519 KHz Signal Question

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BOBRR

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Dec 15, 2004
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1,508
Location
Boston, MA
Hi,

Have a simple long wire ant. outside of about 60 feet, then a UnUn, and a coax run up to the house.
20 miles due West of Boston.

Have been trying to monitor Navtex.
Have a nice spectrum display on receiver, so easy to see signals.

But, no signal, ever, at 518.0 KHz.

There is one at around 518.6, which I assume is too high for Navtex.
True ?

And, surprisingly, it seems to move around a bit during the day and evening, going
up to perhaps 519.0 KHz. (the same for looking at it in any mode)

Any idea what this might be ?
If a Beacon, shouldn't it be steady at one of the frequencies I see it at ?

Agree that it is not Navtex ?

Thanks,
Bob
 

sunwave

Member
Joined
Jan 18, 2023
Messages
343
Location
Oklahoma
Hi,

Have a simple long wire ant. outside of about 60 feet, then a UnUn, and a coax run up to the house.
20 miles due West of Boston.

Have been trying to monitor Navtex.
Have a nice spectrum display on receiver, so easy to see signals.

But, no signal, ever, at 518.0 KHz.

There is one at around 518.6, which I assume is too high for Navtex.
True ?

And, surprisingly, it seems to move around a bit during the day and evening, going
up to perhaps 519.0 KHz. (the same for looking at it in any mode)

Any idea what this might be ?
If a Beacon, shouldn't it be steady at one of the frequencies I see it at ?

Agree that it is not Navtex ?

Thanks,
Bob
There are 21 areas that has 518khz listed here https://www.dxinfocentre.com/navtex.htm

I am guessing their transmitter is drifting. Next time you see this happen take a video recording. Upload it to you YouTube then share the video link in this thread. That will help us help you better. We need to see a visual for this "remote" troubleshooting method which is the RR forums.
 

RFI-EMI-GUY

Member
Joined
Dec 22, 2013
Messages
7,452
Hi,

Have a simple long wire ant. outside of about 60 feet, then a UnUn, and a coax run up to the house.
20 miles due West of Boston.

Have been trying to monitor Navtex.
Have a nice spectrum display on receiver, so easy to see signals.

But, no signal, ever, at 518.0 KHz.

There is one at around 518.6, which I assume is too high for Navtex.
True ?

And, surprisingly, it seems to move around a bit during the day and evening, going
up to perhaps 519.0 KHz. (the same for looking at it in any mode)

Any idea what this might be ?
If a Beacon, shouldn't it be steady at one of the frequencies I see it at ?

Agree that it is not Navtex ?

Thanks,
Bob
What type or model receiver are you using???
 

RFI-EMI-GUY

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Joined
Dec 22, 2013
Messages
7,452
Hi

Icom R8600

Regards,
Bob
Are you using FSK mode? I know the 8600 has an internal FSK decoder. My experience with the IC-R9000 which also has an FSK mode, but requires external decoder. My point being that unless you are using FSK the BFO might be different frequency for USB/LSB or CW. The displayed frequency may be off.
 

dlwtrunked

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Premium Subscriber
Joined
Dec 19, 2002
Messages
2,382
Hi,

Have a simple long wire ant. outside of about 60 feet, then a UnUn, and a coax run up to the house.
20 miles due West of Boston.

Have been trying to monitor Navtex.
Have a nice spectrum display on receiver, so easy to see signals.

But, no signal, ever, at 518.0 KHz.

There is one at around 518.6, which I assume is too high for Navtex.
True ?

And, surprisingly, it seems to move around a bit during the day and evening, going
up to perhaps 519.0 KHz. (the same for looking at it in any mode)

Any idea what this might be ?
If a Beacon, shouldn't it be steady at one of the frequencies I see it at ?

Agree that it is not Navtex ?

Thanks,
Bob

Agree that NAVTEX would not be drifting and also, you should only see it come on twice a day. Boston transmits 5 times during the day - it is West Atlantic F on the link below
Do you see any navigation beacons between 200 and 500 kHz?
If everything on your end is right, this should be easy.
 

spongella

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Premium Subscriber
Joined
Feb 21, 2014
Messages
1,049
Location
W. NJ
Use SSB mode and tune until signal starts to decode. It is NAVTEX. Here in NJ it's never strong but usually copy-able.
 

ind224

Member
Joined
Oct 30, 2004
Messages
800
Location
Indianapolis
I'm way out of the projected service area (Great Lakes got a special mention of no coverage) but for about 8 minutes I had what should have been a good signal but mark and space would not jibe then it sounded like a sweeper came and went and suddenly I have great decode. Real time 2122 EST.
 
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