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Any BC engineers here on this group?

Kriss Kliegle
 

My usual HF music station , WRMI on 9395 kHz, has lately been obliterated by another BC station, WEWN on 9385 kHz. Does the attached images look normal for a BC station? I'm seeing numerous carriers(?) out +20 kHz on either side of the primary carrier. This appears on all my SDR's and with various antennas selected.

What are your thoughts, too much gain on my part, or is the TX on 9385 at fault?
Anyone else see this?

Kriss KA1GJU

jdow
 

Maybe some of each. Drop your front end gain and see if the spurs go down faster than the signal levels. If so your gain is too high. I see it is an HF+ so are you using its AGC or trying to manually set gains? Or is this hidden from you behind the server wall?
{^_^}

On 20191201 17:47:58, Kriss Kliegle wrote:
My usual HF music station , WRMI on 9395 kHz, has lately been obliterated by another BC station, WEWN on 9385 kHz. Does the attached images look normal for a BC station? I'm seeing numerous carriers(?) out +20 kHz on either side of the primary carrier. This appears on all my SDR's and with various antennas selected.
What are your thoughts, too much gain on my part, or is the TX on 9385 at fault?
Anyone else see this?
Kriss KA1GJU
Screenshot-2019-12-01-202151.png
Screenshot-2019-12-01-202246.png

Brendan Wahl
 

Kriss,

NABCE (Not A BC Engineer) here but I'd say WEWN has some real problems. Everything else looks good, no distortion on the other signals shown, and overall the waterfall looks good. Your SDRC settings seem to be no different from my HF+ Disco setup as far as I can tell, so I got nothing on that end.

Radio Havana has recently had some problems at one of their transmitter sites that have pretty much looked the same, obliterating anything near. I measured one broadcast that was causing problems over 100kHz wide! Oddly enough, most of the time they weren't RHC broadcasts, but CRI relays to North America. They have since returned to 'normal,' at least to where and how RHC defines 'normal.'

Too late out here for me on the west coast to check WEWN: the 31m band has completely closed down at the moment, and won't come back up for hours.

Brendan WA7HL

CN88rs

Simon Brown
 

One comment – upgrade the HF+ firmware. Looks like yours is way out of date.

 

Simon Brown, G4ELI

https://www.sdr-radio.com

 

From: main@SDR-Radio.groups.io <main@SDR-Radio.groups.io> On Behalf Of Kriss Kliegle
Sent: 02 December 2019 01:48
To: main@SDR-Radio.groups.io
Subject: [SDR-Radio] Any BC engineers here on this group?

 

My usual HF music station , WRMI on 9395 kHz, has lately been obliterated by another BC station, WEWN on 9385 kHz. Does the attached images look normal for a BC station? I'm seeing numerous carriers(?) out +20 kHz on either side of the primary carrier. This appears on all my SDR's and with various antennas selected.

What are your thoughts, too much gain on my part, or is the TX on 9385 at fault?
Anyone else see this?

Kriss KA1GJU

kb3cs
 

9385 looks over-modulated to me. but i would first check using other remote receivers before sending a note (with spectrum pix!) to the station.

once upon a time not long ago, i noticed a metropolitan station's FM subcarrier used for book reading to the blind had dropped off significantly. i monitored for another week before sending messages with before and after spectrum graphs. the before graph i was able to locate from someone's FMdx blog. almost needless to say, the subcarrier was restored to its former glory about a week afterward (and i suspect some sharp words were directed at the station's technical staff).

Bjarne Mjelde
 

I've seen this exact pattern on loads of Chinese MW stations. 

--
Bjarne Mjelde
arcticdx.blogspot.com
Remote receivers: 
arcticsdr.ddns.net:8073/
kongsdr.ddns.net:8074

David J Taylor
 

From: kb3cs

9385 looks over-modulated to me. but i would first check using other remote receivers before sending a note (with spectrum pix!) to the station.
================================================

Is it possible with SDR Console (or SDR#, HDSDR, SDRangel etc.) to display the incoming RF waveform - i.e. use the program like a simple oscilloscope? That might make overmodulation or clipping on SSB easier to spot.

73,
David GM8ARV
--
SatSignal Software - Quality software for you
Web: http://www.satsignal.eu
Email: david-taylor@...
Twitter: @gm8arv