[mdmars_members] Re: Cascade Repeater

  • From: "Forrester, Pudge" <Pudge.Forrester@xxxxxxxxxxxxxx>
  • To: <mdmars_members@xxxxxxxxxxxxx>
  • Date: Tue, 6 Oct 2009 18:26:59 -0400

Thanks for the update Gary,
I replaced the Civil Air Patrol Mastr II repeater with a new Motorola
unit.  The old one has 143.7 or very close to that for the input and
148. 125 or 148.150 output.  It is about 5 feet tall.  Other than being
very dirty from rodents (They had it running without the covers), it was
working well right up to the time I took it out of service.  
This machine does not have to be turned in to the Air Force and can be
reassigned to another government agency, but my thinking is to keep it
on the CAP asset list at its $100 value.  Then I'm hoping the paperwork
just gets lost and nobody asks about it in the future.
Jim had talked about a repeater on Sideling Hill west of Hancock,
however Greg Freis has a free site on Dans Rock west of Cumberland at
about 3,000 feet elevation, where the Hams have a 110 foot tower, shack,
and power.  My Boss and a Dentist bought replacement Rohn 45 sections
last winter to get that tower up.
God bless,

Systems Administrator 
Congressman Roscoe Bartlett 
2412 RHOB 
Washington, DC 20515 
Phone: 202 225 2721; Fax: 202 225 2193 



From: mdmars_members-bounce@xxxxxxxxxxxxx
[mailto:mdmars_members-bounce@xxxxxxxxxxxxx] On Behalf Of R HENDRICKSON
Sent: Tuesday, October 06, 2009 5:29 PM
To: mdmars_members@xxxxxxxxxxxxx
Cc: aat3ok@xxxxxxxxx
Subject: [mdmars_members] Re: Cascade Repeater

The Duplexer at Cascade is a standard Motorola 4-can High-Band unit.  To
set the reject notches on each can, you have to slide the coupling links
back and forth to find the null, then set them in place with a thumbnut.
Unfortunately, these duplexers have a reputation of not holding the
notch very well when subjected to any mechanical vibration or other
motion.  Just flexing the mounting frame can cause the notch to change.
What I think happened to the duplexer tuning is that when the repeater
was being carried in Wayne's pick-up truck, the vibration caused the
duplexer tuning to get off.  It appears to me that the repeater now has
a desense problem, possibly due to the duplexer notch tuning being out
of alignment.
 I have the equipment needed to go retune it on site.  I have also just
finished tuning an old Sinclair 4-cavity duplexer.  It has pretty good
numbers - 86 dB rejection, and just 1.8 dB insertion loss on the
transmit side, and 0.6 dB loss on the receive side.  So we can replace
the Motorola duplexer with the Sinclair unit - there is room inside the
cabinet for the larger Sinclair unit.
However, if you can "acquire" a better, more stable, unit, let's go for
it!  Or perhaps the entire repeater could be used to replace the current
machine in DC.  
Thanks for watching out for us!
73,  Gary  W3DTN/AAR3EY

--- On Tue, 10/6/09, pudgeforrester@xxxxxxxxxxxxx
<pudgeforrester@xxxxxxxxxxxxx> wrote:

        From: pudgeforrester@xxxxxxxxxxxxx
        Subject: [mdmars_members] Re: Cascade Repeater
        To: mdmars_members@xxxxxxxxxxxxx
        Date: Tuesday, October 6, 2009, 2:10 PM
        Confidential please.
        What duplexer does the Cascade repeater have in it?  I just took
a GE Mastr II out of service at Wheeling CAP and it has a DB products 4
can duplexer in it.  I'm quietly "setting" on that repeater in hopes it
can be recrystaled and used for MARS in the future.
        God bless,


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