Phase noise or front end overload #elad


Patrick Bouldin KM5L <patrick@...>
 

Thanks Clint, great info!

73, Patrick KM5L


Clint Chron
 

Hi Patrick,

 

I have a home brew Antenna TR switch that I use with my Wellbrook mag loop antenna.  In the Antenna TR switch box, I have a AM band stop LC filter. I can bypass the LC filter as needed.  The AM band stop filter is the top board.  The same board (Mini-Kits) can also be used to build out a AM broadcast band high pass filter.

 

 

73

Clint

W7KEC

 

From: EladSDR@groups.io [mailto:EladSDR@groups.io] On Behalf Of Patrick Bouldin KM5L
Sent: Sunday, July 12, 2020 3:28 PM
To: EladSDR@groups.io
Subject: Re: [EladSDR] Phase noise or front end overload #elad

 

Got it Clint, now is the band stop filter in software, within SW2 or are you switching hardware in/out?


Patrick Bouldin KM5L <patrick@...>
 

Got it Clint, now is the band stop filter in software, within SW2 or are you switching hardware in/out?


Clint Chron
 

Hi Patrick,

 

My band stop filter notches out all frequencies in the range of 550 KHz to 1600 KHz.   A high pass filter would also work to get rid of the AM broadcast station overload, but I wanted to listen to the frequencies of 200 KHz to 500 KHz.  It might be difficult to come up with a solution without knowing the source of your overload.  An occasional ADC Clip flash might not be indicative of your overload situation.

 

73

Clint

W7KEC

 

From: EladSDR@groups.io [mailto:EladSDR@groups.io] On Behalf Of Patrick Bouldin KM5L
Sent: Sunday, July 12, 2020 10:07 AM
To: EladSDR@groups.io
Subject: Re: [EladSDR] Phase noise or front end overload #elad

 

Hey Clint, thanks for responding. Gosh with so much crowding during field day I don't think I could answer those questions. I see the ADC flash now and then, always have, I thought I heard that was "normal". Didn't notice the DUO PK light but I'll start to look.

Your last comment, what is that, a high pass filter that blocks anything lower than 160 meters? Tell me about the filter!

Thanks and 73,
Patrick KM5L


Patrick Bouldin KM5L <patrick@...>
 

Hey Clint, thanks for responding. Gosh with so much crowding during field day I don't think I could answer those questions. I see the ADC flash now and then, always have, I thought I heard that was "normal". Didn't notice the DUO PK light but I'll start to look.

Your last comment, what is that, a high pass filter that blocks anything lower than 160 meters? Tell me about the filter!

Thanks and 73,
Patrick KM5L


Clint Chron
 

Hi Patrick,

 

If the problem signal was adjacent band, then external band pass filters will most likely help.  You need to know the source of the signal that was causing the problem.  If the signal was in-band, then a band pass filter will probably not help.

Did you see the “PK” light on the front of the Duo or the ADC Clip light on the SW-2 software?

 

At my home QTH, I get overload from the strong AM broadcast stations that are about 12 miles from my house.  I have an external AM band-stop filter on my Duo that gets rid of the overload.

 

73

Clint

W7KEC

 

From: EladSDR@groups.io [mailto:EladSDR@groups.io] On Behalf Of Patrick Bouldin KM5L
Sent: Sunday, July 12, 2020 7:33 AM
To: EladSDR@groups.io
Subject: [EladSDR] Phase noise or front end overload #elad

 

Greetings!

Hey I started out using the FDM DUO for Field day, almost all CW. Had to stop because with so much traffic something was creating a lot of phase noise, or just overload of some kind.

Have others experienced this? I don't have any of the external bandpass filters, maybe this will solve, what do you think?

73, 
Patrick KM5L


Patrick Bouldin KM5L <patrick@...>
 

Greetings!

Hey I started out using the FDM DUO for Field day, almost all CW. Had to stop because with so much traffic something was creating a lot of phase noise, or just overload of some kind.

Have others experienced this? I don't have any of the external bandpass filters, maybe this will solve, what do you think?

73, 
Patrick KM5L