Weak receive and noise floor under -125 when I boot up Radio on 20 Meters on Ant 1. Stonger receive

Julie KC0TMD

Hello,

Am Julie B KC0TMD.

I own a Flex 6600M Radio with the newest software Version v3.0.27.

My Flex 6600M is acting in a strange way. When I boot up the Radio and load SDR on my PC. The first thing I notice on 20 Meters is a very low receive single of +3 on a moderate to strong single with a noise floor of -125. Also I do not see a lot of stations that my folded dipole antenna can revive on my FT-857D Radio. If I do a few different combination of events, I can get higher noise floor and stronger single strength. Below I will list the different events that will get it up to full receive  strength, with the Pre Amps set in recommended specs.

I have discovered if I click on DIV on DIV off, and then click Ant 1, Ant 2 and Ant1 again, the Noise will Jump to -125 and moderate to strong singles will jump between 7+ to 9+. And I see a lot of stations I can't before. If I switch from Ant1 to Ant2, and put my TX/RX Antenna a Folded HF Dipole, I will boot up the Radio and load the software. The noise floor will be -125 with moderate to strong singles between 7+ to  9+. If I Click on DVI and change from Ant 1 to RX A, I will get stronger singles and all of the stations.

What gets more stranger with the use of Multi Flex. If I change the band on my Flex-6600M Screen or band on my SDR software. 20 Meters will get stronger single with all the stations. If I bring back the SDR and the Flex-6600M to the same band, The Noise Floor and many stations will drop out leaving me with a lower single receive.

I could put the main TX/RX folded dipole antenna, and call it a day, but I would like to have this issues resolved as it is frustrating.

I did put in a Ticket Monday afternoon. Still waiting for replay. I hope this is a simple fix or something they can sent me in the mail that I can install my self like you do a PC.

Any input on this matter would be greatly appreciated.

My contact number is 636-578-1990

Thank You.

Julie B KC0TMD.

James Charlton

Hi,
I can't say that I have experienced exactly the same problem you describe, but I did see a few odd behaviors before I really became familiar with my 6600m.  Most of them were related to the preamp/attenuator and filter settings.

I found that as I switched things around, I accidentally changed the gain and this made it seem like the sensitivity of the receiver randomly increased or decreased.  Also the width and number of panadapters can change the way the radio samples and can make the noise floor seem to increase. 

You mention that you are using a folded dipole antenna.  The ATU in the radio may be having a problem matching that without a balun.  The ATU is present on both transmit and receive and a mismatch can reduce received signal strength.

You did not mention if you experience the same results when operating the radio via its front panel controls or what happens when you transmit.

None of the above may be relevant in you case, but it might give you some new ideas of things to try.  
Regards,
James Charlton  AD0AB

  
 

Julie KC0TMD

James , Am using a Palstar La-1K Amplifier running in to Palstar Auto Trunner,. When I turn, I get a SWR of 1.2 to 1.0. Transmitting works prefect. Julie B KC0TMD.

Cal N3CAL

Julie,  I would double check what your antenna preamp settings are under Ant 1 and Ant 2.  Your Ant 1 might be starting with -8db of attenuation??  You should try cycling through the various preamp settings and note if there is a change in signal level and also note if the noise floor changes level?

Cal/N3CAL

William Osborne

Julie, I have a 6600M also and I had various issues after I upgraded to v2.5.  Most were related to the table of band preferences which in v25 and v3 must be setup for your situation.  also after the download and install of the software be sure you disconnect the 12vdc for 30 secs or so the reconnect and start the radio with a factory reset. The after it bots reload your SAVED profiles.

Good luck  Bill--K5ZQ