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PA2AGA > HDDIG 04.10.99 22:30l 240 Lines 7240 Bytes #-9730 (0) @ EU
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From: pa2aga
To: hd_broadcast@pa2aga
Subject: HamDigitalDigest 99/248B
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> if the error rates increase, the power can gradually increased for
> compensating for this. Such 10/100 W variable power system would most
> likely cut down the link down time to one tenth in adverse weather
> condition without causing too much interference to distant links.
Oh, more "it has to be perfect" again.
The justification is to link networks that otherwise CANNOT be linked
over ham radio. We have some long stretches of "empty" here in the
Western US.
--
... Hank
http://horedson.home.att.net
>.
------------------------------
Date: Fri, 1 Oct 1999 18:33:21 -0700
From: "Hank Oredson" <horedson@att.net>
Subject: 56k UHF-100W / 19.2K VHF -50W
Rob Janssen <nomail@pe1chl.demon.nl> wrote in message
news:slrn7v8j09.bc.nomail@linux.pe1chl.ampr.org...
> Hank Oredson <horedson@att.net> wrote:
>
> [posts dumb comments and asks stupid questions]
>
> >Same old arguments. "The network MUST be built of flea power
> >stations located very close to each other. Nothing else is useful."
>
> Hank, I don't mind that you babble about the technical aspects of a
> network, but the fact remains that you have not been able to construct it,
> while "we, the Europeans" have. Using the model I described.
>
> And believe me, we have tried it using the model suggested by the original
> poster: a "backbone" on a single frequency with nodes shouting at
eachother
> at high power. Does not work.
Of course it does not work. Only the ignorant expect it to work.
> You need point-to-point links with directional antennas to overcome lots
of
> problems, like the more knowledgable on this group have explained many
> times already.
Of course you do. That is what I use.
> With these directional antennas you don't need 100W, because if it does
not
> work with about 5W on UHF it will not reasonably work with 100W either.
Two posters have said this same thing. It is contrary to my experience,
on HF, VHF and UHF. Why 5W? Why not .5W or 5 mw? You see the
point? There is no magic "cutoff power level" involved. You simply need
enough power spread (ERP above receiver noise floor) to obtain the S/N
you need FOR THE PATH INVOLVED. Longer paths need more,
shorter paths need less. I do understand that you live where long paths
may not be required to build a network. Others live in places where
long paths (200 km and above) are in fact common. 20 db more ERP
gets you 20 db better S/N on any path with any system on any band.
Don't confuse this issue (required power spread to obtain specified
S/N over given path) with issues such as multipath. They are independent.
> HF is a different story, of course. I suggest you stick to that.
Why is HF different?
With two stations on HF, two on VHF and three on UHF, I can observe
how things work on all those different frequencies. They all work about
the same: if reasonable S/N can be obtained, the links work. If it cannot,
they do not work. Better S/N can be obtained by the use of either silicon
or aluminium. Once you have run out of both (as big an antenna array as
you can fit/afford/lift/stays up, as much power as you can afford/legally
run)
then you know you have a link which you cannot make work.
i.e. I prefer to make links work rather than find excuses why they wont.
per Gary's suggestion I've been buying test gear. Was able to reduce packet
loss on one of my links from just over 1% to well below 1%. Darn receiver
had drifted just enough to move the edge of the passband to where it was
in the way of the bits.
--
... Hank
http://horedson.home.att.net
>.
------------------------------
Date: Sat, 02 Oct 1999 11:27:47 +0300
From: Paul Keinanen <keinanen@sci.fi>
Subject: 56k UHF-100W / 19.2K VHF -50W
On Fri, 1 Oct 1999 18:33:21 -0700, "Hank Oredson" <horedson@att.net>
wrote:
>
You simply need
>enough power spread (ERP above receiver noise floor) to obtain the S/N
>you need FOR THE PATH INVOLVED. Longer paths need more,
>shorter paths need less. I do understand that you live where long paths
>may not be required to build a network. Others live in places where
>long paths (200 km and above) are in fact common.
What ???
Do you really build that long link hops ?
The average tropospheric refraction constant must be much different
over there. Over here, the sanity is questioned of anybody designing
over 100 km link hops :-), since such links would work reliably only
during some pre-dawn hours.
With such overstrething links, the link reliability is somewhere
between 50 and 95 % and as such, the link is interesting only to
bulletin forwarders, no wonder that the interest for packet radio is
decaying in the US and in other places with low population (and ham)
density.
Paul OH3LWR
>.
------------------------------
Date: Sat, 02 Oct 1999 11:40:55 +0300
From: Paul Keinanen <keinanen@sci.fi>
Subject: 56k UHF-100W / 19.2K VHF -50W
On Fri, 1 Oct 1999 18:37:13 -0700, "Hank Oredson" <horedson@att.net>
wrote:
<Link usability times below 90 %>
>Which is MUCH better than having no link at all, where the usability
>time is exactly zero.
With usability times that low, the link is usable mainly to bulletin
forwarders, for others, such links are much less usable.
Paul OH3LWR
>.
------------------------------
Date: Sat, 02 Oct 1999 00:14:21 -0400
From: John Vause <jdv@iglou.com>
Subject: 56k UHF-100W / 19.2K VHF -50W
Mike, you could always convert your 1200b stuff to an APRS digi.
That is what I did 3 years ago when I realized the local packet
traffic was dying off.
Mike Wiley wrote:
>
>>SNIP<<
> I also see
> no reason to put my 1200b stuff back on the air if there is no one to
> talk to or a BBS anywhere near.
> Mike WB5GMK
--
* John Vause KF4ERV jdv@igloudot.com *
NOTE: email address altered for benefit of Spambots
--
>.
------------------------------
Date: Sat, 02 Oct 1999 05:17:44 GMT
From: "Dave VanHorn" <dvanhorn@cedar.net>
Subject: 56k UHF-100W / 19.2K VHF -50W
> Mike, you could always convert your 1200b stuff to an APRS digi.
> That is what I did 3 years ago when I realized the local packet
> traffic was dying off.
There's still a lot of uncovered ground, especially out west.
>.
------------------------------
Date: Sat, 2 Oct 1999 09:02:22 GMT
From: nomail@pe1chl.demon.nl (Rob Janssen)
Subject: 56k UHF-100W / 19.2K VHF -50W
Hank Oredson <horedson@att.net> wrote:
>> If you need nearly the
>> full power most of the time, there are going to be quite long times
>> when the receiving signal is below minimum, thus the link usability
>> time might be well below 90 %.
>Which is MUCH better than having no link at all, where the usability
>time is exactly zero.
This attitude has driven the users in the hands of the Internet forwarders.
To be continued in digest: hd_99_248C
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