"Excess power detected on receiver"

  • 3
  • Problem
  • Updated 2 years ago
Operating Flex 6400 on Win 10 Home v1803
Smart SDR
Simple all band vertical antenna and only antenna connected to Antenna 1 port on 6400

Plain jane setup.

Low and behold I go to make a CW contact and for each tap of the paddle I get a cascading series of Smart SDR error messages

"An Error Has Occurred"  "Excess Power Detected on Receiver (>+20 dBm), transmitter has been unkeyed and receiver disconnected to protect hardware" 

What the ....  there is no other radio transmitting .. this only happens when I hit the CW key and attempt to transmit .. this is a head scratcher as I don't know of any changes to the config

Tim ... HELP ... I'm unable to transmit ... rx only ...



Photo of Ed W2MKM


  • 42 Posts
  • 3 Reply Likes

Posted 2 years ago

  • 3
Photo of mikeatthebeach .

mikeatthebeach .

  • 486 Posts
  • 86 Reply Likes
Try Downloading to a Lower Version of Software and see if it happens
Then Upload to a Higher Version and see if still there 
73 Mike
Photo of Ed W2MKM


  • 42 Posts
  • 3 Reply Likes
Thanks Mike .. but is this a known issue?  I've successfully worked CW on this radio since I got it ... and have updated to v2.3.7  some time ago .. I've only come across one other issue with the same description and it was when there was another radio operating nearby ... this is not the case ..

This is a new one for sure

Respectfully the procedure you note seems like "not sure .. but give it a try" ..

Photo of Bill -VA3WTB

Bill -VA3WTB

  • 4656 Posts
  • 1099 Reply Likes
It is not a version problem.
Do a factory reset, and bring back your profiles that you saved.
Photo of N8SDR


  • 210 Posts
  • 31 Reply Likes
Sounds to me like a lot of common mode, Is there any balun on the vertical? how is the vertical grounded? can you try winding a loop of coax before the radio , 6-8 turn in 8 inch loop or so. 
Photo of Craig Williams

Craig Williams

  • 89 Posts
  • 35 Reply Likes
For me it always turns out to be a bad PL-259.
Photo of Ed W2MKM


  • 42 Posts
  • 3 Reply Likes
Certainly a solution I’ve considered but this has been a stable setup for some time.

This occurs with little or no output power.

Seems like a mouse turd floating around the memory of the 6400 and I will try a factory reboot and go from there

I will advise ASAP

Photo of donh


  • 11 Posts
  • 0 Reply Likes
 I’ve experienced the same message twice over months of operating ft8 at 13w. Each time I remember hearing a much louder relay ‘click’ than normal that accompanied the message as the sw transitioned from receive to transmit mode. My swr as measured by my 6300 is between 1:1 and 1.5:1 without ATU and about 1.25:1 with ATU. I don’t remember experiencing this prior to the last two sw updates.

My set up is simple - PC running WSJT-X, wired LAN, Flex 6300, BigIR with xcvr frequency controlled antenna setting.  The WSJT-X does a frequency shift on transmit, but does not cause the antenna to adjust.  The BigIR is used for both transmit and receive.  There is a loop antenna connected to the 6300, pre-amp off.

Normal receive to transmit sequence:
1. Relay 'click'
2. Transmit frequency adjust, waterfall to transmit observed, no output
3. Ft8 transmission observed on waterfall
4. Waterfall no power output, frequency adjusts back from transmit
5. Relay 'click'

Is it possible for a flex 6000 to enter transmit mode before disengaging receive mode when using a single antenna, single slice?

The photo was captured shortly after the most recent occurrence.  The noted frequency is much lower than expected from the normal 14.074 during receive.

Photo of N9VC


  • 214 Posts
  • 65 Reply Likes
By chance, is full duplex enabled on the radio?

73, Jim N9VC
Photo of donh


  • 11 Posts
  • 0 Reply Likes
The FDX button is grayed out.  I have never knowingly enabled any full duplex operation.  I'm still learning to use split TX/RX using slices (not for ft8 which uses the WSJT-X 'fake it' option) for working stations running split mode.

If I understand correctly, the 6300 does FDX using the XVTR port.  The XVTR tab on Radio Settings is empty.

The receive loop antenna is on ANT2, is used occasionally independently for SWL off the ham bands.  The loop preamp is off unless doing SWL and was off during the two noted instances.

don wa0ruf