Re: FDM-DUO overload issues

Clint Chron

Hi Steve,


If you see the PK light flashing , then that does sound like you have an in-band or adjacent band station that is causing the overload.  However, a flashing light is not nearly as serious as the light coming on steady.  Is there any way that you could get the SW-2 software installed on a PC?  You could quickly find the offending station with the spectrum display.  Any SDR radio that does not have front end receiver band pass filters is going to have the same problem with front end overload, if strong stations are nearby.  Some of the early Flex 6000 series radios had the same problem.  I think that Flex now has front end band pass filters in all of their radios.


If one installs a front end pre-selector on the Duo, then the overload capability is better than most other SDR radios, including the Icom IC-7300.


The QSF is a nice box, but kind of pricey even if you only purchase one filter.  If the overload is coming from a single station, then it would be much cheaper to install the appropriate TX band pass filter.  Here is a link for such filters:











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.


Join to automatically receive all group messages.