That works. It also doubles to break a possible current loop path by
disconnecting you from the power mains and "floating" the radio.
--- w7why@frontier.com wrote:
From: "Tom Osborne" <w7why@frontier.com>
To: <Yaesu@contesting.com>
Subject: Re: [Yaesu] FT890 strange behavior
Date: Thu, 11 Jul 2013 18:41:51 -0700
Hi Earl
Or - you could hook the radio to a battery and see if it still folds. 73
Tom W7WHY
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
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