Flex radio glitches... on transmit...

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  • Updated 3 years ago
My flex 1500 glitches sometimes on transmit.  Usually when I have my SS linear at about 50W.

For example sending CW it will just suddenly stop transmitting.  IE the key does nothing.  So far the only solution seems to be to shutdown Flex software, power off the radio and restart both. 

Those steps will bring it back alive.   

Now I have a really good RF ground.  8' copper rods into the soil, big heavy gage wire for the ground.  

My antenna is j-pole used as a vertical in a tree about 50 feet away and up about 30 feet.

My computer is a Windows 10 core i7 and I am still working on shielding all of that but the symptom doesn't seem to be computer based unless the SDR software is glitching.

Any ideas?
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Mark - WS7M

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Posted 3 years ago

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WX7Y

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You may need to install several RF Beads out by the feed point of the Antenna which is called a "line isolator",  here is Palomar web site to read up on this. http://palomar-engineers.com/rfi-kits/antenna-rfi-kits
 RFI has very little to do with DC grounding or earth ground but rather keeping the RF off the outside of the Coax feed line from coming back into the radio and computer is I'm sure your main goal.

This may or may not help but I believe this could be your issue.

73's
Bret
WX7Y
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K2CM

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RF feedback is most likely the culprit. Try transmitting without the amp...use about a watt. If the problem does not occur at that level; but, occurs with the amp, it is RF feedback. Put split Ferrite cores on all cables. That should fix it.
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Mark - WS7M

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Thanks guys... I've got a bunch of ferrites coming.  It does not glitch even at full 5W.  It doesn't glitch usually at 35W but at about 50 to 60 or higher it is pretty consistent.
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Burt Fisher

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I never had a problem with my Icom ProIII with rf shutting the rig off, or causing it to reset. With all this talk of RF beads was there any thought to put the RF beads inside so we don't have to put them outside? Is there any protection at all for RF in the Flex 6000 series. If it's my fault (RF) (poor grounding) why did my 5000 work OK, same house, same antennas?
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Mark - WS7M

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Well Burt, this is a new station.  Still working out the kinks.  I made sure to create a really good RF ground.  Now I need to shield a bunch of cables.  I have braid coming from Digikey in the next day or so.  I also have an MFJ antenna tuner and perhaps there are issues there. 

This is part of the fun, tracking down the little gremlins.

One thing I will say is I converted everything to solid DC power, no wall warts.  I made sure the RF ground was HUGE and my ambient S noise on almost all bands dropped from about S8 to S4.  Not sure if that is quantifiable as band conditions change but the signals are bigger now!

My antenna is a j-pole tunable from 160 to 50 and its in a tree as a base feed vertical about 30 feet up.  It is only fed by RG58 which is all I can get through the conduit so I have to deal with the loss but I can certainly put beads on that line.

I plan to put beads on a bunch of the lines all over the place.  As one person said in their powerpoint here on this forum, you can never have too many RF chokes.  So I bought like 30 of them and plan to use them all.   :-)

My computer is a screaming i7 development machine and I'm sure its making lots of noise so when the braid arrives all of those cables will be braided and grounded.  It is also a fair distance from the radio.  

So its coming together.  I just hope to get everything stable.  it is frustrating to be in a CW QSO and have the glitch happen.  The other station is like where did you go!?  

Anyway it will get there.  I'm currently using an RM amp which I don't like very much.  It is very finicky about its protection and faults a lot.  This could be a sign of the RF problem.

I have a TenTec amp coming but who knows when it will get here.  I like that amp a lot more.

I really want to stay at about 50W I figure if you can't hear me with that then I don't deserve to be heard.

Mark - WS7M
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Tim - W4TME, Customer Experience Manager

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Sometime "too much" grounding is a bad thing when it is not doing what you intended for it to do electrically.  I have solved may a RF issue by disconnecting the ground.

Building a proper RF ground is difficult.  It isn't about ground rods, but how the circuit behaves at different RF frequencies.  If you have RF common mode currents on the coax shield coming back into the shack, these need to be shunted to ground.  Ferrite beads are one tool.  Proper grounding of the coax shield so the currents have somewhere to go is the other half of the equation.  If this cannot be done adequately, the no ground connection to the hardware may be an option.  There is a great article on the HelpDesk about RF grounds.  I recommend it to anyone thinking about constructing an RF ground, as it looks at it from the circuit perspective and shows the math to back it up

https://helpdesk.flexradio.com/hc/en-us/articles/204779159-Grounding-Systems-in-the-Ham-Shack-Paradi...
(Edited)
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Mark - WS7M

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Tim,

Thanks for the info I'll check it out.
(Edited)