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Author Topic: How NOT to test your 11m linear...  (Read 11205 times)
AD7DB
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« Reply #15 on: July 10, 2015, 03:06:54 PM »

Out on the open interstates in the California deserts (I-15, 40, 10, and Cool and other long highways (86, 111 and 395), I've sometimes heard truckers talking on channel 19. With a good audio DSP that removes the heterodynes it's tolerable.
But I've also heard a lot of passenger car activity on FRS channels, usually car-to-car of folks headed for Vegas, The River, or sand dunes. Seems FRS was made for this. Low range, FM, no skipland stuff.
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KJ6ZOL
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« Reply #16 on: July 10, 2015, 06:18:39 PM »

Out on the open interstates in the California deserts (I-15, 40, 10, and Cool and other long highways (86, 111 and 395), I've sometimes heard truckers talking on channel 19. With a good audio DSP that removes the heterodynes it's tolerable.
But I've also heard a lot of passenger car activity on FRS channels, usually car-to-car of folks headed for Vegas, The River, or sand dunes. Seems FRS was made for this. Low range, FM, no skipland stuff.


The assigning of CB to what are essentially shortwave frequencies was a major screwup by the FCC. Apparently the concepts of such things as MUF freqs were poorly understood in the 50s. In that same time period the FCC briefly assigned a TV Channel 1 in the 50 Mhz area, only to discover that it acted more like SW during a solar maximum, a bad thing for a service intended to be regional. So that's why US analog TV started at channel 2. Doh! CB was apparently designed to be similar to FRS in usage, a local radio service that didn't require the technical knowledge of the Amateur Service. As for truckers, they seem to be mostly on channel 6 up north (I'm in Sacramento). Sometimes I can hear a lot of Spanish, apparently truckers in Mexico brought in by skip. I know that FRS is so packed here that when my dad bought a 2 pack of FRS sets for use around the house, he ultimately tossed them because every channel was always in use. Instead, he uses a pair of GE System 3 walkie talkies that my folks bought for me when I was a kid. I don't know what freq they operate on.
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SOFAR
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Posts: 520




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« Reply #17 on: July 10, 2015, 06:51:22 PM »

CB started out at 460 to 470 mhz, the technology was not affordable at the time. There was class a and class b CB, class a went on to become GMRS. .... Kind of pointless to second guess decisions made 65 years ago, without at least reading the history.
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NO2A
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« Reply #18 on: October 15, 2015, 11:40:07 AM »

Children's band is still used,at least by truckers. I know of a truck driver who refused to use channel 19 because of "those idiots ". However, channel 19 can be a real lifesaver due to traffic alerts. It's good knowing if there's an accident a mile ahead, especially when trying to stop a heavy truck /trailer. 19 is also good for checking band openings for 10/12m.
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KD0REQ
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« Reply #19 on: October 15, 2015, 12:39:05 PM »

TV channel allocations were initially made before WWII, and modified afterwards.  the use of Channel 1 by local law enforcement led to its being deleted.
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WW7KE
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Posts: 308




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« Reply #20 on: October 15, 2015, 04:07:12 PM »

TV channel allocations were initially made before WWII, and modified afterwards.  the use of Channel 1 by local law enforcement led to its being deleted.

The postwar Channel 1 spectrum (44-50 MHz) had been part of the original FM band before it was allocated to TV in 1945 and FM was kicked upstairs to its current band (the wartime Ch. 1 had been 50-56 MHz).  It had been allocated as a "community" channel, and only had one CP assigned to it for its entire 3-year life, KARO in Riverside CA.  KARO never went on the air.  It was either reallocated to public safety after that, or it had been shared spectrum.
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KM4JOJ
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Posts: 58




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« Reply #21 on: October 17, 2015, 05:54:36 AM »

Maybe that applied to very old analog phones

Verizon was the only provider that was maintaining the AMPS network; and the FCC let them turn it off maybe 5 years ago or so.
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