Mode ?

Robert11
Posts: 83
Joined: Fri Aug 21, 2020 8:49 pm

Mode ?

#1

Unread post by Robert11 »

Hi,

Was wondering:

Is there any "clever" way when looking at the Spectrum View at a particular waveform (in my case, often corrupted with noise, etc.)
to determine if it is USB, LSB, or am ?

Bob

User avatar
KA1GJU
Posts: 264
Joined: Tue Aug 11, 2020 2:16 pm

Re: Mode ?

#2

Unread post by KA1GJU »

GM Bob from seat 7F awaiting to leave Philadelphia!
An AM signal will have the carrier, the thin line on the spectrum and waterfall with audio on either side that is symmetrical.
Also, if you are in LSB or USB, you will hear the carrier as a tone when it falls within the audio passpand (vertical green band in spectrum display).

Typically LSB is used below 10mhz, and USB when used above 10mhz when in the Ham bands.
Commercial HF operators are usually USB everywhere, ie Aeronautical, military, and marine traffic.

Pirate broadcasters in the 6.9-7.0 MHz use anything they want. ie 6925, 6935, 6950 kHz.
https://www.hfunderground.com/board/in ... d,3.0.html

73 Kriss KA1GJU/AM ✈️
73 Kriss KA1GJU Home of the KA1GJU Super Station SDRC Servers in NH, USA (FN42mw & FN43na)

Robert11
Posts: 83
Joined: Fri Aug 21, 2020 8:49 pm

From OP: Re: Mode ?

#3

Unread post by Robert11 »

Hi Kriss,

Nice to hear from you.
Quick thanks for All the past help; much appreciated.

Good, very clear (as usual) explanation.
Just what I wanted (and need).

Much thanks.

Stay well, regards,
Bob

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KA1GJU
Posts: 264
Joined: Tue Aug 11, 2020 2:16 pm

Re: Mode ?

#4

Unread post by KA1GJU »

Here's a screen shot of some 40M 40 Meter Band AM BC stations thisw evening at 8:37 EDT. If you ever want to know possibly where and what the station is, just Google the frequency in kHz, i.e. "7375 kHz" and open the link with short-wave in the address... such as: https://short-wave.info/?freq=7375
You can drag and drop the green dot to your position on the globe, and the website will estimate your theoretical signal strength.
Find attached some details for ID'ing AM and LSB signals.
USB signals will be the opposite, the low audio frequencies (bass) will now be on the left and highs (treble) on the right. Once again, Amateur radio operators use LSB<10 Mhz and USB>10 MHz.
Amateur radio ops frequently operate with lots of bass to "sound good", hence the low audio frequency portion of the display is usually stronger (brighter on SDRC screen), but that's a whole 'nother topic that gets debated ad nauseam on QRZ.com's forums section! :oops:

73 Kriss KA1GJU
Attachments
BOB1.jpg
73 Kriss KA1GJU Home of the KA1GJU Super Station SDRC Servers in NH, USA (FN42mw & FN43na)

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