Griff, Just be careful there. The current FCC regs for 70cm only allow 56 kilobauds and FSK would be one bit per baud. You are also limited to 100 Khz bandwidth. See http://www.w5yi.org/page.php?id=139 97.307(f)6 and http://www.w5yi.org/page.php?id=137 (70cm Emission Types) Tom was chiding me on a radio being built that I am involved in. On Wed, Jan 21, 2015 at 4:41 PM, Griff <griff@thehamlins.org> wrote:
For a 100kbps link on 70cm, check out the inexpensive ($25) "moteino" digital 70cm transceiver at http://lowpowerlab.com". These have only a 0.1 watt FSK transmitter, with settable data rates between about 9600bps and 600kbps, using signal bandwidths from about 10khz to 600khz. I see a range at 70kbps of about 1/4 mile between two mobile antennas. For longer range, I will soon receive an inexpensive ($50) Chinese 3 to 5 watt power amplifier. Search ebay.com for " 433mhz fsk radio amplifier 3-5W" and you'll see them. There is also an inexpensive 7-watt power amplifier from http://www.minikits.com.au/70cm-7W-Amplifier. There is also a more expensive ($215) 30 watt amplifier, 7025PA, from Down East Microwave (http://fwfvq.tehfm.servertrust.com/category-s/ 1836.htm). Down East Microwave engineer says it should work fine with FSK, but I haven't tried it.
Griff W5VWP
On 01/21/2015 04:01 PM, Tom Hayward wrote:
On Wed, Jan 21, 2015 at 3:52 PM, John D. Hays <john@hays.org> wrote:
Pointing the dish could be accomplished over a much lower rate and more robust radio link.
Sure. My hypothetical also assumes no link redundancy. So far HamWAN has redundant links, so this wouldn't be an issue.
But let's explore the robust link option... Do you know where we might get a medium-speed link? 100kbps over UHF would be ideal, but I don't have the hardware to do it. ;-)
Tom KD7LXL
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