Why are some HF bands USB and some LSB?
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- čas přidán 29. 08. 2024
- Why are some HF bands USB and some LSB?
There is a convention where some HF bands are lower sideband (LSB) and others upper sideband (USB). One possible answer lies in a QST article.
Thanks to @TankRadio for the question in his livestream!
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The most concise explanation of SSB I've heard yet. Thanks for sharing. KC3UEE
KNOWS
HER
SHIT!
Thanks for the info! Great job 👍👍
Only hams use LSB, it's a historical oddity with no reason to still be happening. The military, aircraft, and commercial services all use USB. LSB is a legacy from the early days of tube-type radios when the major manufacturers designed around a 9 MHz IF in their radios. I think that started with either Collins or Drake.
CB radio still uses LSB but for a different reason. The band is made of 10KHz A.M. channels and SSB has to fit in with that so you either get the upper sideband of that channel or the lower sideband. I guess it could have been made 5KHz channels of USB all those years ago but then that might have meant more XTALs in the days before frequency synthesis was a thing.
Interesting. I have a couple SSB receivers and noticed that they picked up most signals on both bands but tended to be a bit clearer on one or the other. I didnt understand why. I suppose reducing my bandwidth would change those results.
Thanks for the lesson. I had no idea what was going on.
Unless they’re very old this isn’t the reason. I think there is some other reason in your case.
@@n2rj they're an ATS100 and XHDATA D-808, definitely not old but they're fairly sensitive and relatively cheap radios. Maybe it the style of board? They do get alot of bleed over from other channels on AM.
Roughly the same as my understanding, that it was based on generating USB at 9MHz and mixing with a 5.0 - 5.5MHz VFO.
Great job, Ria! Short, sweet and to the point! AC3IK
Operators use whatever they feel like (CW AM LSB USB etc) on all bands actually. Might have been a guide for lower bands but not set in stone so to speak in the past. Some will even go with 4k+ wide....
Correct but you really don’t see deviation from the established convention. Yes a few do it but the vast majority follow the convention. Also most radios today are programmed to follow the convention by default. Finally it makes sense in a crowded band to follow the convention so you can hear each other and mitigate interference.
Also in the United States you cannot use phone on certain segments. You can use CW everywhere but phone you’re restricted. And on 60m you must strictly follow the stipulation of USB and 2.8kHz bandwidth or less. I would also argue that ESSB falls outside of good engineering practice as you don’t need high fidelity for speech but that’s another video.
ARC-5s were great fun! Dynamoters to power them was fun too. :) Tnx Ria - 73 - KF6IF
Ria excellent explanation. Well done !
That’s darn good question.
Cheap and easy yes. When one Ham does something for a dollar another will find a way to do it for a dime.
Then they both show up at a Hamfest with big bucks in there pockets and spend it all.
30 year vet of Dayton Hamvention been there and done that ; )
Nice explanation!
Thanks for the history lesson.
Are USB and nellis be the same as putting in upper and lower channels into a CB
Ria .. you are correct! That is exactly how it took place. Back then, SSB "RUINED" Ham Radio! :P AM was KING! Funny ... there seems to always be something NEW that is ruining Ham Radio! :) Keep up the great work! 73 - KF6IF