Re: [Repeater-Builder] Re: New article on Channel Element/ICOM stability - W3KKC

[Kevin Custer]

Hi John,

The input to the ICOM compensation pin requires very little current, and 
since there is already a 10 volt regulator in the MASTR II, it's easier 
and cheaper to use two resistors.


Kevin

John wrote:

Kevin Custer wrote:


I'll post that text here, so you don't have to go to the article:
/There is one way to cheat if all you have is ECs.   An EC will 
maintain better than 5ppm from +32 degrees F to above 120 degrees F 
only if you have a stable +5v DC voltage on the compensation line./


Kevin,

Would it be better to replace the 2 resistors with a small low current 
TO-92 +5v regulator.

That will provide a more stable voltage and is smaller than 2 resistors.

Just my 2¢
John 

Re: [Repeater-Builder] Re: New article on Channel Element/ICOM stability - W3KKC

[John]

Kevin Custer wrote:



I'll post that text here, so you don't have to go to the article:
There is one way to cheat if all you have is ECs.   An EC will 
maintain better than 5ppm from +32 degrees F to above 120 degrees F 
only if you have a stable +5v DC voltage on the compensation line.



Kevin,

Would it be better to replace the 2 resistors with a small low current 
TO-92 +5v regulator.

That will provide a more stable voltage and is smaller than 2 resistors.

Just my 2¢

John

John Mc Hugh, K4AG
Coordinator for Amateur Radio  
National Hurricane Center, WX4NHC

Home page:- http://www.wx4nhc.org

Re: [Repeater-Builder] Re: New article on Channel Element/ICOM stability - W3KKC

[Mike Morris WA6ILQ]

At 09:25 PM 02/03/07, you wrote:
>At 2/3/2007 20:09, you wrote:
> >If there is such a thing - ICM in OKC would be tops, then Bomar, and down
> >the line.  sb
>
>Given the horror story given here recently by Dave KA9FUR, I can't even
>consider ICM at this point.  It's as if most of the crystal manufacturers
>just don't care if they put out a decent product anymore.
>
>Maybe the answer is DDS modules.  Sure, they need stabilization or
>compensation as well, but at least they become an integral, non-replaceable
>part of the radio.  Not sure how you'd direct FM them, though - they may
>not like having their reference modulated.
>
>Bob NO6B

I, for one, would LOVE to see a DDS (or some other technology)
based channel element / ICOM replacement.  Something that I could
program, plug into the radio, and ignore.  I don't care if its programmed
via solder blobs, dip switches, rs232, or with a RS-to-TTL converter
like a Moto RIB.

The unit would have to run off of +9.6 or 10vDC, and output
a tripled signal (most Moto elements contain a tripler), and
to accept a modulation signal...

Even if each one (transmit or receive) was the size of a double
deck of cards that wouldn't be a problem in most base stations.

Heck, it reminds me of running a GLB synthesizer up front with
a pair of RG174 cables back to the trunk... I was using a set of
channel elements as buffer/triplers.

Back then my elements that had RCA  connectors mounted in
the top covers got some strange looks.

Mike WA6ILQ

RE: [Repeater-Builder] Re: New article on Channel Element/ICOM stability - W3KKC

[N9WYS]

Neither would I...  I've used them several times in the past year to re-rock
some UHF Motorola elements, and I have no complaints at all.

Mark - N9WYS

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

I don't remember Dave's problem.  However, I wouldn't hesitate to use ICM.
I have used them for crystals to be installed by me & have had them
compensate ICOMS for me.  I call my order in.  The nice ladies take my order
& send an email to confirm.  I check the email & have caught a couple of
errors over the years.  A reply to the email gets things corrected ASAP.  I
have never had a ICM crystal not net to frequency or have trouble staying on
frequency.

Fred N4GER

-Original Message-
From: Repeater-Builder@yahoogroups.com On Behalf Of no6b

Given the horror story given here recently by Dave KA9FUR, I can't even 
consider ICM at this point.  It's as if most of the crystal manufacturers 
just don't care if they put out a decent product anymore.

Maybe the answer is DDS modules.  Sure, they need stabilization or 
compensation as well, but at least they become an integral, non-replaceable 
part of the radio.  Not sure how you'd direct FM them, though - they may 
not like having their reference modulated.

Bob NO6B 

RE: [Repeater-Builder] Re: New article on Channel Element/ICOM stability - W3KKC

[Fred Flowers]

I don't remember Dave's problem.  However, I wouldn't hesitate to use ICM.
I have used them for crystals to be installed by me & have had them
compensate ICOMS for me.  I call my order in.  The nice ladies take my order
& send an email to confirm.  I check the email & have caught a couple of
errors over the years.  A reply to the email gets things corrected ASAP.  I
have never had a ICM crystal not net to frequency or have trouble staying on
frequency.

Fred N4GER

-Original Message-
From: Repeater-Builder@yahoogroups.com
[mailto:[EMAIL PROTECTED] On Behalf Of
[EMAIL PROTECTED]
Sent: Saturday, February 03, 2007 11:25 PM
To: Repeater-Builder@yahoogroups.com
Subject: Re: [Repeater-Builder] Re: New article on Channel Element/ICOM
stability - W3KKC

At 2/3/2007 20:09, you wrote:
>If there is such a thing - ICM in OKC would be tops, then Bomar, and down 
>the line.  sb

Given the horror story given here recently by Dave KA9FUR, I can't even 
consider ICM at this point.  It's as if most of the crystal manufacturers 
just don't care if they put out a decent product anymore.

Maybe the answer is DDS modules.  Sure, they need stabilization or 
compensation as well, but at least they become an integral, non-replaceable 
part of the radio.  Not sure how you'd direct FM them, though - they may 
not like having their reference modulated.

Bob NO6B






 
Yahoo! Groups Links

Re: [Repeater-Builder] Re: New article on Channel Element/ICOM stability - W3KKC

[no6b]

At 2/3/2007 20:09, you wrote:
>If there is such a thing - ICM in OKC would be tops, then Bomar, and down 
>the line.  sb

Given the horror story given here recently by Dave KA9FUR, I can't even 
consider ICM at this point.  It's as if most of the crystal manufacturers 
just don't care if they put out a decent product anymore.

Maybe the answer is DDS modules.  Sure, they need stabilization or 
compensation as well, but at least they become an integral, non-replaceable 
part of the radio.  Not sure how you'd direct FM them, though - they may 
not like having their reference modulated.

Bob NO6B

Re: [Repeater-Builder] Re: New article on Channel Element/ICOM stability - W3KKC

[Steve Bosshard (NU5D)]

If there is such a thing - ICM in OKC would be tops, then Bomar, and down
the line.  sb


On 2/3/07, [EMAIL PROTECTED] <[EMAIL PROTECTED]>
wrote:


At 2/3/2007 06:06, you wrote:
>>On 2/2/07, Kevin Custer <[EMAIL PROTECTED]>
wrote:
>e.
>





, I really wonder if there's anyone out

there that can truly be considered unconditionally reliable.  I mean, is
there any ONE crystal supplier that EVERYONE considers a "rock" of
stability? (pun intended!)  I suppose that's partly why I've resorted to
developing my own alternative methods of frequency stabilization; file
under "if you want something done right, do it yourself".

Bob NO6B








--
Ham Radio Spoken Here.NU5D
Visit the Temple Ham Club Website
http://www.tarc.org

Re: [Repeater-Builder] Re: New article on Channel Element/ICOM stability - W3KKC

[no6b]

At 2/3/2007 06:06, you wrote:
>>On 2/2/07, Kevin Custer <[EMAIL PROTECTED]> wrote:
>
>>But I doubt I'll ever have time to test that possibility.  However, it 
>>might explain why a lot of people have fairly good luck just stuffing 
>>crystals in ICOM's.  There's probably a fairly small range of caps used 
>>to bring "the usual" crystals into spec...  and a good chance that your 
>>new crystal behaves similarly enough to the original that it will work 
>>some large percentage of the time.
>
>I wouldn't say "a lot of people have good luck".  Have you seen the amount 
>of posts on Repeater-Builder and the other radio branded lists on the 
>subject over the years?

FWIW, I've had both good luck & bad with recrystalling Mastr II 
ICOMs.  I'll also say that they appear to have more than one temperature 
compensating capacitor in them.  The reason I say that is that after 
installing a PTC thermistor on the crystal to thermally stabilize it, I 
would still see thermal drift in the oscillator, & replacing just one or 
two of those little blue capacitors didn't fix it - I had to remove all of 
them.  I think there were 4 of them total in the one ICOM I moded but not 
sure.  I did decide not to try that mod on a Mastr II again though.  The 
MVPs are much easier as they only use 1 temp. comp. cap & for some reason 
most of the MVP crystal modules I have don't have any at all.

I agree that from the end users (the repeater builder) standpoint, sending 
elements in for temperature compensation is the easiest way to go.  The 
problem I see is with all the talk about declining quality amongst the 
different crystal vendors today, I really wonder if there's anyone out 
there that can truly be considered unconditionally reliable.  I mean, is 
there any ONE crystal supplier that EVERYONE considers a "rock" of 
stability? (pun intended!)  I suppose that's partly why I've resorted to 
developing my own alternative methods of frequency stabilization; file 
under "if you want something done right, do it yourself".

Bob NO6B