Hello Bob
Thanks for your reply to my earlier posting and offer to help. Below is a copy
of an earlier posted request for anybody with a thought to be properly IFR
1100S to run a test on their 1100S to help me to determine as to whether mine
is typical or has an abnormally leaky spectrum mode sweep oscillator.
Ron was the only responder to my request-----He ran the test and reported that
his had the same problem as mine. Would it be possible for you to run my test
and report?------if yours is quiet, mine can be too-----but if it isn't, I'll
be a step closer to deciding that it is an 1100S design defect that I'm up
against.
Many thanks Bob------send me your phone number if you don't mind and a good
time for me to call-----we can discuss a lot more a lot quicker than this way.
Scott, N6NXI
COPY----------
Hello Ron
First, many thanks for your answer to my call-----You are the first 1100S user
to do so.
It seems to me that my 1100S has extreme RF leakage from the spectrum analyzer
mode internal sweep oscillator when it is activated by putting the unit into
the spectrum analyzer mode. My 1000S manual shows this oscillator to be
centered at 145.000 Mc. and that it sweeps above and below this frequency at
the analyzer sweep rate as set by the "DISPR" control------ and my 1100S is
unusable around this frequency from the "Antenna" connector in the normal
sensitivity setting unless a distant antenna is connected----unusable with a
rubber duck directly on the antenna connector.
I would like for you to set up your 1100S as below and tell me what happens----
----set up conditions first-----
RCVR---selected
FM ---selected
BFO ---off
Input Level---NORM
"Rubber Duck" antenna like used on HT's on the "Antenna" connector via a
BNC 90
RCVR---selected ------try all three bandwidths----
Scope on in either AC or DC
ANALY DISPR---on-------- Spectrum Analyzer mode active----move control
cw/ccw
Squelch---off
Volume----up enough to hear noise
RF FREQUENCY----set to 145.000Mc.
Now----The question----Do you hear a spectrum analyzer sweep buzz and see
"birdies" on the scope or is the speaker noise clean no signal noise and does
the scope show just no signal noise? If you hear sweep buzz ---try all three
receiver bandwidths-----switching the "ANALY DISPR" control to off should stop
the noise-----and if you hear a local signal at 145.000 it is OK to move the
test up or down for a clear spot.
Hopefully you will not hear any sweep buzz and I will then know that something
has gone bad in my unit and that I can fix it. But looking at this situation
from how much attenuation by shielding is necessary between the sweep
oscillator and an antenna on the front for no interference to be present, I
wonder if I'm asking or expecting to much-----but then the book doesn't suggest
any limitations and other service monitors that I am familiar with don't hear
themselves----but also, IFR changed things spectrum analyzer wise in their 1200
which I assume was next. Who knows?----Your test will tell.
Again, Thanks much---hope to hear from you soon--
Scott
END OF COPY--------
----- Original Message -----
From: neufeldrobert
To: [email protected]
Sent: Thursday, July 05, 2007 3:11 PM
Subject: [Repeater-Builder] Re: IFR 1100S Service Monitor
--- In [email protected], "Scott Overstreet"
<[EMAIL PROTECTED]> wrote:
>
> Anybody out there have an IFR 1100S service monitor in good working
operation----I have a problem with one that we just bought for use
within our repeater group. I need to talk with somebody who has
experience with this particular IFR model to find out just what I can
expect of the spectrum analyser mode.
>
> And also, now that I realize the age of this unit, is there anybody
out there that would like to sell me a junker for future parts?
>
> Please communicate off the [EMAIL PROTECTED]
>
> Thanks
>
> Scott, N6NXI
>Scott
I obtained an original IFR 1100S manual for $150. I wrote the IFR
company about putting it into *.pdf format since it is copyrite about
1984, but they never answered me. If I could obtain permission, I
would put it into readable pdf and send it to repeater-builder, so
everyone could have it. I earlier thought I had the right one and
sent it to repeater-builder, but to my chagrin it was the same manual
that was already there for the IFR 1000S (AN/GRM-114).
It took me considerable time before I realized the differences. It
is very hard to work on the 1100S with the military manual which is
on CD, although many of the modules are the same.
The main difference between the 1000S and the 1100S is mainly the
power-supply and the power-termination unit. On the 1000S there are
three separtate sections for the 20db, the power sensor and the
relays. On the 1100S, it is one unit.
If anyone needs help with the 1100S, I will be happy to correspond
by telephone or email, although, unless the company give us
permission, I cannot copy the manual.
As I stated, they ignored my email; but perhaps they would respond if
something more official was sent to them from repeater-builder.
If someone wanted to send me the unit, I would be happy to look at it
and would only charge if I was able to fix it. I spent many hours
over months fixing my own unit.
Bob Neufeld
N3AU
