[Flexradio] Question about TX harmonics

[Mark Lunday]

I was attempting to break through the pileup for 5H1WW on 80 CW the other
night. A ham emailed me the next morning and said he could hear a harmonic
of my CW signal 1.2 kHz down from my main.which unfortunately was right on
top of the DX station.

This is the first time someone has told me about this, but I think I read
somewhere about it happening to another ham on 160 meters.

Does this sound familiar to anyone? How did you resolve it? I was running
an amp at the time into an inverted L.

Mark Lunday, WD4ELG
Greensboro, NC FM06be
***@arrl.net
http://wd4elg.blogspot.com

[Patrick Greenlee]

Mark, Harmonics are integral multiples of your frequency so whatever was
happening it wasn't a harmonic of your signal.

How close was the reporting station to your QTH? Strange things happen
when someone experiences fundamental overload of their receiver. If
able, arrange to have a look at your emissions on a good spectrum
analyzer. It might not be something you are emitting but something
created in his receiver.

One time in the early 60's I was reported to the FCC as causing TVI. I
had a 2nd class licensee prepare a fact finding report in response to
"The Letter" from the FCC. I was putting out a very clean 3 Watts on
the CB band and the "ancient" TV I was interfering with had an IF with
band width covering the CB freqs. I was transmitting directly into one
of the TV receiver's IF circuits. Solution: Hey dude, get a more modern
TV. End of story.

Post by Mark Lunday
I was attempting to break through the pileup for 5H1WW on 80 CW the other
night. A ham emailed me the next morning and said he could hear a harmonic
of my CW signal 1.2 kHz down from my main.which unfortunately was right on
top of the DX station.
This is the first time someone has told me about this, but I think I read
somewhere about it happening to another ham on 160 meters.
Does this sound familiar to anyone? How did you resolve it? I was running
an amp at the time into an inverted L.
Mark Lunday, WD4ELG
Greensboro, NC FM06be
http://wd4elg.blogspot.com
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FlexRadio Systems Mailing List
http://mail.flex-radio.biz/mailman/listinfo/flexradio_flex-radio.biz

[Mark Lunday]

Thanks Patrick.

It was two stations about 700 miles away in different directions.

Instead of harmonic, I should have said Spur. I shall open a ticket with
Flex.

Mark Lunday, WD4ELG
Greensboro, NC FM06be
***@arrl.net
http://wd4elg.blogspot.com


-----Original Message-----
From: FlexRadio [mailto:flexradio-***@flex-radio.biz] On Behalf Of
Patrick Greenlee
Sent: Friday, November 25, 2016 8:27 AM
To: ***@flex-radio.biz
Subject: Re: [Flexradio] Question about TX harmonics

Mark, Harmonics are integral multiples of your frequency so whatever was
happening it wasn't a harmonic of your signal.

How close was the reporting station to your QTH? Strange things happen when
someone experiences fundamental overload of their receiver. If able,
arrange to have a look at your emissions on a good spectrum analyzer. It
might not be something you are emitting but something created in his
receiver.

One time in the early 60's I was reported to the FCC as causing TVI. I had
a 2nd class licensee prepare a fact finding report in response to "The
Letter" from the FCC. I was putting out a very clean 3 Watts on the CB band
and the "ancient" TV I was interfering with had an IF with band width
covering the CB freqs. I was transmitting directly into one of the TV
receiver's IF circuits. Solution: Hey dude, get a more modern TV. End of
story.

[Ray Andrews, K9DUR]

Mark,

1.2 kHz down would be an image response of your xmt signal if the
sidetone frequency is the default value of 600 Hz -- as if the opposite
sideband was not being suppressed.

You did not say what type of radio. IF FLEX-1500, FLEX-3000, or
FLEX-5000, try doing a reset to factory defaults. Starting with a clean
database cures a myriad of ailments.

73, Ray, K9DUR
http://k9dur.info

[GARY HUBER]

Mark, I no longer have your original message, but if the "spur" was 1.2
kHz as I recall, I'm wondering if you have a local AM broadcast station
which may have mixed in your final. I have seen sum and difference
products from local transmitters mixing in a transmitter result in
"spurs". Sometimes it is a matter of running intermod calculations on
the local transmitters, identifying what is getting into your PA and
then filtering them to prevent further problems. I'm not say its one
transmitter, it could be two or more or it may not even be a mixing
problem... just a thought outside the box.

73 ES DX,
Gary - AB9M

Post by Mark Lunday
Thanks Patrick.
It was two stations about 700 miles away in different directions.
Instead of harmonic, I should have said Spur. I shall open a ticket with
Flex.
Mark Lunday, WD4ELG
Greensboro, NC FM06be
http://wd4elg.blogspot.com
-----Original Message-----
Patrick Greenlee
Sent: Friday, November 25, 2016 8:27 AM
Subject: Re: [Flexradio] Question about TX harmonics
Mark, Harmonics are integral multiples of your frequency so whatever was
happening it wasn't a harmonic of your signal.
How close was the reporting station to your QTH? Strange things happen when
someone experiences fundamental overload of their receiver. If able,
arrange to have a look at your emissions on a good spectrum analyzer. It
might not be something you are emitting but something created in his
receiver.
One time in the early 60's I was reported to the FCC as causing TVI. I had
a 2nd class licensee prepare a fact finding report in response to "The
Letter" from the FCC. I was putting out a very clean 3 Watts on the CB band
and the "ancient" TV I was interfering with had an IF with band width
covering the CB freqs. I was transmitting directly into one of the TV
receiver's IF circuits. Solution: Hey dude, get a more modern TV. End of
story.
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FlexRadio Systems Mailing List
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