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ZL4AJS > WLAN 18.05.05 17:57l 60 Lines 2762 Bytes #999 (0) @ WW
BID : 310211ZL4AJS
Read: GUEST DK5RAS DO6NP
Subj: Re: Re^2: Packet vs WiFi
Path: DB0FHN<DB0MRW<DB0WUE<DK0WUE<7M3TJZ<ZL2BAU<ZL2WA<ZL4AA<ZL4GQ
Sent: 050518/0232Z @:ZL4GQ.#95.NZL.OC #:25649 [Invercargill] FBB7.00i
From: ZL4AJS@ZL4GQ.#95.NZL.OC
To : WLAN@WW
DF3VI wrote:
> This is only true if you use the same kind of modulation.
> But 1k2 uses AFSK (normal FM modulated with tones), while 9k6 uses FSK
> (the carrier frequency is modulated). You surely are a ham enough to
> understand the fundamental difference?
Yes I see the difference between 1k2 and 9k6 baud. There could be some
advantage with 9k6 because of it's direct FSK modulation. However if we
are tying to lure more ops onto Packet, we won't do it by going to 9k6
anyway. There is not a very proficient source of transceivers that will
accept direct FSK and demodulation, although quite a few could be
modified. Unfortunately I can't think of many new hams or prospective
new Packet ops willing to modify rigs or go to the trouble of getting
one that will work on 9600. Also modems and TNCs become even rarer if
you need one for 9k6. It's hard enough finding one for 1200!
> I wrote:
>> Not often! Using the same power and antenna gain at each end, 23cm
>> will be a weaker
>
> Not true because of two reasons. You have to compare the same antenna
> size (a 4 element on 2m has the size of a 13 element on 23cm), and
> hen the gain on 23cm is much bigger. Also 23cm is less affected by
> fading. On the other side, 23cm needs a more optical line of sight (no
> free sight means no good link in general, but I work my node on 23cm
> without seeing it).
Yes, 1.2/2.4 GHz antennae can have much higher gain than a 2m antenna
for the same size and cost, and thus will work better in most cases for
equivalent size antenna and power level than 2m. But, as you say, links
will only work over long distance with optical line-of-sight. Not many
hams will have good paths to the BBS or node, even in a city.
> A second advantage of 23cm is that there is much more space, so you
> can run many individual links, instead of crowded places on 2m. That
> increases the throughput dramatically again!
Space is not a problem on 2m here! We have miles of empty frequencies,
but I can't say the same for a city in Europe or other high-population
areas. The reason we only have one BBS channel here is more a lack of
resources to operate two or more. Most BBSs are lucky to get one decent
radio and antenna, especially with the decline in activity causing less
interest in keeping BBSs up-to-date.
Of course, I speak from a NZ point of view. Things may be different in
other countries.
Seventy-Three.
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::: Andrew ZL4AJS@ZL4GQ.#95.NZL.OC :::
::: High School Student :::
::: Ohai, Southland, New Zealand :::
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Message sent: 18-May-2005
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