Re: [Repeater-Builder] Too fast squelch on GE Master

[Jim B.]

[EMAIL PROTECTED] wrote:

> Really!  I noticed some decay problems with an RLC-MOT we have on an SCom 
> 7k.  I've always attributed it to COS line propagation delay in the 
> controller, but perhaps the 2.2 µF cap is the major culprit.  We solved the 
> problem by using the onboard audio gating, which I see uses pins 6 & 7 of 
> the Micor squelch IC.
> 
> Bob NO6B

And there is some. I experienced the same with my 6K, and did use gated 
audio to drive the 6K. Basically the controller is taking the place of 
the original squelch gate board, audio-wise.
If you have a really good signal from the repeater, ie, sitting at the 
site, and a good radio/speaker, and you turn the volume up high enough, 
you can hear the gate close slightly after the squelch closes, maybe 
another 2-5mS. (Actually, I remember the gating time was measured by Bob 
and crew, but I don't remember the time frame.)

-- 
Jim Barbour
WD8CHL

Re: [Repeater-Builder] Too fast squelch on GE Master

[no6b]

At 1/27/2007 19:18, you wrote:

> >> Bob Wrote:
> >> FWIW, I never use pin 10 at all;
> > Kevin wrote:
> > I try to use that pin when I can, and prefer it over the open emitter
> > shunt switches.
>
>Incidentally, the Link-Comm board uses the 2.2 uF cap / pin 10
>combination to drive the COR output...
>FWIW

Really!  I noticed some decay problems with an RLC-MOT we have on an SCom 
7k.  I've always attributed it to COS line propagation delay in the 
controller, but perhaps the 2.2 µF cap is the major culprit.  We solved the 
problem by using the onboard audio gating, which I see uses pins 6 & 7 of 
the Micor squelch IC.

Bob NO6B

Re: [Repeater-Builder] Too fast squelch on GE Master

[no6b]

At 1/27/2007 18:37, you wrote:

>>the circuit I've been using is at
>>http://www.tasma.org/micorsq.png.
>>
>
>I see some potentially major problems with the TASMA circuit, as it is not 
>a replica of the OEM Motorola circuitry; like the one I provided.

That circuit is essentially a copy of a circuit designed by Bill Wood W6FXJ 
(ex-WB6FXJ) of the Goldstone ARC/JPLARC in 1979.  Bill also included some 
active pre-filtering which I later determined had no effect.  As far as the 
other differences go, I've never analyzed them in detail but knowing Bill, 
he wouldn't make a change without a good reason.  I suppose I should send 
him a query sometime & find out just what his reasoning was for the changes.

I never thought pin 10 was ever intended to drive a squelch gate.  The one 
thing I like most about the Micor squelch is how fast the decay time is for 
strong signals: at around a millisecond or two, it's even faster than the 
Mastr II fast squelch.  If it's done right (not just the circuit itself but 
the audio gating as well - no "pops") & the user doesn't have a "dirty" 
unkey, you almost can't tell when the user stopped TXing.  Of course now 
with ADMs abound, I guess the squelch decay time isn't as important anymore.

>inconsistent with the OEM Micor circuitry.  Maybe they don't make that 
>much difference in real world use, but I'll bet my money on the original 
>Micor circuitry.
>
>YMMV...
>Kevin

FWIW, the adapted FXJ Micor squelch circuit is in use on at least 7 systems 
here on 220 & 440 MHz & has worked quite well for us.  The power supply 
filtering on pin 9 could be improved, though I think it was assumed that 
the power was from a "clean source", & in many cases is actually from the 
regulated 10 V bus of the G.E. MVP.

Bob NO6B

Re: [Repeater-Builder] Too fast squelch on GE Master

[Kevin Custer]

>> Bob Wrote:
>> FWIW, I never use pin 10 at all; 
> Kevin wrote:
> I try to use that pin when I can, and prefer it over the open emitter 
> shunt switches. 

Incidentally, the Link-Comm board uses the 2.2 uF cap / pin 10 
combination to drive the COR output...
FWIW

Kevin

Re: [Repeater-Builder] Too fast squelch on GE Master

[Kevin Custer]

[EMAIL PROTECTED] wrote:

At 1/26/2007 16:09, you wrote:

  
The only thing I can say is try one for yourself.  If you don't want to 
spend the $50 or so on the Link-Comm unit (cheap in my opinion), you can 
adapt a Micor audio/squelch board into a Mastr II, or get a chip off of a 
board and build one of these circuits yourself - maybe for a little less:



Hope this helps...
Kevin Custer



Hmmm, that's an awfully big capacitor hanging off of pin 10.  I assume that 
"COS out" is used to drive some visual indicator, as the 2.2 µF cap. will 
prevent really fast short squelch (< 3 millisecond) closing action.
  


That capacitor size is what is in some Mobiles and all Station A&S boards.
In a Micor EMS mobile repeater, its value is 3.3 uF.
FWIW, I never use pin 10 at all; 


I try to use that pin when I can, and prefer it over the open emitter 
shunt switches.   The pin is not used elsewhere in the Station, it's 
only connected to the 2.2 uF cap to ground.  In most Mobiles, the value 
of the pin 10 cap is .47 uF. and the signal there is called RUI 
(receiver unsquelched indicator). 

I use this circuit to buffer the output of pin 10.  It was copied 
directly from the Railroad Micor:

http://www.repeater-builder.com/pix/cosswitch.gif
It was in working with the Railroad Micor that I found that using pin 10 
of the chip (pin 8 of the A&S board) and the associated transistor 
buffer to be my choice of COS generation when using the Micor Squelch 
Chip.  In the Railroad Micor, the value of the pin 10 cap is 2.2 uF.  It 
might be that 2.2 uF is too big to achieve 3 millisecond or less 
closure, but I never thought using this value made it too slow?  Most of 
our conversions are Mobiles, where the default value is .47 uF.  It 
might be that this output is fairly robust, and the actual value is not 
critical...  I don't know, I never measured the differences when using 
different size capacitors here.


the circuit I've been using is at 
http://www.tasma.org/micorsq.png.
  


I see some potentially major problems with the TASMA circuit, as it is 
not a replica of the OEM Motorola circuitry; like the one I provided.
I see a potential for problems with the values of the capacitors 
associated with the input pre-emphasis, they are C3, and C4 in my 
diagram.  The series cap after the squelch pot is 15 times smaller than 
OEM, and the cap across the pre-emphasis resistor is twice the original 
value.  Then is the value between pins 1, and 2; it's less than half the 
OEM size and with a 100 pF hanging on the output, that's a big deal.  
Then is the cap going to pin 4, likely not a big deal, but we've already 
made several caps in this chain smaller than OEM.  Then is the obviously 
too small power supply decoupling cap on pin 9 (.01 uF) after the 15 ohm 
series resistor.  The squelch chip draws some current, and a .01 is just 
too small.  These values are *very* inconsistent with the OEM Micor 
circuitry.  Maybe they don't make that much difference in real world 
use, but I'll bet my money on the original Micor circuitry.


YMMV...
Kevin

Re: [Repeater-Builder] Too fast squelch on GE Master

[no6b]

At 1/26/2007 16:09, you wrote:

>The only thing I can say is try one for yourself.  If you don't want to 
>spend the $50 or so on the Link-Comm unit (cheap in my opinion), you can 
>adapt a Micor audio/squelch board into a Mastr II, or get a chip off of a 
>board and build one of these circuits yourself - maybe for a little less:
>
>
>Hope this helps...
>Kevin Custer

Hmmm, that's an awfully big capacitor hanging off of pin 10.  I assume that 
"COS out" is used to drive some visual indicator, as the 2.2 µF cap. will 
prevent really fast short squelch (< 3 millisecond) closing action.

FWIW, I never use pin 10 at all; the circuit I've been using is at 
http://www.tasma.org/micorsq.png.

Bob NO6B

Re: [Repeater-Builder] Too fast squelch on GE Master

[Kevin Custer]

Hi Nate,
Comments threaded...



Kevin wrote:
After you get frustrated with trying the above   do this:



Nate Duehr wrote:
Kevin,

Any good notes on how to specifically install one of these into a GE MASTR II floating 
around anywhere or any data on just how much it "helps"?
  



It's easy to connect, just power it, and connect VOL/SQ High to the 
input.  As far as 'data' on how much it helps, I think its a matter of 
preference.  I use a repeaters to the end of their string.  Having a 
really good carrier squelch is a necessity when you are on the fringes, 
or syllable chop will result.  The dual action of the Micor squelch is 
something that I have always liked.  It's quick when it can be, and slow 
when it needs to be.


While the GE Mastr II is designed to have both slow and fast, the fast 
function is disabled in the Station configuration from the factory; it's 
only allowed to be slow.  I have never seen a GE Mastr II squelch 
perform like a Micor squelch.  It's supposed to, and I have spent days 
working on it, with only some improvement, which is what is documented.  
I'm guessing that GE couldn't make it stop chopping syllables in 
repeater duty, and is why they chose to disable the fast function.  Even 
when the fast squelch is disabled, the slow squelch isn't slow enough; 
in my opinion - on some bands.


The Micor carrier squelch really works.  It is nice to have near instant 
closure when the receiver quieting is good, and have slw closure 
when signals are in the noise.  The Micor squelch is one of most popular 
options on our GE Mastr II mobile repeater conversions. We've had 
several folks complain about the action of the OEM GE carrier squelch, I 
have never had a complaint about a GE conversion using a Micor carrier 
squelch.


The real show off for a Micor squelch is on a UHF repeater where rapid 
deep nulls can exist.  A mobile approaching a stop light is a good 
example.  The GE squelch will chop them, /no matter how loose you set 
it/, but the Micor squelch will follow them into the noise and out the 
other side.

From what we've seen here, if the squelch on the MASTR II is set right
on the station, using "AND" squelch  (logically AND'ing the CAS and
CTCSS in the controller itself) works VERY well, timing-wise, and also
keeps virtually all noise/interference out of the system.
  


I agree, set correctly the GE squelch works very well; a heck of a lot 
better than a lot of receivers I have seen.

But...  not as good as a Micor - IMHO

AND squelch is a good way to do it, for sure.  Luckily, most  repeater 
controllers these days have AND squelch as an available option; so we no 
longer have to add the logic components.

I know that comment doesn't help those who want to run
carrier-squelch, but it really does work well on our systems here.


The only thing I can say is try one for yourself.  If you don't want to 
spend the $50 or so on the Link-Comm unit (cheap in my opinion), you can 
adapt a Micor audio/squelch board into a Mastr II, or get a chip off of 
a board and build one of these circuits yourself - maybe for a little less:



Hope this helps...
Kevin Custer

Re: [Repeater-Builder] Too fast squelch on GE Master

[no6b]

At 1/23/2007 13:22, you wrote:
>We are using a GE Master II with an RLC Club controller for our 444.600
>repeater. On weak signals the repeater chops words. I have determined
>this is due to very fast action of the CAS turning the controller audio
>off and on. Looking at the schematic, U603 has internal fast and slow
>modes. There is an adjustment, R622 that I can't find in the book. Does
>anyone know how to slow down or improve the squelch action?

The Mastr II squelch does tend to chop if it's set anywhere other than 
threshold.  Make sure it's set as low as possible without hanging open.  If 
it still doesn't perform to your expectations or you must set the squelch 
tighter, retrofitting a Micor squelch circuit would be best; see 
http://linkcomm.com/controllers/accessories/rlcmot/rlc-mot.htm.

The Micor squelches perform much better than the G.E. when the noise 
squelch must be set several dB above threshold as they "chop" much 
less.  At threshold, the difference between the two squelches is only subtle.

Bob NO6B

Re: [Repeater-Builder] Too fast squelch on GE Master

[Sean Fitzharris]

There is an article on the Repeater Builder web site about improving the
stock Mastr II squelch.

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

-Sean

> We are using a GE Mastr II with an RLC Club controller for our 444.600
> repeater. On weak signals the repeater chops words. I have determined
> this is due to very fast action of the CAS turning the controller audio
> off and on. Looking at the schematic, U603 has internal fast and slow
> modes. There is an adjustment, R622 that I can't find in the book. Does
> anyone know how to slow down or improve the squelch action?
>
>
>

Re: [Repeater-Builder] Too fast squelch on GE Master

[Nate Duehr]

On 1/23/07, Kevin Custer <[EMAIL PROTECTED]> wrote:

> > anyone know how to slow down or improve the squelch action?
>
> http://www.repeater-builder.com/ge/mastrIIsquelchmod.html
>
> After you get frustrated with trying the above   do this:
> 

Kevin,

Any good notes on how to specifically install one of these into a GE
MASTR II floating around anywhere or any data on just how much it
"helps"?

>From what we've seen here, if the squelch on the MASTR II is set right
on the station, using "AND" squelch  (logically AND'ing the CAS and
CTCSS in the controller itself) works VERY well, timing-wise, and also
keeps virtually all noise/interference out of the system.

I know that comment doesn't help those who want to run
carrier-squelch, but it really does work well on our systems here.

Nate WY0X

Re: [Repeater-Builder] Too fast squelch on GE Master

[Kevin Custer]

wa5luy wrote:
> We are using a GE Master II with an RLC Club controller for our 444.600 
> repeater. On weak signals the repeater chops words. I have determined 
> this is due to very fast action of the CAS turning the controller audio 
> off and on. Looking at the schematic, U603 has internal fast and slow 
> modes. There is an adjustment, R622 that I can't find in the book. Does 
> anyone know how to slow down or improve the squelch action? 

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

After you get frustrated with trying the above   do this:


Kevin

Re: [Repeater-Builder] Too fast squelch on GE Master

[Nate Duehr]

On 1/23/07, wa5luy <[EMAIL PROTECTED]> wrote:
> We are using a GE Master II with an RLC Club controller for our 444.600
> repeater. On weak signals the repeater chops words. I have determined
> this is due to very fast action of the CAS turning the controller audio
> off and on. Looking at the schematic, U603 has internal fast and slow
> modes. There is an adjustment, R622 that I can't find in the book. Does
> anyone know how to slow down or improve the squelch action?

How did you set the squelch?  Is it set to a known signal level?  When
I've seen this happen the squelch is usually set too tight on the
Stations.

If you're talking about a converted mobile... well, read on...

This article may be a lot more useful to you than finding R622:
http://www.repeater-builder.com/ge/mastrIIsquelchmod.html

Nate WY0X

[Repeater-Builder] Too fast squelch on GE Master

[wa5luy]

We are using a GE Master II with an RLC Club controller for our 444.600 
repeater. On weak signals the repeater chops words. I have determined 
this is due to very fast action of the CAS turning the controller audio 
off and on. Looking at the schematic, U603 has internal fast and slow 
modes. There is an adjustment, R622 that I can't find in the book. Does 
anyone know how to slow down or improve the squelch action?