Mike,
Did you just build up these repeaters? If so, you need to remember to install a
load on the audio output of the receiver audio amplifier. This can be placed at
the speaker connections. If there is not an 8 Ohm load on the audio output, it
will produce a low level oscillation in the audio circuits around 500 hz which
some people call Hum.
I modify my GE Mstr II mobile receivers by adding a switch in series with R616
on the Audio Squelch board which is a 30 ohm resistor feeding regulated 10
volts to the Audio IC U604. Opening this switch turns off the audio amplifier
when no speaker audio is desired.
This also helps reduce current draw from the receiver.
Just a suggestion,
John, K7JL
Intermountain Intertie
3d. Re: Ge mastr 2 link question
Posted by: "Mike DeWaele" [EMAIL PROTECTED] firechief762
Date: Sun Oct 19, 2008 5:28 pm ((PDT))
Paul, Eric
Thanks for the response. I did some more testing with your suggestions. I
tried hooking both radios up to a deep cycle battery. The hum is still there
so I think that rules out the astrons! The audio from the main repeater to
the link isn't as bad as from the link back to the main repeater. Both have
a hum to them however the 2 meter to the 440 you can hear the voice. the
other way all you get is the hum.
For testing I have it on the bench in the basement. the only common
connection is only the audio and tx lines between the two radios. I have
also tried it with a common ground as suggested by NHRC in the controller
directions. Both have the same results.
I want to make sure it works here before it goes back to the hill. At the
site it's just my radio equipment and Wifi internet which has not given me
any problems with both machines working there prior to bringing them to my
house to work on this linking project.
Maybe tomorrow I will give NHRC a call and see if they have run into this
problem before.
Thanks,
Mike KA2NDW
-----Original Message-----
From: [email protected]
[mailto:[EMAIL PROTECTED] Behalf Of Paul Plack
Sent: Sunday, October 19, 2008 4:59 PM
To: [email protected]
Subject: Re: [Repeater-Builder] Ge mastr 2 link question
