Re: [Repeater-Builder] Pager Interference to 2-meter & VHF Public Service Band

[DCFluX]

I'd use a really fast spectrum analyzer, meaning an analog one and
point a video camera at it

On Wed, Oct 28, 2009 at 10:19 PM, Kris Kirby  wrote:
> On Wed, 28 Oct 2009, Facility 406 DM09 wrote:
>> I am interested in such things!  Anyone have any good suggestions or
>> input regarding software or systems?
>
> Cavity -> digital storage oscilliscope.
>
> --
> Kris Kirby, KE4AHR
> Disinformation Analyst
>
>
> 
>
>
>
> Yahoo! Groups Links
>
>
>
>

Re: [Repeater-Builder] Pager Interference to 2-meter & VHF Public Service Band

[Kris Kirby]

On Wed, 28 Oct 2009, Facility 406 DM09 wrote:
> I am interested in such things!  Anyone have any good suggestions or 
> input regarding software or systems?

Cavity -> digital storage oscilliscope.

--
Kris Kirby, KE4AHR
Disinformation Analyst

Re: [Repeater-Builder] Pager Interference to 2-meter & VHF Public Service Band

[Facility 406 DM09]

: There is some software that allows finger printing of a transmission
: base on the lockup signature and oscillator stability as seen on the
: transmitted signal.

I am interested in such things!  Anyone have any good suggestions or input
regarding software or systems?

Kurt

Re: [Repeater-Builder] Pager Interference to 2-meter & VHF Public Service Band

[Glenn Little WB4UIV]

Locally, years ago, we had a military transmitter that had a 
wandering spur. I am near Charleston, SC. The spur was strong enough 
to key up amateur radio repeaters in the two meter band from 
Wilmington, NC to Savannah, Ga.
The offender turned out to be a 250 Watt base station used to cover 
approximately 10 Acres.
The radio was a Motorola MICOR.
The service shop could not fix the problem, so, they replaced the transmitter.

This may be a spur from a transmitter.
The spur that we experienced wandered up the band, then, down the band.
The wander was slow enough that you could hear it approaching the 
repeater input frequency as a weak off frequency signal.
It would wander through the passband of the repeater in about 30-45 
seconds and again sound like a weak off frequency signal as the squelch closed.
The repeater was either in the 148 or the 150 MHz range and 
interfered with a 146.79, 146.82, 146.88 and a 149.94 MHz repeater.
It took about a week to get the problem taken care of.
The military had tried to classify the frequency of the repeater on 
this base due to the type of traffic that they handled.

Kind of hard to hide what you are doing when transmitting in the 
clear with that much power and having a spur keying up repeaters over 
the distance that this one did.

There is some software that allows finger printing of a transmission 
base on the lockup signature and oscillator stability as seen on the 
transmitted signal.
You could possibly compare the known probable offender with the 
offender through one of the interfered with repeaters or it's input frequency.

Wish you well with resolving the problem.

73
Glenn
WB4UIV


At 11:51 PM 10/28/2009, you wrote:
>I have to wonder how he can say his stuff is clean when this just
>started a couple weeks ago. Did he perform a PM check within the last
>two weeks? Unlikely.
>
>Stuff can go south in a minute, and seldom just before you check it.
>
>Joe M.
>
>Paul Plack wrote:
> >
> >
> > Mike,
> >
> > If it moves around based on time of day, my first guess is a PA that's
> > gone bad, and has a parasitic that's temperature-related.
> >
> > If you've tracked an individual spur drifting 70 kHz up the band during
> > a single transmission, this is not some (intentional) oscillator
> > drifting, but some combination of failed components or tuning which has
> > produced a parasitic.
> >
> > Sorry to say, but a paging transmitter owner swearing his stuff is clean
> > is pretty meaningless. The assumption in his industry is the
> > professionals who maintain his stuff are not the problem, it's "those
> > damn hams." Sadly, it may more often be the other way around these days,
> > as companies maintaining paging equipment have transitioned to
> > underpaid, under-trained card-swappers instead of component-level
> > technicians with a clue about RF systems.
> >
> > 73,
> > Paul, AE4KR
> >
> >
> > - Original Message -
> > *From:* Mike 
> > *To:* Repeater-Builder@yahoogroups.com
> > 
> > *Sent:* Wednesday, October 28, 2009 12:28 PM
> > *Subject:* [Repeater-Builder] Pager Interference to 2-meter & VHF
> > Public Service Band
> >
> >
> >
> > A couple of weeks ago, our repeater system started to experience
> > interference from a paging system...
> >
> >
> > ...one evening I tracked it from about 145.120 to 145.190 as it
> > swept through each transmission...
> >
> >
> >
> > .
> >
> >
> >
> >
> >
> >
> > 
> >
> >
> > Internal Virus Database is out of date.
> > Checked by AVG - www.avg.com
> > Version: 8.5.387 / Virus Database: 270.13.38/2274 - Release Date: 
> 07/31/09 05:58:00
> >
>
>
>
>
>
>
>Yahoo! Groups Links
>
>
>

RE: [Repeater-Builder] MSR2000 TRN9689 R1 Audio board schematic needed......

[Eric Lemmon]

Wayne,

In compliance with copyright infringement laws, you won't find Motorola
manuals on this site while they are still in print.  The detailed
information on the TRN9689 module is contained in the MSR2000 Control and
Applications manual 6881061E40, which is available for purchase from
Motorola Parts for about $60.

73, Eric Lemmon WB6FLY
 

-Original Message-
From: Repeater-Builder@yahoogroups.com
[mailto:repeater-buil...@yahoogroups.com] On Behalf Of Wayne
Sent: Wednesday, October 28, 2009 3:26 PM
To: Repeater-Builder@yahoogroups.com
Subject: [Repeater-Builder] MSR2000 TRN9689 R1 Audio board schematic
needed..

  

I am in need of the schematic for the TRN 9689 R1 Audio volume and squelch
board. Anyone that has a scanned or PDF file, I would appreciate a copy. I
have checked the RB web site and not found it.

Thank You

Wayne, WA5LUY

Re: [Repeater-Builder] Pager Interference to 2-meter & VHF Public Service Band

[MCH]

I have to wonder how he can say his stuff is clean when this just 
started a couple weeks ago. Did he perform a PM check within the last 
two weeks? Unlikely.

Stuff can go south in a minute, and seldom just before you check it.

Joe M.

Paul Plack wrote:
> 
> 
> Mike,
>  
> If it moves around based on time of day, my first guess is a PA that's 
> gone bad, and has a parasitic that's temperature-related.
>  
> If you've tracked an individual spur drifting 70 kHz up the band during 
> a single transmission, this is not some (intentional) oscillator 
> drifting, but some combination of failed components or tuning which has 
> produced a parasitic.
>  
> Sorry to say, but a paging transmitter owner swearing his stuff is clean 
> is pretty meaningless. The assumption in his industry is the 
> professionals who maintain his stuff are not the problem, it's "those 
> damn hams." Sadly, it may more often be the other way around these days, 
> as companies maintaining paging equipment have transitioned to 
> underpaid, under-trained card-swappers instead of component-level 
> technicians with a clue about RF systems.
>  
> 73,
> Paul, AE4KR
>  
> 
> - Original Message -
> *From:* Mike 
> *To:* Repeater-Builder@yahoogroups.com
> 
> *Sent:* Wednesday, October 28, 2009 12:28 PM
> *Subject:* [Repeater-Builder] Pager Interference to 2-meter & VHF
> Public Service Band
> 
>  
> 
> A couple of weeks ago, our repeater system started to experience
> interference from a paging system...
> 
> 
> ...one evening I tracked it from about 145.120 to 145.190 as it
> swept through each transmission...
> 
>  
> 
> .
> 
> 
> 
> 
> 
> 
> 
> 
> 
> Internal Virus Database is out of date.
> Checked by AVG - www.avg.com 
> Version: 8.5.387 / Virus Database: 270.13.38/2274 - Release Date: 07/31/09 
> 05:58:00
> 

Re: [Repeater-Builder] Pager Interference to 2-meter & VHF Public Service Band

[Joe]

Hello Mike.

The first clue is that the signal is moving up and down the 2 meter 
band.  This would tell me that something not frequency controlled is 
causing the interference.  Not frequency controlled would mean that the 
transmitter is not crystal or GPS locked to a specific frequency.  Now, 
something that is frequency controlled may be involved with the IMD mix, 
but the signal that is free running is possibly causing an IMD mix to 
drift.  I have seen this happen in a PA when it was NOT transmitting.  
We had a case of a paging transmitter PA that would go into self 
oscillation when it was not keyed by the exciter.  The PA had power to 
it at all times and it would create interference when it was idle.



Some random thoughts:

Your paging company signal may be mixing with it, but they may not be 
the culprit.

10AM can be busy time for a paging company, so the fact that it happens 
around that time would not be unusual.

How do you know the data is from a specific paging company?  Did you 
listen to their signal and the interference at the same time?  Is it 
exactly the same?

He says that he has remote control of the transmitters.  What happens 
when he shuts them both off?  As someone else pointed out, does he have 
a link frequency that he ties the sites together with?  The link 
transmitter may be causing the interference, or be part of the RF mix.

An IMD program will be useless to figure the IMD of a drifting 
transmitter that is part of a mix.

You said 462.850 and 462.925 are also involved.  What is on those 
frequencies?  Who is on these frequencies and how are they involved?

A lightning hit may have caused this all to happen.

In my last job I troubleshooted lots of interference.  You really need 
to take an antenna and directional find the source of the interference.  
It is time consuming, but will lead you to the physical source of the 
interference.  Don't be fooled that it is positively the paging 
companies fault, as it may just be a mix in some other service PA.  The 
last one I found was interference on a 53.85 Mhz repeater.  At first, 
the culprit seemed to be the NOAA weather station on 162.55Mhz.  NOAA 
weather audio was coming through the repeater crystal clear.  It turned 
out to be a telemetry station PA that was mixing  4 X 53.85 - 162.55 = 
52.85Mhz.  The mix was exactly on the input!  The telemetry station was 
owned by the water company that allowed us on the site, so we ended up 
moving the repeater to 53.71Mhz.  We could have pushed the water company 
to fix their equipment, but probably would have been asked to leave the 
site.  Sometimes diplomacy rules.

I worked for paging companies for quite awhile and know that they get a 
bad rap, probably rightfully so for the most part.  This sounds like the 
paging company is willing to work with you.  My gut feeling is that you 
are going to find something else causing the problem.  Again, diplomacy 
rules.

73, Joe, K1ike




Mike wrote:
> A couple of weeks ago, our repeater system started to experience interference 
> from a paging system.  The repeater is on 146.850 (-600 KHz), with the 
> antenna system about 120 feet up a water tower.  T

RE: [Repeater-Builder] Pager Interference to 2-meter & VHF Public Service Band

[Mike Besemer (WM4B)]

Strangely enough, I happen to be an O-O (as is the another club member, who
sponsors the 145.110 repeater. which is also being interfered with) and have
been in touch with our coordinator.  He's been very helpful in urging us
along and providing us guidance (or reassurance) that we're going about this
the right way.  He's also indicated that he's willing to go to ARRL HQ with
it if we need to and then let them go lateral to the FCC.  We had a great
experience with Laura Smith about a year ago when we needed help convincing
a banned user to stay off our systems.  It took one letter to her (complete
with recordings) and one phone call to get our banned user a nice letter
from Laura reminding him that he really couldn't afford to pay what she was
prepared to charge him for using our repeater!  So. I think that, armed with
enough ammunition, we can go that route.

 

However, I REALLY don't want to.  The fellow who owns the paging company has
tried to work with us, and although it's not going as fast as we'd like, I
understand that he's got a different motivation than we do.Aside from
that, he helped us out with a professional climbing crew a couple of years
ago, got us a good deal on a DB-224, and cut us a break on some hardline and
connectors.  The bottom line is, it's not a relationship we want to end
through a Federal intervention!  That being said, I HAVE reminded him that
he's admitted that we're carrying his data on our repeater, and whether or
not it's his equipment at fault or somebody else's, HE'S going to be the
first person they come looking for and it'll be a terrible pain in his butt.
and wallet.  He acknowledges that fact.  So. while I'd like for him to do
some things differently. I get where he's coming from and I appreciate that
he's helped as much as he has.

 

On the other hand, if it turns out to be equipment that belongs to another
company. I'll drop a dime in a heartbeat if I don't get satisfaction from
them!

 

73,

 

Mike

WM4B

 

From: Repeater-Builder@yahoogroups.com
[mailto:repeater-buil...@yahoogroups.com] On Behalf Of Paul Plack
Sent: Wednesday, October 28, 2009 7:48 PM
To: Repeater-Builder@yahoogroups.com
Subject: Re: [Repeater-Builder] Pager Interference to 2-meter & VHF Public
Service Band

 

  

Mike, the interference is clearly not caused by your own rusty roof, and is
both eggregious and easily documented. I know we hate to go there unless
it's a last resort, but I'll bet the FCC is almost as tired of non-compliant
pager systems as we are. Perhaps that "technique" would prove "motivating."

 

- Original Message - 

From: Mike Besemer (WM4B)   

To: Repeater-Builder@yahoogroups.com 

Sent: Wednesday, October 28, 2009 5:34 PM

Subject: RE: [Repeater-Builder] Pager Interference to 2-meter & VHF Public
Service Band

 

  

I'm with ya on your third paragraph.  We've worked well together so far, but
we have very different techniques and motivations... 

.

 
 

Re: [Repeater-Builder] Pager Interference to 2-meter & VHF Public Service Band

[Paul Plack]

Mike, the interference is clearly not caused by your own rusty roof, and is 
both eggregious and easily documented. I know we hate to go there unless it's a 
last resort, but I'll bet the FCC is almost as tired of non-compliant pager 
systems as we are. Perhaps that "technique" would prove "motivating."

  - Original Message - 
  From: Mike Besemer (WM4B) 
  To: Repeater-Builder@yahoogroups.com 
  Sent: Wednesday, October 28, 2009 5:34 PM
  Subject: RE: [Repeater-Builder] Pager Interference to 2-meter & VHF Public 
Service Band



  I'm with ya on your third paragraph.  We've worked well together so far, but 
we have very different techniques and motivations... 


  . 

  

Re: [Repeater-Builder] MSR2000 TRN9689 R1 Audio board schematic needed......

[George Henry]

Replied direct.




- Original Message - 
From: "Wayne" 
To: 
Sent: Wednesday, October 28, 2009 5:26 PM
Subject: [Repeater-Builder] MSR2000 TRN9689 R1 Audio board schematic 
needed..


I am in need of the schematic for the TRN 9689 R1 Audio volume and squelch 
board. Anyone that has a scanned or PDF file, I would  appreciate a copy. I 
have checked the RB web sight and not found it.

Thank You

Wayne, WA5LUY

RE: [Repeater-Builder] Pager Interference to 2-meter & VHF Public Service Band

[Mike Besemer (WM4B)]

Ya'll know as much as I do about what the paging equipment is.  I'm working
with limited knowledge. only what gets passed on to me from the owner.

 

I'll ask about that, as well as the exciter frequencies.

 

 

 

From: Repeater-Builder@yahoogroups.com
[mailto:repeater-buil...@yahoogroups.com] On Behalf Of Kevin King
Sent: Wednesday, October 28, 2009 6:02 PM
To: Repeater-Builder@yahoogroups.com
Subject: RE: [Repeater-Builder] Pager Interference to 2-meter & VHF Public
Service Band

 

  

I would look at the exciter freq on the uhf paging transmitter. 

It would help with some info on the paging transmitters. Model and such.

-Original Message-
From: Repeater-Builder@yahoogroups.com
 
[mailto:Repeater-Builder@yahoogroups.com
 ] On Behalf Of Mike
Sent: Wednesday, October 28, 2009 1:29 PM
To: Repeater-Builder@yahoogroups.com
 
Subject: [Repeater-Builder] Pager Interference to 2-meter & VHF Public
Service Band

A couple of weeks ago, our repeater system started to experience
interference from a paging system. The repeater is on 146.850 (-600 KHz),
with the antenna system about 120 feet up a water tower. The repeater
itself is an Advanced Communications System KRP-5000 running 35 watts
through a set of 4 WACOM cans. The feedline is 7/8" hardline feeding a
DB-224. All jumpers are RG-214 MILSPEC with MILSPEC connectors. This
system has been in service for years and has never given us any problems,
and we are the only ones at the site.

To be clear, the interference we are experiencing is clearly audible on the
repeater input. I have the capability to monitor via telephone and have
heard it on the receiver, and I've also traveled to the site and heard the
interference on my mobile radio hooked to the repeater antenna. The
interference is also audible on the input in various locations around town.
Also, the interference can be heard on the input regardless of whether or
not the repeater transmitter is on. It also continued to be present during
several days of continuous heavy rain. 

The interference typically shows up at least once a day, although some days
(rarely) it does not show up at all and other days it will show up several
times. Lately, it's been making an appearance around 10 a.m. and hangs
around for an hour or two. As it begins to disappear, it sounds as though
it is moving off frequency. 

This interference has also been heard on at least two other repeaters in the
area. One is about 22 air-miles from the 146.85 machine and is on 145.110
(-600 KHz). It has also been heard on or near the output frequency of that
machine, and one evening I tracked it from about 145.120 to 145.190 as it
swept through each transmission. The other repeater it has been heard on is
147.300 (+600 KHz). I also have reports from a neighboring county a
ham/deputy sheriff there has been hearing it on VHF public safety
frequencies. As you can see, it's all over the place.

I've been working with the owner of a local paging company and we can
clearly tell that the data we're hearing is coming from 152.480 and 462.775.
He has two sites (about 20 miles apart) that simulcasts on both frequencies
and when those transmitters are active it's easy to tell that the data is
the same. He also tells me that he can key each transmitter separately and
the data from each transmitter will be heard on our repeater. We also
believe that there are other systems on nearby frequencies that are being
heard on our repeater, specifically 462.850 and 462.925.

I've run IMD numbers on everything I can think of, but can't come up with a
common thread. For it to be moving all through the 2-meter band and for it
to be mixing with several different frequencies, it seems to me that it's
got to be very ugly and unstable. What am I missing here?

Mike
WM4B



Yahoo! Groups Links

RE: [Repeater-Builder] Pager Interference to 2-meter & VHF Public Service Band

[Mike Besemer (WM4B)]

Paul,

 

I'm with ya on your third paragraph.  We've worked well together so far, but
we have very different techniques and motivations.  

 

Right now, my motivation is to make is stop before I go crazy.  I'm hearing
paging tones in my sleep!  

 

I kinda think one of the sites took a lightning strike about the time this
started (we had a pretty good lightning event about that time), so I think
the PA is a good possibility.  Or an isolator/combiner.  

 

I'd like to have the first whack with a baseball bat when we find it!

 

73,

 

Mike

WM4B

 

From: Repeater-Builder@yahoogroups.com
[mailto:repeater-buil...@yahoogroups.com] On Behalf Of Paul Plack
Sent: Wednesday, October 28, 2009 6:29 PM
To: Repeater-Builder@yahoogroups.com
Subject: Re: [Repeater-Builder] Pager Interference to 2-meter & VHF Public
Service Band

 

  

Mike,

 

If it moves around based on time of day, my first guess is a PA that's gone
bad, and has a parasitic that's temperature-related.

 

If you've tracked an individual spur drifting 70 kHz up the band during a
single transmission, this is not some (intentional) oscillator drifting, but
some combination of failed components or tuning which has produced a
parasitic.

 

Sorry to say, but a paging transmitter owner swearing his stuff is clean is
pretty meaningless. The assumption in his industry is the professionals who
maintain his stuff are not the problem, it's "those damn hams." Sadly, it
may more often be the other way around these days, as companies maintaining
paging equipment have transitioned to underpaid, under-trained card-swappers
instead of component-level technicians with a clue about RF systems.

 

73,

Paul, AE4KR

 

- Original Message - 

From: Mike   

To: Repeater-Builder@yahoogroups.com 

Sent: Wednesday, October 28, 2009 12:28 PM

Subject: [Repeater-Builder] Pager Interference to 2-meter & VHF Public
Service Band

 

  

A couple of weeks ago, our repeater system started to experience
interference from a paging system...


...one evening I tracked it from about 145.120 to 145.190 as it swept
through each transmission...

 

.

 
 

[Repeater-Builder] MSR2000 TRN9689 R1 Audio board schematic needed......

[Wayne]

I am in need of the schematic for the TRN 9689 R1 Audio volume and squelch 
board. Anyone that has a scanned or PDF file, I would  appreciate a copy. I 
have checked the RB web sight and not found it.

Thank You

Wayne, WA5LUY

Re: [Repeater-Builder] Pager Interference to 2-meter & VHF Public Service Band

[Paul Plack]

Mike,

If it moves around based on time of day, my first guess is a PA that's gone 
bad, and has a parasitic that's temperature-related.

If you've tracked an individual spur drifting 70 kHz up the band during a 
single transmission, this is not some (intentional) oscillator drifting, but 
some combination of failed components or tuning which has produced a parasitic.

Sorry to say, but a paging transmitter owner swearing his stuff is clean is 
pretty meaningless. The assumption in his industry is the professionals who 
maintain his stuff are not the problem, it's "those damn hams." Sadly, it may 
more often be the other way around these days, as companies maintaining paging 
equipment have transitioned to underpaid, under-trained card-swappers instead 
of component-level technicians with a clue about RF systems.

73,
Paul, AE4KR

  - Original Message - 
  From: Mike 
  To: Repeater-Builder@yahoogroups.com 
  Sent: Wednesday, October 28, 2009 12:28 PM
  Subject: [Repeater-Builder] Pager Interference to 2-meter & VHF Public 
Service Band


A couple of weeks ago, our repeater system started to experience 
interference from a paging system...


  ...one evening I tracked it from about 145.120 to 145.190 as it swept through 
each transmission...


  . 

  

[Repeater-Builder] Re: Mitrek/MSR200 preamp needed

[Wayne]

For anyone that wants to do this I just finished hooking a non factory preamp 
to the pins where the factory unit plugged in and it did work. I used a plug 
from the junk box and kept the leads as short as possible with no connectors to 
eliminate loss. 
73 and thanks for all the replies

Wayne, WA5LUY

--- In Repeater-Builder@yahoogroups.com, "Wayne"  wrote:
>
> Hello Joe and every one else. 
> In case we can't find the factory version has anyone else tried hooking a 
> preamp to the pins where the factory version plugs in? That would put some 
> filter ahead of the preamp.
> 
> Wayne, WA5LUY
> 
> --- In Repeater-Builder@yahoogroups.com, "tahrens301"  wrote:
> >
> > Hi Joe,
> > 
> > I'm looking for one as well, if your junk box is that deep!
> > (VHF MSR2000)
> > 
> > Thanks,
> > 
> > Tim  W5FN
> > 
> > 
> > 
> > --- In Repeater-Builder@yahoogroups.com, "burkleo"  wrote:
> > >
> > > Wayne,
> > > I have had much better luck with Angle Linear preamps than the 
> > > Mitrek/MSR2000 units.
> > > 
> > > Chip does offer a Amateur Discount also.
> > > 
> > > If you absolutely have to have a factory preamp, I will look through my 
> > > MSR2000/Mitrek VHF units and see if I have one.
> > > 
> > > Joe - WA7JAW
> > > 
> > > --- In Repeater-Builder@yahoogroups.com, "Wayne"  wrote:
> > > >
> > > > I am in need of a HLD4051A or HLD4052A receiver preamp out of a Mitrek 
> > > > or MSR2000. This is the plug in preamp that goes in the helical 
> > > > resonator. This is for vhf 146.xx. If anyone has one or two let me know 
> > > > how much you want.
> > > > 
> > > > Thanks
> > > > Wayne
> > > >
> > >
> >
>

RE: [Repeater-Builder] Pager Interference to 2-meter & VHF Public Service Band

[Kevin King]

I would look at the exciter freq on the uhf paging transmitter. 

It would help with some info on the paging transmitters. Model and such.

-Original Message-
From: Repeater-Builder@yahoogroups.com
[mailto:repeater-buil...@yahoogroups.com] On Behalf Of Mike
Sent: Wednesday, October 28, 2009 1:29 PM
To: Repeater-Builder@yahoogroups.com
Subject: [Repeater-Builder] Pager Interference to 2-meter & VHF Public
Service Band

A couple of weeks ago, our repeater system started to experience
interference from a paging system.  The repeater is on 146.850 (-600 KHz),
with the antenna system about 120 feet up a water tower.  The repeater
itself is an Advanced Communications System KRP-5000 running 35 watts
through a set of 4 WACOM cans.  The feedline is 7/8" hardline feeding a
DB-224.  All jumpers are RG-214 MILSPEC with MILSPEC connectors.  This
system has been in service for years and has never given us any problems,
and we are the only ones at the site.

To be clear, the interference we are experiencing is clearly audible on the
repeater input.  I have the capability to monitor via telephone and have
heard it on the receiver, and I've also traveled to the site and heard the
interference on my mobile radio hooked to the repeater antenna.  The
interference is also audible on the input in various locations around town.
Also, the interference can be heard on the input regardless of whether or
not the repeater transmitter is on.  It also continued to be present during
several days of continuous heavy rain.  

The interference typically shows up at least once a day, although some days
(rarely) it does not show up at all and other days it will show up several
times.  Lately, it's been making an appearance around 10 a.m. and hangs
around for an hour or two.  As it begins to disappear, it sounds as though
it is moving off frequency.  

This interference has also been heard on at least two other repeaters in the
area.  One is about 22 air-miles from the 146.85 machine and is on 145.110
(-600 KHz).  It has also been heard on or near the output frequency of that
machine, and one evening I tracked it from about 145.120 to 145.190 as it
swept through each transmission.  The other repeater it has been heard on is
147.300 (+600 KHz).  I also have reports from a neighboring county a
ham/deputy sheriff there has been hearing it on VHF public safety
frequencies.  As you can see, it's all over the place.

I've been working with the owner of a local paging company and we can
clearly tell that the data we're hearing is coming from 152.480 and 462.775.
He has two sites (about 20 miles apart) that simulcasts on both frequencies
and when those transmitters are active it's easy to tell that the data is
the same.  He also tells me that he can key each transmitter separately and
the data from each transmitter will be heard on our repeater.  We also
believe that there are other systems on nearby frequencies that are being
heard on our repeater, specifically 462.850 and 462.925.

I've run IMD numbers on everything I can think of, but can't come up with a
common thread.  For it to be moving all through the 2-meter band and for it
to be mixing with several different frequencies, it seems to me that it's
got to be very ugly and unstable.  What am I missing here?

Mike
WM4B








Yahoo! Groups Links

Re: [Repeater-Builder] Anyone want BNC Pigtials One sided 12" to 18"

[AA8K73 GMail]

Thanks, got my BNC pigtails in good shape today.



bbfmrf wrote:
>  
> 
> Is anyone interested in some one sided BNC pigtails?
> 
> I have a bunch, (50+) of RG58U BNC Pigtails that were removed from a 
> rack mounted test jig. They range from 12 inches to 18 inches.
> 
> I hate to just throw them away, so I am offering them to anyone that may 
> want them.
> 
> I am asking $1.00 per dozen plus shipping just to cover my Paypal fees 
> and time.
> 
> Contact me directly at bbfmrf at yahoo.com if interested.
> 

Re: [Repeater-Builder] Repeater Kenwood TKR-720

[DCFluX]

The TKR-820 Manual should be close enough.

http://www.repeater-builder.com/kenwood/pdfs/tkr-820-svc-man-large.pdf

On Wed, Oct 28, 2009 at 3:43 AM, Gustavo(Pu3gbw)  wrote:

>
>
> Ok Richard!
> First very grateful for the return. But this link only has the scheme
> electrical her and I need is the User manual or operations manual.
>
> Again grateful
> Gustavo - Pu3gbw
>
>  *From:* Richard Fletcher 
> *Sent:* Wednesday, October 28, 2009 1:23 AM
> *To:* Repeater-Builder@yahoogroups.com
> *Subject:* Re: [Repeater-Builder] Repeater Kenwood TKR-720
>
>
>
>  Hello Gustavo, (in English)
>  Try this one and tell if you can use this or not. I hope it is what you
> are looking for.
> Cheers
> http://www.eserviceinfo.com/index.php?what=search2&searchstring=TKR-720
> In Portuguese
>  Olá Gustavo,
>
>   Tente este e dizer se você pode usar este ou não. Espero que seja o que
> você está procurando.
>
> abraço
>
> -Richard
>
>
>  --
> *From:* Gustavo (Pu3gbw) 
> *To:* Repeater-Builder@yahoogroups.com
> *Sent:* Tue, October 27, 2009 1:54:17 PM
> *Subject:* [Repeater-Builder] Repeater Kenwood TKR-720
>
>
>
> Greetings to all the group!
> Hello everybody I am a resident of the Brazilian city of São Lourenço do
> Sul, State of Rio Grande do Sul, which I am very sorry for layman
> the English language.
> I come to ask some of the friends who have possession of the old manual
> Repeater Kenwood TKR-720 model.
>
> Already grateful
> Gustavo - Pu3gbw
>
>
>
>
> 

Re: [Repeater-Builder] Repeater Kenwood TKR-720

[Gustavo(Pu3gbw)]

Ok Richard! 
First very grateful for the return. But this link only has the scheme 
electrical her and I need is the User manual or operations manual. 

Again grateful 
Gustavo - Pu3gbw


From: Richard Fletcher 
Sent: Wednesday, October 28, 2009 1:23 AM
To: Repeater-Builder@yahoogroups.com 
Subject: Re: [Repeater-Builder] Repeater Kenwood TKR-720


  
Hello Gustavo, (in English)
 Try this one and tell if you can use this or not. I hope it is what you are 
looking for.
Cheers
http://www.eserviceinfo.com/index.php?what=search2&searchstring=TKR-720

In Portuguese
Olá Gustavo, 

  Tente este e dizer se você pode usar este ou não. Espero que seja o que você 
está procurando. 

abraço

-Richard





From: Gustavo (Pu3gbw) 
To: Repeater-Builder@yahoogroups.com
Sent: Tue, October 27, 2009 1:54:17 PM
Subject: [Repeater-Builder] Repeater Kenwood TKR-720

  
Greetings to all the group! 
Hello everybody I am a resident of the Brazilian city of São Lourenço do Sul, 
State of Rio Grande do Sul, which I am very sorry for layman 
the English language. 
I come to ask some of the friends who have possession of the old manual 
Repeater Kenwood TKR-720 model. 

Already grateful 
Gustavo - Pu3gbw

Re: [Repeater-Builder] Pager Interference to 2-meter & VHF Public Service Band

[MCH]

Mixing products generally don't sweep through the spectrum, as usually 
both TXs are stable and the mix would be as well.

Joe M.

Matt Harker wrote:
> 
> 
> Sounds like a bad case of mixing products (i.e. 2A-B) where A is 
> frequency A and B is frequency B.  Several years ago, I helped cure a 
> similar problem on 146.820 MHz.  Turned out four transmitters were 
> involved in that fracas and it only took two to start the repeater howling.
>  
> 152.480 is one of the common paging frequencies.  There is another 
> around 157 MHz that is usually a troublemaker for 2m amateur 
> repeaters.  A lot paging transmitters are NOT properly filtered.  I have 
> run across some that were connected directly to the feedline and antenna 
> with no circulator, no isolator, nothing.  This is unacceptable 
> practice.  No transmitter or receiver should be looking directly into a 
> feedline at any fixed site where multiple transmitters are in operation 
> or, where interference could likely erupt.
>  
> I doubt the UHF paging transmitters has a whole lot to do with the 
> problem although there is a slim chance they might.  Chances are, the 
> VHF transmitter is the one involved. 
>  
> The next thing I'd be curious about, given the paging company's comments 
> about the ability to key the transmitters separately, is this:  How are 
> they getting the data from their offices to the transmitters?  By radio 
> link? By wireline? or both?  If by radio, therein may lie the second 
> transmitter in the mix.  If not, keep searching.
>  
> One thing to keep in mind with the spectrum analyzer is that it is not 
> likely as sensitive as the repeater's receiver.  Some spec an's are 
> pretty sensitive, others not so sensitive.  So you may want to visit the 
> paging site with it and see what you find.  Especially around 304.960 
> MHz which is the double of 152.480 MHz.
>  
>  
> KC5DBH Matt
> 
> 
> 
> *From:* Mike 
> *To:* Repeater-Builder@yahoogroups.com
> *Sent:* Wed, October 28, 2009 1:28:56 PM
> *Subject:* [Repeater-Builder] Pager Interference to 2-meter & VHF Public 
> Service Band
> 
> A couple of weeks ago, our repeater system started to experience 
> interference from a paging system.  The repeater is on 146.850 (-600 
> KHz), with the antenna system about 120 feet up a water tower.  The 
> repeater itself is an Advanced Communications System KRP-5000 running 35 
> watts through a set of 4 WACOM cans.  The feedline is 7/8" hardline 
> feeding a DB-224.  All jumpers are RG-214 MILSPEC with MILSPEC 
> connectors.  This system has been in service for years and has never 
> given us any problems, and we are the only ones at the site.
> 
> To be clear, the interference we are experiencing is clearly audible on 
> the repeater input.  I have the capability to monitor via telephone and 
> have heard it on the receiver, and I've also traveled to the site and 
> heard the interference on my mobile radio hooked to the repeater 
> antenna.  The interference is also audible on the input in various 
> locations around town.  Also, the interference can be heard on the input 
> regardless of whether or not the repeater transmitter is on.  It also 
> continued to be present during several days of continuous heavy rain. 
> 
> The interference typically shows up at least once a day, although some 
> days (rarely) it does not show up at all and other days it will show up 
> several times.  Lately, it's been making an appearance around 10 a.m. 
> and hangs around for an hour or two.  As it begins to disappear, it 
> sounds as though it is moving off frequency. 
> 
> This interference has also been heard on at least two other repeaters in 
> the area.  One is about 22 air-miles from the 146.85 machine and is on 
> 145.110 (-600 KHz).  It has also been heard on or near the output 
> frequency of that machine, and one evening I tracked it from about 
> 145.120 to 145.190 as it swept through each transmission.  The other 
> repeater it has been heard on is 147.300 (+600 KHz).  I also have 
> reports from a neighboring county a ham/deputy sheriff there has been 
> hearing it on VHF public safety frequencies.  As you can see, it's all 
> over the place.
> 
> I've been working with the owner of a local paging company and we can 
> clearly tell that the data we're hearing is coming from 152.480 and 
> 462.775.  He has two sites (about 20 miles apart) that simulcasts on 
> both frequencies and when those transmitters are active it's easy to 
> tell that the data is the same.  He also tells me that he can key each 
> transmitter separately and the data from each transmitter will be heard 
> on our repeater.  We also believe that there are other systems on nearby 
> frequencies that are being heard on our repeater, specifically 462.850 
> and 462.925.
> 
> I've run IMD numbers on everything I can think of, but can't come up 
> with a common thread.  For it to be moving all through t

Re: [Repeater-Builder] Pager Interference to 2-meter & VHF Public Service Band

[MCH]

Dirty paging TX. Seen that many times.

Joe M.

Mike wrote:
> A couple of weeks ago, our repeater system started to experience interference 
> from a paging system.  The repeater is on 146.850 (-600 KHz), with the 
> antenna system about 120 feet up a water tower.  The repeater itself is an 
> Advanced Communications System KRP-5000 running 35 watts through a set of 4 
> WACOM cans.  The feedline is 7/8" hardline feeding a DB-224.  All jumpers are 
> RG-214 MILSPEC with MILSPEC connectors.  This system has been in service for 
> years and has never given us any problems, and we are the only ones at the 
> site.
> 
> To be clear, the interference we are experiencing is clearly audible on the 
> repeater input.  I have the capability to monitor via telephone and have 
> heard it on the receiver, and I've also traveled to the site and heard the 
> interference on my mobile radio hooked to the repeater antenna.  The 
> interference is also audible on the input in various locations around town.  
> Also, the interference can be heard on the input regardless of whether or not 
> the repeater transmitter is on.  It also continued to be present during 
> several days of continuous heavy rain.  
> 
> The interference typically shows up at least once a day, although some days 
> (rarely) it does not show up at all and other days it will show up several 
> times.  Lately, it's been making an appearance around 10 a.m. and hangs 
> around for an hour or two.  As it begins to disappear, it sounds as though it 
> is moving off frequency.  
> 
> This interference has also been heard on at least two other repeaters in the 
> area.  One is about 22 air-miles from the 146.85 machine and is on 145.110 
> (-600 KHz).  It has also been heard on or near the output frequency of that 
> machine, and one evening I tracked it from about 145.120 to 145.190 as it 
> swept through each transmission.  The other repeater it has been heard on is 
> 147.300 (+600 KHz).  I also have reports from a neighboring county a 
> ham/deputy sheriff there has been hearing it on VHF public safety 
> frequencies.  As you can see, it's all over the place.
> 
> I've been working with the owner of a local paging company and we can clearly 
> tell that the data we're hearing is coming from 152.480 and 462.775.  He has 
> two sites (about 20 miles apart) that simulcasts on both frequencies and when 
> those transmitters are active it's easy to tell that the data is the same.  
> He also tells me that he can key each transmitter separately and the data 
> from each transmitter will be heard on our repeater.  We also believe that 
> there are other systems on nearby frequencies that are being heard on our 
> repeater, specifically 462.850 and 462.925.
> 
> I've run IMD numbers on everything I can think of, but can't come up with a 
> common thread.  For it to be moving all through the 2-meter band and for it 
> to be mixing with several different frequencies, it seems to me that it's got 
> to be very ugly and unstable.  What am I missing here?
> 
> Mike
> WM4B
> 
> 
> 
> 
> 
> 
> 
> 
> Yahoo! Groups Links
> 
> 
> 
> 

[Repeater-Builder] Re: Pager Interference to 2-meter & VHF Public Service Band

[larynl2]

We had a similar problem here years ago, caused by a city fire dispatch 
transmitter 30 miles away.  It had a spur that we could follow around in 
frequency too.  Our repeater is on 2M and their transmitter was on 154.37, if I 
remember.  Their transmitter was the entire cause of the problem; no mixing was 
involved.

I'd carefully check that, in fact, the suspect transmitters were disabled for 
the tests you mentioned.  The linking scheme to them is also suspect as 
suggested.  

Are you hearing any other audio in the spur?  If not I think it's a dirty 
transmitter; no mixing or intermod involved.

Laryn K8TVZ

Re: [Repeater-Builder] Pager Interference to 2-meter & VHF Public Service Band

[mwbesemer]

 Good question about how the data was getting to both transmitter 
sites.  I've been meaning to ask that question and keep forgetting.


I'll report back.

Mike
WM4B

On Wed, Oct 28, 2009 at 3:16 PM, Matt Harker wrote:


Sounds like a bad case of mixing products (i.e. 2A-B) where A is 
frequency A and B is frequency B.  Several years ago, I helped cure a 
similar problem on 146.820 MHz.  Turned out four transmitters were 
involved in that fracas and it only took two to start the repeater 
howling.


152.480 is one of the common paging frequencies.  There is another 
around 157 MHz that is usually a troublemaker for 2m amateur repeaters. 
A lot paging transmitters are NOT properly filtered.  I have run across 
some that were connected directly to the feedline and antenna with no 
circulator, no isolator, nothing.  This is unacceptable practice.  No 
transmitter or receiver should be looking directly into a feedline at 
any fixed site where multiple transmitters are in operation or, where 
interference could likely erupt.


I doubt the UHF paging transmitters has a whole lot to do with the 
problem although there is a slim chance they might.  Chances are, the 
VHF transmitter is the one involved.


The next thing I'd be curious about, given the paging company's comments 
about the ability to key the transmitters separately, is this:  How are 
they getting the data from their offices to the transmitters?  By radio 
link? By wireline? or both?  If by radio, therein may lie the second 
transmitter in the mix.  If not, keep searching.


One thing to keep in mind with the spectrum analyzer is that it is not 
likely as sensitive as the repeater's receiver.  Some spec an's are 
pretty sensitive, others not so sensitive.  So you may want to visit the 
paging site with it and see what you find.  Especially around 304.960 
MHz which is the double of 152.480 MHz.



KC5DBH Matt

___

From: Mike 
To: Repeater-Builder@ yahoogroups. com
Sent: Wed, October 28, 2009 1:28:56 PM
Subject: [Repeater-Builder] Pager Interference to 2-meter & VHF Public 
Service Band


A couple of weeks ago, our repeater system started to experience 
interference from a paging system.  The repeater is on 146.850 (-600 
KHz), with the antenna system about 120 feet up a water tower.  The 
repeater itself is an Advanced Communications System KRP-5000 running 35 
watts through a set of 4 WACOM cans.  The feedline is 7/8" hardline 
feeding a DB-224.  All jumpers are RG-214 MILSPEC with MILSPEC 
connectors.  This system has been in service for years and has never 
given us any problems, and we are the only ones at the  site.


To be clear, the interference we are experiencing is clearly audible on 
the repeater input.  I have the capability to monitor via telephone and 
have heard it on the receiver, and I've also traveled to the site and 
heard the interference on my mobile radio hooked to the repeater 
antenna.  The interference is also audible on the input in various 
locations around town.  Also, the interference can be heard on the input 
regardless of whether or not the repeater transmitter is on.  It also 
continued to be present during several days of continuous heavy rain.


The interference typically shows up at least once a day, although some 
days (rarely) it does not show up at all and other days it will show up 
several times.  Lately, it's been making an appearance around 10 a.m. 
and hangs around for an hour or two.  As it begins to disappear, it 
sounds as though it is moving off frequency.


This  interference has also been heard on at least two other repeaters 
in the area.  One is about 22 air-miles from the 146.85 machine and is 
on 145.110 (-600 KHz).  It has also been heard on or near the output 
frequency of that machine, and one evening I tracked it from about 
145.120 to 145.190 as it swept through each transmission.  The other 
repeater it has been heard on is 147.300 (+600 KHz).  I also have 
reports from a neighboring county a ham/deputy sheriff there has been 
hearing it on VHF public safety frequencies.  As you can see, it's all 
over the place.


I've been working with the owner of a local paging company and we can 
clearly tell that the data we're hearing is coming from 152.480 and 
462.775.  He has two sites (about 20 miles apart) that simulcasts on 
both frequencies and when those transmitters are active it's easy to 
tell that the data is the same.  He also tells me that he can key each 
transmitter  separately and the data from each transmitter will be heard 
on our repeater.  We also believe that there are other systems on nearby 
frequencies that are being heard on our repeater, specifically 462.850 
and 462.925.


I've run IMD numbers on everything I can think of, but can't come up 
with a common thread.  For it to be moving all through the 2-meter band 
and for it to be mixing with several different frequencies, it seems to 
me that it's got to be very ugly and unstable.  What am

Re: [Repeater-Builder] Pager Interference to 2-meter & VHF Public Service Band

[Matt Harker]

Sounds like a bad case of mixing products (i.e. 2A-B) where A is frequency A 
and B is frequency B.  Several years ago, I helped cure a similar problem on 
146.820 MHz.  Turned out four transmitters were involved in that fracas and it 
only took two to start the repeater howling.

152.480 is one of the common paging frequencies.  There is another around 157 
MHz that is usually a troublemaker for 2m amateur repeaters.  A lot paging 
transmitters are NOT properly filtered.  I have run across some that were 
connected directly to the feedline and antenna with no circulator, no isolator, 
nothing.  This is unacceptable practice.  No transmitter or receiver should be 
looking directly into a feedline at any fixed site where multiple transmitters 
are in operation or, where interference could likely erupt. 

I doubt the UHF paging transmitters has a whole lot to do with the problem 
although there is a slim chance they might.  Chances are, the VHF transmitter 
is the one involved.  

The next thing I'd be curious about, given the paging company's comments about 
the ability to key the transmitters separately, is this:  How are they getting 
the data from their offices to the transmitters?  By radio link? By wireline? 
or both?  If by radio, therein may lie the second transmitter in the mix.  If 
not, keep searching.

One thing to keep in mind with the spectrum analyzer is that it is not likely 
as sensitive as the repeater's receiver.  Some spec an's are pretty sensitive, 
others not so sensitive.  So you may want to visit the paging site with it and 
see what you find.  Especially around 304.960 MHz which is the double of 
152.480 MHz.
 
 KC5DBH Matt 





From: Mike 
To: Repeater-Builder@yahoogroups.com
Sent: Wed, October 28, 2009 1:28:56 PM
Subject: [Repeater-Builder] Pager Interference to 2-meter & VHF Public Service 
Band

A couple of weeks ago, our repeater system started to experience interference 
from a paging system.  The repeater is on 146.850 (-600 KHz), with the antenna 
system about 120 feet up a water tower.  The repeater itself is an Advanced 
Communications System KRP-5000 running 35 watts through a set of 4 WACOM cans.  
The feedline is 7/8" hardline feeding a DB-224.  All jumpers are RG-214 MILSPEC 
with MILSPEC connectors.  This system has been in service for years and has 
never given us any problems, and we are the only ones at the site.

To be clear, the interference we are experiencing is clearly audible on the 
repeater input.  I have the capability to monitor via telephone and have heard 
it on the receiver, and I've also traveled to the site and heard the 
interference on my mobile radio hooked to the repeater antenna.  The 
interference is also audible on the input in various locations around town.  
Also, the interference can be heard on the input regardless of whether or not 
the repeater transmitter is on.  It also continued to be present during several 
days of continuous heavy rain.  

The interference typically shows up at least once a day, although some days 
(rarely) it does not show up at all and other days it will show up several 
times.  Lately, it's been making an appearance around 10 a.m. and hangs around 
for an hour or two.  As it begins to disappear, it sounds as though it is 
moving off frequency.  

This interference has also been heard on at least two other repeaters in the 
area.  One is about 22 air-miles from the 146.85 machine and is on 145.110 
(-600 KHz).  It has also been heard on or near the output frequency of that 
machine, and one evening I tracked it from about 145.120 to 145.190 as it swept 
through each transmission.  The other repeater it has been heard on is 147.300 
(+600 KHz).  I also have reports from a neighboring county a ham/deputy sheriff 
there has been hearing it on VHF public safety frequencies.  As you can see, 
it's all over the place.

I've been working with the owner of a local paging company and we can clearly 
tell that the data we're hearing is coming from 152.480 and 462.775.  He has 
two sites (about 20 miles apart) that simulcasts on both frequencies and when 
those transmitters are active it's easy to tell that the data is the same.  He 
also tells me that he can key each transmitter separately and the data from 
each transmitter will be heard on our repeater.  We also believe that there are 
other systems on nearby frequencies that are being heard on our repeater, 
specifically 462.850 and 462.925.

I've run IMD numbers on everything I can think of, but can't come up with a 
common thread.  For it to be moving all through the 2-meter band and for it to 
be mixing with several different frequencies, it seems to me that it's got to 
be very ugly and unstable.  What am I missing here?

Mike
WM4B








Yahoo! Groups Links




  

Re: [Repeater-Builder] Pager Interference to 2-meter & VHF Public Service Band

[mwbesemer]

There are at least two transmitters at two sites... not likely they're 
all bad.  But... the owner has assured me they're clean and I haven't 
seen anything hokey on the spectrum analyzer from the repeater site.

Mike
WM4B

On Wed, Oct 28, 2009 at 2:46 PM, dmur...@verizon.net wrote:
Did you look a the output of the paging transmitters with a spectrum 
analyzer?




Oct 28, 2009 06:29:13 PM, Repeater-Builder@yahoogroups.com   wrote:









A couple of weeks ago, our repeater system started to experience 
interference from a paging system.  The repeater is on 146.850 (-600 
KHz), with the antenna system about 120 feet up a water tower.  The 
repeater itself is an Advanced Communications System KRP-5000 running 35 
watts through a set of 4 WACOM cans.  The feedline is 7/8" hardline 
feeding a DB-224.  All jumpers are RG-214 MILSPEC with MILSPEC 
connectors.  This system has been in service for years and has never 
given us any problems, and we are the only ones at the site.



  To be clear, the interference we are experiencing is clearly audible 
on the repeater input.  I have the capability to monitor via telephone 
and have heard it on the receiver, and I've also traveled to the site 
and heard the interference on my mobile radio hooked to the repeater 
antenna.  The interference is also audible on the input in various 
locations around town.  Also, the interference can be heard on the input 
regardless of whether or not the repeater transmitter is on.  It also 
continued to be present during several days of continuous heavy rain.



  The interference typically shows up at least once a day, although some 
days (rarely) it does not show up at all and other days it will show up 
several times.  Lately, it's been making an appearance around 10 a.m. 
and hangs around for an hour or two.  As it begins to disappear, it 
sounds as though it is moving off frequency.



  This interference has also been heard on at least two other repeaters 
in the area.  One is about 22 air-miles from the 146.85 machine and is 
on 145.110 (-600 KHz).  It has also been heard on or near the output 
frequency of that machine, and one evening I tracked it from about 
145.120 to 145.190 as it swept through each transmission.  The other 
repeater it has been heard on is 147.300 (+600 KHz).  I also have 
reports from a neighboring county a ham/deputy sheriff there has been 
hearing it on VHF public safety frequencies.  As you can see, it's all 
over the place.



  I've been working with the owner of a local paging company and we can 
clearly tell that the data we're hearing is coming from 152.480 and 
462.775.  He has two sites (about 20 miles apart) that simulcasts on 
both frequencies and when those transmitters are active it's easy to 
tell that the data is the same.  He also tells me that he can key each 
transmitter separately and the data from each transmitter will be heard 
on our repeater.  We also believe that there are other systems on nearby 
frequencies that are being heard on our repeater, specifically 462.850 
and 462.925.



  I've run IMD numbers on everything I can think of, but can't come up 
with a common thread.  For it to be moving all through the 2-meter band 
and for it to be mixing with several different frequencies, it seems to 
me that it's got to be very ugly and unstable.  What am I missing here?



  Mike

  WM4B























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[Repeater-Builder] Pager Interference to 2-meter & VHF Public Service Band

[Mike]

A couple of weeks ago, our repeater system started to experience interference 
from a paging system.  The repeater is on 146.850 (-600 KHz), with the antenna 
system about 120 feet up a water tower.  The repeater itself is an Advanced 
Communications System KRP-5000 running 35 watts through a set of 4 WACOM cans.  
The feedline is 7/8" hardline feeding a DB-224.  All jumpers are RG-214 MILSPEC 
with MILSPEC connectors.  This system has been in service for years and has 
never given us any problems, and we are the only ones at the site.

To be clear, the interference we are experiencing is clearly audible on the 
repeater input.  I have the capability to monitor via telephone and have heard 
it on the receiver, and I've also traveled to the site and heard the 
interference on my mobile radio hooked to the repeater antenna.  The 
interference is also audible on the input in various locations around town.  
Also, the interference can be heard on the input regardless of whether or not 
the repeater transmitter is on.  It also continued to be present during several 
days of continuous heavy rain.  

The interference typically shows up at least once a day, although some days 
(rarely) it does not show up at all and other days it will show up several 
times.  Lately, it's been making an appearance around 10 a.m. and hangs around 
for an hour or two.  As it begins to disappear, it sounds as though it is 
moving off frequency.  

This interference has also been heard on at least two other repeaters in the 
area.  One is about 22 air-miles from the 146.85 machine and is on 145.110 
(-600 KHz).  It has also been heard on or near the output frequency of that 
machine, and one evening I tracked it from about 145.120 to 145.190 as it swept 
through each transmission.  The other repeater it has been heard on is 147.300 
(+600 KHz).  I also have reports from a neighboring county a ham/deputy sheriff 
there has been hearing it on VHF public safety frequencies.  As you can see, 
it's all over the place.

I've been working with the owner of a local paging company and we can clearly 
tell that the data we're hearing is coming from 152.480 and 462.775.  He has 
two sites (about 20 miles apart) that simulcasts on both frequencies and when 
those transmitters are active it's easy to tell that the data is the same.  He 
also tells me that he can key each transmitter separately and the data from 
each transmitter will be heard on our repeater.  We also believe that there are 
other systems on nearby frequencies that are being heard on our repeater, 
specifically 462.850 and 462.925.

I've run IMD numbers on everything I can think of, but can't come up with a 
common thread.  For it to be moving all through the 2-meter band and for it to 
be mixing with several different frequencies, it seems to me that it's got to 
be very ugly and unstable.  What am I missing here?

Mike
WM4B

[Repeater-Builder] Re: Voice and digipeater on same antenna

[larynl2]

Yep thanx Frank, that's the article I was thinking about...

Laryn K8TVZ

Re: [Repeater-Builder] Tait UHF Standby Repeater D-Band

[Marcus]

yes i do have black faced 300 series

i also have a T346-03 Transmitter which is the same colour as the T856-24



Gareth Bennett wrote:
 


Marcus,
Do you realise that the Tait repeater that you have purchased has 50 
KHz channel spacing?
The T345 RX has a very different IF section compared to a 12.5 or 25 
KHz model T345 RX
You describe what probably was an ex Transpower radio link 
(Bearer) for protection signalling. The Transmitters were designed to 
run 10 Watts at 100% duty cycle. They were also configured as N+1 Hot 
standby links, hence the TX and RX monitor modules.
The T856-24 was a custom build by Tait Electronics for Transpower NZ, 
as the original T346 TX modules had lots of issues with P/A's etc and 
were deemed too unreliable, hence the swapout to a later T800 series TX.
If you are very unlucky, you have black faced T300 series equipment, 
The later stuff was straw colour, the same as the T800 radio.
 
They are not particularly friendly to convert back to a conventional 
voice repeater, especially without the proper manuals and test gear.
 
Cheers
 
Gareth Bennett
 


- Original Message -
*From:* Marcus 
*To:* Repeater-Builder@yahoogroups.com

*Sent:* Wednesday, October 28, 2009 8:04 PM
*Subject:* Re: [Repeater-Builder] Tait UHF Standby Repeater D-Band

 


Also i am running the system up on 465.61244 RX and 470.79996 TX
and the Transmiter i am running is a Tait T856-24 with a T341 Tx
Monitor
duplexor
T345 Receiver T343 Receiver Monitor + a text panel
 


Marcus

Re: [Repeater-Builder] Tait UHF Standby Repeater D-Band

[Gareth Bennett]

Marcus, 
Do you realise that the Tait repeater that you have purchased has 50 KHz 
channel spacing? 
The T345 RX has a very different IF section compared to a 12.5 or 25 KHz model 
T345 RX
You describe what probably was an ex Transpower radio link (Bearer) for 
protection signalling. The Transmitters were designed to run 10 Watts at 100% 
duty cycle. They were also configured as N+1 Hot standby links, hence the TX 
and RX monitor modules.
The T856-24 was a custom build by Tait Electronics for Transpower NZ, as the 
original T346 TX modules had lots of issues with P/A's etc and were deemed too 
unreliable, hence the swapout to a later T800 series TX.
If you are very unlucky, you have black faced T300 series equipment, The later 
stuff was straw colour, the same as the T800 radio.

They are not particularly friendly to convert back to a conventional voice 
repeater, especially without the proper manuals and test gear.

Cheers

Gareth Bennett

  - Original Message - 
  From: Marcus 
  To: Repeater-Builder@yahoogroups.com 
  Sent: Wednesday, October 28, 2009 8:04 PM
  Subject: Re: [Repeater-Builder] Tait UHF Standby Repeater D-Band


Also i am running the system up on 465.61244 RX and 470.79996 TX
  and the Transmiter i am running is a Tait T856-24 with a T341 Tx Monitor
  duplexor
  T345 Receiver T343 Receiver Monitor + a text panel
   

  Marcus


  Gareth Bennett wrote: 

  

Hi Marcus,
These come in all shapes and sizes, D band cavities are particularly hard 
to obtain at the best of times. Quite often cavities are not needed, especially 
if the Duplexer is a bandpass item.  these are usually added on a "per site" 
basis. 
It's good housekeeping to have a bandpass filter system, generally as the 
Tait duplexers are notch devices only.

Cheers

Gareth Bennett

(- Original Message - 
  From: Marcus 
  To: Repeater-Builder@yahoogroups.com 
  Sent: Monday, October 26, 2009 11:26 PM
  Subject: Re: [Repeater-Builder] Tait UHF Standby Repeater D-Band



  i have added your email addy to my address book in case i need any more 
duplexors

  what i need is a price first for a cavity filter or two

  not a duplexor, nor a diplexor, nor a arieal, nor anything else 

  am just after a price and availibility of Cavity filters

  Marcus



  Gareth Bennett wrote: 

  
Hi Marcus,

How many do you require, and what model Tait?

I have either T300 or T800 Series rackmount duplexers available

Cheers


Gareth Bennett

(- Original Message - 
  From: Marcus 
  To: Repeater-Builder@yahoogroups.com 
  Sent: Monday, October 26, 2009 1:30 PM
  Subject: [Repeater-Builder] Tait UHF Standby Repeater D-Band



  is there anyone on this list that resides in NZ and if so/not does 
  anyone have any Cavity filters, if so how much
  i have a Tait Repeater running D-BAND it was a backup system

  would like to get it running, forgive the contradiction, the system 
is 
  fully operational, i would like to put it to some use

  must be loads of points i have not mentioned, so if need be fire 
away, i 
  shall answer all my old almost had it brain can conjur up

  Marcus




  

Re: [Repeater-Builder] Tait UHF Standby Repeater D-Band

[Marcus]

Also i am running the system up on 465.61244 RX and 470.79996 TX
and the Transmiter i am running is a Tait T856-24 with a T341 Tx Monitor
duplexor
T345 Receiver T343 Receiver Monitor + a text panel


Marcus


Gareth Bennett wrote:
 


Hi Marcus,
These come in all shapes and sizes, D band cavities are particularly 
hard to obtain at the best of times. Quite often cavities are not 
needed, especially if the Duplexer is a bandpass item.  these are 
usually added on a "per site" basis.
It's good housekeeping to have a bandpass filter system, generally as 
the Tait duplexers are notch devices only.
 
Cheers
 
Gareth Bennett
 
(- Original Message -


*From:* Marcus 
*To:* Repeater-Builder@yahoogroups.com

*Sent:* Monday, October 26, 2009 11:26 PM
*Subject:* Re: [Repeater-Builder] Tait UHF Standby Repeater D-Band

 


i have added your email addy to my address book in case i need any
more duplexors

what i need is a price first for a cavity filter or two

not a duplexor, nor a diplexor, nor a arieal, nor anything else

am just after a price and availibility of Cavity filters

Marcus



Gareth Bennett wrote:

 
Hi Marcus,
 
How many do you require, and what model Tait?
 
I have either T300 or T800 Series rackmount duplexers available
 
Cheers
 
 
Gareth Bennett
 
(- Original Message -


*From:* Marcus 
*To:* Repeater-Builder@yahoogroups.com

*Sent:* Monday, October 26, 2009 1:30 PM
*Subject:* [Repeater-Builder] Tait UHF Standby Repeater D-Band

 


is there anyone on this list that resides in NZ and if so/not
does
anyone have any Cavity filters, if so how much
i have a Tait Repeater running D-BAND it was a backup system

would like to get it running, forgive the contradiction, the
system is
fully operational, i would like to put it to some use

must be loads of points i have not mentioned, so if need be
fire away, i
shall answer all my old almost had it brain can conjur up

Marcus