Re: [Repeater-Builder] Re: Radio for repeater use Response to Tom's comments

[Chuck Kelsey]

I'd suggest turning the power up more. You have it set at about 50% and the 
transmitter may be intermittently spurious at that level.

Watch the wattmeter when things act up and see if anything changes when you 
notice the desense happening. You can also pull the TX ICOM when the problem 
is happening and see if the receive clears up on the local speaker.

There are so many things that could be at fault - loose connector, bad 
antenna, problem with transmitter, problem with receiver, intermod issue, 
etc.

Ask the people you got the radio from if they had the same problem with it.

Chuck
WB2EDV



- Original Message - 
From: "W3ML" 
To: 
Sent: Monday, October 05, 2009 8:33 PM
Subject: [Repeater-Builder] Re: Radio for repeater use Response to Tom's 
comments


> Hi Tom,
>
>
>
> I did crank up the power to 55 watts out of radio and that gives me 45 out 
> of the duplexer.  Decided on this wattage until I can figure the problem 
> better. It is working better than before, but still having trouble.
>
> So from what you said about power coming out duplexer, the duplexer must 
> still be okay.
>
> However, during the day today there were 3 hams talking and they said 
> (later) that all of them were loud and clear. But, when I got home and 
> tried to call one of them, he was covered in noise.
>
> Later one of the others called in and he would be clear, then the repeater 
> would cut out and his signal would be gone, then it would come back with 
> noise on his signal and then clear again.
>
> Then the other one came in with a lot of noise, then he would come in with 
> a little noise and then no noise at all and then back again through this 
> cycle.
>
> This cycle of noise and then no noise is driving me crazy.
>
> The set up is this:
>
> GE Mastr II VHF mobile running into a 6 cavity duplexer set to our freqs 
> with a service monitor prior to bringing it here.
>
> There is a bandpass filter on the receive side after the duplexer and 
> before the radio.
>
> We have used 1/2 inch hardline going up to the used G7-144.
>
> Then only thing I can think of is the radio is bad, the antenna is no good 
> and the coax is shot.
>
> Now, the radio was given to us by a group that had used it, but decided to 
> replace it with a Kenwood.
>
> I am thinking that they had the same problem and that is why they gave it 
> away.
>
> Any advice would be greatly appreciated.
>
> 73
> John, W3ML
>
>
> - In Repeater-Builder@yahoogroups.com, W9SRV  wrote:
>>
>> Ok-
>>
>> 1. Where are you checking the swr at in the chain? Make sure you bypass 
>> the duplexers to check the antenna, the cans can throw off the reading on 
>> some meters like you describe using. If you are less than 1.5:1 I would 
>> not worry too much more about it, any reflected power will get eaten up 
>> back in the cans. If you are really concerned about protecting the TX put 
>> a circulator in-line with it.
>>
>> 2. Make sure all the interconnecting cables are good shielded and not 
>> foil/ braid type. RG-213 and RG-400 are good choices, though there are a 
>> few more.
>>
>> 3. Terminate into a good dummy load. Set you output power to 80-90W. Then 
>> run thru the duplexer and check the power coming out of the cans. You 
>> should see something like 60-70w, depending on the spec of the duplexer. 
>> If your seeing much less than you may have a duplexer tuning issue.
>>
>> Figure out the real problem, let the radio run at a real spec power 
>> output, than absorb the title of "far lord" as every one thanks you for 
>> giving the repeater twice as many s-units. (then be prepared for the next 
>> round of complaints that become your problem)
>>
>> Tom
>> W9SRV
>>
>> Sent from my iPhone
>>
>> On Oct 4, 2009, at 5:46 PM, "W3ML"  wrote:
>>
>> No, except when it was at the 2o watts the swr was almost 1 and someone 
>> said that was the problem causing the de-sense.  So we were afraid to run 
>> it higher.
>>
>> Like you said guess it was only a problem from running too little of 
>> power.
>>
>>
>> Thanks and 73
>> John
>>
>>
>> --- In Repeater-Builder@yahoogroups.com, W9SRV  wrote:
>>
>> You answered your own question :
>>
>> "So it appears that this radio, which is a GE Mastr II mobile, doesn't 
>> like to run at the lower wattage of 10 to 20 watts out."
>>
>> 110w radio will not be stable at 10-20w. If you look at your output on a 
>> spectrum you probably have spurs all over the place. Any reason you 
>> cannot run it at least 1/2-2/3 power?
>>
>> Tom
>> W9SRV
>>
>> Sent from my iPhone
>>
>> On Oct 4, 2009, at 4:46 PM, "W3ML"  wrote:
>>
>> So it appears that this radio, which is a GE Mastr II mobile, doesn't 
>> like to run at the lower wattage of 10 to 20 watts out.
>>
>>
>>
>>
>>
>> 
>>
>>
>>
>> Yahoo! Groups Links
>>
>
>
>
>
> 
>
>
>
> Yahoo! Groups Links
>
>
>
> 

Re: [Repeater-Builder] Re: Radio for repeater use Response to Tom's comments

[Tom Parker]

Hello W3ML,

I've been following this thread over the weekend and I think the issue 
has been addressed.  I would check the antenna and related connectors.  
In fact, for my 2 cents, I'd replace the G7 with a commercial grade 
antenna, such as a DB product or equal.  Now, to your scenario today, I 
would ask what the wind was like?  If memory serves me correctly, that 
G7 has a couple of joints and is somewhat flimsy in terms of material 
strength and antenna height. 


There ya go,

thp

W3ML wrote:
 


Hi Tom,

I did crank up the power to 55 watts out of radio and that gives me 45 
out of the duplexer. Decided on this wattage until I can figure the 
problem better. It is working better than before, but still having 
trouble.


So from what you said about power coming out duplexer, the duplexer 
must still be okay.


However, during the day today there were 3 hams talking and they said 
(later) that all of them were loud and clear. But, when I got home and 
tried to call one of them, he was covered in noise.


Later one of the others called in and he would be clear, then the 
repeater would cut out and his signal would be gone, then it would 
come back with noise on his signal and then clear again.


Then the other one came in with a lot of noise, then he would come in 
with a little noise and then no noise at all and then back again 
through this cycle.


This cycle of noise and then no noise is driving me crazy.

The set up is this:

GE Mastr II VHF mobile running into a 6 cavity duplexer set to our 
freqs with a service monitor prior to bringing it here.


There is a bandpass filter on the receive side after the duplexer and 
before the radio.


We have used 1/2 inch hardline going up to the used G7-144.

Then only thing I can think of is the radio is bad, the antenna is no 
good and the coax is shot.


Now, the radio was given to us by a group that had used it, but 
decided to replace it with a Kenwood.


I am thinking that they had the same problem and that is why they gave 
it away.


Any advice would be greatly appreciated.

73
John, W3ML

- In Repeater-Builder@yahoogroups.com 
, W9SRV  wrote:

>
> Ok-
>
> 1. Where are you checking the swr at in the chain? Make sure you 
bypass the duplexers to check the antenna, the cans can throw off the 
reading on some meters like you describe using. If you are less than 
1.5:1 I would not worry too much more about it, any reflected power 
will get eaten up back in the cans. If you are really concerned about 
protecting the TX put a circulator in-line with it.

>
> 2. Make sure all the interconnecting cables are good shielded and 
not foil/ braid type. RG-213 and RG-400 are good choices, though there 
are a few more.

>
> 3. Terminate into a good dummy load. Set you output power to 80-90W. 
Then run thru the duplexer and check the power coming out of the cans. 
You should see something like 60-70w, depending on the spec of the 
duplexer. If your seeing much less than you may have a duplexer tuning 
issue.

>
> Figure out the real problem, let the radio run at a real spec power 
output, than absorb the title of "far lord" as every one thanks you 
for giving the repeater twice as many s-units. (then be prepared for 
the next round of complaints that become your problem)

>
> Tom
> W9SRV
>
> Sent from my iPhone
>
> On Oct 4, 2009, at 5:46 PM, "W3ML"  wrote:
>
> No, except when it was at the 2o watts the swr was almost 1 and 
someone said that was the problem causing the de-sense. So we were 
afraid to run it higher.

>
> Like you said guess it was only a problem from running too little of 
power.

>
>
> Thanks and 73
> John
>
>
> --- In Repeater-Builder@yahoogroups.com 
, W9SRV  wrote:

>
> You answered your own question :
>
> "So it appears that this radio, which is a GE Mastr II mobile, 
doesn't like to run at the lower wattage of 10 to 20 watts out."

>
> 110w radio will not be stable at 10-20w. If you look at your output 
on a spectrum you probably have spurs all over the place. Any reason 
you cannot run it at least 1/2-2/3 power?

>
> Tom
> W9SRV
>
> Sent from my iPhone
>
> On Oct 4, 2009, at 4:46 PM, "W3ML"  wrote:
>
> So it appears that this radio, which is a GE Mastr II mobile, 
doesn't like to run at the lower wattage of 10 to 20 watts out.

>
>
>
>
>
> 
>
>
>
> Yahoo! Groups Links
>

Re: [Repeater-Builder] Re: Radio for repeater use Response to Tom's comments

[Lee Pennington]

I've been following it too. You can lead a horse to water, but you can't
make him drink.

K4LJP

On Mon, Oct 5, 2009 at 8:49 PM, Tom Parker  wrote:

>
>
> Hello W3ML,
>
> I've been following this thread over the weekend and I think the issue has
> been addressed.  I would check the antenna and related connectors.  In fact,
> for my 2 cents, I'd replace the G7 with a commercial grade antenna, such as
> a DB product or equal.  Now, to your scenario today, I would ask what the
> wind was like?  If memory serves me correctly, that G7 has a couple of
> joints and is somewhat flimsy in terms of material strength and antenna
> height.
>
> There ya go,
>
> thp
>
> W3ML wrote:
>
>
>
> Hi Tom,
>
> I did crank up the power to 55 watts out of radio and that gives me 45 out
> of the duplexer. Decided on this wattage until I can figure the problem
> better. It is working better than before, but still having trouble.
>
> So from what you said about power coming out duplexer, the duplexer must
> still be okay.
>
> However, during the day today there were 3 hams talking and they said
> (later) that all of them were loud and clear. But, when I got home and tried
> to call one of them, he was covered in noise.
>
> Later one of the others called in and he would be clear, then the repeater
> would cut out and his signal would be gone, then it would come back with
> noise on his signal and then clear again.
>
> Then the other one came in with a lot of noise, then he would come in with
> a little noise and then no noise at all and then back again through this
> cycle.
>
> This cycle of noise and then no noise is driving me crazy.
>
> The set up is this:
>
> GE Mastr II VHF mobile running into a 6 cavity duplexer set to our freqs
> with a service monitor prior to bringing it here.
>
> There is a bandpass filter on the receive side after the duplexer and
> before the radio.
>
> We have used 1/2 inch hardline going up to the used G7-144.
>
> Then only thing I can think of is the radio is bad, the antenna is no good
> and the coax is shot.
>
> Now, the radio was given to us by a group that had used it, but decided to
> replace it with a Kenwood.
>
> I am thinking that they had the same problem and that is why they gave it
> away.
>
> Any advice would be greatly appreciated.
>
> 73
> John, W3ML
>
> - In Repeater-Builder@yahoogroups.com ,
> W9SRV  wrote:
> >
> > Ok-
> >
> > 1. Where are you checking the swr at in the chain? Make sure you bypass
> the duplexers to check the antenna, the cans can throw off the reading on
> some meters like you describe using. If you are less than 1.5:1 I would not
> worry too much more about it, any reflected power will get eaten up back in
> the cans. If you are really concerned about protecting the TX put a
> circulator in-line with it.
> >
> > 2. Make sure all the interconnecting cables are good shielded and not
> foil/ braid type. RG-213 and RG-400 are good choices, though there are a few
> more.
> >
> > 3. Terminate into a good dummy load. Set you output power to 80-90W. Then
> run thru the duplexer and check the power coming out of the cans. You should
> see something like 60-70w, depending on the spec of the duplexer. If your
> seeing much less than you may have a duplexer tuning issue.
> >
> > Figure out the real problem, let the radio run at a real spec power
> output, than absorb the title of "far lord" as every one thanks you for
> giving the repeater twice as many s-units. (then be prepared for the next
> round of complaints that become your problem)
> >
> > Tom
> > W9SRV
> >
> > Sent from my iPhone
> >
> > On Oct 4, 2009, at 5:46 PM, "W3ML"   wrote:
> >
> > No, except when it was at the 2o watts the swr was almost 1 and someone
> said that was the problem causing the de-sense. So we were afraid to run it
> higher.
> >
> > Like you said guess it was only a problem from running too little of
> power.
> >
> >
> > Thanks and 73
> > John
> >
> >
> > --- In Repeater-Builder@yahoogroups.com,
> W9SRV  wrote:
> >
> > You answered your own question :
> >
> > "So it appears that this radio, which is a GE Mastr II mobile, doesn't
> like to run at the lower wattage of 10 to 20 watts out."
> >
> > 110w radio will not be stable at 10-20w. If you look at your output on a
> spectrum you probably have spurs all over the place. Any reason you cannot
> run it at least 1/2-2/3 power?
> >
> > Tom
> > W9SRV
> >
> > Sent from my iPhone
> >
> > On Oct 4, 2009, at 4:46 PM, "W3ML"  wrote:
> >
> > So it appears that this radio, which is a GE Mastr II mobile, doesn't
> like to run at the lower wattage of 10 to 20 watts out.
> >
> >
> >
> >
> >
> > 
> >
> >
> >
> > Yahoo! Groups Links
> >
>
>
>



-- 
"Always drink upstream from the herd."

RE: [Repeater-Builder] Re: Radio for repeater use Response to Tom's comments

[David Murman]

Sounds like he has a noise source near by causing him his problems. Probably
not in the repeater at all.  Had similar experience with a 50 mhz repeater
located on a mountain top. Grounding wasn't the best and any noise generated
by the wind moving the towers made the repeater at times almost unusable.
Times signals were full quieting and then they were noisy.

 

 

 

David

 

-Original Message-
From: Repeater-Builder@yahoogroups.com
[mailto:repeater-buil...@yahoogroups.com] On Behalf Of Chuck Kelsey
Sent: Monday, October 05, 2009 7:47 PM
To: Repeater-Builder@yahoogroups.com
Subject: Re: [Repeater-Builder] Re: Radio for repeater use Response to Tom's
comments

 

  

I'd suggest turning the power up more. You have it set at about 50% and the 
transmitter may be intermittently spurious at that level.

Watch the wattmeter when things act up and see if anything changes when you 
notice the desense happening. You can also pull the TX ICOM when the problem

is happening and see if the receive clears up on the local speaker.

There are so many things that could be at fault - loose connector, bad 
antenna, problem with transmitter, problem with receiver, intermod issue, 
etc.

Ask the people you got the radio from if they had the same problem with it.

Chuck
WB2EDV

- Original Message - 
From: "W3ML" mailto:w3ml%40arrl.net> >
To: mailto:Repeater-Builder%40yahoogroups.com>
yahoogroups.com>
Sent: Monday, October 05, 2009 8:33 PM
Subject: [Repeater-Builder] Re: Radio for repeater use Response to Tom's 
comments

> Hi Tom,
>
>
>
> I did crank up the power to 55 watts out of radio and that gives me 45 out

> of the duplexer. Decided on this wattage until I can figure the problem 
> better. It is working better than before, but still having trouble.
>
> So from what you said about power coming out duplexer, the duplexer must 
> still be okay.
>
> However, during the day today there were 3 hams talking and they said 
> (later) that all of them were loud and clear. But, when I got home and 
> tried to call one of them, he was covered in noise.
>
> Later one of the others called in and he would be clear, then the repeater

> would cut out and his signal would be gone, then it would come back with 
> noise on his signal and then clear again.
>
> Then the other one came in with a lot of noise, then he would come in with

> a little noise and then no noise at all and then back again through this 
> cycle.
>
> This cycle of noise and then no noise is driving me crazy.
>
> The set up is this:
>
> GE Mastr II VHF mobile running into a 6 cavity duplexer set to our freqs 
> with a service monitor prior to bringing it here.
>
> There is a bandpass filter on the receive side after the duplexer and 
> before the radio.
>
> We have used 1/2 inch hardline going up to the used G7-144.
>
> Then only thing I can think of is the radio is bad, the antenna is no good

> and the coax is shot.
>
> Now, the radio was given to us by a group that had used it, but decided to

> replace it with a Kenwood.
>
> I am thinking that they had the same problem and that is why they gave it 
> away.
>
> Any advice would be greatly appreciated.
>
> 73
> John, W3ML
>
>
> - In Repeater-Builder@ <mailto:Repeater-Builder%40yahoogroups.com>
yahoogroups.com, W9SRV  wrote:
>>
>> Ok-
>>
>> 1. Where are you checking the swr at in the chain? Make sure you bypass 
>> the duplexers to check the antenna, the cans can throw off the reading on

>> some meters like you describe using. If you are less than 1.5:1 I would 
>> not worry too much more about it, any reflected power will get eaten up 
>> back in the cans. If you are really concerned about protecting the TX put

>> a circulator in-line with it.
>>
>> 2. Make sure all the interconnecting cables are good shielded and not 
>> foil/ braid type. RG-213 and RG-400 are good choices, though there are a 
>> few more.
>>
>> 3. Terminate into a good dummy load. Set you output power to 80-90W. Then

>> run thru the duplexer and check the power coming out of the cans. You 
>> should see something like 60-70w, depending on the spec of the duplexer. 
>> If your seeing much less than you may have a duplexer tuning issue.
>>
>> Figure out the real problem, let the radio run at a real spec power 
>> output, than absorb the title of "far lord" as every one thanks you for 
>> giving the repeater twice as many s-units. (then be prepared for the next

>> round of complaints that become your problem)
>>
>> Tom
>> W9SRV
>>
>> Sent from my iPhone
>>
>> On Oct 4, 2009, at 5:46 PM, "W3ML"  wrote:
>>
>> No, except wh

RE: [Repeater-Builder] Re: Radio for repeater use Response to Tom's comments

[Mark]

John,

I'll chime in here and agree with Chuck's suggestion to try a little more
"fire in the wire"...  

It sounds as if your PA is less spurious now than before, but you need to
dial it up more to eliminate all the spurious products.  Solid state PAs,
especially mobiles, are noted for this when run at considerably less than
rated output.  If I remember the beginning of the thread, this was a
Mastr-II mobile...  

Seems as if I remember a rule of thumb that a solid state PA won't be stable
beginning around 60-70% of its rated output.  If you're at 55W now, another
10-15W won't make much difference in the received signal strength, but will
help a LOT to stabilize the PA.

This article: http://www.repeater-builder.com/ge/mastrIIgeneral.html says
not to run Mastr-II PAs at less than 40%.  In your case, you're at about 50%
now and still a little spurious, so... crank her up a tad more (to maybe
70W) and see if that clears it all up.  ;-)  The article also has other
suggestions on how to deal with desense.

73,
Mark - N9WYS

-Original Message-
From: Repeater-Builder@yahoogroups.com  On Behalf Of W3ML

I probably will turn it up more to see what happens.  When I had it at 5
watts out we had no problems at all.

Over the 10 watts is when the noise was really bad.  Now at 55 it works and
then it doesn't and then it works again.

So, yes I still have something wrong and maybe one of  these days I will get
another grant and convince the club to buy another GE Mastr II and and a new
antenna and coax. Maybe that will fix it.  

People we got radio from are not answering.

John


--- In Repeater-Builder@yahoogroups.com, "Chuck Kelsey"  wrote:
>
> I'd suggest turning the power up more. You have it set at about 50% and
the 
> transmitter may be intermittently spurious at that level.
> 
> Watch the wattmeter when things act up and see if anything changes when
you 
> notice the desense happening. You can also pull the TX ICOM when the
problem 
> is happening and see if the receive clears up on the local speaker.
> 
> There are so many things that could be at fault - loose connector, bad 
> antenna, problem with transmitter, problem with receiver, intermod issue, 
> etc.
> 
> Ask the people you got the radio from if they had the same problem with
it.
> 
> Chuck
> WB2EDV

Re: [Repeater-Builder] Re: Radio for repeater use Response to Tom's comments

[Tom Parker]

Mastr II is a good radio.  Likely not much wrong with it.  They're a 
great deal better than most of what you buy today; however, we're pretty 
impressed with the Kenwood TKR's in our shop for mid tier units.  Our 22 
trunk sites are made up of Micors, Mastr II's, Johnsons, and one site of 
MSR 2000's and one site of R1225's with Henry amps.  Most are five 
channel and up.  The TKR's are in stand alone situations or conventional 
users who own their on.


You ought to stick with what you have and work out the problems or get 
some help.


thp

W3ML wrote:
 

I probably will turn it up more to see what happens. When I had it at 
5 watts out we had no problems at all.


Over the 10 watts is when the noise was really bad. Now at 55 it works 
and then it doesn't and then it works again.


So, yes I still have something wrong and maybe one of these days I 
will get another grant and convince the club to buy another GE Mastr 
II and and a new antenna and coax. Maybe that will fix it.


People we got radio from are not answering.

John

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

>
> I'd suggest turning the power up more. You have it set at about 50% 
and the

> transmitter may be intermittently spurious at that level.
>
> Watch the wattmeter when things act up and see if anything changes 
when you
> notice the desense happening. You can also pull the TX ICOM when the 
problem

> is happening and see if the receive clears up on the local speaker.
>
> There are so many things that could be at fault - loose connector, bad
> antenna, problem with transmitter, problem with receiver, intermod 
issue,

> etc.
>
> Ask the people you got the radio from if they had the same problem 
with it.

>
> Chuck
> WB2EDV
>
>
>
> - Original Message -
> From: "W3ML" 
> To: >

> Sent: Monday, October 05, 2009 8:33 PM
> Subject: [Repeater-Builder] Re: Radio for repeater use Response to 
Tom's

> comments
>
>
> > Hi Tom,
> >
> >
> >
> > I did crank up the power to 55 watts out of radio and that gives 
me 45 out
> > of the duplexer. Decided on this wattage until I can figure the 
problem

> > better. It is working better than before, but still having trouble.
> >
> > So from what you said about power coming out duplexer, the 
duplexer must

> > still be okay.
> >
> > However, during the day today there were 3 hams talking and they said
> > (later) that all of them were loud and clear. But, when I got home 
and

> > tried to call one of them, he was covered in noise.
> >
> > Later one of the others called in and he would be clear, then the 
repeater
> > would cut out and his signal would be gone, then it would come 
back with

> > noise on his signal and then clear again.
> >
> > Then the other one came in with a lot of noise, then he would come 
in with
> > a little noise and then no noise at all and then back again 
through this

> > cycle.
> >
> > This cycle of noise and then no noise is driving me crazy.
> >
> > The set up is this:
> >
> > GE Mastr II VHF mobile running into a 6 cavity duplexer set to our 
freqs

> > with a service monitor prior to bringing it here.
> >
> > There is a bandpass filter on the receive side after the duplexer and
> > before the radio.
> >
> > We have used 1/2 inch hardline going up to the used G7-144.
> >
> > Then only thing I can think of is the radio is bad, the antenna is 
no good

> > and the coax is shot.
> >
> > Now, the radio was given to us by a group that had used it, but 
decided to

> > replace it with a Kenwood.
> >
> > I am thinking that they had the same problem and that is why they 
gave it

> > away.
> >
> > Any advice would be greatly appreciated.
> >
> > 73
> > John, W3ML
> >
> >
> > - In Repeater-Builder@yahoogroups.com 
, W9SRV  wrote:

> >>
> >> Ok-
> >>
> >> 1. Where are you checking the swr at in the chain? Make sure you 
bypass
> >> the duplexers to check the antenna, the cans can throw off the 
reading on
> >> some meters like you describe using. If you are less than 1.5:1 I 
would
> >> not worry too much more about it, any reflected power will get 
eaten up
> >> back in the cans. If you are really concerned about protecting 
the TX put

> >> a circulator in-line with it.
> >>
> >> 2. Make sure all the interconnecting cables are good shielded and 
not
> >> foil/ braid type. RG-213 and RG-400 are good choices, though 
there are a

> >> few more.
> >>
> >> 3. Terminate into a good dummy load. Set you output power to 
80-90W. Then
> >> run thru the duplexer and check the power coming out of the cans. 
You
> >> should see something like 60-70w, depending on the spec of the 
duplexer.

> >> If your seeing much less than you may have a duplexer tuning issue.
> >>
> >> Figure out the real problem, let the radio run at a real spec power
> >> output, than absorb the title of "far lord" as every one thanks 
you for
> >> giving the r

Re: [Repeater-Builder] Re: Radio for repeater use Response to Tom's comments

[Tom Parker]

Well then, that's what everyone on this group is here for.  All you have 
to do is ask, and you've done that.  All the advice tonight is valid, so 
now you need to make some measurements.  You definitely need an iso-tee, 
and good watt meter, i.e., Bird or Telewave, and a service monitor with 
at least a spectrum analyser would be a good start.  Read the RB page 
and follow the suggestions.  We actually had a couple of Mastr II 
mobiles rigged as repeaters, but we didn't de-rate the PA's.  They saw 
heavy use with zero problems for over ten years before we replaced them 
with stations.  Of course the tower building was a constant 74oF in the 
Texas sun and the A/C ran most of the winter.  It's a shame there's not 
another antenna on the tower you could "borrow" for a few minutes.


thp

W3ML wrote:

 


Thanks Tom,

Getting help around here is the hard part. I am the most experience 
and that is mostly from book reading and now a little playing around 
with the radio. No one else knows anything about repeaters either.


We are just now getting into the repeater stage for our club.

73
John

--- In Repeater-Builder@yahoogroups.com 
, Tom Parker  wrote:

>
> Mastr II is a good radio. Likely not much wrong with it. They're a
> great deal better than most of what you buy today; however, we're 
pretty

> impressed with the Kenwood TKR's in our shop for mid tier units. Our 22
> trunk sites are made up of Micors, Mastr II's, Johnsons, and one 
site of

> MSR 2000's and one site of R1225's with Henry amps. Most are five
> channel and up. The TKR's are in stand alone situations or conventional
> users who own their on.
>
> You ought to stick with what you have and work out the problems or get
> some help.
>
> thp
>
> W3ML wrote:
> >
> >
> > I probably will turn it up more to see what happens. When I had it at
> > 5 watts out we had no problems at all.
> >
> > Over the 10 watts is when the noise was really bad. Now at 55 it 
works

> > and then it doesn't and then it works again.
> >
> > So, yes I still have something wrong and maybe one of these days I
> > will get another grant and convince the club to buy another GE Mastr
> > II and and a new antenna and coax. Maybe that will fix it.
> >
> > People we got radio from are not answering.
> >
> > John
> >
> > --- In Repeater-Builder@yahoogroups.com 


> > , "Chuck Kelsey"
> >  wrote:
> > >
> > > I'd suggest turning the power up more. You have it set at about 50%
> > and the
> > > transmitter may be intermittently spurious at that level.
> > >
> > > Watch the wattmeter when things act up and see if anything changes
> > when you
> > > notice the desense happening. You can also pull the TX ICOM when 
the

> > problem
> > > is happening and see if the receive clears up on the local speaker.
> > >
> > > There are so many things that could be at fault - loose 
connector, bad

> > > antenna, problem with transmitter, problem with receiver, intermod
> > issue,
> > > etc.
> > >
> > > Ask the people you got the radio from if they had the same problem
> > with it.
> > >
> > > Chuck
> > > WB2EDV
> > >
> > >
> > >
> > > - Original Message -
> > > From: "W3ML" 
> > > To: 

> > >
> > > Sent: Monday, October 05, 2009 8:33 PM
> > > Subject: [Repeater-Builder] Re: Radio for repeater use Response to
> > Tom's
> > > comments
> > >
> > >
> > > > Hi Tom,
> > > >
> > > >
> > > >
> > > > I did crank up the power to 55 watts out of radio and that gives
> > me 45 out
> > > > of the duplexer. Decided on this wattage until I can figure the
> > problem
> > > > better. It is working better than before, but still having 
trouble.

> > > >
> > > > So from what you said about power coming out duplexer, the
> > duplexer must
> > > > still be okay.
> > > >
> > > > However, during the day today there were 3 hams talking and 
they said
> > > > (later) that all of them were loud and clear. But, when I got 
home

> > and
> > > > tried to call one of them, he was covered in noise.
> > > >
> > > > Later one of the others called in and he would be clear, then the
> > repeater
> > > > would cut out and his signal would be gone, then it would come
> > back with
> > > > noise on his signal and then clear again.
> > > >
> > > > Then the other one came in with a lot of noise, then he would 
come

> > in with
> > > > a little noise and then no noise at all and then back again
> > through this
> > > > cycle.
> > > >
> > > > This cycle of noise and then no noise is driving me crazy.
> > > >
> > > > The set up is this:
> > > >
> > > > GE Mastr II VHF mobile running into a 6 cavity duplexer set to 
our

> > freqs
> > > > with a service monitor prior to bringing it here.
> > > >
> > > > There is a bandpass filter on the receive side after the 
duplexer and

> > > > before the radio.
> > > >
> > > > W

RE: [Repeater-Builder] Re: Radio for repeater use Response to Tom's comments

[Eric Lemmon]

John,

One thing to keep in mind about a particular PA's tendency to "go spurious"
is that it will probably be well-behaved when tested on the bench while
feeding a dummy load.  A good dummy load is purely resistive, while a
duplexer input is highly reactive- just what a flaky PA needs as a trigger
to become unstable.  Any additional triggers, such as loose connections,
aging coax, or an antenna with loose elements, can quickly become a
nightmare.  It may be helpful to monitor your repeater's emissions on a
spectrum analyzer when the noise occurs.  Use a short whip on the analyzer
to pick up the signal- don't connect into the feedline at all, since doing
so will upset the conditions you want to monitor.  It's possible that the
radio itself may have a problem, and I don't think that has been ruled out
yet.

73, Eric Lemmon WB6FLY


-Original Message-
From: Repeater-Builder@yahoogroups.com
[mailto:repeater-buil...@yahoogroups.com] On Behalf Of W3ML
Sent: Monday, October 05, 2009 7:25 PM
To: Repeater-Builder@yahoogroups.com
Subject: [Repeater-Builder] Re: Radio for repeater use Response to Tom's
comments

  

Thanks Mark,

I will go read that article. Thought I read them all, since January, trying
to learn all I can.

That is when I decided to get into this repeater business. It has been a
great learning experience for sure.

73
John, W3ML

--- In Repeater-Builder@yahoogroups.com
 , "Mark"  wrote:
>
> John,
> 
> I'll chime in here and agree with Chuck's suggestion to try a little more
> "fire in the wire"... 
> 
> It sounds as if your PA is less spurious now than before, but you need to
> dial it up more to eliminate all the spurious products. Solid state PAs,
> especially mobiles, are noted for this when run at considerably less than
> rated output. If I remember the beginning of the thread, this was a
> Mastr-II mobile... 
> 
> Seems as if I remember a rule of thumb that a solid state PA won't be
stable
> beginning around 60-70% of its rated output. If you're at 55W now, another
> 10-15W won't make much difference in the received signal strength, but
will
> help a LOT to stabilize the PA.
> 
> This article: http://www.repeater-builder.com/ge/mastrIIgeneral.html
  says
> not to run Mastr-II PAs at less than 40%. In your case, you're at about
50%
> now and still a little spurious, so... crank her up a tad more (to maybe
> 70W) and see if that clears it all up. ;-) The article also has other
> suggestions on how to deal with desense.
> 
> 73,
> Mark - N9WYS
> 
> -Original Message-
> From: Repeater-Builder@yahoogroups.com
  On Behalf Of W3ML
> 
> I probably will turn it up more to see what happens. When I had it at 5
> watts out we had no problems at all.
> 
> Over the 10 watts is when the noise was really bad. Now at 55 it works and
> then it doesn't and then it works again.
> 
> So, yes I still have something wrong and maybe one of these days I will
get
> another grant and convince the club to buy another GE Mastr II and and a
new
> antenna and coax. Maybe that will fix it. 
> 
> People we got radio from are not answering.
> 
> John
> 
> 
> --- In Repeater-Builder@yahoogroups.com
 , "Chuck Kelsey" 
wrote:
> >
> > I'd suggest turning the power up more. You have it set at about 50% and
> the 
> > transmitter may be intermittently spurious at that level.
> > 
> > Watch the wattmeter when things act up and see if anything changes when
> you 
> > notice the desense happening. You can also pull the TX ICOM when the
> problem 
> > is happening and see if the receive clears up on the local speaker.
> > 
> > There are so many things that could be at fault - loose connector, bad 
> > antenna, problem with transmitter, problem with receiver, intermod
issue, 
> > etc.
> > 
> > Ask the people you got the radio from if they had the same problem with
> it.
> > 
> > Chuck
> > WB2EDV
>

Re: [Repeater-Builder] Re: Radio for repeater use Response to Tom's comments

[Chuck Kelsey]

That's typical. Duplex is a different animal. If there's a slight problem 
with a connection in the antenna, it will show up in duplex service.

Chuck
WB2EDV


- Original Message - 
From: "W3ML" 
To: 
Sent: Monday, October 05, 2009 10:54 PM
Subject: [Repeater-Builder] Re: Radio for repeater use Response to Tom's 
comments


> >
> Funny thing is when I hook the G7 to a regular 2 meter radio and transmit 
> on simplex, it works really well, hearing stations far a way and putting 
> out a solid signal.
>
> 73
> John
>
> 

RE: [Repeater-Builder] Re: Radio for repeater use Response to Tom's comments

[Eric Lemmon]

Tom,

You mentioned in an earlier posting that you had a six-cavity duplexer.
Most six-cavity duplexers will have an insertion loss of about 2.25 dB,
which means that with 70 watts in, you should see about 42 watts out.  If
you actually were measuring 45 watts out with 55 watts in, your duplexer has
an insertion loss of only 0.9 dB.  If your measurements are accurate, the
duplexer tuning seems to be way off.  What make and model duplexer is it?
What instrument are you using to measure RF power?

73, Eric Lemmon WB6FLY
 

-Original Message-
From: Repeater-Builder@yahoogroups.com
[mailto:repeater-buil...@yahoogroups.com] On Behalf Of W3ML
Sent: Monday, October 05, 2009 7:54 PM
To: Repeater-Builder@yahoogroups.com
Subject: [Repeater-Builder] Re: Radio for repeater use Response to Tom's
comments

  

Thanks Tom,

Yes, the advice is all good and I have tried several of the suggestions and
most, if not all, did help some.

Tomorrow, I will turn it up to 70 watts out, which should give me 60 out of
the duplexer, if it works like it does not at 55 and 45 out.

Then we will see what happens.

In fact I did hook it up to another antenna on an adjacent tower. It worked
worse than the G7.

Funny thing is when I hook the G7 to a regular 2 meter radio and transmit on
simplex, it works really well, hearing stations far a way and putting out a
solid signal.

73
John

--- In Repeater-Builder@yahoogroups.com
 , Tom Parker  wrote:
>
> Well then, that's what everyone on this group is here for. All you have 
> to do is ask, and you've done that. All the advice tonight is valid, so 
> now you need to make some measurements. You definitely need an iso-tee, 
> and good watt meter, i.e., Bird or Telewave, and a service monitor with 
> at least a spectrum analyser would be a good start. Read the RB page 
> and follow the suggestions. We actually had a couple of Mastr II 
> mobiles rigged as repeaters, but we didn't de-rate the PA's. They saw 
> heavy use with zero problems for over ten years before we replaced them 
> with stations. Of course the tower building was a constant 74oF in the 
> Texas sun and the A/C ran most of the winter. It's a shame there's not 
> another antenna on the tower you could "borrow" for a few minutes.
> 
> thp
> 
> W3ML wrote:
> 
> > 
> >
> > Thanks Tom,
> >
> > Getting help around here is the hard part. I am the most experience 
> > and that is mostly from book reading and now a little playing around 
> > with the radio. No one else knows anything about repeaters either.
> >
> > We are just now getting into the repeater stage for our club.
> >
> > 73
> > John
> >
> > --- In Repeater-Builder@yahoogroups.com
  
> > , Tom Parker  wrote:
> > >
> > > Mastr II is a good radio. Likely not much wrong with it. They're a
> > > great deal better than most of what you buy today; however, we're 
> > pretty
> > > impressed with the Kenwood TKR's in our shop for mid tier units. Our
22
> > > trunk sites are made up of Micors, Mastr II's, Johnsons, and one 
> > site of
> > > MSR 2000's and one site of R1225's with Henry amps. Most are five
> > > channel and up. The TKR's are in stand alone situations or
conventional
> > > users who own their on.
> > >
> > > You ought to stick with what you have and work out the problems or get
> > > some help.
> > >
> > > thp
> > >
> > > W3ML wrote:
> > > >
> > > >
> > > > I probably will turn it up more to see what happens. When I had it
at
> > > > 5 watts out we had no problems at all.
> > > >
> > > > Over the 10 watts is when the noise was really bad. Now at 55 it 
> > works
> > > > and then it doesn't and then it works again.
> > > >
> > > > So, yes I still have something wrong and maybe one of these days I
> > > > will get another grant and convince the club to buy another GE Mastr
> > > > II and and a new antenna and coax. Maybe that will fix it.
> > > >
> > > > People we got radio from are not answering.
> > > >
> > > > John
> > > >
> > > > --- In Repeater-Builder@yahoogroups.com
  
> > 
> > > > , "Chuck Kelsey"
> > > >  wrote:
> > > > >
> > > > > I'd suggest turning the power up more. You have it set at about
50%
> > > > and the
> > > > > transmitter may be intermittently spurious at that level.
> > > > >
> > > > > Watch the wattmeter when things act up and see if anything changes
> > > > when you
> > > > > notice the desense happening. You can also pull the TX ICOM when 
> > the
> > > > problem
> > > > > is happening and see if the receive clears up on the local
speaker.
> > > > >
> > > > > There are so many things that could be at fault - loose 
> > connector, bad
> > > > > antenna, problem with transmitter, problem with receiver, intermod
> > > > issue,
> > > > > etc.
> > > > >
> > > > > Ask the people you got the 

Re: [Repeater-Builder] Re: Radio for repeater use Response to Tom's comments

[TGundo 2003]

Well, you don't really need my input, you certainly have gotten plenty of 
quality responses tonight...

Don't let the flurry of ideas overwhelm you. Take it one step at a time. You 
still might be too low on the power output. I had a transmitter
that didnt like to be turned down less than 2/3 rated power, at 1/2
power it would create problems on the reciever, its spurs would mix
with some local 2-way stuff and come thru on the receiver from time to
time, had me convinced it was local interference and I needed
filtering. Turning up the power solved the problem. KISS method is
always a worth a try. There are way more qualified guys on the list here to 
help you, but here is what I would do (without having a spectrum analyzer to 
look at your output):

1. Terminate the TX into a dummy load. Turn the power up to 80W. Key the 
transmitter for a good long time and get it warmed up. Keep your wattmeter in 
line and watch it, make sure it stays stable at 80W. If you notice it acting up 
then you have a problem in the radio. If not- go to step two. 

2. Once the transmitter is nice and warmed up have someone with a weaker signal 
start giving you a signal on the input. Leave the transmitter hooked up to the 
dummy load for this test and the reciever hooked up to the antenna system. 
First, disable the transmitter and have them continue transmissions while you 
monitor the input. It may take several tests like this if it is outside 
interference, since it's likely not consistent. Try and notate any particular 
times of day the noise happens to get a better clue into this. If you do hear 
the noise, then you know its interference or something in the antenna system. 
If not, then move on to step three.

3. With your friend still sending a signal on the input enable the transmitter 
into the dummy load. If the noise appears then something in the radio is amiss, 
like the PA is going spurious or there's a bad jumper or connector somewhere . 
If not- move onto step four.

4. Reconnect everything back to normal. Leave the power level at 80W. If the 
noise re-appears then you still need to look into the antenna system. The G7 
could have a problem, or something in the feedline. If all is well then it was 
likely the power level of the PA was still too low. Problem solved!

Hopefully one of these steps without the proper test gear will get you pointed 
in the right direction. Let us know your findings!

Tom
W9SRV

--- On Mon, 10/5/09, W3ML  wrote:

From: W3ML 
Subject: [Repeater-Builder] Re: Radio for repeater use Response to Tom's 
comments
To: Repeater-Builder@yahoogroups.com
Date: Monday, October 5, 2009, 7:33 PM

Hi Tom,



I did crank up the power to 55 watts out of radio and that gives me 45 out of 
the duplexer.  Decided on this wattage until I can figure the problem better. 
It is working better than before, but still having trouble.

So from what you said about power coming out duplexer, the duplexer must still 
be okay.

However, during the day today there were 3 hams talking and they said (later) 
that all of them were loud and clear. But, when I got home and tried to call 
one of them, he was covered in noise.

Later one of the others called in and he would be clear, then the repeater 
would cut out and his signal would be gone, then it would come back with noise 
on his signal and then clear again.

Then the other one came in with a lot of noise, then he would come in with a 
little noise and then no noise at all and then back again through this cycle.
 
This cycle of noise and then no noise is driving me crazy.

The set up is this:

GE Mastr II VHF mobile running into a 6 cavity duplexer set to our freqs with a 
service monitor prior to bringing it here. 

There is a bandpass filter on the receive side after the duplexer and before 
the radio.

We have used 1/2 inch hardline going up to the used G7-144.

Then only thing I can think of is the radio is bad, the antenna is no good and 
the coax is shot.

Now, the radio was given to us by a group that had used it, but decided to 
replace it with a Kenwood.

I am thinking that they had the same problem and that is why they gave it away.

Any advice would be greatly appreciated. 

73
John, W3ML


- In Repeater-Builder@yahoogroups.com, W9SRV  wrote:
>
> Ok-
> 
> 1. Where are you checking the swr at in the chain? Make sure you bypass the 
> duplexers to check the antenna, the cans can throw off the reading on some 
> meters like you describe using. If you are less than 1.5:1 I would not worry 
> too much more about it, any reflected power will get eaten up back in the 
> cans. If you are really concerned about protecting the TX put a circulator 
> in-line with it. 
> 
> 2. Make sure all the interconnecting cables are good shielded and not foil/ 
> braid type. RG-213 and RG-400 are good choices, though there are a few more.
> 
> 3. Terminate into a good dummy load. Set you output power to 80-90W. Then run 
> thru the duplexer and check the power coming out of the cans

Re: [Repeater-Builder] Re: Radio for repeater use Response to Tom's comments

[Nate Duehr]

Just throwing a side-comment in here...

How do you know if a PA is spurious or if you're bothering your  
spectrum neighbors?  You MUST MEASURE IT.

Beg, borrow, or steal the proper test gear for working on repeaters  
and this whole "process of elimination by e-mail" disappears...

Spectrum analyzer, and/or a good RF Service Monitor, a known good- 
quality dummy load, "bias T" or directional coupler, high-quality  
double-shielded test cables, Bird or other good quality Wattmeter...  
all these things really SHOULD make their way into any Repeater- 
Builder's box of tricks, sooner or later.

We've ALL seen repeaters that "worked the 1st time out" without  
measuring anything.  We've all also seen repeater owners fight and  
claw and struggle for months trying to figure out a problem, without  
the proper test gear, and wondering if they'll ever figure it out.

It's s much less time-consuming and easier to just measure the  
repeater and find the problem than to go back and forth with symptoms  
and possible solutions.

When I started reading this thread, my first thought was "desense  
isn't caused by changes in RF power".  Of course, I also thought, "The  
MASTR II PA is known for going spurious at low power settings, wonder  
which PA he has... the little one with only a driver, or a 110W one  
that could likely freak out at that low a power."  Then the new  
symptom that measured SWR was changing with power level... "Oh man,  
that thing's probably throwing spurs", I thought to myself... but...

I kinda refuse to get into guessing games.  It just leads to making  
more problems you have to fix later if we all guess wrong.

The way to find out if the PA is spurring, is to look at the output of  
the repeater on a Spectrum Analyzer.

(And if you don't know, how do you know you're within your coordinated  
repeater spectrum limits?  Is there an adjacent pair repeater above/ 
below you?  Do you owe it to them to KNOW and not be guessing?)

Trying to troubleshoot repeaters without begging, borrowing, or  
stealing the proper test gear, is kinda like shooting fish in a  
barrel, but in a dark cave with no lights on...

You might hit the fish, or you might blow your foot off.

Don't wait until the adjacent repeater pair repeater owner sends you  
and the coordinator a nasty-gram.  Ya know?  If you're throwing spurs,  
you need to fix your station... and if you don't know if you're  
throwing spurs, you need to find out... and the only way to do that  
is...

Measure it.

--
Nate Duehr, WY0X
n...@natetech.com

Re: [Repeater-Builder] Re: Radio for repeater use Response to Tom's comments

[Nate Duehr]

P.S. Before I get flame-broiled by the group for "being mean"...

Realize that I'm not an ogre, and the answers you're getting from  
other folks might sound more friendly, and so far, they're all leading  
the right direction too, it'll just be a long "journey" to get there  
without the proper test gear.

None of the below is meant in anger or in any way "negative".  In  
fact, you MUST imagine me asking the questions below with a twinkle in  
my eye and a friendly inquisitive but forceful demeanor to "get" how I  
would ask the questions in person, if they were posed on the phone, or  
face-to-face.

A repeater guru who taught me once asked, with that same twinkle in  
his eye, right after I said that "I thought" XYZ was wrong with my  
repeater...

"Are you a thinkin' man, or are you a KNOWIN' man?"

:-) <--- NOTE BIG SMILE... and a real one on my face, typing this.

Here's something I've always wanted to do, but never had time... write  
up the learning process I personally went through, including ALL of  
the annoying things I've chased and troubleshot on repeaters that led  
me to buy (or beg, or steal... okay, not steal... but you know what I  
mean) the right test gear over the last number of years.  All those  
"learning experiences" put together in story format, might convince  
someone that:

a) Repeater operation just isn't for them.
b) Repeater operation is just bloody expensive to do right.
c) Repeater operators are crazy and often spend as much time/money/ 
effort on really well done repeaters as the most crazed HF contester  
does on his station.  (Yep! That's it!)

Nate WY0X

On Oct 5, 2009, at 11:37 PM, Nate Duehr wrote:

> Just throwing a side-comment in here...
>
> How do you know if a PA is spurious or if you're bothering your
> spectrum neighbors? You MUST MEASURE IT.
>
> Beg, borrow, or steal the proper test gear for working on repeaters
> and this whole "process of elimination by e-mail" disappears...
>
> Spectrum analyzer, and/or a good RF Service Monitor, a known good-
> quality dummy load, "bias T" or directional coupler, high-quality
> double-shielded test cables, Bird or other good quality Wattmeter...
> all these things really SHOULD make their way into any Repeater-
> Builder's box of tricks, sooner or later.
>
> We've ALL seen repeaters that "worked the 1st time out" without
> measuring anything. We've all also seen repeater owners fight and
> claw and struggle for months trying to figure out a problem, without
> the proper test gear, and wondering if they'll ever figure it out.
>
> It's s much less time-consuming and easier to just measure the
> repeater and find the problem than to go back and forth with symptoms
> and possible solutions.
>
> When I started reading this thread, my first thought was "desense
> isn't caused by changes in RF power". Of course, I also thought, "The
> MASTR II PA is known for going spurious at low power settings, wonder
> which PA he has... the little one with only a driver, or a 110W one
> that could likely freak out at that low a power." Then the new
> symptom that measured SWR was changing with power level... "Oh man,
> that thing's probably throwing spurs", I thought to myself... but...
>
> I kinda refuse to get into guessing games. It just leads to making
> more problems you have to fix later if we all guess wrong.
>
> The way to find out if the PA is spurring, is to look at the output of
> the repeater on a Spectrum Analyzer.
>
> (And if you don't know, how do you know you're within your coordinated
> repeater spectrum limits? Is there an adjacent pair repeater above/
> below you? Do you owe it to them to KNOW and not be guessing?)
>
> Trying to troubleshoot repeaters without begging, borrowing, or
> stealing the proper test gear, is kinda like shooting fish in a
> barrel, but in a dark cave with no lights on...
>
> You might hit the fish, or you might blow your foot off.
>
> Don't wait until the adjacent repeater pair repeater owner sends you
> and the coordinator a nasty-gram. Ya know? If you're throwing spurs,
> you need to fix your station... and if you don't know if you're
> throwing spurs, you need to find out... and the only way to do that
> is...
>
> Measure it.
>
> --
> Nate Duehr, WY0X
> n...@natetech.com

Re: [Repeater-Builder] Re: Radio for repeater use Response to Tom's comments

[Chuck Kelsey]

John -

A word of caution may be in order since you are dealing with a club.

These days, the typical ham doesn't begin to comprehend the complexity of a 
repeater system. To many, one simply needs to go out a purchase new 
equipment, plug it all together, and it runs. Wrong!

Don't let your club go down that path. The end result will be lots of money 
being spent and unhappy results. I've watched it happen.

If you are running a repeater, you WILL have problems with it, no matter 
what brand of equipment you use, no matter if it's new or used.

You appear to be taking the steps to learn about it. It's the only way 
you'll be able to cope unless the club pays a commercial two-way shop to 
maintain the system.

In the meantime, keep plugging away. It can get very frustrating at times.

Chuck
WB2EDV



- Original Message - 
>>
>> I will go read that article. Thought I read them all, since January, 
>> trying to learn all I can.
>>
>> That is when I decided to get into this repeater business.  It has been a 
>> great learning experience for sure.
>>
>> 73
>> John, W3ML
> 

Re: [Repeater-Builder] Re: Radio for repeater use Response to Tom's comments

[Eric Lowell]

Your antenna needs to come down and be gone over before you buy anything new. 
Those G7s will get bad connections in them that act like diodes and rectify all 
kinds of crud to desense your otherwise good system. I understand that there is 
a document on the RB site about refurbing that antenna. You may have heard this 
before.
 
Good Luck, Eric (W1EL)

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


--- On Tue, 10/6/09, W3ML  wrote:


From: W3ML 
Subject: [Repeater-Builder] Re: Radio for repeater use Response to Tom's 
comments
To: Repeater-Builder@yahoogroups.com
Date: Tuesday, October 6, 2009, 5:36 PM


  



Well Chuck, there will be no new radio unless I buy it out of my pocket and 
that won't happen as I need a new rotor.

This club has no money. I was able to get a grant for emergency communications 
and that is how I ended up with the stuff we have now.

My big problem seems to be that I took this radio in for free instead of buying 
one from that ham in Florida that sells GEs for repeaters.

As I have said before being a ham for 30 years now has taught me nothing about 
the maintenance of a repeater. I have built rigs before and trouble shot many a 
good HF radio, and now I am actually somewhat having fun playing with this 
thing.

I have done more reading on repeaters than I have at my regular job and that is 
the Teaching of English Literature.

Of course if we were to buy a new one, hi hi, then there would be nothing to 
learn and we all need to keep learning to keep our brains working.

I really appreciate everyone on here helping out not only myself, but the 
others that come on here who need help and are just starting out in this area 
of ham radio like me.

73
John

--- In Repeater-Builder@ yahoogroups. com, "Chuck Kelsey"  wrote:
>
> John -
> 
> A word of caution may be in order since you are dealing with a club.
> 
> These days, the typical ham doesn't begin to comprehend the complexity of a 
> repeater system. To many, one simply needs to go out a purchase new 
> equipment, plug it all together, and it runs. Wrong!
> 
> Don't let your club go down that path. The end result will be lots of money 
> being spent and unhappy results. I've watched it happen.
> 
> If you are running a repeater, you WILL have problems with it, no matter 
> what brand of equipment you use, no matter if it's new or used.
> 
> You appear to be taking the steps to learn about it. It's the only way 
> you'll be able to cope unless the club pays a commercial two-way shop to 
> maintain the system.
> 
> In the meantime, keep plugging away. It can get very frustrating at times.
> 
> Chuck
> WB2EDV
> 
> 
> 
> - Original Message - 
> >>
> >> I will go read that article. Thought I read them all, since January, 
> >> trying to learn all I can.
> >>
> >> That is when I decided to get into this repeater business. It has been a 
> >> great learning experience for sure.
> >>
> >> 73
> >> John, W3ML
> >
>

















  

Re: [Repeater-Builder] Re: Radio for repeater use Response to Tom's comments

[Ralph Mowery]

--- On Tue, 10/6/09, W3ML  wrote:

> From: W3ML 
> Subject: [Repeater-Builder] Re: Radio for repeater use Response to Tom's 
> comments
> To: Repeater-Builder@yahoogroups.com
> Date: Tuesday, October 6, 2009, 5:36 PM
> Well Chuck, there will be no new
>> 
> As I have said before being a ham for 30 years now has
> taught me nothing about the maintenance of a repeater. I
> have built rigs before and trouble shot many a good HF
> radio, and now I am actually somewhat having fun playing
> with this thing.
> 
> I have done more reading on repeaters than I have at my
> regular job and that is the Teaching of English Literature.
> 
>

When getting into the ham radio repeater business, have a good hammer ready.  
Either hit the repeater, the users or just hit yourself in the head.  I have 
been messing with the repeaters for over 30 years and have felt like doing all 
three.



  

Re: [Repeater-Builder] Re: Radio for repeater use Response to Tom's comments

[Nate Duehr]

On Oct 6, 2009, at 10:12 AM, Douglas wrote:

>
> Let me tell you a little story about this kind of problem. I had a  
> similar situation on a VHF mastr II repeater where a signal sounded  
> great one time and noisy the next. The problem turned out to be a  
> hairline crack in a solder pad that was used to bridge two circuit  
> boards and the output connectors to a circuit board, within the PA  
> assembly. It would run great power and then low power from one  
> transmission to the next. The output power would drop noticably as  
> seen on a relative signal meter on my rig. That was how I localized  
> it.
>
> When we would put a meter on the output, it had just enough sstress  
> on the cable to make a good connection and all was well, hookk it  
> back to the duplexer, and the intermittant problem returned.
>
> I suspect that same kind of thing could happen on a receiver  
> connection.
>
> The only real way to fix is to touch all the solder terminals that  
> are used for primary signal in the input or output route.
>
> Good luck. I liked to have lost my brain over that one (what brain  
> is left from the 60s).
>
> Doug
>
> KC0SDQ

MASTR II PA's can also make funny noises (really ugly stuff on a  
spectrum analyzer) if they're experiencing this type of crack at the  
PA output going into the harmonic filter board... you literally can  
HEAR it happening on the repeater's output.  Often the arcing  
happening over that joint "modulates" the FM signal in the form of a  
low-level squeal in the background of the repeater's signal, and/or a  
"frying" sound.  It's not pleasant, but also not always so bad you can  
hear it.

http://www.repeater-builder.com/ge/pix/mvc-474f.jpg

From:

http://www.repeater-builder.com/ge/mastrIIparepair.html

Look carefully.  Sometimes it's hard to spot.  There's a little strip  
of metal under that solder blob, that bridges that gap, which is  
almost under that capacitor.  Re-heating this area, you'll often find  
the problem, but be careful not to cook the cap.  We've done the  
"bump" fix, and we've also done the "just clean up the pads and re-use  
the factory metal strip" fix.  Can't say that either way is "better"  
when the screws surrounding the joint are torqued to factory  
specifications.  If either side is "loose", or "too tight" the boards  
will flex during heating and cooling and break the connection again.  
Had one that was so burnt the board itself and the "charcoal" became  
conductive and it would visibly arc over every time it was keyed.   
That one had to have both the final board and the harmonic filter  
board replaced, and was stinky.  Usually they're sneakier than that,  
though.

I was fighting with VHF PA's a couple of years ago, and when I finally  
enlisted the help of someone FAR more patient than I to completely  
rebuild one, including pulling ALL of the boards off the PA heatsink,  
scraping all of the old/dead heatsink compound off of everything and  
re-applying new, re-torquing all the screws to FACTORY specs (it's in  
the LBI, and many late model repeater PA's, not the mobiles usually,  
have stickers with the EXACT torque specs of all screw types on the PA  
board), resoldering every joint with good quality solder... etc.  A  
real "re-work" job.

This was done slowly and carefully by Scott W0KU... then following the  
"rule" we've given ourselves that ALL MASTR II PAs get an isolator...

His rebuilt PA has gone through antenna hell (long story, but let's  
just say it wasn't radiating, feeding into the isolator at 85W  
continuous for hours and hours) plus has also worked great on-the-air  
for three years now.

I now really believe that these 30 year old PA's just need a little  
bench TLC before they go up to a site, and I'm MORE than willing to go  
work them over thoroughly, and buy beers for Scott to enjoy in his  
backyard shed after the soldering and tricky stuff is done with.

I rebuilt two, they died.  Scott rebuilt one, after I explained what I  
thought I'd rushed through, or done badly, and how frustrating it was  
to see two of them die... we made a plan to meet up and work slowly  
and carefully and do a complete tear-down and rebuild on one utilizing  
whatever boards/parts we had on-hand.  That rebuilt PA has kept  
working now for a long time.

I definitely credit the removal and replacement of the completely  
dried out, dead heatsink compound as a component of much of this  
"success."  After seeing the flaky, useless "stuff" that came off the  
heatsink (the date stamp read 1981 on this particular PA), I highly  
recommend the full tear-down and rebuild of MASTR II PA's before  
giving them a week long "stress test" at 110W into a dummy load in the  
basement for a week... before they ever go anywhere near a repeater  
site.

Also I mention this, but don't think from your symptoms it's what's  
happening, but it's good info for anyone taking over a MASTR II...  
since what you're fighting is on and off receiver