[Repeater-Builder] Re: Info needed on older Kenwood radios...

[skipp025]

I bought one of these type of mics... cut the modular phone plug 
off the end and matched the proper wires to the proper 8-pin 
plug... I then soldered the wires on. 

DTMF 16 key Mic for Kenwood TK-868 TK-768 Car radio
Ebay Item number: 350058495894  

cheers, 
skipp 

> Mike Morris WA6ILQ <[EMAIL PROTECTED]> wrote:
>
> Does anybody know what microphones fit a Kenwood 231
> and 241 ?
> 
> I'm helping a couple of folks locate parts to resurrect a
> semi-abandoned city EOC. There are two 231 radios
> and one 241 radio involved.
> 
> Does anybody have schematics?  All we need to make work
> is PTT and mic, we don't need DTMF or any up/down buttons
> or other on-the-mic controls.
> 
> If anyone has a mic or two on the shelf that are in working
> shape let me know, they may be interested in buying them.
> If the price is right they would like to buy enough mics to
> have a spare of each.
> 
> Mike WA6ILQ
>

RE: [Repeater-Builder] Info needed on older Kenwood radios...

[Mike Morris WA6ILQ]

At 04:01 PM 05/10/08, Gary <[EMAIL PROTECTED]> wrote:
>Mike,
>just about any of Kenwood's hand mics with DTMF and the circular 8-pin
>connector will work fine on those radios including but not limited to
>the MC-43's and MC-53's. The original mics for both were the teardrop
>shaped MC-43's which, by the way, sound a bit better on TX than the
>backlit MC-53's but a cap change improves that.
>Off to drive cross country to Dayton..
>Gary
>N6LRV

At 07:22 PM 05/10/08, "MR. B" <[EMAIL PROTECTED]> wrote:
>Go to the microphone connection page
>
>http://homepage.ntlworld.com/rg4wpw/date.html
>
>Ron

At 07:43 PM 05/10/08, Ron Wright <[EMAIL PROTECTED]> wrote:
>Mike,
>
>The TM241 uses a MC-44 mike.  The MC44DM has the DTMF pad.
>My 241a mike had no model on it.
>
>Try http://www.universal-radio.com/catalog/fm_txvrs/TM241A.html
>for info on the 241.  It has long been discountinued.  I use mine for packet.
>
>73, ron, n9ee/r

Thanks to all three folks for the info.  With it we now know what model number
of microphone to look for, and if we can't find the exact one how to rewire
what we are able to find.  I just wish I had the funds and time to go to
Dayton - they'd be on the shopping list.

The TM-231s are voice radios, the TM241 is on a packet system that hasn't
been turned on in years (the computer is a 386-33 Compaq that amazingly
still runs).  One of the voice radios has a mic, the other does not, so we
need two mics just to get started (i.e. to have one for each radio).

Mike WA6ILQ

[Repeater-Builder] Re: Best coax for short jumpers in repeater cabinet?

[KF4TNP]

RG-393/U
M17/127
I use this cable in most runs in the transmitter buildings to and from each
station since it has the dual silver shields, I don't have dissimilar metals
to worry about.
And can handle 1.8kw @950Mhz it works out great.
Brent KF4TNP
 
 
 
 
  _  

From: Repeater-Builder@yahoogroups.com
[mailto:[EMAIL PROTECTED] On Behalf Of skipp025
Sent: Saturday, May 10, 2008 12:10 PM
To: Repeater-Builder@yahoogroups.com
Subject: [Repeater-Builder] Re: Best coax for short jumpers in repeater
cabinet?
 
> I think the LMR400 is a double shielded with each shield 
> different metals. One braid and one foil. This is a no-no 
> for duplexed repeaters for the higher TX RF will generate 
> noise getting into receiver. 

Just to be clear... 

The dissimilar shield metals is the potential problem source, 
not the braid - foil combination. And notice I used the term 
"potential problem source". It's not always automatic gremlin 
101 right out of the starting gate... Some years back I used 
a fairly large amount of LMR-400 feed line in various new radio 
& repeater system (applications) until I sourced more than an 
unacceptable number of antenna system "train wrecks" specific 
back to the LM-400 (and LMR-600) cable. 

Sometimes the problem took months and even years to develop... 
but from memory I've never had an installation of conventional 
antenna hard-line or coax feed sabotage a radio system like the 
many examples I've had to ferret out from or back to LMR-400. 

No more LMR-400 for me or any antenna system I'm involved 
with. 

The other cute dissimilar metal shielded coax problem is how 
physical cable movement can easily be a noise generator. There 
is a potential for LMR-400 coax moving in the wind to be noisy... 
and I have seen that demonstrated in an actual installation. 

cheers, 
skipp 
skipp025 at yahoo.com 
www.radiowrench.com 
 

Re: [Repeater-Builder] Re: Best coax for short jumpers in repeater cabinet?

[k7pfj]

Hi Brent,

I agree with Skipp, the LMR is not the cable i would recomend in a duplex 
preeater install. If you want jumper coax, i only use RG400 and it is a plenum 
rated silver plated with double shield brade silver. Both Motorola and Kenwood 
systems use this coax for there internal cableing inside the cabinet. I yet 
have seen them use LMR coax. Spend the little extra for good coax and you will 
find yourself much happier and not searching for weird site problems. For the 
main feed line, you cant get any better then Andrew's LDF coax for repeater 
installs. 

Mike Mullarkey K7PFJ

-- Original message -- 
From: "KF4TNP" <[EMAIL PROTECTED]> 
RG-393/U
M17/127
I use this cable in most runs in the transmitter buildings to and from each 
station since it has the dual silver shields, I don’t have dissimilar metals to 
worry about.
And can handle 1.8kw @950Mhz it works out great.
Brent KF4TNP







From: Repeater-Builder@yahoogroups.com [mailto:[EMAIL PROTECTED] On Behalf Of 
skipp025
Sent: Saturday, May 10, 2008 12:10 PM
To: Repeater-Builder@yahoogroups.com
Subject: [Repeater-Builder] Re: Best coax for short jumpers in repeater cabinet?

> I think the LMR400 is a double shielded with each shield 
> different metals. One braid and one foil. This is a no-no 
> for duplexed repeaters for the higher TX RF will generate 
> noise getting into receiver. 

Just to be clear... 

The dissimilar shield metals is the potential problem source, 
not the braid - foil combination. And notice I used the term 
"potential problem source". It's not always automatic gremlin 
101 right out of the starting gate... Some years back I used 
a fairly large amount of LMR-400 feed line in various new radio 
& repeater system (applications) until I sourced more than an 
unacceptable number of antenna system "train wrecks" specific 
back to the LM-400 (and LMR-600) cable. 

Sometimes the problem took months and even years to develop... 
but from memory I've never had an installation of conventional 
antenna hard-line or coax feed sabotage a radio system like the 
many examples I've had to ferret out from or back to LMR-400. 

No more LMR-400 for me or any antenna system I'm involved 
with. 

The other cute dissimilar metal shielded coax problem is how 
physical cable movement can easily be a noise generator. There 
is a potential for LMR-400 coax moving in the wind to be noisy... 
and I have seen that demonstrated in an actual installation. 

cheers, 
skipp 
skipp025 at yahoo.com 
www.radiowrench.com 
 

RE: [Repeater-Builder] Re: Best coax for short jumpers in repeater cabinet?

[n9wys]

Looks like you and I are in the minority, Brent.  I mentioned this same
cable about a week ago, and it went virtually "unnoticed".  :-(

 

Mark - N9WYS

 

From: Repeater-Builder@yahoogroups.com On Behalf Of KF4TNP



RG-393/U

M17/127

I use this cable in most runs in the transmitter buildings to and from each
station since it has the dual silver shields, I don't have dissimilar metals
to worry about.

And can handle 1.8kw @950Mhz it works out great.

Brent KF4TNP

 

  _  

From: Repeater-Builder@yahoogroups.com On Behalf Of skipp025

> I think the LMR400 is a double shielded with each shield 
> different metals. One braid and one foil. This is a no-no 
> for duplexed repeaters for the higher TX RF will generate 
> noise getting into receiver. 

Just to be clear... 

The dissimilar shield metals is the potential problem source, 
not the braid - foil combination. And notice I used the term 
"potential problem source". It's not always automatic gremlin 
101 right out of the starting gate... Some years back I used 
a fairly large amount of LMR-400 feed line in various new radio 
& repeater system (applications) until I sourced more than an 
unacceptable number of antenna system "train wrecks" specific 
back to the LM-400 (and LMR-600) cable. 

Sometimes the problem took months and even years to develop... 
but from memory I've never had an installation of conventional 
antenna hard-line or coax feed sabotage a radio system like the 
many examples I've had to ferret out from or back to LMR-400. 

No more LMR-400 for me or any antenna system I'm involved 
with. 

The other cute dissimilar metal shielded coax problem is how 
physical cable movement can easily be a noise generator. There 
is a potential for LMR-400 coax moving in the wind to be noisy... 
and I have seen that demonstrated in an actual installation. 

cheers, 
skipp 
skipp025 at yahoo.com 
www.radiowrench.com  

[Repeater-Builder] Re: Best coax for short jumpers in repeater cabinet?

[skipp025]

Re: Best coax for short jumpers in repeater cabinet? 

It's easy just to use some practical rule of thumb guidelines 
for coax runs. One doesn't have to use ultra over kill coax 
in every application. 

How long? - Length being enough to cause a loss, desired or 
otherwise (...and yes there is more than one case for a 
desired feed-line loss)

Does the size matter? - Does the diameter of the cable make it 
practical to fit the application and are the connectors fairly 
easy to deal with in both size and price?  Large RG-8 diameter 
size coax can become unwieldy in tight corner and space limited 
locations. 

Price? - Is the resultant purchase a good dollar to performance 
value and is the actual performance "good enough" for the 
application? 

One doesn't have to go high dollar overkill spec all the time. 
I'm also a fairly big fan of RG-233 Coax for many repeater 
system/equipment applications.  RG-233 seems to be the ignored 
step child of the coax family, which means it's not instant shark 
bait every time it pops up on Ebay and the surplus radio world 
market. 

I found a fairly decent price on some pre-made RG-233 Coax runs 
on Ebay: 

Cable Assembly RF Coax 7 ft RG-223/U N-Fe to SMA Male
Ebay Item number: 190175957842

My offer to the seller for 2/3 the asking amount was accepted and 
I now have a fair number of those lines in my collection at a 
much better than the $3.10 (Tessco) list price per foot. 

Not a bad deal if you want to take the plunge... 

cheers, 
skipp 
skipp025 at yahoo.com 
www.radiowrench.com 



"See you at Dayton! I'm the short chubby guy with red hair."


> [EMAIL PROTECTED] wrote:
> Hi Brent,
> I agree with Skipp, the LMR is not the cable i would recommend 
> in a duplex repeater install. If you want jumper coax, I only 
> use RG400 and it is a plenum rated silver plated with double 
> shield braid silver. Both Motorola and Kenwood systems use 
> this coax for there internal cableing inside the cabinet. I 
> yet have seen them use LMR coax. Spend the little extra for 
> good coax and you will find yourself much happier and not 
> searching for weird site problems. For the main feed line, you 
> can't get any better then Andrew's LDF coax for repeater installs. 

[Repeater-Builder] Re: Best coax for short jumpers in repeater cabinet?

[skipp025]

Hi Mark, 

Probably not ignored or unnoticed... but more related to how 
easy it is to find and of course the cost before applying at 
least some portions of the rules of thumb check list mentioned 
in my last post. 

Much of what many surplus equipment builders use is directly 
related to what we find cheap, easy and good enough to make 
the application properly play.

cheers,
skipp 

> "n9wys" <[EMAIL PROTECTED]> wrote:
> Looks like you and I are in the minority, Brent.  I mentioned 
> this same cable about a week ago, and it went virtually 
> "unnoticed".  :-(
> Mark - N9WYS
> 
>  
> > On Behalf Of KF4TNP
> > RG-393/U
> > M17/127
> >
> > I use this cable in most runs in the transmitter buildings 
> > to and from each station since it has the dual silver shields, 
> > I don't have dissimilar metals to worry about.
> > 
> > And can handle 1.8kw @950Mhz it works out great.
> > Brent KF4TNP

RE: [Repeater-Builder] Re: Best coax for short jumpers in repeater cabinet?

[n9wys]

That's true too, Skipp. 

Hope to bump into you at Dayton, since we've talked on the phone and via
e-mail!  It'll be nice to put a face to the keyboard/phone voice!  ;-)
I'll look hard around the Brat vendor for sure!!

BTW - I'll at least be wearing a tag with my callsign.

Mark - N9WYS

-Original Message-
From: Repeater-Builder@yahoogroups.com On Behalf Of skipp025

Hi Mark, 

Probably not ignored or unnoticed... but more related to how 
easy it is to find and of course the cost before applying at 
least some portions of the rules of thumb check list mentioned 
in my last post. 

Much of what many surplus equipment builders use is directly 
related to what we find cheap, easy and good enough to make 
the application properly play.

cheers,
skipp 

> "n9wys" <[EMAIL PROTECTED]> wrote:
> Looks like you and I are in the minority, Brent.  I mentioned 
> this same cable about a week ago, and it went virtually 
> "unnoticed".  :-(
> Mark - N9WYS
> 
>  
> > On Behalf Of KF4TNP
> > RG-393/U
> > M17/127
> >
> > I use this cable in most runs in the transmitter buildings 
> > to and from each station since it has the dual silver shields, 
> > I don't have dissimilar metals to worry about.
> > 
> > And can handle 1.8kw @950Mhz it works out great.
> > Brent KF4TNP

[Repeater-Builder] VXR7000 Squelch

[kc0voo]

Anyone else here have problems with their squelch on the vxr7000
repeater?  On our 2meter repeater the squelch is terribly loose, all
over the place, to get it to play friendly I have to crank it almost
80% closed, and then our guys using handhelds seem to have problems
getting in.

To combat noise and desense issues we are also using a 10" dia notch
pass inline with the receive...  

Just seems no matter what I do, the squelch on this darn repeater is
all over the place...

[Repeater-Builder] Wacom Duplexer Desense Problem - Mystery

[blisswheeler]

I really appreciate all of the comments on my duplexer mystery.

I made sure everything was tuned properly and took it back to my
friends home location.  We put it back on the air and experienced <2db
of signal desense with an output of 15 watts. That still doesn't
duplicate the results of the dummy load test, but that's a far cry
from the 30db I was experiencing here at my home shop. Some of the
things I did learn from the experience was that:

1. Though an antenna may only have a 1.5 SWR doesn't mean that the
antenna is a 50 ohm match. Using my MFJ ("Mighty Fine Junk" which, by
the way work pretty darned good, but not in a high RF environment)
antenna analyzer, the antenna that gave me the most difficulty
presented an 80 ohm load.  The SWR was 1.5.  A discone antenna worked
the best and it presented a 55 ohm load with a 1.2 SWR.

2. Double shielded coax is a must in repeater operation.  I
experienced this first hand.  I had one short jumper I thought was
double shielded and was not which caused an intermittent such that one
time it worked into a dummy load and the next it went flaky.  Moving
the coax with the repeater transmitter keyed revealed the culprit.  Use 
hardline or double shielded coax.  Hardline to the antenna is very
important.

3.  Bench testing duplexers into a dummy load may not duplicate the
results experienced with the antenna.

4. In theory isn't necessarily the same as reality.  I suppose if you
know all the variables the problem can be calculated and identified,
but there are a lot of unknown variables when working with RF.

5. The environment your repeater is in can cause you to loose your
hair. Yes it is related to the rf generated, no not because of the
health effects but because it makes you tear your hear out trying to
identify a problem.

6. I learned about whiskers in GE Mastr II receivers...  I experienced
their effects and how to fix the problem, though maybe for only a year
or two, but I learned to to disassemble and retune the receiver.

7. Your experienced Techie RF friends are a great help.  I have three
good friends that gave me a lot of ideas and helped me trouble shoot
this problem. The folks here on Repeater-Builder gave me some good
tips which pointed in the right direction as well, for that I thank
you all.

Respectfully,
Bliss

[Repeater-Builder] Need some help

[Rich Summers]

I need to build a simple circuit to enable a voice scrambler in a radio.
What I need is a momentary contact by pressing a button so that the
activation lead goes to ground and when this happens I need an led
indication that the unit has been activated. 
I also need the led to turn off when the button is pressed again. This
deactivates the board and the radio returns to normal mode.
I need this in a small box.
Does anyone have a circuit I could build for this particular application?

Thanks,

Rich

RE: [Repeater-Builder] Re: Best coax for short jumpers in repeater cabinet?

[Eric Lemmon]

Brent,

RG-393 cable is definitely good stuff.  The Mil-Spec can be downloaded here:


Looking in the TESSCO catalog, I don't see any connectors listed for RG-393,
which is a little bit smaller in diameter than RG-213.  I suppose connectors
intended for RG-213 could be used in a pinch, but I'd be concerned about the
impedance bump caused by using a mismatched connector.  I'm not saying there
are no connectors made for RG-393, only that they may be hard to find.
Where did you find connectors made for your cable?

73, Eric Lemmon WB6FLY


 

-Original Message-
From: Repeater-Builder@yahoogroups.com
[mailto:[EMAIL PROTECTED] On Behalf Of KF4TNP
Sent: Sunday, May 11, 2008 6:14 AM
To: Repeater-Builder@yahoogroups.com
Subject: [Repeater-Builder] Re: Best coax for short jumpers in repeater
cabinet?

RG-393/U

M17/127

I use this cable in most runs in the transmitter buildings to and from each
station since it has the dual silver shields, I don't have dissimilar metals
to worry about.

And can handle 1.8kw @950Mhz it works out great.

Brent KF4TNP

 

 

 

 



From: Repeater-Builder@yahoogroups.com
[mailto:[EMAIL PROTECTED] On Behalf Of skipp025
Sent: Saturday, May 10, 2008 12:10 PM
To: Repeater-Builder@yahoogroups.com
Subject: [Repeater-Builder] Re: Best coax for short jumpers in repeater
cabinet?

 

> I think the LMR400 is a double shielded with each shield 
> different metals. One braid and one foil. This is a no-no 
> for duplexed repeaters for the higher TX RF will generate 
> noise getting into receiver. 

Just to be clear... 

The dissimilar shield metals is the potential problem source, 
not the braid - foil combination. And notice I used the term 
"potential problem source". It's not always automatic gremlin 
101 right out of the starting gate... Some years back I used 
a fairly large amount of LMR-400 feed line in various new radio 
& repeater system (applications) until I sourced more than an 
unacceptable number of antenna system "train wrecks" specific 
back to the LM-400 (and LMR-600) cable. 

Sometimes the problem took months and even years to develop... 
but from memory I've never had an installation of conventional 
antenna hard-line or coax feed sabotage a radio system like the 
many examples I've had to ferret out from or back to LMR-400. 

No more LMR-400 for me or any antenna system I'm involved 
with. 

The other cute dissimilar metal shielded coax problem is how 
physical cable movement can easily be a noise generator. There 
is a potential for LMR-400 coax moving in the wind to be noisy... 
and I have seen that demonstrated in an actual installation. 

cheers, 
skipp 
skipp025 at yahoo.com 
www.radiowrench.com 

 

[Repeater-Builder] Re: Need some help

[dallasreact112]

Sounds Like a flip flop R S latch circuit to me. Google that and you
will find something. A 7400 IC could do the latch part.  Not knowing
voltage and current requirements I really can't go into more detail.

73

Bernie Parker

K5BP


--- In Repeater-Builder@yahoogroups.com, "Rich Summers" <[EMAIL PROTECTED]>
wrote:
>
> I need to build a simple circuit to enable a voice scrambler in a radio.
> What I need is a momentary contact by pressing a button so that the
> activation lead goes to ground and when this happens I need an led
> indication that the unit has been activated. 
> I also need the led to turn off when the button is pressed again. This
> deactivates the board and the radio returns to normal mode.
> I need this in a small box.
> Does anyone have a circuit I could build for this particular
application?
> 
> Thanks,
> 
> Rich
>

Re: [Repeater-Builder] Need some help

[MCH]

A simple flip flop chip should work nicely.

Joe M.

Rich Summers wrote:
> I need to build a simple circuit to enable a voice scrambler in a radio.
> What I need is a momentary contact by pressing a button so that the
> activation lead goes to ground and when this happens I need an led
> indication that the unit has been activated. 
> I also need the led to turn off when the button is pressed again. This
> deactivates the board and the radio returns to normal mode.
> I need this in a small box.
> Does anyone have a circuit I could build for this particular application?
> 
> Thanks,
> 
> Rich
> 
> 
> 
> 
> 
> 
> 
> Yahoo! Groups Links
> 
> 
> 
> 
> 

Re: [Repeater-Builder] Need some help

[MCH]

For that matter, why not just a toggle switch?

Joe M.

Rich Summers wrote:
> I need to build a simple circuit to enable a voice scrambler in a radio.
> What I need is a momentary contact by pressing a button so that the
> activation lead goes to ground and when this happens I need an led
> indication that the unit has been activated. 
> I also need the led to turn off when the button is pressed again. This
> deactivates the board and the radio returns to normal mode.
> I need this in a small box.
> Does anyone have a circuit I could build for this particular application?
> 
> Thanks,
> 
> Rich
> 
> 
> 
> 
> 
> 
> 
> Yahoo! Groups Links
> 
> 
> 
> 
> 

Re: [Repeater-Builder] Need some help

[Chuck Kelsey]

Or a "push-on" "push-off" switch if a toggle isn't acceptable.

Chuck
WB2EDV



- Original Message - 
From: "MCH" <[EMAIL PROTECTED]>
To: 
Sent: Sunday, May 11, 2008 3:38 PM
Subject: Re: [Repeater-Builder] Need some help


> For that matter, why not just a toggle switch?
>
> Joe M.
>
> Rich Summers wrote:
>> I need to build a simple circuit to enable a voice scrambler in a radio.
>> What I need is a momentary contact by pressing a button so that the
>> activation lead goes to ground and when this happens I need an led
>> indication that the unit has been activated.
>> I also need the led to turn off when the button is pressed again. This
>> deactivates the board and the radio returns to normal mode.
>> I need this in a small box.
>> Does anyone have a circuit I could build for this particular application?
>>
>> Thanks,
>>
>> Rich
>>
>>
>>
>> 
>>
>>
>>
>> Yahoo! Groups Links
>>
>>
>>
>>
>>
>
> 
>
>
>
> Yahoo! Groups Links
>
>
>

RE: [Repeater-Builder] Re: Best coax for short jumpers in repeater cabinet?

[no6b]

At 5/11/2008 08:52, you wrote:

>Looks like you and I are in the minority, Brent.  I mentioned this same 
>cable about a week ago, and it went virtually unnoticed &  :-(
>
>
>
>Mark N9WYS
>
>
>
>From: Repeater-Builder@yahoogroups.com On Behalf Of KF4TNP
>
>RG-393/U

I have a hardline to antenna jumper that's RG-393.  It's good stuff, just 
don't see it often at the swap meets.  RG-214 & RG-223 are the usual finds.

& yes stay away from the "TYPE" stuff at all costs for duplexed lines.  I 
think every RG-214 jumper & bought that says that is either copper or 
tinned braid.  OK for radio to duplexer connections but no good for 
duplexed connections (on or after the duplexer T).

Bob NO6B

RE: [Repeater-Builder] Wacom Duplexer Desense Problem - Mystery

[Gary Schafer]

A couple of notes on this:

Beware of the mfj to read impedance/swr. I have an mfj 259B and it is
terrible on 2 meters. With a GOOD dummy load it shows a higher swr the
higher you go in frequency with it. I think it will show around 1.5:1 and an
impedance of around 42 ohms on the good dummy load. On lower (HF) it works
fine.

The problems that you found with the cable may not have been because it was
not double shielded. Especially if things changed as you wiggled it around.
It may have been poor connector installation. Most people that experience
cable problems do not look at the connectors as being installed improperly
or braid broken loose from extended use. 

I used to sell service monitors to two way shops and would bring the
monitors in the shop to demonstrate them. I found that about 80% of the test
cables that the shop had (and used on a regular basis) were bad! Usually
intermittent from bad connector installation. It seems kind of unbelievable
that guys that were using this equipment in day to day work would not be
aware of the bad cables.
Just think of how many goofy problems could be avoided with known good test
equipment. After a short time I always made sure that I brought my own
cables along for the demo.

I used to pick up coax jumpers at hamfests for use around my shack. I can't
remember the last time I got one with the connectors installed properly
(always loose connectors) other than commercially made cables. Now I don't
even bother to pick them up anymore.

Check those connectors. If you can rotate them at all on the cable they are
not installed properly and will give problems.

73
Gary  K4FMX

> -Original Message-
> From: Repeater-Builder@yahoogroups.com [mailto:Repeater-
> [EMAIL PROTECTED] On Behalf Of blisswheeler
> Sent: Sunday, May 11, 2008 12:38 AM
> To: Repeater-Builder@yahoogroups.com
> Subject: [Repeater-Builder] Wacom Duplexer Desense Problem - Mystery
> 
> I really appreciate all of the comments on my duplexer mystery.
> 
> I made sure everything was tuned properly and took it back to my
> friends home location.  We put it back on the air and experienced <2db
> of signal desense with an output of 15 watts. That still doesn't
> duplicate the results of the dummy load test, but that's a far cry
> from the 30db I was experiencing here at my home shop. Some of the
> things I did learn from the experience was that:
> 
> 1. Though an antenna may only have a 1.5 SWR doesn't mean that the
> antenna is a 50 ohm match. Using my MFJ ("Mighty Fine Junk" which, by
> the way work pretty darned good, but not in a high RF environment)
> antenna analyzer, the antenna that gave me the most difficulty
> presented an 80 ohm load.  The SWR was 1.5.  A discone antenna worked
> the best and it presented a 55 ohm load with a 1.2 SWR.
> 
> 2. Double shielded coax is a must in repeater operation.  I
> experienced this first hand.  I had one short jumper I thought was
> double shielded and was not which caused an intermittent such that one
> time it worked into a dummy load and the next it went flaky.  Moving
> the coax with the repeater transmitter keyed revealed the culprit.  Use
> hardline or double shielded coax.  Hardline to the antenna is very
> important.
> 
> 3.  Bench testing duplexers into a dummy load may not duplicate the
> results experienced with the antenna.
> 
> 4. In theory isn't necessarily the same as reality.  I suppose if you
> know all the variables the problem can be calculated and identified,
> but there are a lot of unknown variables when working with RF.
> 
> 5. The environment your repeater is in can cause you to loose your
> hair. Yes it is related to the rf generated, no not because of the
> health effects but because it makes you tear your hear out trying to
> identify a problem.
> 
> 6. I learned about whiskers in GE Mastr II receivers...  I experienced
> their effects and how to fix the problem, though maybe for only a year
> or two, but I learned to to disassemble and retune the receiver.
> 
> 7. Your experienced Techie RF friends are a great help.  I have three
> good friends that gave me a lot of ideas and helped me trouble shoot
> this problem. The folks here on Repeater-Builder gave me some good
> tips which pointed in the right direction as well, for that I thank
> you all.
> 
> Respectfully,
> Bliss
> 
> 
> 
> 
> 
> 
> 
> Yahoo! Groups Links
> 
> 
> 

RE: [Repeater-Builder] Re: Best coax for short jumpers in repeater cabinet?

[KF4TNP]

Eric,
The connectors I have for the 393 are from Times Microwave. Times
Recommended the use of the below LMR4oo connectors.
 
TC-400-716MC and the TC-400-716FC
7/16" Din male and female
 
TheType "N" connectors are
Times TC-400-NFC-BH Female connectors and Amphenol 82-209-1006 
Male Time TC-400-NMC-RA
 
Brent KF4TNP
 
 
 
 
 
 
  _  

From: Repeater-Builder@yahoogroups.com
[mailto:[EMAIL PROTECTED] On Behalf Of Eric Lemmon
Sent: Sunday, May 11, 2008 1:09 PM
To: Repeater-Builder@yahoogroups.com
Subject: RE: [Repeater-Builder] Re: Best coax for short jumpers in repeater
cabinet?
 
Brent,

RG-393 cable is definitely good stuff. The Mil-Spec can be downloaded here:


Looking in the TESSCO catalog, I don't see any connectors listed for RG-393,
which is a little bit smaller in diameter than RG-213. I suppose connectors
intended for RG-213 could be used in a pinch, but I'd be concerned about the
impedance bump caused by using a mismatched connector. I'm not saying there
are no connectors made for RG-393, only that they may be hard to find.
Where did you find connectors made for your cable?

73, Eric Lemmon WB6FLY

-Original Message-
From: Repeater-Builder@ 
yahoogroups.com
[mailto:Repeater-Builder@ 
yahoogroups.com] On Behalf Of KF4TNP
Sent: Sunday, May 11, 2008 6:14 AM
To: Repeater-Builder@ 
yahoogroups.com
Subject: [Repeater-Builder] Re: Best coax for short jumpers in repeater
cabinet?

RG-393/U

M17/127

I use this cable in most runs in the transmitter buildings to and from each
station since it has the dual silver shields, I don't have dissimilar metals
to worry about.

And can handle 1.8kw @950Mhz it works out great.

Brent KF4TNP



From: Repeater-Builder@ 
yahoogroups.com
[mailto:Repeater-Builder@ 
yahoogroups.com] On Behalf Of skipp025
Sent: Saturday, May 10, 2008 12:10 PM
To: Repeater-Builder@ 
yahoogroups.com
Subject: [Repeater-Builder] Re: Best coax for short jumpers in repeater
cabinet?

> I think the LMR400 is a double shielded with each shield 
> different metals. One braid and one foil. This is a no-no 
> for duplexed repeaters for the higher TX RF will generate 
> noise getting into receiver. 

Just to be clear... 

The dissimilar shield metals is the potential problem source, 
not the braid - foil combination. And notice I used the term 
"potential problem source". It's not always automatic gremlin 
101 right out of the starting gate... Some years back I used 
a fairly large amount of LMR-400 feed line in various new radio 
& repeater system (applications) until I sourced more than an 
unacceptable number of antenna system "train wrecks" specific 
back to the LM-400 (and LMR-600) cable. 

Sometimes the problem took months and even years to develop... 
but from memory I've never had an installation of conventional 
antenna hard-line or coax feed sabotage a radio system like the 
many examples I've had to ferret out from or back to LMR-400. 

No more LMR-400 for me or any antenna system I'm involved 
with. 

The other cute dissimilar metal shielded coax problem is how 
physical cable movement can easily be a noise generator. There 
is a potential for LMR-400 coax moving in the wind to be noisy... 
and I have seen that demonstrated in an actual installation. 

cheers, 
skipp 
skipp025 at yahoo.com 
www.radiowrench.com 
 

Re: [Repeater-Builder] Wacom Duplexer Desense Problem - Mystery

[no6b]

At 5/10/2008 21:38, you wrote:

>I really appreciate all of the comments on my duplexer mystery.
>
>I made sure everything was tuned properly and took it back to my
>friends home location. We put it back on the air and experienced <2db
>of signal desense with an output of 15 watts. That still doesn't
>duplicate the results of the dummy load test, but that's a far cry
>from the 30db I was experiencing here at my home shop.

Yup, all makes sense.  The 2 meter repeater I recently built & put on the 
air here with 10 dB of desense is down to ~2 dB of desense at the site, & 
that's probably due to the antenna being fed with RG-8 (I pointed that out 
to the owner the second I found out, but he had already installed it; we 
already have plans to rip it out & replace with 100% 1/2" hardline & RG-214 
from the duplexer T on out).

>  Some of the
>things I did learn from the experience was that:
>
>1. Though an antenna may only have a 1.5 SWR doesn't mean that the
>antenna is a 50 ohm match. Using my MFJ ("Mighty Fine Junk" which, by

Not sure what you're getting at, but there is a direct correlation between 
VSWR & impedance.  It's possible to have several different complex 
impedances that all result in the same VSWR, but if the impedance is 50 + 
j0, the VSWR by definition is 1:1.

>2. Double shielded coax is a must in repeater operation. I
>experienced this first hand. I had one short jumper I thought was
>double shielded and was not which caused an intermittent such that one
>time it worked into a dummy load and the next it went flaky. Moving
>the coax with the repeater transmitter keyed revealed the culprit. Use 
>hardline or double shielded coax. Hardline to the antenna is very
>important.

Your bad jumper was probably copper braided.  The double shielding isn't 
that important, but since single-shielded silver braided coax is pretty 
rare, just making sure all duplexed lines are hardline or silver braided is 
good enough.

>3. Bench testing duplexers into a dummy load may not duplicate the
>results experienced with the antenna.

Yes, but at least you know the duplexers are performing to specs, & hence 
probably not the problem.

>5. The environment your repeater is in can cause you to loose your
>hair. Yes it is related to the rf generated, no not because of the
>health effects but because it makes you tear your hear out trying to
>identify a problem.

Very true, especially on 2 meters where the short 600 kHz spacing lends 
itself to all kinds of mixes within consumer electronics devices.

>6. I learned about whiskers in GE Mastr II receivers... I experienced
>their effects and how to fix the problem, though maybe for only a year
>or two, but I learned to to disassemble and retune the receiver.

When I run into them, I just screw all the helicals all the way down & then 
retune.  I figure if they took 30+ years to grow long enough to short 
something out, it'll take another 30 years for them to grow back again.  If 
I'm still using this nearly obsolete equipment after another 30 years 
something's wrong  :O

Bob NO6B

Re: [Repeater-Builder] Wacom Duplexer Desense Problem - Mystery

[Paul Plack]

Are you sure it's the MFJ?

I thought my MFJ 259 was behaving badly at some frequencies, and it turned out 
to be the dummy loads. One in particular was flat everywhere but 6 meters, and 
it took me years to notice because I don't deal with that band often.

I also have noticed the problems in high RF environments, but that's not MFJ's 
fault. No SWR bridge works accurately measuring an antenna with a few 
milliwatts at a 100 kilowatt broadcast site.

Paul, AE4KR

  - Original Message - 
  From: Gary Schafer 
  To: Repeater-Builder@yahoogroups.com 
  Sent: Sunday, May 11, 2008 1:56 PM
  Subject: RE: [Repeater-Builder] Wacom Duplexer Desense Problem - Mystery


  A couple of notes on this:

  Beware of the mfj to read impedance/swr. I have an mfj 259B and it is
  terrible on 2 meters. With a GOOD dummy load it shows a higher swr the
  higher you go in frequency with it. I think it will show around 1.5:1 and an
  impedance of around 42 ohms on the good dummy load. On lower (HF) it works
  fine.

  The problems that you found with the cable may not have been because it was
  not double shielded. Especially if things changed as you wiggled it around.
  It may have been poor connector installation. Most people that experience
  cable problems do not look at the connectors as being installed improperly
  or braid broken loose from extended use. 

  I used to sell service monitors to two way shops and would bring the
  monitors in the shop to demonstrate them. I found that about 80% of the test
  cables that the shop had (and used on a regular basis) were bad! Usually
  intermittent from bad connector installation. It seems kind of unbelievable
  that guys that were using this equipment in day to day work would not be
  aware of the bad cables.
  Just think of how many goofy problems could be avoided with known good test
  equipment. After a short time I always made sure that I brought my own
  cables along for the demo.

  I used to pick up coax jumpers at hamfests for use around my shack. I can't
  remember the last time I got one with the connectors installed properly
  (always loose connectors) other than commercially made cables. Now I don't
  even bother to pick them up anymore.

  Check those connectors. If you can rotate them at all on the cable they are
  not installed properly and will give problems.

  73
  Gary K4FMX

  > -Original Message-
  > From: Repeater-Builder@yahoogroups.com [mailto:Repeater-
  > [EMAIL PROTECTED] On Behalf Of blisswheeler
  > Sent: Sunday, May 11, 2008 12:38 AM
  > To: Repeater-Builder@yahoogroups.com
  > Subject: [Repeater-Builder] Wacom Duplexer Desense Problem - Mystery
  > 
  > I really appreciate all of the comments on my duplexer mystery.
  > 
  > I made sure everything was tuned properly and took it back to my
  > friends home location. We put it back on the air and experienced <2db
  > of signal desense with an output of 15 watts. That still doesn't
  > duplicate the results of the dummy load test, but that's a far cry
  > from the 30db I was experiencing here at my home shop. Some of the
  > things I did learn from the experience was that:
  > 
  > 1. Though an antenna may only have a 1.5 SWR doesn't mean that the
  > antenna is a 50 ohm match. Using my MFJ ("Mighty Fine Junk" which, by
  > the way work pretty darned good, but not in a high RF environment)
  > antenna analyzer, the antenna that gave me the most difficulty
  > presented an 80 ohm load. The SWR was 1.5. A discone antenna worked
  > the best and it presented a 55 ohm load with a 1.2 SWR.
  > 
  > 2. Double shielded coax is a must in repeater operation. I
  > experienced this first hand. I had one short jumper I thought was
  > double shielded and was not which caused an intermittent such that one
  > time it worked into a dummy load and the next it went flaky. Moving
  > the coax with the repeater transmitter keyed revealed the culprit. Use
  > hardline or double shielded coax. Hardline to the antenna is very
  > important.
  > 
  > 3. Bench testing duplexers into a dummy load may not duplicate the
  > results experienced with the antenna.
  > 
  > 4. In theory isn't necessarily the same as reality. I suppose if you
  > know all the variables the problem can be calculated and identified,
  > but there are a lot of unknown variables when working with RF.
  > 
  > 5. The environment your repeater is in can cause you to loose your
  > hair. Yes it is related to the rf generated, no not because of the
  > health effects but because it makes you tear your hear out trying to
  > identify a problem.
  > 
  > 6. I learned about whiskers in GE Mastr II receivers... I experienced
  > their effects and how to fix the problem, though maybe for only a year
  > or two, but I learned to to disassemble and retune the receiver.
  > 
  > 7. Your experienced Techie RF friends are a great help. I have three
  > good friends that gave me a lot of ideas and helped me trouble shoot
  > this problem. The folks 

[Repeater-Builder] Adding Control Receiver without Separate Antenna

[John Transue]

I would like to add a control receiver to a UHF (446 MHz) repeater. The
repeater is at a hospital that has allowed us to put up the repeater
antenna but is very hesitant to permit additional antennas. So, is there
a way that I can use the repeater antenna for both the repeater and the
control receiver?

John AF4PD

[Repeater-Builder] Feedlines In and Out of Repeater Cabinet

[John Transue]

I have followed with interest the thread treating feed line to use to
connect repeater/duplexer/antenna, and I think I should replace the
cables that are now in use on my 2-m repeater. But now the repeater TX
and RX and a remote base use short cables to a feedthrough on the top of
the cabinet. There are 90 degree elbows on the feedthroughs. Would it be
better to eliminate these feedthroughs and elbows by just cutting a hole
in the cabinet and routing the cables directly to the radios? What is
common practice?

Thanks for your help.

John AF4PD

RE: [Repeater-Builder] Re: Best coax for short jumpers in repeater cabinet?

[Eric Lemmon]

Brent,

Thanks for the feedback.  I found that RF Industries does have connectors
for RG-393/U, which they call Cable Group "I".

73, Eric Lemmon WB6FLY
 

-Original Message-
From: Repeater-Builder@yahoogroups.com
[mailto:[EMAIL PROTECTED] On Behalf Of KF4TNP
Sent: Sunday, May 11, 2008 12:58 PM
To: Repeater-Builder@yahoogroups.com
Subject: RE: [Repeater-Builder] Re: Best coax for short jumpers in repeater
cabinet?

Eric,

The connectors I have for the 393 are from Times Microwave. Times
Recommended the use of the below LMR4oo connectors.

 

TC-400-716MC and the TC-400-716FC

7/16" Din male and female

 

TheType "N" connectors are

Times TC-400-NFC-BH Female connectors and Amphenol 82-209-1006 

Male Time TC-400-NMC-RA

 

Brent KF4TNP

[Repeater-Builder] Re: Adding Control Receiver without Separate Antenna

[Laryn Lohman]

--- In Repeater-Builder@yahoogroups.com, "John Transue" <[EMAIL PROTECTED]>
wrote:
>
> I would like to add a control receiver to a UHF (446 MHz) repeater. 

If you can use a frequency for control that is within several channels
of your input, you can split the receive coax from your duplexer to
each receiver.  Use a split channel for control if possible.  If you
use a preamp and split the output properly you'll experience no loss
in sensitivity to your repeater receiver.  It works great here.  

Laryn K8TVZ

RE: [Repeater-Builder] Adding Control Receiver without Separate Antenna

[Ron Wright]

John,

For a UHF control receiver one solution is to parallel another recevier 
a channel away from your repeater input using a splitter for the 2 
receivers using the same feed from your duplexer.


Most duplexers have notch 100 kHz or so wide so it will work for both 
receivers.  Know this might be on another repeaters input, but often 
they are far away.  Can look on both sides of your input freq.  This 
approach also would not require another antenna/feedline...just another 
box.


Make sure you tone or secure the control rcvr.  If have DCS might 
consider this since few use it, but seems most rigs these days are 
coming with it. Otherwise use a CTCSS that is not common in your area.


For equipment I have used Motorola Micor receivers.  One can get in 19" 
rack mount.  Normally have to build in a small 9.6 VDC supply or some 
come with it.  These were used as second receivers in base stations, 
voting systems, etc.  You can also run off repeater supply since rcvr 
draws little current (don't need the speaker audio), but should have a 
9.6 V regulator.  GE makes similar rcvrs.


73, ron, n9ee/r


Ron Wright, N9EE

727-376-6575

MICRO COMPUTER CONCEPTS

Owner 146.64 repeater Tampa Bay, FL

No tone, all are welcome.




On Sun, May 11, 2008 at  5:33 PM, John Transue wrote:

I would like to add a control receiver to a UHF (446 MHz) repeater. The 
repeater is at a hospital that has allowed us to put up the repeater 
antenna but is very hesitant to permit additional antennas. So, is there 
a way that I can use the repeater antenna for both the repeater and the 
control receiver?

John AF4PD

[Repeater-Builder] Re: new MSR2000 group

[l_digit]

--- In Repeater-Builder@yahoogroups.com, Ron Wright <[EMAIL PROTECTED]> wrote:
>
> Hi all,
> 
> I have started a new MSR2000 yahoo group at:
> 
> http://groups.yahoo.com/group/MSR2000
> 
> I hope this is not redundant, but could only find a Mitrek group
with similar MSR2000 interest.
> 
> I know this is a repeater group and I like what it does fro so many.
 I received much help with MSR2000s here and the info on the board is
very useful.
> 
> Know many here are interested in repeaters so wanted to welcome others.
> 
> 73, ron, n9ee/r
> 
> 
> Ron Wright, N9EE
> 727-376-6575
> MICRO COMPUTER CONCEPTS
> Owner 146.64 repeater Tampa Bay, FL
> No tone, all are welcome.
>
It would be nice if you would started a new Mcc yahoo group to take
care of the people you sold RC-100 and RC-1000 repeater controllers to.

RE: [Repeater-Builder] Re: Adding Control Receiver without Separate Antenna

[John Transue]

Laryn K8TVZ,

  So, if I understand, I should put a splitter after the pre-amp, and
the control frequency should be a split channel. Does this mean that I
use half way between two channels? 

  Another question, who makes a good splitter, and how can I know I am
getting a good splitter?

  Ron N9EE also has given some good advice. I will use a tone on the
control.  I already have a receiver. It is synthesized so it is easy for
me to use whatever frequency turns out to be free. 

  Many thanks to both you and Ron. 

John AF4PD

 

-Original Message-
From: Repeater-Builder@yahoogroups.com
[mailto:[EMAIL PROTECTED] On Behalf Of Laryn Lohman
Sent: Sunday, May 11, 2008 6:40 PM
To: Repeater-Builder@yahoogroups.com
Subject: [Repeater-Builder] Re: Adding Control Receiver without Separate
Antenna

 

--- In Repeater-Builder@ 
yahoogroups.com, "John Transue" <[EMAIL PROTECTED]>
wrote:
>
> I would like to add a control receiver to a UHF (446 MHz) repeater. 

If you can use a frequency for control that is within several channels
of your input, you can split the receive coax from your duplexer to
each receiver. Use a split channel for control if possible. If you
use a preamp and split the output properly you'll experience no loss
in sensitivity to your repeater receiver. It works great here. 

Laryn K8TVZ

 

__ NOD32 2918 (20080303) Information __

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

RE: [Repeater-Builder] Wacom Duplexer Desense Problem - Mystery

[Gary Schafer]

Yes it is the MFJ. I have many good loads that I have also checked with a
return loss bridge and tracking setup. They are very flat. I have talked to
several others that have experienced the same problem with the MFJ. One guy
told me that he changed out the SO239 jack to a type N and it was much
better.

I don't know if there are things to adjust in the MFJ to balance it at VHF
or not.

 

73

Gary  K4FMX

 

  _  

From: Repeater-Builder@yahoogroups.com
[mailto:[EMAIL PROTECTED] On Behalf Of Paul Plack
Sent: Sunday, May 11, 2008 5:08 PM
To: Repeater-Builder@yahoogroups.com
Subject: Re: [Repeater-Builder] Wacom Duplexer Desense Problem - Mystery

 

Are you sure it's the MFJ?

 

I thought my MFJ 259 was behaving badly at some frequencies, and it turned
out to be the dummy loads. One in particular was flat everywhere but 6
meters, and it took me years to notice because I don't deal with that band
often.

 

I also have noticed the problems in high RF environments, but that's not
MFJ's fault. No SWR bridge works accurately measuring an antenna with a few
milliwatts at a 100 kilowatt broadcast site.

 

Paul, AE4KR

 

- Original Message - 

From: Gary Schafer   

To: Repeater-Builder@yahoogroups.com 

Sent: Sunday, May 11, 2008 1:56 PM

Subject: RE: [Repeater-Builder] Wacom Duplexer Desense Problem - Mystery

 

A couple of notes on this:

Beware of the mfj to read impedance/swr. I have an mfj 259B and it is
terrible on 2 meters. With a GOOD dummy load it shows a higher swr the
higher you go in frequency with it. I think it will show around 1.5:1 and an
impedance of around 42 ohms on the good dummy load. On lower (HF) it works
fine.

The problems that you found with the cable may not have been because it was
not double shielded. Especially if things changed as you wiggled it around.
It may have been poor connector installation. Most people that experience
cable problems do not look at the connectors as being installed improperly
or braid broken loose from extended use. 

I used to sell service monitors to two way shops and would bring the
monitors in the shop to demonstrate them. I found that about 80% of the test
cables that the shop had (and used on a regular basis) were bad! Usually
intermittent from bad connector installation. It seems kind of unbelievable
that guys that were using this equipment in day to day work would not be
aware of the bad cables.
Just think of how many goofy problems could be avoided with known good test
equipment. After a short time I always made sure that I brought my own
cables along for the demo.

I used to pick up coax jumpers at hamfests for use around my shack. I can't
remember the last time I got one with the connectors installed properly
(always loose connectors) other than commercially made cables. Now I don't
even bother to pick them up anymore.

Check those connectors. If you can rotate them at all on the cable they are
not installed properly and will give problems.

73
Gary K4FMX

> -Original Message-
> From: Repeater-Builder@ 
yahoogroups.com [mailto:Repeater-
> [EMAIL PROTECTED]  .com] On Behalf Of
blisswheeler
> Sent: Sunday, May 11, 2008 12:38 AM
> To: Repeater-Builder@ 
yahoogroups.com
> Subject: [Repeater-Builder] Wacom Duplexer Desense Problem - Mystery
> 
> I really appreciate all of the comments on my duplexer mystery.
> 
> I made sure everything was tuned properly and took it back to my
> friends home location. We put it back on the air and experienced <2db
> of signal desense with an output of 15 watts. That still doesn't
> duplicate the results of the dummy load test, but that's a far cry
> from the 30db I was experiencing here at my home shop. Some of the
> things I did learn from the experience was that:
> 
> 1. Though an antenna may only have a 1.5 SWR doesn't mean that the
> antenna is a 50 ohm match. Using my MFJ ("Mighty Fine Junk" which, by
> the way work pretty darned good, but not in a high RF environment)
> antenna analyzer, the antenna that gave me the most difficulty
> presented an 80 ohm load. The SWR was 1.5. A discone antenna worked
> the best and it presented a 55 ohm load with a 1.2 SWR.
> 
> 2. Double shielded coax is a must in repeater operation. I
> experienced this first hand. I had one short jumper I thought was
> double shielded and was not which caused an intermittent such that one
> time it worked into a dummy load and the next it went flaky. Moving
> the coax with the repeater transmitter keyed revealed the culprit. Use
> hardline or double shielded coax. Hardline to the antenna is very
> important.
> 
> 3. Bench testing duplexers into a dummy load may not duplicate the
> results experienced with the antenna.
> 
> 4. In theory isn't necessarily the same as reality. I suppose if you
> know all the variables the problem can be calculated and identified,
> but there are 

RE: [Repeater-Builder] Re: Best coax for short jumpers in repeater cabinet?

[KF4TNP]

No Problem Eric,
 
 
  _  

From: Repeater-Builder@yahoogroups.com
[mailto:[EMAIL PROTECTED] On Behalf Of Eric Lemmon
Sent: Sunday, May 11, 2008 5:40 PM
To: Repeater-Builder@yahoogroups.com
Subject: RE: [Repeater-Builder] Re: Best coax for short jumpers in repeater
cabinet?
 
Brent,

Thanks for the feedback. I found that RF Industries does have connectors
for RG-393/U, which they call Cable Group "I".

73, Eric Lemmon WB6FLY


-Original Message-
From: Repeater-Builder@ 
yahoogroups.com
[mailto:Repeater-Builder@ 
yahoogroups.com] On Behalf Of KF4TNP
Sent: Sunday, May 11, 2008 12:58 PM
To: Repeater-Builder@ 
yahoogroups.com
Subject: RE: [Repeater-Builder] Re: Best coax for short jumpers in repeater
cabinet?

Eric,

The connectors I have for the 393 are from Times Microwave. Times
Recommended the use of the below LMR4oo connectors.

TC-400-716MC and the TC-400-716FC

7/16" Din male and female

TheType "N" connectors are

Times TC-400-NFC-BH Female connectors and Amphenol 82-209-1006 

Male Time TC-400-NMC-RA

Brent KF4TNP
 

Re: [Repeater-Builder] Need some help

[Rich Summers]

I can't use a toggle switch because the contact to
enable the scramble board needs to be momentary to
turn on the board and then a momentary contact to
switch off the board. This contact will be using an
enable wire from the board and another wire that is a
ground. I think a flip flop MAY be the way to go. I
was also wondering if there is a  push button switch
that has 2 spst contacts?
Thanks. 
--- MCH <[EMAIL PROTECTED]> wrote:

> For that matter, why not just a toggle switch?
> 
> Joe M.
> 
> Rich Summers wrote:
> > I need to build a simple circuit to enable a voice
> scrambler in a radio.
> > What I need is a momentary contact by pressing a
> button so that the
> > activation lead goes to ground and when this
> happens I need an led
> > indication that the unit has been activated. 
> > I also need the led to turn off when the button is
> pressed again. This
> > deactivates the board and the radio returns to
> normal mode.
> > I need this in a small box.
> > Does anyone have a circuit I could build for this
> particular application?
> > 
> > Thanks,
> > 
> > Rich
> > 
> > 
> > 
> > 
> > 
> > 
> > 
> > Yahoo! Groups Links
> > 
> > 
> > 
> > 
> > 
> 



  

Be a better friend, newshound, and 
know-it-all with Yahoo! Mobile.  Try it now.  
http://mobile.yahoo.com/;_ylt=Ahu06i62sR8HDtDypao8Wcj9tAcJ

RE: [Repeater-Builder] Re: new MSR2000 group

[Ron Wright]

A yahoo group for the RC-100, RC-1000 and the repeaters we sell might be 
good idea.  I typically see the yahoo groups as kinda non-business, but 
know there are some on the net.


We try to handle questions via direct e-mails and phone calls, but know 
what one might ask could be used by others.


Not sure how yahoo sees this.

73, ron, n9ee/r


Ron Wright, N9EE

727-376-6575

MICRO COMPUTER CONCEPTS

Owner 146.64 repeater Tampa Bay, FL

No tone, all are welcome.




On Sun, May 11, 2008 at  5:38 PM, l_digit wrote:

--- In Repeater-Builder@ yahoogroups. com 
 , Ron Wright <[EMAIL PROTECTED]> 
wrote:


Hi all,
I have started a new MSR2000 yahoo group at:
http://groups. yahoo.com/ group/MSR2000 


I hope this is not redundant, but could only find a Mitrek group

with similar MSR2000 interest.


I know this is a repeater group and I like what it does fro so many.

I received much help with MSR2000s here and the info on the board is
very useful.


Know many here are interested in repeaters so wanted to welcome 
others.

73, ron, n9ee/r

Ron Wright, N9EE 727-376-6575 MICRO COMPUTER CONCEPTS Owner 146.64 
repeater Tampa Bay, FL No tone, all are welcome.

It would be nice if you would started a new Mcc yahoo group to take
care of the people you sold RC-100 and RC-1000 repeater controllers to.

 

Re: [Repeater-Builder] Need some help

[MCH]

I would see what those wires are doing on the board. It may be easier to 
interface to that point rather than the inputs.

Joe M.

Rich Summers wrote:
> I can't use a toggle switch because the contact to
> enable the scramble board needs to be momentary to
> turn on the board and then a momentary contact to
> switch off the board. This contact will be using an
> enable wire from the board and another wire that is a
> ground. I think a flip flop MAY be the way to go. I
> was also wondering if there is a  push button switch
> that has 2 spst contacts?
> Thanks. 
> --- MCH <[EMAIL PROTECTED]> wrote:
> 
>> For that matter, why not just a toggle switch?
>>
>> Joe M.
>>
>> Rich Summers wrote:
>>> I need to build a simple circuit to enable a voice
>> scrambler in a radio.
>>> What I need is a momentary contact by pressing a
>> button so that the
>>> activation lead goes to ground and when this
>> happens I need an led
>>> indication that the unit has been activated. 
>>> I also need the led to turn off when the button is
>> pressed again. This
>>> deactivates the board and the radio returns to
>> normal mode.
>>> I need this in a small box.
>>> Does anyone have a circuit I could build for this
>> particular application?
>>> Thanks,
>>>
>>> Rich
>>>
>>>
>>>
>>> 
>>>
>>>
>>>
>>> Yahoo! Groups Links
>>>
>>>
>>>
>>>
>>>
> 
> 
> 
>   
> 
> Be a better friend, newshound, and 
> know-it-all with Yahoo! Mobile.  Try it now.  
> http://mobile.yahoo.com/;_ylt=Ahu06i62sR8HDtDypao8Wcj9tAcJ
> 
> 
> 
> 
> 
> Yahoo! Groups Links
> 
> 
> 
> 
> 

[Repeater-Builder] Re: Adding Control Receiver without Separate Antenna

[Laryn Lohman]

--- In Repeater-Builder@yahoogroups.com, "John Transue" <[EMAIL PROTECTED]>
wrote:
>
> Laryn K8TVZ,
> 
>   So, if I understand, I should put a splitter after the pre-amp, and
> the control frequency should be a split channel. Does this mean that I
> use half way between two channels? 

Right, one of the 12.5 kc. in-between channels would be less likely to
have something on them.


> 
>   Another question, who makes a good splitter, and how can I know I am
> getting a good splitter?


Well, I've seen 50 ohm splitters quite often at hamfests.  I don't
have a good brand name to point you to.  I am, however, using a 75 ohm
TV splitter.  Purists will hate this, but especially, if you are after
a preamp, I don't see this as a big deal.  It works just fine here
with no measured loss in repeater receiver sensitivity through the
system.  Use quality coax and fittings.  I've found that RG142 works
reasonably well with the TV splitters since it has a solid center
conductor.

If you are not using a preamp, then you really need to do things
right, using a proper splitter, and still you may lose some sensitivity.

Some of you are saying, where's the quality in that splitter scheme? 
Well, experimentally I've found it works well here, so after initial
measurements showed me that things were still the same, I'll tend to
stay with what works, but ready to ditch the whole thing if needed and
go another route.  Sometimes  takes the form of performance,
not looks or perfection.  If system sensitivity had suffered it
wouldn't be there for more than 15 minutes.  

Laryn K8TVZ

Re: [Repeater-Builder] Adding Control Receiver without Separate Antenna

[no6b]

At 5/11/2008 14:33, you wrote:

>I would like to add a control receiver to a UHF (446 MHz) repeater. The 
>repeater is at a hospital that has allowed us to put up the repeater 
>antenna but is very hesitant to permit additional antennas. So, is there a 
>way that I can use the repeater antenna for both the repeater and the 
>control receiver?
>
>John AF4PD

Sure, if your input & control RX freqs. are close enough.  I have 2 sites 
where the input & link RXs are only ~600 kHz apart.  Since I have plenty of 
link margin, I put a 10 dB coupler on the output of the RX preamp (fed by 
the RX port of the duplexer through a pass cavity) & feed the coupled port 
to the link RX.  The off-channel loss of the pass cavity & pass response of 
the duplexer results in a few more dB of loss, but since my link paths are 
line-of-sight I don't notice the loss.

Bob NO6B

Re: [Repeater-Builder] Feedlines In and Out of Repeater Cabinet

[no6b]

At 5/11/2008 14:39, you wrote:

>I have followed with interest the thread treating feed line to use to 
>connect repeater/duplexer/antenna, and I think I should replace the cables 
>that are now in use on my 2-m repeater. But now the repeater TX and RX and 
>a remote base use short cables to a feedthrough on the top of the cabinet. 
>There are 90 degree elbows on the feedthroughs. Would it be better to 
>eliminate these feedthroughs and elbows by just cutting a hole in the 
>cabinet and routing the cables directly to the radios? What is common practice?

Feedthroughs are always better, provided they're N connectors.  Among other 
things, they help keep the rodents out of the cabinet.  N elbows are good 
up to a least a couple GHz, so they should work fine @ 440 & lower.  SO-239 
feedthroughs are all bad @ 440, as are PL-259 elbows.  I even had one cause 
desense @ 146 MHz (nothing but a dummy load on the other side; remove the 
elbow, desense gone!).

Bob NO6B

Re: [Repeater-Builder] Best coax for short jumpers in repeater cabinet?

[Wayne]

  I have some cable that I cannot find the true information for.
  it is labeled as follows:
68999, TIMES MICROWAVE SYSTEMS, RT142
  It is not listed, at least not readily seen, on the Times microwave web  
site.
  It appears to be a version of RG142.
  It is tan outer cover
  Double shielded, high density silvered (or tinned) with insulation  
between teh two shields..
  clear solid inner insulation, and stiff solid center conductor.
  I bought it to use as RG142 for jumpers.
  It looks virtually the same as some labeled RG142 that came with a Micor  
UHF duplexer, though less flexible than the RG142 seems to be.
  I now wonder if it is interchangeabe or not?
  I have never seen any cable labeled RT instead of RG...

  Wayne WA2YNE


On Fri, 09 May 2008 22:37:00 -0500, Laryn Lohman <[EMAIL PROTECTED]>  
wrote:

>  RG400, RG214, Superflex and RG142 if handled carefully/infrequently,
> and others, are good inside the cabinet.
>
> Some seem to be concerned about the larger vs. smaller cables,
> implying less vs. more loss.  Generally these jumpers are so short
> it's not an issue.  Perhaps it starts to be at 900 mc. and above,
> however.  Moving to something like 1/2" Superflex would help there.
>
> Laryn K8TVZ
>



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Re: [Repeater-Builder] FCC Denies Petition to Utilize 2m Sub-Band for Digita

[wd8chl]

Ron Wright wrote:
> Jim,
> 
> I tend to agree more spectrum is not needed on 2 meters just to
> accommodate D-Star or any other mode, digital or analog.  Many analog
> boys are also starving for space for their repeaters.
> 
> D-Star does look for the proper D-Star format to "unsquelch" as one
> might say.  It does not simply turn on with signal like many analog
> rigs do.  The repeaters and rigs do this.

Right. I'm looking at provisions to monitor the frequency for NON D* 
activity before transmitting. Most P25 radios can be set up in 
"dual-mode" where it will also respond to analog FM with or without a 
CTCSS/DCS code, as programmed. D* should have that, or a commercial-type 
hangup clip arrangement, or a busy-lockout that keeps the radio from 
transmitting if there is other activity...or the choice to program one 
of the above.

> This is why, as you very well know, we use CTCSS...to unsquelch the
> rcvr when the proper tone rcv'd.
> 
> The petition to the FCC was an attempt to gain more repeater pairs
> mainly for D-Star.  I am sure the petitioners would have wanted the
> expansion to go for digital only.  I am sure the FCC saw thru this.

Yeah...nope-they're just gonna have to live alongside the rest of us 
that can't spend $1000 on a radio...|cP

Re: [Repeater-Builder] Best coax for short jumpers in repeater cabinet?

[wd8chl]

RG-213 is NOT double-shielded and should NOT be used in a full duplex 
repeater system.
RG-214 is the corrct substitute.

Ron Wright wrote:
> Kris,
> 
> I guess the question would be are you now having problems you think
> are caused by internal cable???
> 
> If not replacing RG213 with 142 is not a positive move.  That is the
> 213 is ok.
> 
> The 142 is easier to work with because it is smaller and I would
> prefer it when building a repeater.
> 
> 73, ron, n9ee/r
> 
> 
>> So RG-142 > RG-213? I've got a six-foot jumper of RG-213, which I
>> can replace with some RG-142, but the 142 is .25" diameter and the
>> 213 is .5" diameter.
>> 
>> -- Kris Kirby, KE4AHR  <[EMAIL PROTECTED]> But remember, with no
>> superpowers comes no responsibility. --rly

Re: [Repeater-Builder] Re: antenna question - Dip It and Scotch Kote and Kry

[wd8chl]

Paul Plack wrote:
> Actually, in theory, a fiberglas-enclosed colinear array fed from one
> end requires more elements and length to equal the gain of an
> otherwise comparable colinear array fed at each element. The upper
> elements of a Stationmaster are seeing less RF current than the ones
> closer to the feedpoint, which degrades the pattern and gain.
> 


Well, the point was that a VHF 4-bay winds up being about 20', and 
yields about 6 dBd gain. A typical VHF Stationmaster-type colinear 
array, is about 23' long, and is spec'd at 5.2dBd gain or so.
A 10dB gain Stationmaster-type antenna for VHF would be VERY long, and 
not mechanically stable, which I think you were getting at too.

There are 9dB folded dipole arrays made for VHF, ie, and 8-bay. They are 
about 40' long, but because of that, they are only suitable for side 
mounting, they need a support at the bottom and in the middle.

Re: [Repeater-Builder] FCC Denies Petition to Utilize 2m Sub-Band for Digital Repeater Operation

[wd8chl]

Nate Duehr wrote:
> wd8chl wrote:
> 
>> Good. D-Star and other digital voice modes do NOT need more spectrum on 2M.
>>
>> If a digital voice mode does not have some sort of provision for 
>> monitoring for non-digital activity, or preventing transmission if there 
>> is any, it needs to be redesigned, as it can easily be considered 
>> illegal. P25 has it.
> 
> The requirement for repeaters to monitor their output frequency was 
> dropped years ago Jim, if that's where you're headed. 

No, it wasn't.

  A D-STAR repeater
>   doesn't monitor for non-digital activity, and neither does a modern 
> analog repeater monitor for someone talking on the output frequency.

No, only concerned with end-user radios.

> (Yes, there were once requirements long before I was even a ham to do 
> so, as I've learned from others.)

I think I heard that too-but I don't know repeaters here that ever did it!

> As far as user rigs go, the Icom D-STAR user rigs do have the ability to 
> do a busy channel lockout on both analog and digital signals.  So that's 
> covered.  Just like SOME P25 rigs.  (Remember D-STAR is just an open 
> protocol, Icom just happens to be the only manufacturer making them 
> right now.  A ham in Japan has built a fully-working D-STAR interface to 
> hook to his FT-817 that works just fine also.)

That's what I was headed towards. The original post of the FCC answer 
(the part I quoted) seemed to lead that the petitioners were requesting 
additional repeater spectrum partially based on D-Star users not being 
able to determine if a frequency was in use by another mode. That is 
decidedly NOT a legitimate concern! There needs to be means to determine 
that there is other traffic on the frequency, somehow.

> 
> Your assertion that ALL P25 rigs do busy channel lockout, is flat out 
> wrong. 

I never said that. I said that they all have some means of monitoring 
the channel for activity. Most have the 'dual-mode' feature I mentioned, 
most DO have BCL (but MOST don't have it programmed), and all at least 
have either a hangup clip function for mobiles, or a monitor button next 
to the PTT for handhelds.

RE: [Repeater-Builder] Best coax for short jumpers in repeater cabinet?

[Eric Lemmon]

Wayne,

RT142 is a triaxial cable that is no longer in the Times Microwave catalog.
Since the two shields are insulated from each other, that cable will not
perform well where two shields are needed.  It is a special-purpose cable
that is intended for use with Trompeter and similar triaxial connectors.
Moreover, it is not a Mil-Spec cable and is not interchangeable with RG-142
or similar double-shielded cable in which the shields are directly in
contact with each other.

73, Eric Lemmon WB6FLY
 

-Original Message-
From: Repeater-Builder@yahoogroups.com
[mailto:[EMAIL PROTECTED] On Behalf Of Wayne
Sent: Sunday, May 11, 2008 8:34 PM
To: Repeater-Builder@yahoogroups.com
Subject: Re: [Repeater-Builder] Best coax for short jumpers in repeater
cabinet?

  I have some cable that I cannot find the true information for.
  it is labeled as follows:
68999, TIMES MICROWAVE SYSTEMS, RT142
  It is not listed, at least not readily seen, on the Times microwave web  
site.
  It appears to be a version of RG142.
  It is tan outer cover
  Double shielded, high density silvered (or tinned) with insulation  
between the two shields..
  clear solid inner insulation, and stiff solid center conductor.
  I bought it to use as RG142 for jumpers.
  It looks virtually the same as some labeled RG142 that came with a Micor  
UHF duplexer, though less flexible than the RG142 seems to be.
  I now wonder if it is interchangeabe or not?
  I have never seen any cable labeled RT instead of RG...

  Wayne WA2YNE

[Repeater-Builder] Re: Wacom Duplexer Desense Problem - Mystery

[skipp025]

One of the things I never saw asked... are any of your 
Jumpers the LMR-400 type coax?  One of my LMR-400 train 
wreck stories started with a Wacom Duplexer and a jumper 
of the mentioned.  The story ended when I replaced the 
jumper with rg-214

just curious... 
s. 

>  "blisswheeler" <[EMAIL PROTECTED]> wrote:
>
> I really appreciate all of the comments on my duplexer mystery.
> 
> I made sure everything was tuned properly and took it back to my
> friends home location.  We put it back on the air and experienced <2db
> of signal desense with an output of 15 watts. That still doesn't
> duplicate the results of the dummy load test, but that's a far cry
> from the 30db I was experiencing here at my home shop. Some of the
> things I did learn from the experience was that:
> 
> 1. Though an antenna may only have a 1.5 SWR doesn't mean that the
> antenna is a 50 ohm match. Using my MFJ ("Mighty Fine Junk" which, by
> the way work pretty darned good, but not in a high RF environment)
> antenna analyzer, the antenna that gave me the most difficulty
> presented an 80 ohm load.  The SWR was 1.5.  A discone antenna worked
> the best and it presented a 55 ohm load with a 1.2 SWR.
> 
> 2. Double shielded coax is a must in repeater operation.  I
> experienced this first hand.  I had one short jumper I thought was
> double shielded and was not which caused an intermittent such that one
> time it worked into a dummy load and the next it went flaky.  Moving
> the coax with the repeater transmitter keyed revealed the culprit. 
Use hardline or double shielded coax.  Hardline to the antenna is very
> important.
> 
> 3.  Bench testing duplexers into a dummy load may not duplicate the
> results experienced with the antenna.
> 
> 4. In theory isn't necessarily the same as reality.  I suppose if you
> know all the variables the problem can be calculated and identified,
> but there are a lot of unknown variables when working with RF.
> 
> 5. The environment your repeater is in can cause you to loose your
> hair. Yes it is related to the rf generated, no not because of the
> health effects but because it makes you tear your hear out trying to
> identify a problem.
> 
> 6. I learned about whiskers in GE Mastr II receivers...  I experienced
> their effects and how to fix the problem, though maybe for only a year
> or two, but I learned to to disassemble and retune the receiver.
> 
> 7. Your experienced Techie RF friends are a great help.  I have three
> good friends that gave me a lot of ideas and helped me trouble shoot
> this problem. The folks here on Repeater-Builder gave me some good
> tips which pointed in the right direction as well, for that I thank
> you all.
> 
> Respectfully,
> Bliss
>

Re: [Repeater-Builder] FCC Denies Petition to Utilize 2m Sub-Band for Digit

[wd8chl]

Dan Blasberg wrote:
> On May 9, 2008, at 1:55 PM, Ron Wright wrote:
> 
>> D-Star rigs are expensive as Ham Radio rigs, but how expensive is  
>> P25 radios???
>>
> Depends on the manufacturer and if you want new or used.  Used P25  
> radios can be had for as little as $250 (you still need a programming  
> kit for some) and as high as $2500+ for a new handheld or mobile.
> 
>> Can one add a P25 controller to a typical FM repeater or is it like  
>> Icom and one must ICOM for all.
>>
> No, P25 decoder is built into the radio itself, much like the ICOM  
> radios.  And no one has come out with a "dongle" for P25 probably due  
> to the expense of the codec from DVSI for IMBE.  That may change for  
> phase 2 P25 which will be using an AMBE codec from DVSI.  The question  
> is, is it the same AMBE codec used for D-Star and if so, can someone  
> write the firmware into a dongle to add both P25 and D-Star to the  
> same radio.  If that were to happen that would be pretty kick.


Well, actually there is one I know now, and others are working on it.
Raytheon/JPS has a box that can be added to a system to make an existing 
  analog repeater P25. One unit handles 4 repeaters, so it's really more 
designed for a trunked system. And it's not cheap-list I think is around 
$10K or so. But remember-that is essentially *four* controllers in one 
1RU cabinet.