Dear Eric,
Thank you for your mail.
Yes, we found that the interconnect T-Join between two system is heated up.
Could we just cool down the T-Join for there is other way to solve this issue?
Best Regards,
Kent
--- On Wed, 10/3/10, Eric Lowell <elowell9...@yahoo.com> wrote:
From: Eric Lowell <elowell9...@yahoo.com>
Subject: Re: [Repeater-Builder] Noise Level on a Duplexer
To: Repeater-Builder@yahoogroups.com
Date: Wednesday, 10 March, 2010, 8:54 PM
Kent,
I have seen this sort of problem before in a simaler application. I believe
that your duplexer may have a bad internal connection, possibly at a
fingerstock contact. In my case the problem was solved by replacing the
duplexer. I believe the problem was caused by tuning the duplexer under power
rather than with a network analyser. This occured many years ago, so my memory
may be faulty.
Best Regards de Eric (W1EL)
Eric Lowell
Eastern Maine Electronics Inc.
48 Loon Road
Wesley ME 04686
eme....@starband. net
www.satnetmaine. com
207-210-7469
From: Kent Chong <kentchongkm@ yahoo.com. sg>
To: Repeater-Builder@ yahoogroups. com
Sent: Tue, March 9, 2010 10:31:30 AM
Subject: Re: [Repeater-Builder] Noise Level on a Duplexer
Dear Joe,
Yes, we have observed the signal with a spectrum analyser. It is a broadband
noise covering our entire TETRA band.
Yes, the transmitter is keyed up continually.
Regarding oscillation, what circuitry will develop the oscillation in 3 days?
We are thinking about the heat problem too, as heat may be developed overtime.
Best Regards,
Kent
--- On Tue, 9/3/10, Joe <k1ike_m...@snet. net> wrote:
From: Joe <k1ike_m...@snet. net>
Subject: Re: [Repeater-Builder] Noise Level on a Duplexer
To: Repeater-Builder@ yahoogroups. com
Date: Tuesday, 9 March, 2010, 8:52 PM
Hello Kent,
Have you looked at the noise on a spectrum analyzer? Is is broadbanded
noise, or is it just on your receiver frequencies? If it is only on
specific frequencies, is it frequency stable or does it drift around?
Also, do any of your transmitters stay constantly keyed up?
I'm wondering if something external to your system is oscillating. Your
signals may be causing it to go into self-oscillation. When you shut
your system off it stops. This is just a guess right now.
73, Joe, K1ike
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