Actually, my point is just the opposite. There is delay, but I don't think it accumulates.
JT65a on HF shows me 2 things: 1. Hams will spend a minute per over to get a contact when the band is "dead" 2. Timed TX start is possible and gives a great value One of the problems of digital speech is the S/N figures requires, but if we relax the real time requirement, we can get by with a worse ratio. Couple this with the repeater idea, and you get a real advantage. So, let's say you can (just to pic a random number) send 10 seconds of spech in 30 seconds. So you TX for 30 seconds, starting on the :00 minute boundary. Then you RX for 10 seconds to the higher-power repeater to get (close to) realtime audio. That leaves the other end of you QSO 20 seconds to think and talk 10 seconds worth before :00 comes around and he or she starts to TX. This isn't like PTT for the AOR DV system, but it wouldn't require new hardware designs, just soundcard software. It would have a similar feeling to the JT65a system, which we know people are willing to experiment with. And, it doen't accumulate delay. Leigh/WA5ZNU On Mon, 14 May 2007 9:32 am, W2XJ wrote: > The problem is that if this is a store and forward repeater you will > accumulate too much time delay. > > > Leigh L Klotz, Jr. wrote: >> Here is a related idea: We have seen with JT65a that sometimes when we >> think the band is closed, it is just very poor instead. W1AW, which >> one >> can sometimes hear all lone on the high bands (due to its power and >> antennas) shows us this as well. I..e., what we assume is no >> communications may in fact be just very noisy. >> >> Shannon tells us there is no limit to the S/N we can tolerate if we >> reduce the data rate. >> >> So there may be a place as well for a repeater that receives >> lower-power >> stations slowly and retransmits them as higher power faster, even >> though >> it it couldn't then do the clever interleave that Bonnie proposes for >> other situations. >> >> This idea would be somewhat like VHF FM repeaters, as they use the >> limiting feature of FM to discriminate a noise-free low-power signal >> and >> then retransmit. Instead, it would decode a low baud rate, ECC'd >> signal >> to obtain a noiseless signal to re-encode and retransmit. >> >> Leigh/WA5ZNU >> On Mon, 14 May 2007 3:22 am, bruce mallon wrote: >> >>> Then DO IT and let the FCC rule ..... >>> >>> Just remember for your long distance digipeaters to >>> work the band must be open ..... >>> unless your going to use ECHOLINK and if so whats the >>> point ? >>> >>> >>> --- expeditionradio <[EMAIL PROTECTED]> wrote: >>> >>> >>>> Like many kinds of interesting digital >>>> communications, it seems that >>>> this sort of digital repeater falls into the gray >>>> area of FCC rules. >>>> The "retransmit" rules may preclude it. Welcome to >>>> Technology Jail. >>>> Nothing should stop an operator in another country >>>> from setting one >>>> up, it it could be used by US operators. >>>> >>>> Bonnie KQ6XA >>>> >>>> >>>> >>>> > This type of single channel HF digital voice >>>> repeater is perfectly OK >>>> > under USA's present FCC rules, and the rules of >>>> most other countries. >>>> > >>>> > Bonnie KQ6XA >>>> > >>>> > > > Digital Voice repeaters, using single-channel >>>> > > > near-real-time >>>> > > > interleaved multiplexed OFDM, could work in a >>>> 5kHz >>>> > > > bandwidth. >>>> > >>>> >>>> >>>> >>> >>> >>> >>> ____________________________________________________________________________________Pinpoint >>> customers who are looking for what you sell. >>> http://searchmarketing.yahoo.com/ >>> >>> >>> Announce your digital presence via our Interactive Sked Page at >>> http://www.obriensweb.com/drsked/drsked.php >>> >>> Yahoo! Groups Links >>> >>> >>> >> >> > > > > Announce your digital presence via our Interactive Sked Page at > http://www.obriensweb.com/drsked/drsked.php > > Yahoo! Groups Links > > >
