Tom,
Okay.... I guess I should ask if replacement coils for the Mitrek are
still available from Motorola, and if so, at what cost? If they are no
longer available, or are cost prohibitive, send me one of your Mitrek
receivers and I'll see if I can come up with a new set of coils that
properly tune the whole 2M band.
I guess at this point we should go to private email.
Kevin
Hello Kevin
Thanks for your reply. Your statement is correct in that all of
the receiver coils begin to tune at the bottom of their travel. I
have even tuned two or three too far and they dropped out with the
resulting work to retrieve the screws. When tuned as best I can for
sens the s/n ratio is 1+uv at 12db sinad. The original frequency sens
was less than 1uv-usually about .3uv for 12db sinad. Replacing the
coils are about the only solution I know of for these high split VHF
units. I have in the past replaced two sets of receiver coils with
Motorola coils and found I have good sensitivity as before
modification. The transmitters all tuned well on this split and gave
rated or more power output.
The Mitrek coils looked very much like the Micor coils. I have
replaced probably a half dozen Micor receiver coils proscured from
Motorola in the past 20 or so years. Thanks. 73 de Tom Manning, AF4UG
----- Original Message -----
*From:* Kevin Custer <mailto:kug...@kuggie.com>
*To:* Repeater-Builder@yahoogroups.com
<mailto:Repeater-Builder@yahoogroups.com>
*Sent:* Thursday, December 18, 2008 10:02 PM
*Subject:* Re: [Repeater-Builder] Holiday Special - MICOR 2 meter
receiver conversion from W3KKC
Tom,
You say you find similar operation on 4 or 5 units. By that do
you mean they won't make book specification on any frequency below
146 MHz? If that is the case, I would believe something is
wrong. I have seen many Mitrek high-band receivers that were
tuned for 144 something and had very good sensitivity.
Let me ask you this.... When tuned at 144.89, is the front-end
tuning all "one ended", or is there adjustment to spare? In other
words, can you tune the front-end without the fear of the tuning
screws falling into the casting? If you have room left to go
lower in frequency, then the front-end is not the problem, and
you'll need to look elsewhere for the lack of sensitivity.
Another question - do these 4 or 5 units tune and make book spec
sensitivity on their original high-band channel?
I guess what I'm saying is I doubt the problem is the front-end
helical resonators, but if there is a need for a conversion I'm
not opposed to looking into making a modification available, if it
is needed. If there are others on the list that have had good
luck with the Mitrek on frequencies below 146 MHz, please chime in
and let us know what you have and how well it works.
Kevin
Hello Kevin
You are correct on your freqs for xmit and rcv. The Mitrek
units I have will only tune receive to 146.00Mhz. This leaves
more than one meg to go to meet tolerance on 144.890. I have
tried 4 or 5 units and find similar operation of all. This is
the reason for my question about the Micor coils working for
Mitrek. Thanks. 73 de Tom Manning, AF4UG
----- Original Message -----
*From:* Kevin Custer <mailto:kug...@kuggie.com>
*To:* Repeater-Builder@yahoogroups.com
<mailto:Repeater-Builder@yahoogroups.com>
*Sent:* Tuesday, December 16, 2008 8:44 PM
*Subject:* Re: [Repeater-Builder] Holiday Special - MICOR 2
meter receiver conversion from W3KKC
Tom,
Do you mean 144.89 MHz? I would think your repeater would
*transmit* on 145.490 MHz.... At any rate, no conversion is
necessary for the Mitrek to make book specification
sensitivity on 144.890 MHz.
Kevin
Good afternoon Kevin
My need is to convert two or more Mitrek receivers to
cover 145.49Mhzz, which is our receive freq for our
repeater. Thanks. 73 de Tom Manning, AF4UG
----- Original Message -----
*From:* Kevin Custer <mailto:kug...@kuggie.com>
*To:* Repeater-Builder@yahoogroups.com
<mailto:Repeater-Builder@yahoogroups.com>
*Sent:* Tuesday, December 16, 2008 12:19 PM
*Subject:* Re: [Repeater-Builder] Holiday Special -
MICOR 2 meter receiver conversion from W3KKC
Tom Manning wrote:
Good morning Kevin
I have a question. Will these coils also work in a
Mitrek? Thanks. 73 de Tom Manning, AF4UG
Hi Tom,
To answer your question, the conversion will not work in
the Mitrek.
Unlike the MICOR, the Mitrek high-band unit that is most
common has a lower tuning limit of 146.00 MHz as
specified from the factory. This means that the units
normally tune anywhere in the 2M ham band without
modification. What frequency do you need to listen on?
Kevin
