Rather than pile $25 worth of ferrite and filters on it why not take a divide
and conquer systematic approach to resolving the problem.
Start with the supply. Can you draw 20-30 Amps out of it with just a plain
resistive load? If not, the supply may be defective without even adding the RF
part into the equation.
Next add the radio without all the microphones, CAT interfaces, external
speakers, etc connected. Transmit into a dummy load at a low power level. Do
you notice the issue? Check all bands. If the issue is still non existent
increase power and repeat checking all bands. Check CW and Modulated modes.
If the issue is still not recurring start adding the microphones, head phones,
speakers etc back into the equation and recheck functionality to see what it
takes to make that power supply fold up.
The final stage will be adding the antenna and transmitting full power with
everything hooked up.
Once you know exactly what it takes to make the supply fold up it is going to
be much easier to determine the exact fix. Adding a ferrite bead (what mix??)
to attenuate common mode currents when you are uncertain about which
frequencies or which cables are even causing the issue (1.8-30 MHz is a big
chunk of spectrum)is more of an exercize in how lucky you are rather than how
good you are.
Good luck with the process. Let us know how it comes out.
Earl
N8SS
--- w2iy@verizon.net wrote:
From: Michael Tortorella <w2iy@verizon.net>
To: yaesu@contesting.com
Subject: [Yaesu] FT890 strange behavior
Date: Wed, 10 Jul 2013 22:32:10 -0500 (CDT)
Hi all, using an FT890 with Astron SS-30M supply and DX Lab Suite. Receives FB
but the instant I hit the key, the xcvr shuts off, the supply voltage goes down
to 3 volts. Turn everything off, restart, same deal: receives FB, as soon as I
hit the key, the xcvr shuts off and supply goes to 3V. At first I thought it
was RF getting into the supply so I separated the two by a couple feet and this
_seemed_ to help. But tonight the problem is back fully.
This first happened two days ago. Then last night everything was fine, worked
several stations OK. Tonight, problem. Has anyone seen anything like this
before? Any advice greatly appreciated.
Thanks and 73
Mike W2IY
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