VHF Ethernet

yes its 130MHz-180MHz

I'm sorry for the "Googler" crack - I've seen that you're not some hit-and-run dweeb, but a serious questioner.

Unfortunately, I don't actually have an answer for you. )-;

Regards, Rich

we still need to know how wide a slot you have in that range ?? 5khz ?? 10 ?? 50 ??

cant do anything more than we have without knowing how much space we have to work in !!

You had better read your terms of licence a LOT better. It does NOT support that bandwidth in that frequency range.

OHHH get real -- you can run TCP/IP over packet at 1200 baud FSK in 5khz FM bandwidth, and if you didnt mind moving at a crawl -- you could kick down to

Thats why I keep asking how much of a slot he has so I can pick a modulation scheme that will best use the bandwidth he does have allocated !!

OK keeps asking for commecial solutions -- and I can get him 1200 baud off the shelf -- but he isnt going to do any better than that with OTS hardware in that frequency range without a custom solution -- and if he has more than

other than that -- getting VHF to go 100km just takes a coupla of yagi beams and some reasonably high towers to get a clear line of sight

the only other thing thats really going to hurt him is if he really only has bandwidth for one channel -- if so -- he is stuck with half duplex and its going to be dog slow no matter what the baud rate is... he would be a LOT better off if he had 2 channels spaced 3-5mhz apart to run full duplex

Just a little up from your reply to me is OP's 18MHz bandwidth requirement. That is rather more than 9600 baud. That is why no licence covers it.

OP wants an Ethernet like link, 10 MBits/s and up. Just won't happen on that band, not even esperimentally. WARC and the national and regional watchdogs won't permit it. That is why i told OP to reread his license.

Its a communications problem -- in one post he sez 130-18 is a typo and it means a frequency in the range of 130-180 -- never does he come flat out and say "my allocated bandwidth is"

FSK (1200) and QPSK (9600) modems for VHF are available OTS and run in a "standard voice bandwidth channel"

there are better modulations to use, but all of them pretty much require DSP to pull off -- FHSS, et al, but they can be designed to include forward error correction to mitigate initerference induced errors -- a feature that neither FSK or QPSK has in off the shelf implementations -- and which is probably going to be needed for the specified range -- half duplex is going to be bad enough without retransmitting any more than absolutely neccessary. And I seriously doubt hs has 2 split frequencies for a full duplex link.

an "ethernet-link" link means it carries TCP/IP data -- available bandwidth and modulation style determines the maximum possible speed :)

and I agree -- he needs to read his license and tell us what his allocation is !!

Though he really already has his answer for "commercial implementations" --