Re: FDM-DUO overload issues

Clint Chron

Hi Steve,


Here are some screen snapshots of the SW-2 spectrum display.  I have the spectrum bandwidth set to 6144 KHz.  I am injecting a -10 dbm signal at 4 MHz into the antenna jack on my Duo.  Notice that the ADC Clip light is not on.  The 8 Mhz signal is the 2nd harmonic from my HP signal generator.


I have increased the signal level to -9 dbm and the ADC Clip light is on.  However, the Duo’s ADC chip is not in overload.


I have increased the signal level to -8 dbm.   The ADC Clip light is still on and the ACD chip is in overload.






From: [] On Behalf Of Steve Knell
Sent: Wednesday, May 27, 2020 1:12 PM
Subject: Re: [EladSDR] FDM-DUO overload issues


Yes, I see the PK flashing at times particularly on 80/40 but more recently on 20M because I have improved my antenna setup.  I only use the ham bands and I have no nearby AM broadcast transmitters.  I don't want to criticize the FDM-DUO because it's done a superb job for me and you get what you pay for.  No-one could expect it to compare with one of the high-end $4000 radios.

I was just on in the CW-Ops activity hour on 80/40/20 and I could hear the low level sqwauk of a strong stations on 40M, but I forgot to check the PK indicator at the time.  I've had the Elad for several years and I hadn't even noticed the PK indicator until I started to research ADC overload..!

During the day there is some local electric fence noise - not sure if that is a contributing factor as well, on 20M.

I would be interested to hear from anyone who has that QSF unit and whether it has helped them with ADC overload on the ham bands.


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