6400 Keeps freezing on transmit

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  • Updated 1 year ago
Using 2.49 on 6400.  Often when transmitting, radio freezes up. Will not show up on SDR or CAT program window but radio is still running physically.   At first I thought it was stray RF as I operate downstairs via an Ethernet cable with all equipment upstairs.  Still happens after I liberally applied chokes all over the place and operated barefoot with AMP off. 
Photo of AB9UU


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Posted 1 year ago

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Photo of k3Tim


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Does it happen on all bands or one in particular?
Can you try a dummy load?

I had some similar lockup problems on xmt, a reconfiguration of RF ground and antenna pruning fixed it.
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Burt Fisher

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My 6400M crashes 100% of the time if I run over 80 watts and don't use the ATU, even on a dummy load but not if I use an amplifier and run 500 watts.
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Michael Walker, Employee

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Burt, you have RF getting into your LAN cables somehow.   Maybe even into your DC power cables.   Poor RF cables will radiate RF as well.
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Michael Walker, Employee

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Does it happen if you test with a Lan Cable direct connection between the client and the radio? No switch or router ?  

When the radio freezes, 99% (or more) of the time it is related to a loss of network connectivity.   

To help isolate this, you need to first do a direct LAN cable connection from the client you are using direct to the radio.  If it is still freezing then we need to look at the client or the radio.  If it isn't then, the network can be at fault.

LAN cables and LAN switches do go bad (well discussed in this community).    I had 1 bad LAN cable that works 'ok' until I tried to run CW Skimmer and then Skimmer would crash... all the time.

Mix 43 RF chokes on all Power Lines for switches/routers etc can help.  They also cut down on your receiver noise, so there is a dual win here.  Do you know what types of chokes you used?  

You will need to change a few things to see if the problem gets worse or better.

Let us know how you make out.

73, Mike
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Joel N9LQ

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I developed an RFI problem that was causing freezing when I added a yagi 50 ft above my shack running legal limit.  The problem mostly happened on 17m and higher frequencies.  I assume because at those higher frequencies, every wire in the shack starts to look like an antenna.

What finally solved my problem was stacking two #43 cores, and winding 5 turns of the ethernet cables through it.  I did this for 3 cables: radio to switch, computer to switch, and switch to router.  If that hadn't worked, my next step was to buy new, shielded ethernet cables.  I may still do that.

Prior to that, I added many other chokes on various cables that were suspected.  Common mode chokes on feedlines, chokes on power leads, etc.  I also made sure everything in the shack was bonded to my shack ground.

I know you said that yours is happening at low power and you have already choked everything, but I thought that maybe something in my story might spark an idea for you.  Good luck tracking the problem down.

73, Joel