Receiving Broadcast Short Wave Radio on HF

Boo,

Going back to my 27 Meg CB days you could hear AM on SSB but not the other way around. From memory the AM signal is a combination of upper and lower side bands with a carrier wave in the middle. Therefore the SSB would receive the part of the AM signal it could decipher.

On the other hand SSB transmited would be a garbled noise on AM as it was not a full AM signal.

Jim.

The following is 'untech' speak - Like my Barrett 950, your 9323 probably does have those AM stations that you are listening to set as AM mode - the Barrett has 5 modes that can be selected from for each channel in the setup, including AM, LSB and USB. When you are on one of your broadcast radio channels, there will probably be a cryptic symbol on screen somewhere telling you that the channel in question is in AM mode.

'hf' radio is am band. ssb usb and lsb are just small ' side banded channels' (in am) to encrypt ( to a certain degree) the transmission. your two way should be by default on ssb/am. so i would say that all youre listening channels are ssb naturally.

Read thread 74673 It will probably tell you all you want to know.

You could join and ask on the Codan Yahoo Group.

http://groups.yahoo.com/group/codan_outback_radio/messages

Fantastic amount of HF knowledge in that group even with the sad loss of Jim (Footloose) Potts as one of the moderators.

Cheers

Provided the carrier frequency on your SSB receiver is spot-on to the transmitted carrier, you will receive an AM signal no problems. It's when the receiver's carrier-reinsertion is off-frequency to the transmitted carrier that you get a whistle over the top of the program. (there is actually a whistle, but its frequency is too low to hear, being the difference between the transmitted carrier freq and the reinserted carrier freq in the receiver).
You should receive AM programs no problem on an SSB transreceiver provided that the exact frequency is programmed in.
Gerry

From the 9323 User Guide:

"You can receive AM transmissions on any AM, USB and LSB setting. For an AM broadcast you may find that switching between USB and LSB improves reception."

The AM signal comprises a carrier frequency and upper and lower side bands. The bandwidth of the AM signal is twice the highest modulation frequency. On the broadcast band, the AM channels are 9kHz apart, so you would expect some interference between adjacent stations if they transmitted a 5kHz audio signal.

The SSB signal comprises just the upper or lower sideband (the other sideband and carrier have been suppressed by the transmitter). The SSB receiver has to generate the missing carrier and reinsert it so the signal can be detected. The filters are quite narrow (2.5kHz) so the sound quality is OK for speech but not music.

You can use an SSB receiver to tune into the upper or lower sideband of AM transmissions. Sound quality is poor (because of the 2.5 kHz bandwidth filter), but OK for speech. The real advantage is that if the band is crowded, the overlap between adjacent stations (sometimes 5 kHz apart in the shortwave bands) can be eliminated and otherwise unreadable signals can be understood. The receiver needs a very stable oscillator that can be accurately tuned to the carrier frequency or the carrier signal will 'beat' with the local oscillator and create a whistle.

Tuning AM signals with an SSB radio is called Exalted Carrier Single Sideband (ECSS) reception.