Is there a standard channel spacing for UHF, specifically; for the 70cm ham band? For example, a repeater might be set up with an output frequency of 444.100MHz... what would be the next availiable frequency for use? 444.101? 444.125? On my Yaesu I can choose anywhere from 5 to 50 kHz steps for tuning.
The reason I ask is that I've got a Waris conventional with most of the personalities unused. If there is a standard channel spacing, I would like to fill up the remaining personalities with standard 70cm repeater frequencies so I can scan them or use them if I'm in an area with an active 440 repeater using CSQ.
Thanks,
Eddie
Channel spacing for UHF?
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Tom in D.C.
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440 mHz channels...
Eddie:
440 mHz is still 25 kHz, so it goes .100, .125, .150, etc.
The 12.5 kHz spacing refers to narrower bandwidth for both receive and transmit, which means a tighter receive filter and half, roughly, the deviation on transmit. Many HTs will allow you to program up 12.5 kHz channels but they don't automatically reset the receive bandwidth and transmit deviation when you do this. I have two Vertex VX900s which do this, but it's not common, yet. The new Icom IC208 mobile radio also does it via its program.
There are narrower standards coming into use, specifically steps of 6.25 kHz but they're not common yet.
Getting back to the amateur 440 band, most of the repeaters, at least in the Eastern US, are 25 kHz steps and there's no movement to make it any different. The band is so unpopulated there's no real compelling reason to change anything.
FWIW, the new FCC commercial type acceptance, I believe, now requires 12.5 kHz step capability on all new radios.
Others can jump in and add to this, I'm sure.
440 mHz is still 25 kHz, so it goes .100, .125, .150, etc.
The 12.5 kHz spacing refers to narrower bandwidth for both receive and transmit, which means a tighter receive filter and half, roughly, the deviation on transmit. Many HTs will allow you to program up 12.5 kHz channels but they don't automatically reset the receive bandwidth and transmit deviation when you do this. I have two Vertex VX900s which do this, but it's not common, yet. The new Icom IC208 mobile radio also does it via its program.
There are narrower standards coming into use, specifically steps of 6.25 kHz but they're not common yet.
Getting back to the amateur 440 band, most of the repeaters, at least in the Eastern US, are 25 kHz steps and there's no movement to make it any different. The band is so unpopulated there's no real compelling reason to change anything.
FWIW, the new FCC commercial type acceptance, I believe, now requires 12.5 kHz step capability on all new radios.
Others can jump in and add to this, I'm sure.
Tom in D.C.
In 1920, the U.S. Post Office Department ruled
that children may not be sent by parcel post.
In 1920, the U.S. Post Office Department ruled
that children may not be sent by parcel post.
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ASTROMODAT
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Tom, you mentioned 6.25 kHz UHF channel spacing, although it is "not in common use yet."
Other than some TDMA digital cellular systems, where is 6.25 kHz channel spacing in use anywhere at all? My understanding is that 6.25 kHz is part of P25 Phase II, which is quite far away in time.
Just curious, as I could definitely be wrong.
Larry
Other than some TDMA digital cellular systems, where is 6.25 kHz channel spacing in use anywhere at all? My understanding is that 6.25 kHz is part of P25 Phase II, which is quite far away in time.
Just curious, as I could definitely be wrong.
Larry
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Tom in D.C.
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6.25 spacing?
Larry,
Some time back, someone wrote here on the Board that they had been issued a VHF FCC license (would be analog, of course) with a channel assignment ending in .1125 or something odd such as that. I realize that squeezing analog signals down that tight is a problem with most of today's radios.
Thanks for the reality check.
Regards,
Some time back, someone wrote here on the Board that they had been issued a VHF FCC license (would be analog, of course) with a channel assignment ending in .1125 or something odd such as that. I realize that squeezing analog signals down that tight is a problem with most of today's radios.
Thanks for the reality check.
Regards,
Tom in D.C.
In 1920, the U.S. Post Office Department ruled
that children may not be sent by parcel post.
In 1920, the U.S. Post Office Department ruled
that children may not be sent by parcel post.
Re: 440 mHz channels...
Thanks, Tom. It's unfortunate that 440 isn't very populated. There are three repeaters nearby in Charlotte, NC that get some use. One of the most popular is connected to EchoLink (KC4YOZ).Tom in D.C. wrote:
440 mHz is still 25 kHz, so it goes .100, .125, .150, etc.
All of the type accepted radios I manage will do the 12.5kHz bandwidth. The 'drop dead' date for this changeover is still a ways off, so I change them as they drift through my shop. Does the reduced bandwidth apply to 70cm as well? My Yaesu FT-50R isn't adjustable for bandwidth.
Thanks again,
Eddie
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Tom in D.C.
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440 mHz channel spacing
Eddie:
I have never read the 440 bandplan looking specifically for channel spacing advice and information, but I've also never encountered a 12.5 mHz channel there either.
I don't see any reason why one couldn't set up for 12.5 kHz there but, again, with so little use and underpopulation of the band why bother? "Wideband" sounds better and richer anyway unless you're using a true narrowband radio with the correct IF setup which will recover the full audio.
Here in DC we have a fair amount of UHF activity. One of our local
networks is also IRLP and has ten linked UHF repeaters which cover from the Eastern Shore of MD out to Western MD, then South into Virginia about another 100 miles. There's a similar network in WV which covers from just West of DC all the way over into Kentucky, believe it or not, and that one is a combination VHF and UHF system. It's all just sitting there, waiting to be used and I'm like you in that I wish more people would use UHF.
I have never read the 440 bandplan looking specifically for channel spacing advice and information, but I've also never encountered a 12.5 mHz channel there either.
I don't see any reason why one couldn't set up for 12.5 kHz there but, again, with so little use and underpopulation of the band why bother? "Wideband" sounds better and richer anyway unless you're using a true narrowband radio with the correct IF setup which will recover the full audio.
Here in DC we have a fair amount of UHF activity. One of our local
networks is also IRLP and has ten linked UHF repeaters which cover from the Eastern Shore of MD out to Western MD, then South into Virginia about another 100 miles. There's a similar network in WV which covers from just West of DC all the way over into Kentucky, believe it or not, and that one is a combination VHF and UHF system. It's all just sitting there, waiting to be used and I'm like you in that I wish more people would use UHF.
Tom in D.C.
In 1920, the U.S. Post Office Department ruled
that children may not be sent by parcel post.
In 1920, the U.S. Post Office Department ruled
that children may not be sent by parcel post.