shortwave - digital or USB

[kg4rgn]

Just tuning around the commercial AM bands ( 19m) and wsa having a hard time listening to a few distant stations and then decided to switch to SSB from AM.. The station now comes in loud and clear. Are SW stations now on SSB or is this a digital signal. Thanks...

 

[kg4rgn]

digital, AM or USB on 9.950 mhz

Listening to 9.955, in AM junk, but switch to USB and it is clear.....

what gives..........

 

[n4voxgill]

many of the hf broadcast stations are in AM mode. There audiance may not have SSB capable equipment.

 

[kg4icg]

Also don't forget that WWV Fort Collins, Co. is at 10.000 mhz broadcasting the time signal and also at 5, 15, and 20 mhz, in AM and is a powerfull transmitter and not all comercial broadcasters use AM. Some use sideband too. If you hear it better in ssb then in AM then chances are it's a ssb station.

R Collins

 

[loumaag]

If you hear it better in ssb then in AM then chances are it's a ssb station.

This statement needs some revision. If a station is broadcasting in Single-Sideband, it is not intelligible if you attempt to receive it in AM. It just sounds a lot like Donald Duck. If the station is broadcasting in Double Sideband, Suppressed Carrier mode than indeed you probably will pick it up better on a communications receiver in SSB. (Either sideband.) You can also hear it on AM but, because of the bandwidth necessary for DSB, you will also have more noise, hence unless the signal is strong, or your receiver isn't very good then it will sound better in SSB mode than AM.

 

[Al42]

If you hear it better in ssb then in AM then chances are it's a ssb station.

This statement needs some revision. If a station is broadcasting in Single-Sideband, it is not intelligible if you attempt to receive it in AM. It just sounds a lot like Donald Duck. If the station is broadcasting in Double Sideband, Suppressed Carrier mode than indeed you probably will pick it up better on a communications receiver in SSB. (Either sideband.) You can also hear it on AM but, because of the bandwidth necessary for DSB, you will also have more noise, hence unless the signal is strong, or your receiver isn't very good then it will sound better in SSB mode than AM.

This statement actually needs some revision.

If you listen to SSSC or DSSC on an AM receiver, it'll sound like Donald Duck. If you listen to a normal AM signal on SSB, the carrier and sideband ("selective") fading will be less noticable, or not noticable at all. (There's no carrier for the AM detector to work on in DSSC, so you're not going to understand it in AM unless the carrier suppression is poor.)

Al
W2PMX

 

[kb2vxa]

AM in SSB receive mode

Hi all,

Let's clear up this mess right now! A synchronous AM detector is the very best for reducing selective fades and gives clearer reception overall but very few receivers are equipped with one. Except for high end, rather pricy communications receivers you're SOL.

Second choice is listening in SSB mode, zero beat the carrier and select the sideband that gives best reception if you have splatter from an adjacent channel.

Methinks you guys should learn a bit of radio theory, it's sure helpful in understanding the monitoring hobby. I say this because even a brief tutorial on the spectral composition of an AM signal is a bit much for this post AND I expect you to do your own homework. (;->)

BTW, the original post said 19M, not 19mHz so it looks like you'll have to start out with the rock bottom basics. I don't mean to sound smug but I sure got rid of a lot of confusion by cracking the books in my beginning days of SWLing and DXing.

 

[mancow]

I believe he meant the 19 meter band.

BTW, if it were digital how would you be hearing it without a digital decoder?


mancow