FW: [Repeater-Builder] Cables on Duplexer

2008-07-05 Thread John Transue
Bob,

 

Here it is again. Let me know if my message doesn't appear. Thanks.

 

John

 

-Original Message-
From: John Transue [mailto:[EMAIL PROTECTED] 
Sent: Wednesday, July 02, 2008 1:39 PM
To: 'Repeater-Builder@yahoogroups.com'
Subject: RE: [Repeater-Builder] Cables on Duplexer

 

Bob,

 

I don't have a way to measure this accurately on the receive side, but
just using a signal generator and my ear, there appears to be about a 2
dB loss in the duplexer. 

 

On the transmit side, using a transmitter and Bird power meter, there is
a 2 dB loss in the duplexer. Power in: 94 w; power out: 60 w. Reflected:
2 w. 

 

I don't have a good way to measure the isolation, but using a distant
transmitter, that transmitter had to use about 2 w when the repeater
transmitter was on and only 1 w when the repeater transmitter was off.
It appeared to me that we were getting a little de-sensing.

 

The motivation for this re-tuning of the duplexer is that the repeater
doesn't hear as well as it used to, according to users. I am not
concerned about losing a couple dB on the TX side. I am hoping, though,
that a re-tuning will decrease the de-sensing and, perhaps, add a slight
increase in sensitivity.

 

The system does have a pre-amp that appears to give about 4 dB of gain. 

 

I look forward to your suggestions.

 

John

 

-Original Message-
From: Repeater-Builder@yahoogroups.com
[mailto:[EMAIL PROTECTED] On Behalf Of [EMAIL PROTECTED]
Sent: Wednesday, July 02, 2008 11:35 AM
To: Repeater-Builder@yahoogroups.com
Subject: Re: [Repeater-Builder] Cables on Duplexer

 

At 7/2/2008 06:11, you wrote:

We have a repeater operating on 448.375/443.375 MHz. The cans are
marked 
456.300/451.300. So I conclude they were re-tuned from a commercial
band. 
I suspect (don t really know) that the cables were not lengthened to be

quarter wave (electrical). I would like to make them the optimum
length. 
Also, could someone tell me whether the lengths of cables going to the
tee 
connector are significant? Any information and suggestions are 
appreciated. Thanks.

Is the duplexer not meeting its loss or isolation specs?

Bob NO6B

 

__ NOD32 3192 (20080616) Information __

This message was checked by NOD32 antivirus system.
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RE: [Repeater-Builder] Cables on Duplexer

2008-07-05 Thread John Transue
Bob,

 

Thanks. I have someone with good equipment coming Sunday to check it out
and re-tune as needed. I'll let you know what we found.

 

Re the de-sense, there are two other antennas close by but both are for
much higher frequencies. The three feed lines all go down the same
conduit. We are using 7/8 Heliax and I believe the others are smaller
Heliax or hard line. 

 

I plan to replace the cables in the cabinet when new cables (now
ordered) are ready.

 

John

 

-Original Message-
From: Repeater-Builder@yahoogroups.com
[mailto:[EMAIL PROTECTED] On Behalf Of [EMAIL PROTECTED]
Sent: Thursday, July 03, 2008 12:36 AM
To: Repeater-Builder@yahoogroups.com
Subject: Re: [Repeater-Builder] Cables on Duplexer

 

At 7/2/2008 13:07, you wrote:

Hi John,

I want to suggest that you check the preamp, make sure it didn't get
hit 
by lightning, or overloaded, also (if possible check you cables, I have

had some change things happened that appears that the receiver is to
blame 
but not in all cases) Then check the receiver to make sure it still has

its sensitivity 0.25 - 0.35uv, or better should be good. I will hate to

touch the duplexer without making sure that these other components are 
checked.

Hope you get fix, let us know what you find, when you do.

v44kai.Joel.
- Original Message -
From: mailto:[EMAIL PROTECTED] mailto:jtransue%40cox.net netJohn
Transue
To: 
mailto:Repeater-Builder@ mailto:Repeater-Builder%40yahoogroups.com
yahoogroups.comRepeater-Builder@
mailto:Repeater-Builder%40yahoogroups.com yahoogroups.com
Sent: Wednesday, July 02, 2008 12:38 PM
Subject: RE: [Repeater-Builder] Cables on Duplexer

Bob,



I don't have a way to measure this accurately on the receive side, but

just using a signal generator and my ear, there appears to be about a
2 
dB loss in the duplexer.

OK, now I see your reply. Don't know why this text wasn't there on your 
original reply.

2 dB is rather high for a UHF duplexer. However, you've only moved the 
duplexer less than 2% of it's original frequency, so I doubt that any of

the cables would need to be replaced as a result of the frequency
change.

You're also experiencing a bit of desense as well. Might be worth 
rechecking the duplexer tuning  loss on good test equipment (spectrum 
analyzer with tracking gen. or better yet a VNA if you can get access to

one). However, there are many other possible causes of desense. The most

common I run into are mixes caused by bad hardware in the near field of
the 
antenna (other bad antennas, feedline, loose tower joints, etc.).

Bob NO6B

 

__ NOD32 3192 (20080616) Information __

This message was checked by NOD32 antivirus system.
http://www.eset.com



RE: [Repeater-Builder] Cables on Duplexer

2008-07-05 Thread no6b
John:

I'm not seeing your reply text.  Please turn off all text formatting in 
your e-mail client  resend as plain text.  Thanks.

Bob NO6B

At 7/5/2008 06:32, you wrote:

-Original Message-
From: Repeater-Builder@yahoogroups.com 
[mailto:[EMAIL PROTECTED] On Behalf Of [EMAIL PROTECTED]
Sent: Thursday, July 03, 2008 12:36 AM
To: Repeater-Builder@yahoogroups.com
Subject: Re: [Repeater-Builder] Cables on Duplexer

At 7/2/2008 13:07, you wrote:

 Hi John,
 
 I want to suggest that you check the preamp, make sure it didn't get hit
 by lightning, or overloaded, also (if possible check you cables, I have
 had some change things happened that appears that the receiver is to blame
 but not in all cases) Then check the receiver to make sure it still has
 its sensitivity 0.25 - 0.35uv, or better should be good. I will hate to
 touch the duplexer without making sure that these other components are
 checked.
 
 Hope you get fix, let us know what you find, when you do.
 
 v44kai.Joel.
 - Original Message -
 From: mailto:[EMAIL PROTECTED]John Transue
 To:
 mailto:Repeater-Builder@yahoogroups.commailto:Repeater-Builder%40yaho 
 ogroups.comRepeater-Builder@yahoogroups.com
 Sent: Wednesday, July 02, 2008 12:38 PM
 Subject: RE: [Repeater-Builder] Cables on Duplexer
 
 Bob,
 
 
 
 I don't have a way to measure this accurately on the receive side, but
 just using a signal generator and my ear, there appears to be about a 2
 dB loss in the duplexer.

OK, now I see your reply. Don't know why this text wasn't there on your
original reply.

2 dB is rather high for a UHF duplexer. However, you've only moved the
duplexer less than 2% of it's original frequency, so I doubt that any of
the cables would need to be replaced as a result of the frequency change.

You're also experiencing a bit of desense as well. Might be worth
rechecking the duplexer tuning  loss on good test equipment (spectrum
analyzer with tracking gen. or better yet a VNA if you can get access to
one). However, there are many other possible causes of desense. The most
common I run into are mixes caused by bad hardware in the near field of the
antenna (other bad antennas, feedline, loose tower joints, etc.).

Bob NO6B



RE: [Repeater-Builder] Cables on Duplexer

2008-07-05 Thread John Transue
Bob,

 

Thanks. I have someone with good equipment coming Sunday to check it out
and re-tune as needed. I'll let you know what we found.

 

Re the de-sense, there are two other antennas close by but both are for
much higher frequencies. The three feed lines all go down the same
conduit. We are using 7/8 Heliax and I believe the others are smaller
Heliax or hard line. 

 

I plan to replace the cables in the cabinet when new cables (now
ordered) are ready.

 

John

 

 

 

-Original Message-
From: Repeater-Builder@yahoogroups.com
[mailto:[EMAIL PROTECTED] On Behalf Of [EMAIL PROTECTED]
Sent: Saturday, July 05, 2008 1:59 PM
To: Repeater-Builder@yahoogroups.com
Subject: RE: [Repeater-Builder] Cables on Duplexer

 

John:

I'm not seeing your reply text. Please turn off all text formatting in 
your e-mail client  resend as plain text. Thanks.

Bob NO6B

At 7/5/2008 06:32, you wrote:

-Original Message-
From: Repeater-Builder@ mailto:Repeater-Builder%40yahoogroups.com
yahoogroups.com 
[mailto:Repeater-Builder@ mailto:Repeater-Builder%40yahoogroups.com
yahoogroups.com] On Behalf Of [EMAIL PROTECTED] mailto:no6b%40no6b.com 
Sent: Thursday, July 03, 2008 12:36 AM
To: Repeater-Builder@ mailto:Repeater-Builder%40yahoogroups.com
yahoogroups.com
Subject: Re: [Repeater-Builder] Cables on Duplexer

At 7/2/2008 13:07, you wrote:

 Hi John,
 
 I want to suggest that you check the preamp, make sure it didn't get
hit
 by lightning, or overloaded, also (if possible check you cables, I
have
 had some change things happened that appears that the receiver is to
blame
 but not in all cases) Then check the receiver to make sure it still
has
 its sensitivity 0.25 - 0.35uv, or better should be good. I will hate
to
 touch the duplexer without making sure that these other components
are
 checked.
 
 Hope you get fix, let us know what you find, when you do.
 
 v44kai.Joel.
 - Original Message -
 From: mailto:[EMAIL PROTECTED] mailto:jtransue%40cox.net netJohn
Transue
 To:
 mailto:Repeater-Builder@
mailto:Repeater-Builder%40yahoogroups.com
yahoogroups.commailto:Repeater-Builder%40yaho 
 ogroups.comRepeater-Builder@
mailto:Repeater-Builder%40yahoogroups.com yahoogroups.com
 Sent: Wednesday, July 02, 2008 12:38 PM
 Subject: RE: [Repeater-Builder] Cables on Duplexer
 
 Bob,
 
 
 
 I don't have a way to measure this accurately on the receive side,
but
 just using a signal generator and my ear, there appears to be about
a 2
 dB loss in the duplexer.

OK, now I see your reply. Don't know why this text wasn't there on your
original reply.

2 dB is rather high for a UHF duplexer. However, you've only moved the
duplexer less than 2% of it's original frequency, so I doubt that any
of
the cables would need to be replaced as a result of the frequency
change.

You're also experiencing a bit of desense as well. Might be worth
rechecking the duplexer tuning  loss on good test equipment (spectrum
analyzer with tracking gen. or better yet a VNA if you can get access
to
one). However, there are many other possible causes of desense. The
most
common I run into are mixes caused by bad hardware in the near field of
the
antenna (other bad antennas, feedline, loose tower joints, etc.).

Bob NO6B

 

__ NOD32 3192 (20080616) Information __

This message was checked by NOD32 antivirus system.
http://www.eset.com



[Repeater-Builder] Cables on Duplexer

2008-07-02 Thread John Transue
We have a repeater operating on 448.375/443.375 MHz. The cans are marked
456.300/451.300. So I conclude they were re-tuned from a commercial
band. I suspect (don't really know) that the cables were not lengthened
to be quarter wave (electrical). I would like to make them the optimum
length. Also, could someone tell me whether the lengths of cables going
to the tee connector are significant? Any information and suggestions
are appreciated. Thanks.

 

John Transue

AF4PD



Re: [Repeater-Builder] Cables on Duplexer

2008-07-02 Thread no6b
At 7/2/2008 06:11, you wrote:

We have a repeater operating on 448.375/443.375 MHz. The cans are marked 
456.300/451.300. So I conclude they were re-tuned from a commercial band. 
I suspect (don t really know) that the cables were not lengthened to be 
quarter wave (electrical). I would like to make them the optimum length. 
Also, could someone tell me whether the lengths of cables going to the tee 
connector are significant? Any information and suggestions are 
appreciated. Thanks.

Is the duplexer not meeting its loss or isolation specs?

Bob NO6B



RE: [Repeater-Builder] Cables on Duplexer

2008-07-02 Thread John Transue
Bob,

 

I don't have a way to measure this accurately on the receive side, but
just using a signal generator and my ear, there appears to be about a 2
dB loss in the duplexer. 

 

On the transmit side, using a transmitter and Bird power meter, there is
a 2 dB loss in the duplexer. Power in: 94 w; power out: 60 w. Reflected:
2 w. 

 

I don't have a good way to measure the isolation, but using a distant
transmitter, that transmitter had to use about 2 w when the repeater
transmitter was on and only 1 w when the repeater transmitter was off.
It appeared to me that we were getting a little de-sensing.

 

The motivation for this re-tuning of the duplexer is that the repeater
doesn't hear as well as it used to, according to users. I am not
concerned about losing a couple dB on the TX side. I am hoping, though,
that a re-tuning will decrease the de-sensing and, perhaps, add a slight
increase in sensitivity.

 

The system does have a pre-amp that appears to give about 4 dB of gain. 

 

I look forward to your suggestions.

 

John

 

-Original Message-
From: Repeater-Builder@yahoogroups.com
[mailto:[EMAIL PROTECTED] On Behalf Of [EMAIL PROTECTED]
Sent: Wednesday, July 02, 2008 11:35 AM
To: Repeater-Builder@yahoogroups.com
Subject: Re: [Repeater-Builder] Cables on Duplexer

 

At 7/2/2008 06:11, you wrote:

We have a repeater operating on 448.375/443.375 MHz. The cans are
marked 
456.300/451.300. So I conclude they were re-tuned from a commercial
band. 
I suspect (don t really know) that the cables were not lengthened to be

quarter wave (electrical). I would like to make them the optimum
length. 
Also, could someone tell me whether the lengths of cables going to the
tee 
connector are significant? Any information and suggestions are 
appreciated. Thanks.

Is the duplexer not meeting its loss or isolation specs?

Bob NO6B

 

__ NOD32 3192 (20080616) Information __

This message was checked by NOD32 antivirus system.
http://www.eset.com



Re: [Repeater-Builder] Cables on Duplexer

2008-07-02 Thread Joel
Hi John,

I want to suggest that you check the preamp, make sure it didn't get hit by 
lightning, or overloaded, also (if possible check you cables, I have had some 
change things happened that appears that the receiver is to blame but not in 
all cases) Then check the receiver to make sure it still has its sensitivity  
0.25 - 0.35uv, or better should be good.  I will hate to touch the duplexer 
without making sure that these other components are checked. 

Hope you get fix, let us know what you find, when you do.

v44kai.Joel.
  - Original Message - 
  From: John Transue 
  To: Repeater-Builder@yahoogroups.com 
  Sent: Wednesday, July 02, 2008 12:38 PM
  Subject: RE: [Repeater-Builder] Cables on Duplexer


  Bob,



  I don't have a way to measure this accurately on the receive side, but just 
using a signal generator and my ear, there appears to be about a 2 dB loss in 
the duplexer. 



  On the transmit side, using a transmitter and Bird power meter, there is a 2 
dB loss in the duplexer. Power in: 94 w; power out: 60 w. Reflected: 2 w. 



  I don't have a good way to measure the isolation, but using a distant 
transmitter, that transmitter had to use about 2 w when the repeater 
transmitter was on and only 1 w when the repeater transmitter was off. It 
appeared to me that we were getting a little de-sensing.



  The motivation for this re-tuning of the duplexer is that the repeater 
doesn't hear as well as it used to, according to users. I am not concerned 
about losing a couple dB on the TX side. I am hoping, though, that a re-tuning 
will decrease the de-sensing and, perhaps, add a slight increase in sensitivity.



  The system does have a pre-amp that appears to give about 4 dB of gain. 



  I look forward to your suggestions.



  John



  -Original Message-
  From: Repeater-Builder@yahoogroups.com [mailto:[EMAIL PROTECTED] On Behalf Of 
[EMAIL PROTECTED]
  Sent: Wednesday, July 02, 2008 11:35 AM
  To: Repeater-Builder@yahoogroups.com
  Subject: Re: [Repeater-Builder] Cables on Duplexer



  At 7/2/2008 06:11, you wrote:

  We have a repeater operating on 448.375/443.375 MHz. The cans are marked 
  456.300/451.300. So I conclude they were re-tuned from a commercial band. 
  I suspect (don t really know) that the cables were not lengthened to be 
  quarter wave (electrical). I would like to make them the optimum length. 
  Also, could someone tell me whether the lengths of cables going to the tee 
  connector are significant? Any information and suggestions are 
  appreciated. Thanks.

  Is the duplexer not meeting its loss or isolation specs?

  Bob NO6B


  __ NOD32 3192 (20080616) Information __

  This message was checked by NOD32 antivirus system.
  http://www.eset.com
   


--



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  Checked by AVG. 
  Version: 8.0.101 / Virus Database: 270.4.3/1528 - Release Date: 7/1/2008 7:26 
AM


RE: [Repeater-Builder] Cables on Duplexer

2008-07-02 Thread no6b
I see no added text here, only my forwarded message.

Bob NO6B

At 7/2/2008 10:38, you wrote:

-Original Message-
From: Repeater-Builder@yahoogroups.com 
[mailto:[EMAIL PROTECTED] On Behalf Of [EMAIL PROTECTED]
Sent: Wednesday, July 02, 2008 11:35 AM
To: Repeater-Builder@yahoogroups.com
Subject: Re: [Repeater-Builder] Cables on Duplexer

At 7/2/2008 06:11, you wrote:

 We have a repeater operating on 448.375/443.375 MHz. The cans are marked
 456.300/451.300. So I conclude they were re-tuned from a commercial band.
 I suspect (don t really know) that the cables were not lengthened to be
 quarter wave (electrical). I would like to make them the optimum length.
 Also, could someone tell me whether the lengths of cables going to the tee
 connector are significant? Any information and suggestions are
 appreciated. Thanks.

Is the duplexer not meeting its loss or isolation specs?

Bob NO6B



Re: [Repeater-Builder] Cables on Duplexer

2008-07-02 Thread no6b
At 7/2/2008 13:07, you wrote:

Hi John,

I want to suggest that you check the preamp, make sure it didn't get hit 
by lightning, or overloaded, also (if possible check you cables, I have 
had some change things happened that appears that the receiver is to blame 
but not in all cases) Then check the receiver to make sure it still has 
its sensitivity  0.25 - 0.35uv, or better should be good.  I will hate to 
touch the duplexer without making sure that these other components are 
checked.

Hope you get fix, let us know what you find, when you do.

v44kai.Joel.
- Original Message -
From: mailto:[EMAIL PROTECTED]John Transue
To: 
mailto:Repeater-Builder@yahoogroups.comRepeater-Builder@yahoogroups.com
Sent: Wednesday, July 02, 2008 12:38 PM
Subject: RE: [Repeater-Builder] Cables on Duplexer

Bob,



I don't have a way to measure this accurately on the receive side, but 
just using a signal generator and my ear, there appears to be about a 2 
dB loss in the duplexer.

OK, now I see your reply.  Don't know why this text wasn't there on your 
original reply.

2 dB is rather high for a UHF duplexer.  However, you've only moved the 
duplexer less than 2% of it's original frequency, so I doubt that any of 
the cables would need to be replaced as a result of the frequency change.

You're also experiencing a bit of desense as well.  Might be worth 
rechecking the duplexer tuning  loss on good test equipment (spectrum 
analyzer with tracking gen. or better yet a VNA if you can get access to 
one).  However, there are many other possible causes of desense.  The most 
common I run into are mixes caused by bad hardware in the near field of the 
antenna (other bad antennas, feedline, loose tower joints, etc.).

Bob NO6B