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PA2AGA > HDDIG 12.11.99 15:12l 192 Lines 6399 Bytes #-9687 (0) @ EU
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Date: Fri, 12 Nov 99 07:04:21 MET
Message-Id: <hd_99_288C>
From: pa2aga
To: hd_broadcast@pa2aga
Subject: HamDigitalDigest 99/288C
X-BBS-Msg-Type: B
> The TAPR SS radio project is interesting to watch, because it brings example
> solutions to hard problems of both the RF and the error detection and
> correction.
it's also a good example of problems with putting all your eggs in one
basket. It would have been nice if someone had started importing the 76
K. modems and radios as complete kits. competition is a good thing
especially if it spurs people to build out a network
>
> OK, here's an RF project: Design a module that has four digitally
> programmable oscillators that can generate a carrier from 441 to 445 MHz
> in 10 kHz steps. Each oscillator has to be stable and have over 60 dB of
> attenuation when not selected. One oscillator is programmed with a
> synchronizing frequency. This oscillator is selected (say) 16 times more
> often than the other three. The other three are preloaded with the next
> hopping frequencies, and used round-robin. The total switching time from
> one oscillator to the next is < 10 ms (deselect one, no carrier, select
> next), or however fast you can fill and switch each oscillator to the next
> frequency.
>
> One oscillator design, duplicated four times.
have you looked at using the waveform generators on PC video cards. You
have three (read, blue, green) to work with and they look pretty stable to
me because I don't see much the way of color shift over time.
> The object would be to get the advantage of narrow-band in a
> high-bandwidth product. High speed FSK is actually pretty hard to keep
> aligned. Any drift at either end, and the BER goes to hell in a
> hand-basket.
that might be why people are using FM radio's for the FSK transport.
Wouldn't the capture effect help compensate for some of the drift? Or am I
merely displaying my appalling ignorance of RF systems?
> I'm sorry if my posts seem to be just pissing. I intended only to discuss
> the issue.
thanks. researching and talking about the options and then acting
upon them is probably the best way to deal with the issue of shitty packet
networks.
--- eric
--
Eric S. Johansson ka1eec esj@harvee.billerica.ma.us
This message was composed almost entirely using NaturallySpeaking
>.
------------------------------
Date: Wed, 10 Nov 1999 17:28:38 -0000
From: "RVJM" <postmaster@nospam.demon.co.uk>
Subject: Help with RFC
Mike > wrote in message <80bash$tnm@newton.cc.rl.ac.uk>...
>> >You really are living in a different world ! Or perhaps should not post
>> >this to UK.radio.amateur.
>> RUBBISH! The post is about _REAL_ Ham Radio, and not the
>> consumerist abusive style that has come largely from the CB
>> fraternity.
>Hey - don't be such a prat. Read, understand. Work out who you are
>rubbishing. Pay attention.
>To explain as you clearly totally missed the point, WE DON'T GET THE
>SURPLUS. It is either automatically sent to the dealers, who then sell it
on
>at high prices, or skipped. Mainly skipped for H&S reasons.
Stupid Boy! Is yours typical of the execrable level of intelligence and
politeness to be found at Oxon as well as at Soton?
Pay attention yourself. The post was a response to a query
regarding the availability of test equipment for microwave
purposes.
>.
------------------------------
Date: Mon, 8 Nov 1999 19:04:27 -0600
From: "Steve Sampson" <ssampson@usa-site.net>
Subject: Microwave Help (was RFC)
I remember my first homebrew power amplifier (2 meters). It put out
1/2 Watt and I was impressed. Something was wrong though, as it
could be picked up all over the band, even other bands. Seems the
1/2 Watt referred to all the sidebands that I had along with the carrier
:-)
I guess my point, was that a spectrum analyzer is the best tool I've since
bought, and just plain fun. With a few nudges of the coils, and some
melted wax, I had the amplifier tamed by just looking at a scope.
But I think a spectrum analyzer should be a goal, not the first item bought.
Microwave PA's, on the other hand, are very different than 2 meters. You
can purchase a little "can" that has everything you need in it, and there's
no tuning. The hard part is getting what you might have, multiplied up
to what that little "can" expects for an input.
Simon Lewis wrote
>You don't need any test equipment apart from a VOM to get started on
>microwaves. All you need is a little patience!
>
>I built my first microwave equipment with nothing more than a few basic
>tools, a fine tipped soldering iron, a home made anti-static work
>station (actually a cakeboard covered in aluminium foil!) and a
>voltmeter. Final alignment was carried out with the voltmeter and then a
>small homemade milliwatt meter (a diode and a 50r resistor)
>.
------------------------------
Date: Wed, 10 Nov 1999 08:40:51 -0700
From: doc <k0imj@juno.com>
Subject: Queations about Heathkit?
Get info on 100s of Heathkits at http://home.earthlink.net/~docky
>.
------------------------------
Date: Wed, 10 Nov 1999 19:48:23 +0100
From: "E.D" <ed3@club-internet.fr>
Subject: visit my site
SSTV, Radio, dx, etc
http://perso.club-internet.fr/ed3/
>.
------------------------------
Date: Mon, 8 Nov 1999 08:28:35 -0600
From: "Gilbert Baron" <xzs1947@us.ibm.com>
Subject: WTD PTC-II Pactor Controller
It would be a lot more popular if it were not a proprietary mode that the
owner refuses to license. It is ludicrous to by a new TNC for every mode
that comes along. For that reason, pactor, gtor , etc are useless.
--
Gil Baron gbaron@home.com
EFAX 419-793-4952
"Hierro candente, batir de repente"
W6RCecilA <Cecil.A.Moore@IEEE.org> wrote in message
news:3824EFED.4985561E@IEEE.org...
> Brian Short wrote:
> > I am looking to acquire an SCS PTC-II Pactor Controller.
>
> How popular is PACTOR II?
> --
> 73, Cecil, W6RCA http://www.bigfoot.com/~w6rca
>.
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End of Ham-Digital Digest V99 #288
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To be continued in digest: hd_99_288D
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