175 is the xtal freq.  Since there doesn't appear to be a correlation 
between the 2, you're right in that 157.87 is the place to look.  Actually 
12.46 MHz would also be a good freq. to sniff around at, particularly if a 
157.87 spur is found.

Bob NO6B






 
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Re: [Repeater-Builder] Repeater heard on Aviation Channel! HELP

2005-07-06 Thread Dave VanHorn

At 02:47 PM 7/6/2005, Bob Dengler wrote:
At 7/6/2005 12:26 PM, you wrote:
 No - 157.870 IS the correct mix to combine with 145.410 and end up on
 132.950 MHz - do the math again. The difference is 12.460 MHz.
 
 145.410 - 12.46 = 132.950
 145.410 + 12.46 = 157.870
 
 Joe M.

OK, 12.46 is the difference between the actual spur  Mathew's output, 
12.1175 is the xtal freq.

It's in the neighborhood of 455kC off, but right on that.

Aero radios don't use some whacky IF do they? 





 
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Re: [Repeater-Builder] Repeater heard on Aviation Channel! HELP




Is the 12.46 that you are coming up with, the xtal inside of the transmitter itself. I'm looking, there is a repeater near here that is right around 158 megs, I'm looking it up now.

Mathew
Dave VanHorn [EMAIL PROTECTED] wrote:
At 02:47 PM 7/6/2005, Bob Dengler wrote:At 7/6/2005 12:26 PM, you wrote: No - 157.870 IS the correct mix to combine with 145.410 and end up on 132.950 MHz - do the math again. The difference is 12.460 MHz.  145.410 - 12.46 = 132.950 145.410 + 12.46 = 157.870  Joe M.OK, 12.46 is the difference between the actual spur  Mathew's output, 12.1175 is the xtal freq.It's in the neighborhood of 455kC off, but right on that.Aero radios don't use some whacky IF do they? 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
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Re: [Repeater-Builder] Repeater heard on Aviation Channel! HELP

At 7/6/2005 01:26 PM, you wrote:
Is the 12.46 that you are coming up with, the xtal inside of the 
transmitter itself.  I'm looking, there is a repeater near here that is 
right around 158 megs, I'm looking it up now.

Mathew

No, 12.46 MHz is the difference between your repeater output  the freq. 
you reported your spur to be on.

Bob NO6B






 
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Re: [Repeater-Builder] Repeater heard on Aviation Channel! HELP




The repeater pair that is about 3 miles from here is, and I have not checked to see which way the offset is, but 153.920 and 158.820 is the pair given. 

Mathew
Bob Dengler [EMAIL PROTECTED] wrote:
At 7/6/2005 12:26 PM, you wrote:No - 157.870 IS the correct mix to combine with 145.410 and end up on132.950 MHz - do the math again. The difference is 12.460 MHz.145.410 - 12.46 = 132.950145.410 + 12.46 = 157.870Joe M.OK, 12.46 is the difference between the actual spur  Mathew's output,  12.1175 is the xtal freq. Since there doesn't appear to be a correlation between the 2, you're right in that 157.87 is the place to look. Actually 12.46 MHz would also be a good freq. to sniff around at, particularly if a 157.87 spur is found.Bob NO6BYahoo! 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
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Re: [Repeater-Builder] Repeater heard on Aviation Channel! HELP




Ok, now I get where they came up with that. Was just trying to make the association. I've realigned the transmitter, checked everything that I can think of and still can be heard clipping on 132.950, bu then if I goto 133.075 I can hear the repeater real plain, as also another user that is about 3 miles from the repeater.

Mathew
Bob Dengler [EMAIL PROTECTED] wrote:
At 7/6/2005 01:26 PM, you wrote:Is the 12.46 that you are coming up with, the xtal inside of the transmitter itself. I'm looking, there is a repeater near here that is right around 158 megs, I'm looking it up now.MathewNo, 12.46 MHz is the difference between your repeater output  the freq. you reported your spur to be on.Bob NO6BYahoo! 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/__Do You Yahoo!?Tired of spam?  Yahoo! Mail
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Re: [Repeater-Builder] Repeater heard on Aviation Channel! HELP

OK, 145.410 MHz. I should have read ALL the posts before asking that. Is
there anything in your area on 157.875 MHz? Those could mix to end up on
132.945 MHz. Same with something on 139.180 MHz, although that us much
less likely, I think.

What is your crystal frequency and multiplication factor? There could be
a lower harmonic causing the problem. The math doesn't seem to support
that, though.

Joe M.

mch wrote:
 
 What frequency is your repeater on?
 
 Joe M.
 
 Mathew Quaife wrote:
 
  Ok, the situation is that my repeater is being heard by commercial
  aircraft on 132.950 Mhz.  At first they was able to identify one user
  of the system, this was in June.  Then again the repeater was heard on
  June 22, this time stating they could hear several users on the system.
  The did not give any other specifics other than this.  This comes from
  Pilots whom reported the occurance with the FAA in Chicago.  I'm told
  the interference is only to the planes, and not the ground tower.
  I've looked at the transmitter on the SA, there is one small spur
  there, but this same spur is there if I use just an ht, or any other
  radio for that matter.  This is hooking it to the repeater antenna
  directly, or through the duplexer's.  My question is, could it be
  something in the antenna system, or where might I look.  My system
  consist of a DB224 retuned for the ham bands, up 92' fed with 7/8
  hardline.  There is two horizontal antenna's below the repeater
  antenna, a cushcraft 5 element 6 meter beam and a Hygain TH7 below
  that.  The tower is a guyed tower, with two sets of guys, one set at
  65' and the other at 35'.  There is no breaks in the 1/4 steel
  cables.  The deviation on the repeater into my SM only showed 4.5 to 5
  Khz wide, although the audio was tinny.  Over the past few days I have
  been working on the tinny audio, for which I believe I have fixed, as
  it sounds much better.  The transmitter is the Maggorie Hi Pro EV1 and
  the amplifier is a Vocom 200 watt amp.  90 Watts is what is being fed
  to the antenna from the duplexer.
 
  Mathew
 
 
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Re: [Repeater-Builder] Repeater heard on Aviation Channel! HELP

The only frequency close to that anywhere in the are is the town's sewer repeater at 153.920 and 158.820. The output is 145.410 and the multiplication factor is by 12.

Mathew
mch [EMAIL PROTECTED] wrote:
OK, 145.410 MHz. I should have read ALL the posts before asking that. Isthere anything in your area on 157.875 MHz? Those could mix to end up on132.945 MHz. Same with something on 139.180 MHz, although that us muchless likely, I think.What is your crystal frequency and multiplication factor? There could bea lower harmonic causing the problem. The math doesn't seem to supportthat, though.Joe M.mch wrote: What frequency is your repeater on? Joe M. Mathew Quaife wrote: Ok, the situation is that my repeater is being heard by commercial aircraft on 132.950 Mhz. At first they was able to identify one user of the system, this was in June. Then again the repeater was heard on June 22, this time stating they could hear several users on
the system. The did not give any other specifics other than this. This comes from Pilots whom reported the occurance with the FAA in Chicago. I'm told the interference is only to the planes, and not the ground tower. I've looked at the transmitter on the SA, there is one small spur there, but this same spur is there if I use just an ht, or any other radio for that matter. This is hooking it to the repeater antenna directly, or through the duplexer's. My question is, could it be something in the antenna system, or where might I look. My system consist of a DB224 retuned for the ham bands, up 92' fed with 7/8" hardline. There is two horizontal antenna's below the repeater antenna, a cushcraft 5 element 6 meter beam and a Hygain TH7 below that. The tower is a guyed tower, with two sets of guys, one set at 65' and the
other at 35'. There is no breaks in the 1/4" steel cables. The deviation on the repeater into my SM only showed 4.5 to 5 Khz wide, although the audio was tinny. Over the past few days I have been working on the tinny audio, for which I believe I have fixed, as it sounds much better. The transmitter is the Maggorie Hi Pro EV1 and the amplifier is a Vocom 200 watt amp. 90 Watts is what is being fed to the antenna from the duplexer. MathewYahoo! Groups Links 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
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Re: [Repeater-Builder] Repeater heard on Aviation Channel! HELP

12.46 is the difference if it's a mix. Look at the math I posted.

145.410 - 132.950 = 12.46

145.410 - 12.46 = 132.950
145.410 + 12.46 = 157.870

If it's mixing, the repeater would have to mix (well, the most likely
mix which is 2A-B) with 157.870 to end up on 132.950 MHz.

Joe M.





 
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Re: [Repeater-Builder] Repeater heard on Aviation Channel! HELP

158.820 is too far away. That would mix to produce 133.000 MHz. You're
looking for something on 158.875 MHz which would mix to end up on
132.940 MHz, but that's close enough to hear on 95 if the frequencies
are a little off (145.41 is a little high and 158.875 is a little low).

Joe M.





 
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Re: [Repeater-Builder] Repeater heard on Aviation Channel! HELP

Ooops! I messed up the math. 15*8*.820 MHz is WAY too far away. That
would end up on 132.000 (not 133 MHz - that would be a mix with 157.820
MHz).

You're looking for something on 157.875 MHz, not 158.875 MHz as I stated
below. That is the input to an old IMTS pair, but it wasn't used in the
USA - only Canada. It may be used today for business.

Joe M.

mch wrote:
 
 158.820 is too far away. That would mix to produce 133.000 MHz. You're
 looking for something on 158.875 MHz which would mix to end up on
 132.940 MHz, but that's close enough to hear on 95 if the frequencies
 are a little off (145.41 is a little high and 158.875 is a little low).
 
 Joe M.
 
 
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Re: [Repeater-Builder] Repeater heard on Aviation Channel! HELP




Nothing in the area that I can find that is on that frequency. Will have to listen over then next few days.

Mathew
mch [EMAIL PROTECTED] wrote:
158.820 is too far away. That would mix to produce 133.000 MHz. You'relooking for something on 158.875 MHz which would mix to end up on132.940 MHz, but that's close enough to hear on 95 if the frequenciesare a little off (145.41 is a little high and 158.875 is a little low).Joe M.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/__Do You Yahoo!?Tired of spam?  Yahoo! Mail has the best spam protection around http://mail.yahoo.com 








  
  





  
  
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Re: [Repeater-Builder] Repeater heard on Aviation Channel! HELP

2005-07-06 Thread scomind






Hi Matthew,

  I powered down the Mastr Pro receiver, noise still 
  there,only thing left was the cat controller, powered it down and 
  noise isgone. This noise was heard over a large frequency spread 
  in theaircraft band on the SM. Could it be possible that the 
  controllercould be the cause sending havac out the band.
  
Yes!

RF created by the digital circuits in the controllercanhitch a 
ride on your PTT andaudio lines, where it 
getsinjectedintoan early stage in 
yourtransmitter.The noiseis multiplied (along with the 
desirable signal), amplified, andspewed out all over the spectrum.

Putagood sized ferrite bead oneach wireleaving 
thecontroller.

73,
Bob

Bob Schmid, 
WA9FBO, MemberS-COM, LLCPO Box 1546LaPorte CO 
80535-1546970-416-6505 voice970-419-3222 
faxwww.scomcontrollers.com








  
  





  
  
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Re: [Repeater-Builder] Repeater heard on Aviation Channel! HELP

2005-07-06 Thread Ron Wright





One thing to think about.

145.41/12 = 12.1175 MHz

12.1175 x 11 = 133.2925 MHz

It could be related to this as it is harmonic of the fundamental crystal freq. 
A low pass filter would not take this out. A band pass cavity might do the job if from your tx.

73, ron, n9ee/r








  
  





  
  
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Re: [Repeater-Builder] Repeater heard on Aviation Channel! HELP

But the interference is to 132.950 MHz, not 132.2925 MHz.

The harmonic is about 657.5 kHz away!

Joe M.

From: Ron Wright [EMAIL PROTECTED]

 One thing to think about.
  
 145.41/12 = 12.1175 MHz
  
 12.1175 x 11 = 133.2925 MHz
  
 It could be related to this as it is harmonic of the fundamental
 crystal freq.





 
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Re: [Repeater-Builder] Repeater heard on Aviation Channel! HELP

At 7/6/2005 01:31 PM, you wrote:
The repeater pair that is about 3 miles from here is, and I have not 
checked to see which way the offset is, but 153.920 and 158.820 is the 
pair given.

Mathew

Doesn't sound like that has anything to do with the problem.  If you can 
see the spur coming out of your exciter on the S.A., the problem lies 
somewhere in your system.

Bob NO6B






 
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Re: [Repeater-Builder] Repeater heard on Aviation Channel! HELP




It is very weird, all evening I have been working with the repeater, and what ever it is, it is very inttermittant, because it will come and go, and there is no pattern for it. I just learned of that pair, but it is the only pair that is close to me that I know of. 

Mathew
Bob Dengler [EMAIL PROTECTED] wrote:
At 7/6/2005 01:31 PM, you wrote:The repeater pair that is about 3 miles from here is, and I have not checked to see which way the offset is, but 153.920 and 158.820 is the pair given.MathewDoesn't sound like that has anything to do with the problem. If you can see the spur coming out of your exciter on the S.A., the problem lies somewhere in your system.Bob NO6BYahoo! 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/__Do You
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Re: [Repeater-Builder] Repeater heard on Aviation Channel! HELP

2005-07-06 Thread Mike/k1eg






Mathew you said this problem started when you 
changed the antenna. Did you cut back on the feedline and use a new 
connector? Awhile back there was discussion on here about problems if you 
don't use a new connector. Just a thought hope it helps.

73
Mike/K1EG


  - Original Message - 
  From: 
  Mathew Quaife 

  To: Repeater-Builder@yahoogroups.com 
  
  Sent: Thursday, July 07, 2005 12:14 
  AM
  Subject: Re: [Repeater-Builder] Repeater 
  heard on Aviation Channel! HELP
  
  It is very weird, all evening I have been working with the repeater, and 
  what ever it is, it is very inttermittant, because it will come and go, and 
  there is no pattern for it. I just learned of that pair, but it is the 
  only pair that is close to me that I know of. 
  
  Mathew
  Bob Dengler [EMAIL PROTECTED] 
  wrote:
  At 
7/6/2005 01:31 PM, you wrote:The repeater pair that is about 3 miles 
from here is, and I have not checked to see which way the offset is, 
but 153.920 and 158.820 is the pair 
given.MathewDoesn't sound like that has anything to 
do with the problem. If you can see the spur coming out of your exciter 
on the S.A., the problem lies somewhere in your system.Bob 
NO6BYahoo! 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/
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[Repeater-Builder] Repeater heard on Aviation Channel! HELP

Ok, the situation is that my repeater is being heard by commercial 
aircraft on 132.950 Mhz.  At first they was able to identify one user 
of the system, this was in June.  Then again the repeater was heard on 
June 22, this time stating they could hear several users on the system.
The did not give any other specifics other than this.  This comes from 
Pilots whom reported the occurance with the FAA in Chicago.  I'm told 
the interference is only to the planes, and not the ground tower.  
I've looked at the transmitter on the SA, there is one small spur 
there, but this same spur is there if I use just an ht, or any other 
radio for that matter.  This is hooking it to the repeater antenna 
directly, or through the duplexer's.  My question is, could it be 
something in the antenna system, or where might I look.  My system 
consist of a DB224 retuned for the ham bands, up 92' fed with 7/8 
hardline.  There is two horizontal antenna's below the repeater 
antenna, a cushcraft 5 element 6 meter beam and a Hygain TH7 below 
that.  The tower is a guyed tower, with two sets of guys, one set at 
65' and the other at 35'.  There is no breaks in the 1/4 steel 
cables.  The deviation on the repeater into my SM only showed 4.5 to 5 
Khz wide, although the audio was tinny.  Over the past few days I have 
been working on the tinny audio, for which I believe I have fixed, as 
it sounds much better.  The transmitter is the Maggorie Hi Pro EV1 and 
the amplifier is a Vocom 200 watt amp.  90 Watts is what is being fed 
to the antenna from the duplexer.

Mathew







 
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Re: [Repeater-Builder] Repeater heard on Aviation Channel! HELP

At 08:48 PM 7/5/2005, Mathew Quaife wrote:
Ok, the situation is that my repeater is being heard by commercial
aircraft on 132.950 Mhz.

Ouch!  BTDT, with a kenwood synthesized transmitter that didn't 
detect out of lock properly.
I had to pull the plug till it was resolved.


I've looked at the transmitter on the SA, there is one small spur
there, but this same spur is there if I use just an ht, or any other
radio for that matter.  This is hooking it to the repeater antenna
directly, or through the duplexer's.  My question is, could it be
something in the antenna system, or where might I look.

What I did to fix this, was to first realign the synth so the PLL was in lock.
Then I added a coax stub filter on the transmitter output, cut to be 
an odd 1/4 wave multiple at 121.1 (where my problem was) and an even 
number of 1/4 wavelenghts at 146.730, where our carrier should 
be.  The stub got me 40dB of supression, and the retune got rid of it 
entirely, so even if it happens again, the stub assures that the 
tower will not be hearing from us.
Ideally, tune the stub with an SA and tracking generator, so you can 
be sure the pass and stop are where they should be.
I also made two spares when I made mine, and labeled it so some well 
meaning guy years in the future dosen't remove that useless hunk of coax.

The planes hearing it more than the tower was also the case here, it 
just happens that they frequently overfly the repeater site.


  The transmitter is the Maggorie Hi Pro EV1 and
the amplifier is a Vocom 200 watt amp.  90 Watts is what is being fed
to the antenna from the duplexer.

Crystal or synth transmitter?  If xtal, does the problem show up on 
(your transmit freq - the crystal freq)?
Could be hopping in and out of an overtone mode, maybe a failing 
crystal, or bad component in the osc itself.


My experience with the local tower folks was very good. No heated 
tempers, and they even complimented us to the FCC about how quickly 
and well we resolved the problem.
The funny thing was, this has always been an example I used in talks 
as a nightmare scenario of what could happen...






 
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Re: [Repeater-Builder] Repeater heard on Aviation Channel! HELP

2005-07-05 Thread Ken Arck

At 01:48 AM 7/6/2005 -, you wrote:

Ok, the situation is that my repeater is being heard by commercial 
aircraft on 132.950 Mhz.  At first they was able to identify one user 
of the system, this was in June.  Then again the repeater was heard on 
June 22, this time stating they could hear several users on the system.

---Either your repeater is AMing a lot, or isn't exactly on 132.950 (slope
tuning an FM signal on an AM receiver). 

Did they provide callsigns?

Ken
--
President and CTO - Arcom Communications
Makers of state-of-the-art repeater controllers and accessories.
http://www.ah6le.net/arcom/index.html
We offer complete Kenwood TKR repeater packages!
AH6LE/R - IRLP Node 3000
http://www.irlp.net




 
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Re: [Repeater-Builder] Repeater heard on Aviation Channel! HELP

At 09:06 PM 7/5/2005, Ken Arck wrote:
At 01:48 AM 7/6/2005 -, you wrote:

 Ok, the situation is that my repeater is being heard by commercial
 aircraft on 132.950 Mhz.  At first they was able to identify one user
 of the system, this was in June.  Then again the repeater was heard on
 June 22, this time stating they could hear several users on the system.

---Either your repeater is AMing a lot, or isn't exactly on 132.950 (slope
tuning an FM signal on an AM receiver).

In our case, the audio was as clear on their systems as it is on ours.
The FM deviation slides around on their IF passband slope, creating 
AM where none existed before.

I had several people who were local gurus insisting that this 
couldn't be the case, so I played them the tapes from the tower.

That's another thought I forgot to add. If you ask, they will 
probably be able to let you listen to the tapes, which makes the 
identification much easier.
In our case, there were a few instances of just sylables, but then 
there were others where the repeater courtesy tone was there, as well 
as our most popular user, and then finally one with the repeater ID, 
which pretty much closed the case.





 
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Re: [Repeater-Builder] Repeater heard on Aviation Channel! HELP




Yes, they was able to identify one user of the system, and that particular day they his audio was terrible, to the point I was trying to identify what was wrong with his audio. Ken Arck [EMAIL PROTECTED] wrote:
At 01:48 AM 7/6/2005 -, you wrote:Ok, the situation is that my repeater is being heard by commercial aircraft on 132.950 Mhz. At first they was able to identify one user of the system, this was in June. Then again the repeater was heard on June 22, this time stating they could hear several users on the system.---Either your repeater is AMing a lot, or isn't exactly on 132.950 (slopetuning an FM signal on an AM receiver). Did they provide callsigns?Ken--President and CTO - Arcom CommunicationsMakers of state-of-the-art repeater controllers and accessories.http://www.ah6le.net/arcom/index.htmlWe offer complete Kenwood TKR repeater packages!AH6LE/R - IRLP Node 3000http://www.irlp.netYahoo!
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Re: [Repeater-Builder] Repeater heard on Aviation Channel! HELP

2005-07-05 Thread Eric Lemmon

Mathew,

The Maggiore EV-1 is a very basic, crystal-controlled exciter that has none
of the filters, power control, or SWR protection features of commercial
units.  I have one that I took off the air because of its tendency to
produce spurs.  It is perhaps not a good idea to use a relatively unstable
exciter to feed a 200 watt (!) power amplifier, which itself may not have
all of the controls and protections of a commercial amplifier.  I've never
heard of Vocom, so I don't know where it falls in the quality lineup.

I find it interesting that the fundamental frequency of your exciter,
12.1175 MHz, when mixed with your output frequency of 145.410 MHz, produces
a product at 133.2925 MHz.  This product is in the aviation band and could
be slope-detected with ease by an AM aircraft radio on a nearby frequency.
I'm not suggesting that this is the cause, but it's a coincidence.

You might check to see that the box containing the exciter is tightly
shielded and its power and audio leads are properly bypassed.  Check to see
that all connectors are clean and tight.  Use a spectrum analyzer to see if
your PA is generating spurs.  Try running without the PA, or use a
different and lower-powered PA for comparison.

Another brute-force measure which might be helpful in troubleshooting this
problem, is to put a bandpass cavity between the exciter and the PA, and a
second bandpass cavity at the output of the PA.

Finally, it may be helpful to install a ferrite isolator at the output of
the PA.  There may be intermod issues at work here, and an isolator will
help to make that determination.

73, Eric Lemmon WB6FLY

Mathew Quaife wrote:

 Ok, the situation is that my repeater is being heard by commercial
 aircraft on 132.950 MHz.  At first they were able to identify one user
 of the system, this was in June.  Then again the repeater was heard on
 June 22, this time stating they could hear several users on the system.
 They did not give any other specifics other than this.  This comes from
 Pilots who reported the occurrence to the FAA in Chicago.  I'm told the
 interference is only to the planes, and not the ground tower.  I've
 looked at the transmitter on the SA, there is one small spur there, but
 this same spur is there if I use just an ht, or any other radio for that
 matter.  This is hooking it to the repeater antenna directly, or through
 the duplexer.  My question is, could it be something in the antenna
 system, or where might I look?  My system consists of a DB224 retuned for
 the ham bands, up 92' fed with 7/8 hardline.  There are two horizontal
 antennas below the repeater antenna, a Cushcraft 5 element 6 meter beam
 and a Hygain TH7 below that.  The tower is a guyed tower, with two sets
 of guys, one set at 65' and the other at 35'.  There are no breaks in the
 1/4 steel cables.  The deviation on the repeater into my SM only showed
 4.5 to 5 kHz wide, although the audio was tinny.  Over the past few days
 I have been working on the tinny audio, for which I believe I have fixed,
 as it sounds much better.  The transmitter is the Maggiore Hi Pro EV1 and
 the amplifier is a Vocom 200 watt amp.  90 Watts is what is being fed to
 the antenna from the duplexer.

 Mathew






 
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Re: [Repeater-Builder] Repeater heard on Aviation Channel! HELP

2005-07-05 Thread Glenn Little WB4UIV

Is your repeater on 145.035?

73
Glenn
WB4UIV

At 09:48 PM 07/05/05, you wrote:
Ok, the situation is that my repeater is being heard by commercial
aircraft on 132.950 Mhz.  At first they was able to identify one user
of the system, this was in June.  Then again the repeater was heard on
June 22, this time stating they could hear several users on the system.
The did not give any other specifics other than this.  This comes from
Pilots whom reported the occurance with the FAA in Chicago.  I'm told
the interference is only to the planes, and not the ground tower.
I've looked at the transmitter on the SA, there is one small spur
there, but this same spur is there if I use just an ht, or any other
radio for that matter.  This is hooking it to the repeater antenna
directly, or through the duplexer's.  My question is, could it be
something in the antenna system, or where might I look.  My system
consist of a DB224 retuned for the ham bands, up 92' fed with 7/8
hardline.  There is two horizontal antenna's below the repeater
antenna, a cushcraft 5 element 6 meter beam and a Hygain TH7 below
that.  The tower is a guyed tower, with two sets of guys, one set at
65' and the other at 35'.  There is no breaks in the 1/4 steel
cables.  The deviation on the repeater into my SM only showed 4.5 to 5
Khz wide, although the audio was tinny.  Over the past few days I have
been working on the tinny audio, for which I believe I have fixed, as
it sounds much better.  The transmitter is the Maggorie Hi Pro EV1 and
the amplifier is a Vocom 200 watt amp.  90 Watts is what is being fed
to the antenna from the duplexer.

Mathew








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Re: [Repeater-Builder] Repeater heard on Aviation Channel! HELP

Dave VanHorn [EMAIL PROTECTED] wrote:

At 08:48 PM 7/5/2005, Mathew Quaife wrote:Ok, the situation is that my repeater is being heard by commercialaircraft on 132.950 Mhz.Ouch! BTDT, with a kenwood synthesized transmitter that didn't detect out of lock properly.I had to pull the plug till it was resolved.
This is where I am at, I pulled the plug.I've looked at the transmitter on the SA, there is one small spurthere, but this same spur is there if I use just an ht, or any otherradio for that matter. This is hooking it to the repeater antennadirectly, or through the duplexer's. My question is, could it besomething in the antenna system, or where might I look.What I did to fix this, was to first realign the synth so the PLL was in lock.Then I added a coax stub filter on the transmitter output, cut to be an odd 1/4 wave multiple at 121.1 (where my problem was) and an even number of 1/4 wavelenghts at 146.730, where our carrier should be. The stub got me 40dB of supression, and the retune got rid of it entirely, so even if it happens again, the stub assures that the tower will not be hearing from us.Ideally, tune the stub with an SA and tracking generator, so you can be sure the pass and stop are
where they should be.I also made two spares when I made mine, and labeled it so some well meaning guy years in the future dosen't remove "that useless hunk of coax".The planes hearing it more than the tower was also the case here, it just happens that they frequently overfly the repeater site.
There is a wound of coax on the output of the exciter to reduce the power going into the amplifier, as the amp only needs 2 watts of draw to run it. The transmitter is the Maggorie Hi Pro EV1 andthe amplifier is a Vocom 200 watt amp. 90 Watts is what is being fedto the antenna from the duplexer.Crystal or synth transmitter? If xtal, does the problem show up on (your transmit freq - the crystal freq)?Could be hopping in and out of an overtone mode, maybe a failing crystal, or bad component in the osc itself.
It is a xtal controlled unit, don't seem to be having any troubles on the output of the repeater at 145.410.My experience with the local tower folks was very good. No heated tempers, and they even complimented us to the FCC about how quickly and well we resolved the problem.The funny thing was, this has always been an example I used in talks as a "nightmare scenario" of what could happen...At this point I don't think they have contacted the FCC, at least I have not heard from them as of yet. The gentleman that I spoke to was very pleasant and very helpful. He himself has not heard the interference as it was only reported by the Pilots themselves.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
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Re: [Repeater-Builder] Repeater heard on Aviation Channel! HELP

Nope, it is on 145.410

Mathew
Glenn Little WB4UIV [EMAIL PROTECTED] wrote:
Is your repeater on 145.035?73GlennWB4UIVAt 09:48 PM 07/05/05, you wrote:Ok, the situation is that my repeater is being heard by commercialaircraft on 132.950 Mhz. At first they was able to identify one userof the system, this was in June. Then again the repeater was heard onJune 22, this time stating they could hear several users on the system.The did not give any other specifics other than this. This comes fromPilots whom reported the occurance with the FAA in Chicago. I'm toldthe interference is only to the planes, and not the ground tower.I've looked at the transmitter on the SA, there is one small spurthere, but this same spur is there if I use just an ht, or any otherradio for that matter. This is hooking it to the repeater antennadirectly, or through the duplexer's.
My question is, could it besomething in the antenna system, or where might I look. My systemconsist of a DB224 retuned for the ham bands, up 92' fed with 7/8"hardline. There is two horizontal antenna's below the repeaterantenna, a cushcraft 5 element 6 meter beam and a Hygain TH7 belowthat. The tower is a guyed tower, with two sets of guys, one set at65' and the other at 35'. There is no breaks in the 1/4" steelcables. The deviation on the repeater into my SM only showed 4.5 to 5Khz wide, although the audio was tinny. Over the past few days I havebeen working on the tinny audio, for which I believe I have fixed, asit sounds much better. The transmitter is the Maggorie Hi Pro EV1 andthe amplifier is a Vocom 200 watt amp. 90 Watts is what is being fedto the antenna from the duplexer.MathewYahoo! Groups
LinksYahoo! 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/
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Re: [Repeater-Builder] Repeater heard on Aviation Channel! HELP

The Vocom amp is a commercial made amp, designed for repeater use, this particular model is no longer made, but the company still makes them, all new design and new staff. I think what my biggest concern is, that all of this did not crop up until after I installed the new DB224 antenna. I have another transmitter that I am able to use, have to order an xtal for it and see if does any better.

Mathew
Eric Lemmon [EMAIL PROTECTED] wrote:
Mathew,The Maggiore EV-1 is a very basic, crystal-controlled exciter that has noneof the filters, power control, or SWR protection features of commercialunits. I have one that I took off the air because of its tendency toproduce spurs. It is perhaps not a good idea to use a relatively unstableexciter to feed a 200 watt (!) power amplifier, which itself may not haveall of the controls and protections of a commercial amplifier. I've neverheard of Vocom, so I don't know where it falls in the quality lineup.I find it interesting that the fundamental frequency of your exciter,12.1175 MHz, when mixed with your output frequency of 145.410 MHz, producesa product at 133.2925 MHz. This product is in the aviation band and couldbe slope-detected with ease by an AM aircraft radio on a nearby frequency.I'm not suggesting that this is the
cause, but it's a coincidence.You might check to see that the box containing the exciter is tightlyshielded and its power and audio leads are properly bypassed. Check to seethat all connectors are clean and tight. Use a spectrum analyzer to see ifyour PA is generating spurs. Try running without the PA, or use adifferent and lower-powered PA for comparison.Another brute-force measure which might be helpful in troubleshooting thisproblem, is to put a bandpass cavity between the exciter and the PA, and asecond bandpass cavity at the output of the PA.Finally, it may be helpful to install a ferrite isolator at the output ofthe PA. There may be intermod issues at work here, and an isolator willhelp to make that determination.73, Eric Lemmon WB6FLYMathew Quaife wrote: Ok, the situation is that my repeater is being heard by commercial aircraft on 132.950 MHz. At first they were able to identify one
user of the system, this was in June. Then again the repeater was heard on June 22, this time stating they could hear several users on the system. They did not give any other specifics other than this. This comes from Pilots who reported the occurrence to the FAA in Chicago. I'm told the interference is only to the planes, and not the ground tower. I've looked at the transmitter on the SA, there is one small spur there, but this same spur is there if I use just an ht, or any other radio for that matter. This is hooking it to the repeater antenna directly, or through the duplexer. My question is, could it be something in the antenna system, or where might I look? My system consists of a DB224 retuned for the ham bands, up 92' fed with 7/8" hardline. There are two horizontal antennas below the repeater antenna, a Cushcraft 5 element 6 meter beam and a Hygain TH7 below that. The
tower is a guyed tower, with two sets of guys, one set at 65' and the other at 35'. There are no breaks in the 1/4" steel cables. The deviation on the repeater into my SM only showed 4.5 to 5 kHz wide, although the audio was tinny. Over the past few days I have been working on the tinny audio, for which I believe I have fixed, as it sounds much better. The transmitter is the Maggiore Hi Pro EV1 and the amplifier is a Vocom 200 watt amp. 90 Watts is what is being fed to the antenna from the duplexer. MathewYahoo! 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/
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Re: [Repeater-Builder] Repeater heard on Aviation Channel! HELP








There is a wound of coax on the output of the exciter to reduce the
power going into the amplifier, as the amp only needs 2 watts of draw to
run it.


That dosen't help you here, the stub specifically attenuates the
bad frequency, and passes the good one.
Your repeater cans probably don't do much to the bad
frequency either.



It is a xtal controlled unit, don't seem to be having any troubles on
the output of the repeater at 145.410.

Ours gave no outward symptom on the normal frequency either.









  
  





  
  
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Re: [Repeater-Builder] Repeater heard on Aviation Channel! HELP

At 10:17 PM 7/5/2005, Mathew Quaife wrote:
The Vocom amp is a commercial made amp, designed for repeater use, 
this particular model is no longer made, but the company still makes 
them, all new design and new staff.  I think what my biggest concern 
is, that all of this did not crop up until after I installed the new 
DB224 antenna.  I have another transmitter that I am able to use, 
have to order an xtal for it and see if does any 
better. 


Hmm.. This makes me think of something with reflected power into the 
TX, but it may just be coincidence.

In our case, the PLL was tuned after 24 hours of burn-in, to exactly 
factory spec, but within 6 months it had drifted far enough to be 
partially unlocking.
Worse, the radio didn't detect the unlock, and kept transmitting with 
the VFO hopping between these two frequencies.
I even tied the lock line manually, and the radio just kept right on 
transmitting!







 
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Re: [Repeater-Builder] Repeater heard on Aviation Channel! HELP

2005-07-05 Thread mch

What frequency is your repeater on?

Joe M.

Mathew Quaife wrote:
 
 Ok, the situation is that my repeater is being heard by commercial
 aircraft on 132.950 Mhz.  At first they was able to identify one user
 of the system, this was in June.  Then again the repeater was heard on
 June 22, this time stating they could hear several users on the system.
 The did not give any other specifics other than this.  This comes from
 Pilots whom reported the occurance with the FAA in Chicago.  I'm told
 the interference is only to the planes, and not the ground tower.
 I've looked at the transmitter on the SA, there is one small spur
 there, but this same spur is there if I use just an ht, or any other
 radio for that matter.  This is hooking it to the repeater antenna
 directly, or through the duplexer's.  My question is, could it be
 something in the antenna system, or where might I look.  My system
 consist of a DB224 retuned for the ham bands, up 92' fed with 7/8
 hardline.  There is two horizontal antenna's below the repeater
 antenna, a cushcraft 5 element 6 meter beam and a Hygain TH7 below
 that.  The tower is a guyed tower, with two sets of guys, one set at
 65' and the other at 35'.  There is no breaks in the 1/4 steel
 cables.  The deviation on the repeater into my SM only showed 4.5 to 5
 Khz wide, although the audio was tinny.  Over the past few days I have
 been working on the tinny audio, for which I believe I have fixed, as
 it sounds much better.  The transmitter is the Maggorie Hi Pro EV1 and
 the amplifier is a Vocom 200 watt amp.  90 Watts is what is being fed
 to the antenna from the duplexer.
 
 Mathew
 
 
 Yahoo! Groups Links
 
 
 






 
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Re: [Repeater-Builder] Repeater heard on Aviation Channel! HELP

145.410 Mhz.

Mathew
mch [EMAIL PROTECTED] wrote:
What frequency is your repeater on?Joe M.Mathew Quaife wrote: Ok, the situation is that my repeater is being heard by commercial aircraft on 132.950 Mhz. At first they was able to identify one user of the system, this was in June. Then again the repeater was heard on June 22, this time stating they could hear several users on the system. The did not give any other specifics other than this. This comes from Pilots whom reported the occurance with the FAA in Chicago. I'm told the interference is only to the planes, and not the ground tower. I've looked at the transmitter on the SA, there is one small spur there, but this same spur is there if I use just an ht, or any other radio for that matter. This is hooking it to the repeater antenna directly, or through the duplexer's.
My question is, could it be something in the antenna system, or where might I look. My system consist of a DB224 retuned for the ham bands, up 92' fed with 7/8" hardline. There is two horizontal antenna's below the repeater antenna, a cushcraft 5 element 6 meter beam and a Hygain TH7 below that. The tower is a guyed tower, with two sets of guys, one set at 65' and the other at 35'. There is no breaks in the 1/4" steel cables. The deviation on the repeater into my SM only showed 4.5 to 5 Khz wide, although the audio was tinny. Over the past few days I have been working on the tinny audio, for which I believe I have fixed, as it sounds much better. The transmitter is the Maggorie Hi Pro EV1 and the amplifier is a Vocom 200 watt amp. 90 Watts is what is being fed to the antenna from the duplexer. Mathew Yahoo! Groups Links
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Re: [Repeater-Builder] Repeater heard on Aviation Channel! HELP




I'm almost to the point of just scraping the iron and starting back at the basics. Actually I am almost ready to pull hairs. With so much time lapse in playing with this, I have forgotten most everything, so I really have to scratch my head. Might just have to find an elmer to come in and go through it.

Mathew
Dave VanHorn [EMAIL PROTECTED] wrote:



There is a wound of coax on the output of the exciter to reduce the power going into the amplifier, as the amp only needs 2 watts of draw to run it.
That dosen't help you here, the stub specifically attenuates the "bad" frequency, and passes the good one.Your repeater cans probably don't do much to the "bad" frequency either.


It is a xtal controlled unit, don't seem to be having any troubles on the output of the repeater at 145.410.
Ours gave no outward symptom on the normal frequency either.__Do You Yahoo!?Tired of spam?  Yahoo! Mail has the best spam protection around http://mail.yahoo.com 








  
  





  
  
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Re: [Repeater-Builder] Repeater heard on Aviation Channel! HELP