Sideband ?

[Wire Weasel]

I was actually thinking of the early to mid 70's.

Same time period for me too.

 

[hookedon6]

Is it that there is a 5hz shift upper or lower vs versa between lower and upper ssb and the reception of the AM qrm is equally crap?

well, if ya wanna split hairs, the am qrm is worse when you are on lsb. its a "power under the curve" thing

 

[packrat]

Power under the curve? Ya testing that thing on a spintron? LOL

 

[Captain Kilowatt]

Hi SS,

Yes and No

Hams use UpperSB on their bands that are above 10mhz and Lower SB on the bands below 10mhz. Tune in the ham bands on 40, 80 and 160 meters and you'll find their SSB use is exclusively LSB. The exception is the 5-Channelized 60 meter band. That is designated for USB.

Does anybody know the reason USB is used above 10 MHz and LSB used below 10 MHz. Today it is by convention but there was a technical reason for it way beck when. Anyone know why?

 

[mackmobile43]

Does anybody know the reason USB is used above 10 MHz and LSB used below 10 MHz. Today it is by convention but there was a technical reason for it way beck when. Anyone know why?

There's no reason to use either sideband anymore other than to accomodate someone with a NON-selectable sideband radio

 

[Captain Kilowatt]

True but it is nice when everyone uses the same sideband. Makes for tuning the band easier. Like I said there was a real reason for it way back in the early days of SSB.

 

[n8fgb]

I don't remember the exact details, but it has to do with how they achived each frequency band. They use the harmonics of a base frequency, and when they got above 7 mhz, they had to go USB.
Rich

 

[mackmobile43]

I'm plagiarizing a fellow from qrz to get this so he can sue me but it sounds reasonable.


Back in the late 1940s and early 1950s, a great number of SSB generator circuits used 9 MHz because if you used a 5 MHz VFO frequency to with the signal, you could get both the 75 meter and the 20 meter bands. There were a lot of BC457 and BC458 ARC-5 transmitters around that would work very well as a 5 MHz VFO. However, due to the scheme, lower sideband was produced when operating on 75 meters and upper sideband was produced when operating on 20 meters.

When the bands (160 through 10 meters) were added by the heterodyne method, it was to produce the LSB signals on 160, 80, and 40 meters while it was also to produce the USB signals on 20, 15, and 10 meters. The Central Electronics 10A, 10B, and 20A commercial amateur SSB transmitters are a very good example of this era in technology.

As more advanced transmitters came into vogue, the ability to have both sidebands available on any band came into being. However, was already in place and amateurs have generally used lower sideband below 10 MHz and upper sideband above 10 MHz. Of course, the 30 meter band only allows CW operation so USB is actually above 14 MHz under present regulations.

There is nothing in the regulations that forbids using the sideband. In fact, there are transmitters that actually operate DSB that can be received in either the LSB or USB positions on the receiver but cannot be received in the AM position (the old WRL DSB-100 transmitter is an example of this type of transmitter). But, since the vast majority of amateurs do follow the, you will be very to make a random contact on the sideband.

 

[Captain Kilowatt]

That's pretty much it mack. I believe it goes back a little further than that article suggests but it did have to do with the sidebands being inverted when operating the crystal on a harmonic. When set up for LSB on 40m for instance, it would invert to USB when operating the same crystal on 20m.

 

[KB1UGX]

So as a rookie to HF i should be calling CQ on USB on 10 meters correct?

and LSB on anything less then 10MHZ

Thanks

 

[Beetle]

So as a rookie to HF i should be calling CQ on USB on 10 meters correct?

and LSB on anything less then 10MHZ

Thanks

Except 60M. Only USB permitted.

 

[kd-5-bgt]

From what I have heard yes call CQ on 10 ....most bands CQ will get you replies from North America,Alaska and Hawaii

CQ DX is usually international

I have been scanning around 10 meters the past couple of weeks catching a few contacts here and there...Band is not very stable but you can make conatcts