[Repeater-Builder] Selectone ST-815

[Doug Rehman]

I'm looking for any information on a Selectone ST-815 mobile DTMF decoder.
It's a small box, 2.75x1.5x2, with a monitor/reset button and a horn button
on the front. I don't see any info on the Selectone/Com-Spec website.

I need to know what the pin out on the back is and how it is programmed.

Thanks,
Doug
K4AC

RE: [Repeater-Builder] Repeater Transmitter matching

[Eric Lemmon]

Jeff,

We're on the same wavelength, and your explanation is easier to understand
than mine.

Several years ago, my radio club was running a Yaesu FT-2500M transceiver as
the 2m side of a packet node.  Since we had a nice hilltop site and a DB-225
antenna, I set the power level at the lowest of three options, 5 watts.
After being in service for more than a year, the radio went belly-up.  I
quickly determined that the RF power amplifier module had burned up.  We
bought a new module for about $90 and got the radio working just fine.
Before putting it back in service, I ran several bench tests on it.  Despite
Yaesu's claim that the radio should draw 12, 9, and 5 amperes, respectively,
at the 50, 25, and 5 watt power settings, I found that it drew about 12, 11,
and 10 amperes at those three power settings, which were very close to the
actual power outputs.  Thus, the radio was consuming about 138 watts of DC
input power when producing 5 watts of RF output power.  Do the math:  The
radio was running hotter at the lowest power setting!  When set for 50
watts, the radio was dissipating about 116 watts, but when set for 5 watts,
it was dissipating about 133 watts.  I attribute this lopsided energy
consumption to a very poor design that was made to meet a price target.

When I wrote my earlier post, I neglected to consider the small RF power
input of the exciter to the mix.  However, since most exciters in commercial
radios produce one watt or less, that contribution is swamped by the power
consumption of the PA, and really doesn't alter the outcome.

73, Eric Lemmon WB6FLY
 

-Original Message-
From: Repeater-Builder@yahoogroups.com
[mailto:repeater-buil...@yahoogroups.com] On Behalf Of Jeff DePolo
Sent: Friday, June 26, 2009 7:00 PM
To: Repeater-Builder@yahoogroups.com
Subject: RE: [Repeater-Builder] Repeater Transmitter matching



> What Jeff recommends is adjusting the 
> impedance matching
> device and/or the power setting so as to optimize the 
> efficiency. In other
> words, get more power to the antenna and reduce the amount of internal
> heating. It may turn out that the point of optimum efficiency 
> is not at the
> rated power output setting.

That's kinda what I was saying. You'll always be able to tune the Z-matcher
to find the load Z that yields the best efficiency *at whatever power level
you're targetting* (assuming the Z-matcher is able to yield that optimum Z),
but what that efficiency is (as a ratio of RF out to DC in) is going to
change depending on what power level you're targetting..

In the purest sense, if I'm understanding what Eric is saying, there will be
some power level at which the true maximum efficiency of the amplifier can
be found. That power level isn't necessarily (or likely) the power level
you're planning to operate it at. The PA may be 30% efficient at 50 watts
when the Z-matcher is optimized at that power level, 35% efficient at 75
watts when matched at that level, 40% efficient at 100 watts, etc. Chances
are you'll find the maximum efficiency lies close to, or possibly a bit
above, the rated output level. But that doesn't mean that the *dissipation*
is lowest at the power level that yields the best efficiency! It just means
that the ratio of RF out to DC in is at its peak efficiency, not that the
dissipation is at its minimum.

Did that make sense, or just confuse things?

--- Jeff

[Repeater-Builder] Ex Motorola Employees : Antenna Company

[Paul Metzger]

Looks like I found it. They are the Antenna Factory.

Paul Metzger
  

[Repeater-Builder] Ex Motorola Employees : Antenna Company

[Paul Metzger]

Does anyone know what the name of the Antenna Company is, who was  
composed of Ex-Motorola employees?

Also, if their still in business?


Paul Metzger

RE: [Repeater-Builder] Pass-Notch Duplexer Woes

[Jeff DePolo]

> Ok, now lets do the opposite. Set the spec analyzer to 147.1 & tune
> it up. Set up the sig gen @ 147.7 & UH OH, 2.5dB loss.

The stubs (which I take it you removed) alter the pass response.  They're
really notch cavities.  Adding the stubs will change the response adjacent
to the notch from "high pass" to "low pass".  Many notch cavities designs
are truly a notch; they have somewhat of a high-pass or low-pass effect.

> Am I doing something wrong?

Well, the only thing you're doing wrong (or maybe just haven't done yet) is
look at what the return loss is.  I'd be willing to bet that between the
wrong harness cable lengths and the missing stubs that the return loss is
pretty poor, especially with all eight cavities connected together.


--- Jeff WN3A

RE: [Repeater-Builder] MastrII Receiver Failure

[Jeff DePolo]

Chuck's got you going down the right path.  At 51 MHz, you probably only
have to take one turn off of each of the first two coils.  At 52 MHz or
higher, you might have to take off two.  You need a lot of heat to get the
casting open (hint: a soldering gun, even a 300 watt Weller, ain't gonna cut
it).  Removing the coils/caps once you have the casting apart is pretty
straightfoward, as is removing one turn from each.  It's not that bad of a
job once you've done one or two, but the first one may cause you some grief.
You should find that after the mods the receiver is plenty hot and should
easily beat spec by a few dB.  The LO/multiplier stages don't require any
mods.

If you want to cut corners, you might first see what your effective
sensitivity is at your repeater site on 6m.  You may find that the noise
floor is elevated substantially, and that getting the "bench" sensitivity
down from 1 uV to 0.3 uV isn't going to make a damned bit of difference in
the real world.

--- Jeff


> -Original Message-
> From: Repeater-Builder@yahoogroups.com 
> [mailto:repeater-buil...@yahoogroups.com] On Behalf Of Chris Curtis
> Sent: Friday, June 26, 2009 4:16 PM
> To: Repeater-Builder@yahoogroups.com
> Subject: RE: [Repeater-Builder] MastrII Receiver Failure
> 
> 
> 
> You are correct sir, no mesh.
> Isn't that that pits.
> 
> So I take it I'll be removing some windings from the underside of said
> trimmer caps?
> Or is there an easier route to sensitivity?
> =]
> 
> Chris,
> Kb0wlf
> 
> > -Original Message-
> > From: Repeater-Builder@yahoogroups.com 
>   [mailto:Repeater-
> > buil...@yahoogroups.com  
> ] On Behalf Of Chuck Kelsey
> > Sent: Friday, June 26, 2009 12:09 PM
> > To: Repeater-Builder@yahoogroups.com 
>  
> > Subject: Re: [Repeater-Builder] MastrII Receiver Failure
> > 
> > Do the two front end trimmer caps still have some "mesh" 
> left, or are
> > they
> > at minimum capacitance? That may be your problem.
> > 
> > Chuck
> > WB2EDV
> > 
> > 
> > 
> > - Original Message -
> > From: "Chris Curtis"   >
> > To:   >
> > Sent: Friday, June 26, 2009 10:45 AM
> > Subject: RE: [Repeater-Builder] MastrII Receiver Failure
> > 
> > 
> > I have a mastr EXEC II receiver (33 split) that I can't get 
> sensitivity
> > to
> > increase.
> > 
> > I replaced the fet as outlined below on the mastr II query.
> > No joy though.
> > 
> > I'm using an am/fm-1200s to tune the receiver.
> > 
> > .5~1uv is where the receiver is coming to life.
> > 
> > I have a couple vhf and uhf exec II receivers that tuned up 
> nicely in
> > the
> > .19~.2uv range so I "think" I'm doing/reading it correctly.
> > 
> > Original freq was in the 46~49mHz range.
> > Current crystal (icom sent to and received from Bomar) on 51.75mHz.
> > 
> > Any tips/hints/tricks to get a little more sensitivity?
> > 
> > Thanks for the bandwidth!
> > 
> > Chris
> > Kb0wlf
> > 
> 
> 
> 
> 
> 
> No virus found in this incoming message.
> Checked by AVG - www.avg.com
> Version: 8.5.339 / Virus Database: 270.12.85/2193 - Release 
> Date: 06/26/09 05:53:00
> 
> 
> 

RE: [Repeater-Builder] Repeater Transmitter matching

[Jeff DePolo]

> What Jeff recommends is adjusting the 
> impedance matching
> device and/or the power setting so as to optimize the 
> efficiency. In other
> words, get more power to the antenna and reduce the amount of internal
> heating. It may turn out that the point of optimum efficiency 
> is not at the
> rated power output setting.

That's kinda what I was saying.  You'll always be able to tune the Z-matcher
to find the load Z that yields the best efficiency *at whatever power level
you're targetting* (assuming the Z-matcher is able to yield that optimum Z),
but what that efficiency is (as a ratio of RF out to DC in) is going to
change depending on what power level you're targetting..

In the purest sense, if I'm understanding what Eric is saying, there will be
some power level at which the true maximum efficiency of the amplifier can
be found.  That power level isn't necessarily (or likely) the power level
you're planning to operate it at.  The PA may be 30% efficient at 50 watts
when the Z-matcher is optimized at that power level, 35% efficient at 75
watts when matched at that level, 40% efficient at 100 watts, etc.  Chances
are you'll find the maximum efficiency lies close to, or possibly a bit
above, the rated output level.  But that doesn't mean that the *dissipation*
is lowest at the power level that yields the best efficiency!  It just means
that the ratio of RF out to DC in is at its peak efficiency, not that the
dissipation is at its minimum.

Did that make sense, or just confuse things?

--- Jeff

[Repeater-Builder] Re: Pass-Notch Duplexer Woes

[tahrens301]

No - dB products




--- In Repeater-Builder@yahoogroups.com, DCFluX  wrote:
>
> Hmm, Reject only cans were found in Hybrid Ring duplexers. Is the
> manufacturer Sinclair?
> 
> On Fri, Jun 26, 2009 at 1:10 PM, tahrens301 wrote:
> >  Hi Folks,
> >
> > Here's the tale:
> >
> > Got a 'free' set of cans donated to our ham repeater project.
> > The tags inside say it was originally in the 162 range, but had
> > been re-tuned to the 154 range.
> >
> > Called the new owners of the dB product duplexer line, but it was
> > so old that they had no info.  Was a 'SP' product (special).
> >
> > Tech details:  Total of 8 cans, single entry point into the cavity,
> > with an SO-239 showing.  These had UHF 'T's that made the input &
> > output port.  On one set of 4, there was an additional 'T', in line
> > which had a 15 1/2" stub (end shorted) coming out of it.
> >
> > 1st, let's see the performance of a single can.  Remove the extra T
> > with the stub, so we have a single entry & output port.
> >
> > Plug one side into the spectrum analyzer, and the other into the tracking 
> > generator.  Dial up 147.7 on the analyzer, then tune to
> > center the notch.  Looks like about 18 dB worth of notch.
> >
> > Now, remove the track gen, plug that lead into a sig gen at 147.10.
> > Great!, looks like about .4 dB loss.
> >
> > Ok, now lets do the opposite.  Set the spec analyzer to 147.1 & tune
> > it up.  Set up the sig gen @ 147.7 & UH OH, 2.5dB loss.
> >
> > Looking back with the spec & trk gen, I can see the loss on the high
> > side.
> >
> > Both sets of cans exhibit the same performance.
> >
> > As they are, the 147.7 notch is fine & will pass the 147.1, but
> > reverse will end me up with about 10-12dB of loss.
> >
> > Am I doing something wrong?
> >
> > Thanks,
> >
> > Tim  W5FN
> >
> >
> >
> >
> > 
> >
> >
> >
> > Yahoo! Groups Links
> >
> >
> >
> >
>

RE: [Repeater-Builder] IFR 1500 Manual

[John Transue]

Joe,

Thanks. I have read the Application Notes in the RB files library.
Yes, it is very helpful. I am only guessing, but I think there must
also be a "Users Guide" or "Operator's Manual" or something of the
kind. I have received one response indicating there is such a thing,
and I have requested it be sent to me. So we will see.

Thanks for pointing out the good information in the RB files.

John

>-Original Message-
>From: Repeater-Builder@yahoogroups.com [mailto:Repeater-
>buil...@yahoogroups.com] On Behalf Of Joe
>Sent: Friday, June 26, 2009 7:32 PM
>To: Repeater-Builder@yahoogroups.com
>Subject: Re: [Repeater-Builder] IFR 1500 Manual
>
>I think that I may have just what you need.  It's called "Application
>Notes for the IFR-1500".  I started to scan it, but we are having
>severe
>lightning storms in the area and my UPS switched a few times.  In the
>Repeater-Builder area on YahooGroups, look at:
>
><http://groups.yahoo.com/group/Repeater-Builder/files/IFR1500/>
>
>If you want more, I'll scan it later.
>
>Others with IFR service monitors, or even other types, may want to
>look
>at this.  It gives basic setup configurations for testing.
>
>73, Joe, K1ike
>
>
>
>
>
>
>Yahoo! Groups Links
>
>
>
>
>__ NOD32 4193 (20090626) Information __
>
>This message was checked by NOD32 antivirus system.
>http://www.eset.com

Re: [Repeater-Builder] MastrII Receiver Failure

[Joe]

The manual states .25uV using 12-dB Sinad method, or .35uV using the 
Quieting Method.  I've always used the Sinad method and, to the best of 
my ability to remember, I was able to get .25uV or even a little better.

Joe

Chris Curtis wrote:
> A good question for you:
>
> What should I be looking for on these as far as sensitivity goes?
>
> Should I be happy if I see .35 or should I be able to get a little "more"?
>
> Chris
> Kb0wlf
>
>   
>> -Original Message-
>> From: Repeater-Builder@yahoogroups.com [mailto:Repeater-
>> buil...@yahoogroups.com] On Behalf Of Joe
>> Sent: Friday, June 26, 2009 3:45 PM
>> To: Repeater-Builder@yahoogroups.com
>> Subject: Re: [Repeater-Builder] MastrII Receiver Failure
>>
>> Did you first test it on it's original frequency before you retuned it?
>> It may have had a problem from the start.
>> 

Re: [Repeater-Builder] IFR 1500 Manual

[Joe]

I think that I may have just what you need.  It's called "Application 
Notes for the IFR-1500".  I started to scan it, but we are having severe 
lightning storms in the area and my UPS switched a few times.  In the 
Repeater-Builder area on YahooGroups, look at:



If you want more, I'll scan it later.

Others with IFR service monitors, or even other types, may want to look 
at this.  It gives basic setup configurations for testing.

73, Joe, K1ike

Re: [Repeater-Builder] Re: GE Mastr II Fuzzy audio

[Eric Lowell]

What frequency are you on?
 
I'll need to look at a schematic to come up with much.
 
73 de Eric

Eric Lowell
Eastern Maine Electronics Inc.
48 Loon Road
Wesley ME 04686
eme@starband.net
www.satnetmaine.com
207-210-7469

--- On Fri, 6/26/09, w4sef  wrote:


From: w4sef 
Subject: [Repeater-Builder] Re: GE Mastr II Fuzzy audio
To: Repeater-Builder@yahoogroups.com
Date: Friday, June 26, 2009, 6:14 PM








Hi Lowell,
Near the front end helical section of the reciever there are two crystals and a 
trimmer near them Also, 3 coils that need alignment. There are the ones I am 
talking about. I have a feeling that these are the ones that are not aligned 
properly. The reciever is very sensitive-about. 12 for 12 DB Sinad quieting but 
the audio, especially on a weak signal is distorted.
Thanks for any help.
Steve

- In Repeater-Builder@ yahoogroups. com, Eric Lowell  wrote:
>
> I looked through my notes on the UHF version and I did'nt see anything tricky 
> there. What do you mean by specialized equipment?
>  
> 73 de W1EL
> 
> Eric Lowell
> Eastern Maine Electronics Inc.
> 48 Loon Road
> Wesley ME 04686
> eme@...
> www.satnetmaine. com
> 207-210-7469
> 
> --- On Thu, 6/25/09, Eric Lowell  wrote:
> 
> 
> From: Eric Lowell 
> Subject: Re: [Repeater-Builder] GE Mastr II Fuzzy audio
> To: Repeater-Builder@ yahoogroups. com
> Date: Thursday, June 25, 2009, 9:31 PM
> 
> 
> 
> 
> 
> 
> 
> 
> 
> 
> 
> 
> 
> Seems like I used to have to inject the IF freq and tweek that up first. 
>  
> UHF or VHF? I'll look at my manuals tomorrow.
>  
> E
> 
> Eric Lowell
> Eastern Maine Electronics Inc.
> 48 Loon Road
> Wesley ME 04686
> eme@starband. net
> www.satnetmaine. com
> 207-210-7469
> 
> --- On Thu, 6/25/09, w4sef  wrote:
> 
> 
> From: w4sef 
> Subject: [Repeater-Builder] GE Mastr II Fuzzy audio
> To: Repeater-Builder@ yahoogroups. com
> Date: Thursday, June 25, 2009, 9:08 PM
> 
> 
> 
> 
> Hi all,
> 
> My spare Mastr II reciever audio is best decribed as "fuzzy/slightly 
> distorted.
> It seems worse on a weak noisy signal. I have checked the crystal frequency 
> and
> it is dead on. I went thru the reciever alignment and this reciever is really
> hot as far as quieting goes. I suspect the problem is misalignment in the 3
> coils and trimmer cap near the helical resonator section. According to what I
> have read in the manual it takes some specialized equipment that I don't have.
> Can anyone advise me as to a good way to check this alignment? I am new at the
> GE game so I appeciate any advice.
> 
> Thanks
> Steve W4SEF
>

















  

[Repeater-Builder] Re: GE Mastr II Fuzzy audio

[w4sef]

Hi Lowell,
Near the front end helical section of the reciever there are two crystals and a 
trimmer near them Also, 3 coils that need alignment. There are the ones I am 
talking about. I have a feeling that these are the ones that are not aligned 
properly. The reciever is very sensitive-about.12 for 12 DB Sinad quieting but 
the audio, especially on a weak signal is distorted.
Thanks for any help.
Steve

- In Repeater-Builder@yahoogroups.com, Eric Lowell  wrote:
>
> I looked through my notes on the UHF version and I did'nt see anything tricky 
> there. What do you mean by specialized equipment?
>  
> 73 de W1EL
> 
> Eric Lowell
> Eastern Maine Electronics Inc.
> 48 Loon Road
> Wesley ME 04686
> eme@...
> www.satnetmaine.com
> 207-210-7469
> 
> --- On Thu, 6/25/09, Eric Lowell  wrote:
> 
> 
> From: Eric Lowell 
> Subject: Re: [Repeater-Builder] GE Mastr II Fuzzy audio
> To: Repeater-Builder@yahoogroups.com
> Date: Thursday, June 25, 2009, 9:31 PM
> 
> 
> 
> 
> 
> 
> 
> 
> 
> 
> 
> 
> 
> Seems like I used to have to inject the IF freq and tweek that up first. 
>  
> UHF or VHF? I'll look at my manuals tomorrow.
>  
> E
> 
> Eric Lowell
> Eastern Maine Electronics Inc.
> 48 Loon Road
> Wesley ME 04686
> eme@starband. net
> www.satnetmaine. com
> 207-210-7469
> 
> --- On Thu, 6/25/09, w4sef  wrote:
> 
> 
> From: w4sef 
> Subject: [Repeater-Builder] GE Mastr II Fuzzy audio
> To: Repeater-Builder@ yahoogroups. com
> Date: Thursday, June 25, 2009, 9:08 PM
> 
> 
> 
> 
> Hi all,
> 
> My spare Mastr II reciever audio is best decribed as "fuzzy/slightly 
> distorted.
> It seems worse on a weak noisy signal. I have checked the crystal frequency 
> and
> it is dead on. I went thru the reciever alignment and this reciever is really
> hot as far as quieting goes. I suspect the problem is misalignment in the 3
> coils and trimmer cap near the helical resonator section. According to what I
> have read in the manual it takes some specialized equipment that I don't have.
> Can anyone advise me as to a good way to check this alignment? I am new at the
> GE game so I appeciate any advice.
> 
> Thanks
> Steve W4SEF
>

Re: [Repeater-Builder] Pass-Notch Duplexer Woes

[DCFluX]

Hmm, Reject only cans were found in Hybrid Ring duplexers. Is the
manufacturer Sinclair?

On Fri, Jun 26, 2009 at 1:10 PM, tahrens301 wrote:
>  Hi Folks,
>
> Here's the tale:
>
> Got a 'free' set of cans donated to our ham repeater project.
> The tags inside say it was originally in the 162 range, but had
> been re-tuned to the 154 range.
>
> Called the new owners of the dB product duplexer line, but it was
> so old that they had no info.  Was a 'SP' product (special).
>
> Tech details:  Total of 8 cans, single entry point into the cavity,
> with an SO-239 showing.  These had UHF 'T's that made the input &
> output port.  On one set of 4, there was an additional 'T', in line
> which had a 15 1/2" stub (end shorted) coming out of it.
>
> 1st, let's see the performance of a single can.  Remove the extra T
> with the stub, so we have a single entry & output port.
>
> Plug one side into the spectrum analyzer, and the other into the tracking 
> generator.  Dial up 147.7 on the analyzer, then tune to
> center the notch.  Looks like about 18 dB worth of notch.
>
> Now, remove the track gen, plug that lead into a sig gen at 147.10.
> Great!, looks like about .4 dB loss.
>
> Ok, now lets do the opposite.  Set the spec analyzer to 147.1 & tune
> it up.  Set up the sig gen @ 147.7 & UH OH, 2.5dB loss.
>
> Looking back with the spec & trk gen, I can see the loss on the high
> side.
>
> Both sets of cans exhibit the same performance.
>
> As they are, the 147.7 notch is fine & will pass the 147.1, but
> reverse will end me up with about 10-12dB of loss.
>
> Am I doing something wrong?
>
> Thanks,
>
> Tim  W5FN
>
>
>
>
> 
>
>
>
> Yahoo! Groups Links
>
>
>
>

RE: [Repeater-Builder] MastrII Receiver Failure

[Chris Curtis]

A good question for you:

What should I be looking for on these as far as sensitivity goes?

Should I be happy if I see .35 or should I be able to get a little "more"?

Chris
Kb0wlf

> -Original Message-
> From: Repeater-Builder@yahoogroups.com [mailto:Repeater-
> buil...@yahoogroups.com] On Behalf Of Joe
> Sent: Friday, June 26, 2009 3:45 PM
> To: Repeater-Builder@yahoogroups.com
> Subject: Re: [Repeater-Builder] MastrII Receiver Failure
> 
> Did you first test it on it's original frequency before you retuned it?
> It may have had a problem from the start.
> 
> Years ago, I tuned over 25 MastrII radios I got from the local state
> police to 52.525Mhz as a project.  Probably 2 or 3 of them would just
> not tune up properly in the ham band.  They are only specked out to
> 50Mhz, some may work above that frequency and a few may not.  I kept my
> bad ones for spare parts.  You may have one that just won't go above
> 50Mhz.  You can mod the one you have, or just buy another front end
> assembly.  I definitely would first test it at it's original frequency
> before I did any mods.
> 
> 73, Joe, K1ike
> 
> 
> Chris Curtis wrote:
> > I have a mastr EXEC II receiver (33 split) that I can't get
> sensitivity to
> > increase.
> 
> 
> 
> 
> 
> 
> 
> Yahoo! Groups Links
> 
> 
> 
> No virus found in this incoming message.
> Checked by AVG - www.avg.com
> Version: 8.5.375 / Virus Database: 270.12.83/2191 - Release Date:
> 06/26/09 05:53:00

RE: [Repeater-Builder] MastrII Receiver Failure

[Chris Curtis]

Yes.
I have 2 front ends to work with.
Both showed around .3uv or so @ 46.xxmHz

Chris,
Kb0wlf

> -Original Message-
> From: Repeater-Builder@yahoogroups.com [mailto:Repeater-
> buil...@yahoogroups.com] On Behalf Of Joe
> Sent: Friday, June 26, 2009 3:45 PM
> To: Repeater-Builder@yahoogroups.com
> Subject: Re: [Repeater-Builder] MastrII Receiver Failure
> 
> Did you first test it on it's original frequency before you retuned it?
> It may have had a problem from the start.
> 
> Years ago, I tuned over 25 MastrII radios I got from the local state
> police to 52.525Mhz as a project.  Probably 2 or 3 of them would just
> not tune up properly in the ham band.  They are only specked out to
> 50Mhz, some may work above that frequency and a few may not.  I kept my
> bad ones for spare parts.  You may have one that just won't go above
> 50Mhz.  You can mod the one you have, or just buy another front end
> assembly.  I definitely would first test it at it's original frequency
> before I did any mods.
> 
> 73, Joe, K1ike
> 
> 
> Chris Curtis wrote:
> > I have a mastr EXEC II receiver (33 split) that I can't get
> sensitivity to
> > increase.
> 
> 
> 
> 
> 
> 
> 
> Yahoo! Groups Links
> 
> 
> 
> No virus found in this incoming message.
> Checked by AVG - www.avg.com
> Version: 8.5.375 / Virus Database: 270.12.83/2191 - Release Date:
> 06/26/09 05:53:00

Re: [Repeater-Builder] MastrII Receiver Failure

[Joe]

Did you first test it on it's original frequency before you retuned it?  
It may have had a problem from the start.

Years ago, I tuned over 25 MastrII radios I got from the local state 
police to 52.525Mhz as a project.  Probably 2 or 3 of them would just 
not tune up properly in the ham band.  They are only specked out to 
50Mhz, some may work above that frequency and a few may not.  I kept my 
bad ones for spare parts.  You may have one that just won't go above 
50Mhz.  You can mod the one you have, or just buy another front end 
assembly.  I definitely would first test it at it's original frequency 
before I did any mods.

73, Joe, K1ike


Chris Curtis wrote:
> I have a mastr EXEC II receiver (33 split) that I can't get sensitivity to
> increase.

Re: [Repeater-Builder] Repeater Transmitter matching

[Joe]

Nate Duehr wrote:
> Turning them down (as we've all noted previously) does NOT always mean 
> that they run cooler due to the aforementioned inefficiency "built in" 
> to them, so to speak.  We've all seen that one with an IR temperature 
> measuring device pointed at the heatsink and/or power transistors.
>   

I had noticed that years ago when I tried to turn one down to less than 
half power.  I was watching the PA current reading at the test point and 
noticed that the power was going down, but the current was not.  I 
finally realized that the excess current was going someplace, and that 
was to make heat.  The current has to go somewhere

73, Joe, K1ike

Re: [Repeater-Builder] MastrII Receiver Failure

[Chuck Kelsey]

You could remove a turn (maybe even 1/2 turn) or you could change out the 
trimmer or add a series cap. Yep, it stinks when that happens. Many times 
another front end will work fine.

Chuck



- Original Message - 
From: "Chris Curtis" 
To: 
Sent: Friday, June 26, 2009 4:15 PM
Subject: RE: [Repeater-Builder] MastrII Receiver Failure


> You are correct sir, no mesh.
> Isn't that that pits.
>
> So I take it I'll be removing some windings from the underside of said
> trimmer caps?
> Or is there an easier route to sensitivity?
> =]
>
> Chris,
> Kb0wlf
>
>> -Original Message-
>> From: Repeater-Builder@yahoogroups.com [mailto:Repeater-
>> buil...@yahoogroups.com] On Behalf Of Chuck Kelsey
>> Sent: Friday, June 26, 2009 12:09 PM
>> To: Repeater-Builder@yahoogroups.com
>> Subject: Re: [Repeater-Builder] MastrII Receiver Failure
>>
>> Do the two front end trimmer caps still have some "mesh" left, or are
>> they
>> at minimum capacitance? That may be your problem.
>>
>> Chuck
>> WB2EDV
>>
>>
>>
>> - Original Message -
>> From: "Chris Curtis" 
>> To: 
>> Sent: Friday, June 26, 2009 10:45 AM
>> Subject: RE: [Repeater-Builder] MastrII Receiver Failure
>>
>>
>> I have a mastr EXEC II receiver (33 split) that I can't get sensitivity
>> to
>> increase.
>>
>> I replaced the fet as outlined below on the mastr II query.
>> No joy though.
>>
>> I'm using an am/fm-1200s to tune the receiver.
>>
>> .5~1uv is where the receiver is coming to life.
>>
>> I have a couple vhf and uhf exec II receivers that tuned up nicely in
>> the
>> .19~.2uv range so I "think" I'm doing/reading it correctly.
>>
>> Original freq was in the 46~49mHz range.
>> Current crystal (icom sent to and received from Bomar) on 51.75mHz.
>>
>> Any tips/hints/tricks to get a little more sensitivity?
>>
>> Thanks for the bandwidth!
>>
>> Chris
>> Kb0wlf
>>
>
>
>
> 
>
>
>
> Yahoo! Groups Links
>
>
>

RE: [Repeater-Builder] MastrII Receiver Failure

[Chris Curtis]

You are correct sir, no mesh.
Isn't that that pits.

So I take it I'll be removing some windings from the underside of said
trimmer caps?
Or is there an easier route to sensitivity?
=]

Chris,
Kb0wlf

> -Original Message-
> From: Repeater-Builder@yahoogroups.com [mailto:Repeater-
> buil...@yahoogroups.com] On Behalf Of Chuck Kelsey
> Sent: Friday, June 26, 2009 12:09 PM
> To: Repeater-Builder@yahoogroups.com
> Subject: Re: [Repeater-Builder] MastrII Receiver Failure
> 
> Do the two front end trimmer caps still have some "mesh" left, or are
> they
> at minimum capacitance? That may be your problem.
> 
> Chuck
> WB2EDV
> 
> 
> 
> - Original Message -
> From: "Chris Curtis" 
> To: 
> Sent: Friday, June 26, 2009 10:45 AM
> Subject: RE: [Repeater-Builder] MastrII Receiver Failure
> 
> 
> I have a mastr EXEC II receiver (33 split) that I can't get sensitivity
> to
> increase.
> 
> I replaced the fet as outlined below on the mastr II query.
> No joy though.
> 
> I'm using an am/fm-1200s to tune the receiver.
> 
> .5~1uv is where the receiver is coming to life.
> 
> I have a couple vhf and uhf exec II receivers that tuned up nicely in
> the
> .19~.2uv range so I "think" I'm doing/reading it correctly.
> 
> Original freq was in the 46~49mHz range.
> Current crystal (icom sent to and received from Bomar) on 51.75mHz.
> 
> Any tips/hints/tricks to get a little more sensitivity?
> 
> Thanks for the bandwidth!
> 
> Chris
> Kb0wlf
> 

[Repeater-Builder] Pass-Notch Duplexer Woes

[tahrens301]

  Hi Folks,

Here's the tale:

Got a 'free' set of cans donated to our ham repeater project.
The tags inside say it was originally in the 162 range, but had
been re-tuned to the 154 range.

Called the new owners of the dB product duplexer line, but it was
so old that they had no info.  Was a 'SP' product (special).

Tech details:  Total of 8 cans, single entry point into the cavity,
with an SO-239 showing.  These had UHF 'T's that made the input &
output port.  On one set of 4, there was an additional 'T', in line
which had a 15 1/2" stub (end shorted) coming out of it.

1st, let's see the performance of a single can.  Remove the extra T
with the stub, so we have a single entry & output port.

Plug one side into the spectrum analyzer, and the other into the tracking 
generator.  Dial up 147.7 on the analyzer, then tune to
center the notch.  Looks like about 18 dB worth of notch.

Now, remove the track gen, plug that lead into a sig gen at 147.10.
Great!, looks like about .4 dB loss.

Ok, now lets do the opposite.  Set the spec analyzer to 147.1 & tune
it up.  Set up the sig gen @ 147.7 & UH OH, 2.5dB loss.

Looking back with the spec & trk gen, I can see the loss on the high
side.

Both sets of cans exhibit the same performance.

As they are, the 147.7 notch is fine & will pass the 147.1, but
reverse will end me up with about 10-12dB of loss.

Am I doing something wrong?

Thanks,

Tim  W5FN 
 

Re: [Repeater-Builder] IFR 1500 Manual

[cruising7388]

 
Yes, I can help you.
 
K7IJ
 
 
In a message dated 6/26/2009 11:14:03 A.M. Pacific Daylight Time,  
jtran...@cox.net writes:

_Attachment(s)_ (mip://027f0310/default.html#TopText)  from John Transue  
included below] 

I just bought an IFR FM/AM 1500 service monitor. Now I need a  user's
manual. The service manual on RB and the applications booklet on  RB
are helpful, but the user's manual would be a big help. Please let  me
know if you have one that could be purchased or could be scanned  for
the RB manual archive.

John Transue AF4PD
703 534  5102





 
**Make your summer sizzle with fast and easy recipes for the 
grill. (http://food.aol.com/grilling?ncid=emlcntusfood0005)

[Repeater-Builder] IFR 1500 Manual [1 Attachment]

[John Transue]

I just bought an IFR FM/AM 1500 service monitor. Now I need a user's
manual. The service manual on RB and the applications booklet on RB
are helpful, but the user's manual would be a big help. Please let me
know if you have one that could be purchased or could be scanned for
the RB manual archive.

John Transue AF4PD
703 534 5102

Re: [Repeater-Builder] GE Mastr II Fuzzy audio

[Eric Lowell]

I looked through my notes on the UHF version and I did'nt see anything tricky 
there. What do you mean by specialized equipment?
 
73 de W1EL

Eric Lowell
Eastern Maine Electronics Inc.
48 Loon Road
Wesley ME 04686
eme@starband.net
www.satnetmaine.com
207-210-7469

--- On Thu, 6/25/09, Eric Lowell  wrote:


From: Eric Lowell 
Subject: Re: [Repeater-Builder] GE Mastr II Fuzzy audio
To: Repeater-Builder@yahoogroups.com
Date: Thursday, June 25, 2009, 9:31 PM













Seems like I used to have to inject the IF freq and tweek that up first. 
 
UHF or VHF? I'll look at my manuals tomorrow.
 
E

Eric Lowell
Eastern Maine Electronics Inc.
48 Loon Road
Wesley ME 04686
eme@starband. net
www.satnetmaine. com
207-210-7469

--- On Thu, 6/25/09, w4sef  wrote:


From: w4sef 
Subject: [Repeater-Builder] GE Mastr II Fuzzy audio
To: Repeater-Builder@ yahoogroups. com
Date: Thursday, June 25, 2009, 9:08 PM




Hi all,

My spare Mastr II reciever audio is best decribed as "fuzzy/slightly distorted.
It seems worse on a weak noisy signal. I have checked the crystal frequency and
it is dead on. I went thru the reciever alignment and this reciever is really
hot as far as quieting goes. I suspect the problem is misalignment in the 3
coils and trimmer cap near the helical resonator section. According to what I
have read in the manual it takes some specialized equipment that I don't have.
Can anyone advise me as to a good way to check this alignment? I am new at the
GE game so I appeciate any advice.

Thanks
Steve W4SEF


















  

Re: [Repeater-Builder] MastrII Receiver Failure

[Chuck Kelsey]

Do the two front end trimmer caps still have some "mesh" left, or are they 
at minimum capacitance? That may be your problem.

Chuck
WB2EDV



- Original Message - 
From: "Chris Curtis" 
To: 
Sent: Friday, June 26, 2009 10:45 AM
Subject: RE: [Repeater-Builder] MastrII Receiver Failure


I have a mastr EXEC II receiver (33 split) that I can't get sensitivity to
increase.

I replaced the fet as outlined below on the mastr II query.
No joy though.

I'm using an am/fm-1200s to tune the receiver.

.5~1uv is where the receiver is coming to life.

I have a couple vhf and uhf exec II receivers that tuned up nicely in the
.19~.2uv range so I "think" I'm doing/reading it correctly.

Original freq was in the 46~49mHz range.
Current crystal (icom sent to and received from Bomar) on 51.75mHz.

Any tips/hints/tricks to get a little more sensitivity?

Thanks for the bandwidth!

Chris
Kb0wlf

RE: [Repeater-Builder] repeater control card for master 2

[Eric Lemmon]

New London Technologies has 19D417385G1 Control Boards in stock at $35 each,
here:

Note that the G1 board is for applications without Channel Guard; the G2
board is for applications with CG, and those boards cost $85 each.

The information about the control board is found in LBI-30714, here:


73, Eric Lemmon WB6FLY



-Original Message-
From: Repeater-Builder@yahoogroups.com
[mailto:repeater-buil...@yahoogroups.com] On Behalf Of bratwhatwoman
Sent: Friday, June 26, 2009 8:51 AM
To: Repeater-Builder@yahoogroups.com
Subject: [Repeater-Builder] repeater control card for master 2



well here goes i would like to know if any has or knows where ican find the
plug in controlercard no 417385g1 kf4kqe

[Repeater-Builder] repeater control card for master 2

[bratwhatwoman]

well here goes i would like to know if any has or knows where ican find the 
plug in controlercard no 417385g1  kf4kqe

RE: [Repeater-Builder] Repeater Transmitter matching

[Eric Lemmon]

Although an infrared temperature meter will provide some very useful
information, perhaps a more practical method of determining PA efficiency is
the use of a DC ammeter and a accurate RF power meter.  Since PA efficiency
is the ratio of power out to power in, optimizing that ratio is
straightforward.  For example, if a PA is drawing 20 amperes at 14 VDC, the
power input is 280 watts.  If an accurate RF power meter shows that the
output power is 90 watts, then the efficiency is 90/280 or about 32%.  Since
90 watts is leaving the PA as RF power, the remaining 190 watts is spent
heating up the PA.  What Jeff recommends is adjusting the impedance matching
device and/or the power setting so as to optimize the efficiency.  In other
words, get more power to the antenna and reduce the amount of internal
heating.  It may turn out that the point of optimum efficiency is not at the
rated power output setting.

It's one thing to perform this efficiency test on the bench while feeding a
purely resistive dummy load, and quite another thing to perform it at the
site while feeding a reactive load such as an antenna or a duplexer.  That's
one reason why having an isolator at the PA output is a good thing- it
stabilizes the PA load at 50 ohms.  Even without an isolator, anything that
can be done to reduce the amount of real power expended in the PA
transistors will definitely prolong their lives.

73, Eric Lemmon WB6FLY
 

-Original Message-
From: Repeater-Builder@yahoogroups.com
[mailto:repeater-buil...@yahoogroups.com] On Behalf Of Nate Duehr
Sent: Thursday, June 25, 2009 11:51 PM
To: Repeater-Builder@yahoogroups.com
Subject: Re: [Repeater-Builder] Repeater Transmitter matching



Jeff DePolo wrote:

> The changes that occur are at source end inside the PA. The ideal load Z
> for the output devices changes when you vary the output power. If you
> "tune" the Z-matcher to present a load Z to the devices that results in
them
> operating at maximum efficiency at at 100 watts, and then reduce drive (or
> collector voltage) to yield only 30 watts, the load Z will likely not
yield
> max efficiency at the new power level.
> 
> Make more sense now?

Yup, got it. Your notes here and Bob's comments about the possible 
internal reasons why, and I'm all straightened out.

Interesting that as I think about it from a VERY high-level/general 
point of view... it seems that unless you're willing to take the time to 
do the measurements you've mentioned Jeff to get the maximum efficiency 
at the desired power level, the old saw of "Just run it flat out at 
rated power" for the old MASTR II PA, probably yields the best "general" 
advice for them, especially without a Z-matcher or isolator (!).

Turning them down (as we've all noted previously) does NOT always mean 
that they run cooler due to the aforementioned inefficiency "built in" 
to them, so to speak. We've all seen that one with an IR temperature 
measuring device pointed at the heatsink and/or power transistors.

The reason I mention all of the above... we were "holding back" a little 
more each time we swapped a VHF back when we had them popping like 
lightbulbs. For whatever non-scientific, non-engineering reasons, 
although I'm sure (until we learned better), we thought they would "run 
cooler" backed off 20-25W.

Now I'm starting to see the light as to why other sites (running flat 
out at rated power or REAL close to it with isolators and some with 
internal, some with external Z-matchers, just kept going like the 
Energizer bunny and the sites we had no antenna system problems (that we 
could ever find), kept popping VHF PAs. A later beautiful 
highly-detailed rebuild of the last remaining problem-child site not 
only saw us installing the cleanest rebuilt-from-mobile-parts MASTR II 
VHF PA at any of our sites, but we also let it cruise along at a bit 
higher power.

What say you guys to the idea that minus doing the testing "just run it" 
is good advice for someone incapable or unwilling to do that level of 
testing? I've been doing it now when I can, but we stopped the tsunami 
of dead VHF PA's after five (!) and I haven't had to worry about it 
since then.

BTW: The UHF PA's are tanks. ESPECIALLY the 75W version. NEVER seen 
one of those die, yet. Amazing little beasts. Seen one 100W UHF die in 
seven/eight years. (And we get a TON of lightning so sometimes damage 
occurs that we don't know about... maybe failing during the storm, maybe 
failing much later.)

Nate WY0X

RE: [Repeater-Builder] MastrII Receiver Failure

[Chris Curtis]

I have a mastr EXEC II receiver (33 split) that I can't get sensitivity to
increase.

I replaced the fet as outlined below on the mastr II query.
No joy though.

I'm using an am/fm-1200s to tune the receiver.

.5~1uv is where the receiver is coming to life.

I have a couple vhf and uhf exec II receivers that tuned up nicely in the
.19~.2uv range so I "think" I'm doing/reading it correctly.

Original freq was in the 46~49mHz range.
Current crystal (icom sent to and received from Bomar) on 51.75mHz.

Any tips/hints/tricks to get a little more sensitivity?

Thanks for the bandwidth!

Chris
Kb0wlf

> -Original Message-
> From: Repeater-Builder@yahoogroups.com [mailto:Repeater-
> buil...@yahoogroups.com] On Behalf Of DCFluX
> Sent: Saturday, June 20, 2009 4:13 PM
> To: Repeater-Builder@yahoogroups.com
> Subject: Re: [Repeater-Builder] MastrII Receiver Failure
> 
> Buy a couple of spares and keep them in the manual at the site.
> 
> On Sat, Jun 20, 2009 at 1:48 PM, Adam Feuer
> wrote:
> > Wow! Thanks for the tip.  I changed out that FET and the sensitivity
> is
> > back to normal. I went to Radio Shack and used an MPF-102.
> >
> > Now the question:  Do I put it back at the site with the Radio Shack
> > device? (I'm not sure who makes their transistors) Or do I order
> > something better?
> >
> > Thanks again!
> >
> > Adam N2ACF
> >
> >
> > DCFluX wrote:
> >> Replace the FET that is in the helical casting. on the RF Pre-
> selector
> >> board.  It is a 2N4416, Radioshack carries the MPF-102 as a readily
> >> available substitution. I'd use a J-310 if you have one.
> >>
> >> See:
> >> http://www.repeater-builder.com/ge/lbi-library/lbi-4991g.pdf
> >>
> >> On Fri, Jun 19, 2009 at 11:27 AM, Adam Feuer
> wrote:
> >>
> >>> Hello All
> >>>
> >>> I've had a MastrII low band receiver (29.540) on the air for close
> to 10
> >>> years now with no issues. It's been very sensitive and breaks
> squelch at
> >>> around .17uv.
> >>>
> >>> Recently, after a lightening storm, the receiver went deaf.  I went
> to
> >>> the site thinking that the antenna might have got struck by
> lightening
> >>> but it turns out that the receiver now breaks squelch and around
> 8uv.
> >>> (or whatever is in between the 5 and 10uv setting on my IFR1200S)
> The
> >>> antenna checks out fine.
> >>>
> >>> Having only tuned these receivers up and never having to trouble
> shoot a
> >>> failure, I'm wondering if anyone knows of a "smoking gun" when it
> comes
> >>> to a MastrII receiver failure like this. I'm going to dig out the
> book
> >>> and see what I can find but any help or guidance would be greatly
> >>> appreciated.
> >>>
> >>> Thanks in advance!
> >>>
> >>> Adam N2ACF
> >>>
> >>>
> >>> 
> >>>
> >>>
> >>>
> >>> Yahoo! Groups Links
> >>>
> >>>
> >>>
> >>>
> >>>
> >>
> >>
> >> 
> >>
> >>
> >>
> >> Yahoo! Groups Links
> >>
> >>
> >>
> >>
> >>
> >
> >
> >
> > 
> >
> >
> >
> > Yahoo! Groups Links
> >
> >
> >
> >
> 
> 
> 
> 
> 
> 
> Yahoo! Groups Links
> 
> 
> 
> No virus found in this incoming message.
> Checked by AVG - www.avg.com
> Version: 8.5.339 / Virus Database: 270.12.73/2180 - Release Date:
> 06/20/09 06:15:00

[Repeater-Builder] Re: two repeaters on the same antenna.

[kc7stw]

--- In Repeater-Builder@yahoogroups.com, "kc7stw"  wrote:

I would like to thank everyone who has posted.  This helps out quite allot.  I 
have been a big fan of this forum, and the repeater builder site.
  

Once again.  Thanks!