[GE] Mstr II PA

[Chris Boone]

Turns out the 100+w LMR UHF PAs suffer when you don't use a circulator.(DAMN
that explains why the only MICOR I have ever seen without one, at Lewis
Creek power plant near Willis TX, owned by then Gulf States Utilities now
Entergy, who was my employer from 84-96 and then in 2007!, kept
DYING!!!...It didn't have a circulator and I kept coaxing the PA back to
life for months on end until I had to repair it.then it would do 75W out for
a while.then start failing again.finally bypassed the PA and put a TPL on
it!! Never had a problem after that)..SON OF A ....oops..never mind ;)

 

I'm headed out to the site tomorrow to put a 35w PA on it.which evidently
can live without a circ..and then wait for the new circulator to arrive..and
then put the repaired 100w PA back on.Its going off the combiner
anyway.Duplexing it on the master rcv antenna.which has no tower top
preamp-that will change once I buy the trunker owner out!...BUT does have 1
5/8in Heliax.so it will be duplexer alone and the trunkers will be combined
on split antennas (DB420s at 610/590ft).the xmit bottom DB420 is leaning
anyway since the tower crew didn't tighten the clamps up right the last time
they "fixed" it..and thus the range on it really sucks..the top antenna is
in the clear and straight vertical..

 

BTW anyone have a recommendation on a DECENT tower crew company near SE
Texas?? I am NOT using Lumberton Tower Service ever again..Since Wayne
McDaniel SR left and turned the company over to sonny boy, its been downhill
since (and Wayne Sr would do ham stuff for me gratis!! Jr wouldn't do
ANYTHING to keep his customers happy.which is why they lost Entergy as a
customer too! SOOOO I am in need of a new tower company I can count on;
especially after a hurricane, etc) I have used John Hill's Trico out of
Houston (and their San Antonio site serves S Texas and RGV) and got VERY
good results with them.but wanted to see if anyone else out there was
looking at. I heard of a tower guy or company out of Oklahoma(!) that will
do jobs for less than what Trico will.and that includes travel! GEESH.. cant
believe that.

 

TIA

Chris

SouthEast Texas Telecom (STT)

 

From: n griggs [mailto:n_griggs at bellsouth.net] 
Sent: Saturday, September 24, 2011 8:26 PM
To: Chris Boone; LMR at yahoogroups.com; ge at mailman.qth.net;
general_electric at yahoogroups.com
Subject: Re: [GE] Mstr II PA

 

Chris,

 

The MIII PA wants about 10 mW drive input where the MII is closer to 100 mW
IIRC.  The MIII control cable (the gray cable) requires +12 volts for the
driver circuitry, PA Key (+5 volts)also for the driver circuitry - this is
summed inside the amp with the dc sample of the reflected power, power set -
this is between 4 & 8 volts and is the 'software' power adjustment from the
programming, ground and a power sense output - an analog voltage going back
to the MIII chassis for monitoring the output power.  I have converted
several high band MIII repeaters to the amateur band and, the repeater owner
and I have toyed with doing the opposite of what you are wanting to do -
using a MII amplifier on a MIII system but as a last resort.  I still have
pieces to put together to have two complete systems (146.955 & 146.73) in
case of an emergency.  The repeater builder website has the MIII LBI if you
need it.  Let me know how it turns out!

 

73,

 

Neal KC4YCM