Hi Eric,
The reason for using an external controller is I have two other repeaters (2,
220) on the site that i am interfacing with. The PL level being transmitted is
750 Hz. Under normal operation using a external controller, PL is not passed
through, but is re-incoded by the transmitter. The "whine" appears on the audio
wave from as a high frequency saw tooth pattern.
Steve / K6SCA
Eric Lemmon <[EMAIL PROTECTED]> wrote:
Steve,
I have to wonder why anyone would want to hook up an external controller to
an R1225 radio, when it has a very capable controller built-in. And that
may be at the heart of your problem. I suspect that both the internal and
the external controller are trying to do the same thing at the same time.
If your RC-210 is supplying the PL tone, make certain that the R1225 is not
also generating tone, and vice-versa. I'm not familiar with the RC-210, but
check to see if it is equipped with a high-pass filter that blocks the PL
tone from passing through the repeated audio chain. Even if the R1225 is
not encoding tone, an over-deviated PL tone on a user input can sound quite
raspy on the output if not filtered.
As has been discussed many times on this list, the majority of Amateur-grade
mobile and portable radios seem to be delivered with very "hot" CTCSS
deviation- sometimes as high as 1500 Hz, when it really should be in the 500
to 750 Hz range. When the CTCSS tone generation circuit in a user radio
produces other than a pure sine wave, the tone is so distorted that it
sounds very loud and raspy. Try setting up a commercial-grade radio on your
repeater pair to see if the buzz is still there. Also, try setting up both
the controller and the R1225 as carrier squelch, and test again.
Careful shielding of your audio cables and separation of power and signal
grounds may help. Also, make certain that the R1225 is programmed as a Base
Station, not a repeater. When an external controller is used, the R1225
must do nothing at all besides act as a full-duplex radio.
73, Eric Lemmon WB6FLY
-----Original Message-----
From: [email protected]
[mailto:[EMAIL PROTECTED] On Behalf Of Steve Allred
Sent: Monday, November 12, 2007 9:19 AM
To: [email protected]
Subject: [Repeater-Builder] GR1225
Hi guys,
I need your help on a UHF GR-1225 that has me baffled. There is a audio buzz
(high pitched) that appears on the repeated signal. It is NOT on the hang
time, so it's not comming from the power supply, controller (RC-210),
exciter or PA.. It is only present when a signal is applyed to the input
(service monitor or HT) of the receiver. Also, it was not there when i had
it configured as a repeater using the internal GR1225 controller.
Any ideas? Did i short out a wire and kill something in the audio section of
the receiver or ????? HELP!
Thanks!
Steve / K6SCA
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