> From: "Ian White, G3SEK"
> Subject: Re: Call-Puzzles and advanced coding
> To: MOON-NET@@VM.STLAWU.EDU
>
> Stewart Nelson wrote:
>>
>> A number of the (mostly negative) replies to my original post on this
>> subject used sports analogies, so I will continue in this vein.
>>
>> CW operation is like running - it's done mostly for fun, sometimes
>> competitively. EME is the Marathon. I am not a good runner, so I am
>> trying to build a bicycle. Not knowing much about bikes, I outlined
>> what my first one would look like, hoping to receive suggestions for
>> superior designs.
>>
> OK, it's a good analogy to use, so let's pursue it.
>
>> Instead, most folks told me to continue running, many explained why
>> cycling is not a satisfying sport, one chastised me for failing to
>> attempt the Marathon,
>
> You have a right to decide what you - individually - find enjoyable
> about amateur radio. I'd support that, and defend it against people
> trying to make you enjoy it their way. But...
>
>> and one even suggested that bicycles do not
>> belong on the course!
>>
> In a sense, they don't - at least, they don't belong on the same course
> that the runners are using.
>
> Nobody "owns" the EME path, but we do have to share the amateur bands.
> These so-called ultra-weak-signal modes still involve very strong TX
> signals in the immediate locality (read: anything up to 50-100 miles
> radius). What worries me even more is the fact that these signals will
> be controled by computers that take no account of the other band users.
>
> If the cyclists want to enjoy their own sport, they must find a
> different course that won't interfere with the runners. In particular,
> the cyclists have no right to decide what is and isn't OK for the
> runners.
>
> Us cyclists and the runners had better decide to work together.
> Otherwise, we'll all be mown down by the motor-bikers and the 4x4s!
How True,
Good analogy! Here in Alaska it would be: "Us x-country (Nordic) skiers
and dog mushers...else we're run over by the snow machiners (snow-mobile or
snow-go, depending on the local term in use). So some would prefer to
stretch their own muscles, others would prefer to train some dogs to do it,
while others would prefer to just enjoy the ride (maybe being physically
unfit to do the other methods) and letting the machinery do all the work!
Hopefully there is room for all.
Just a little disturbed at the reaction of some to an attempt to
innovation. What has attracted me to eme is: (1) the technical challenge,
and (2) the pursuit of technological excellence. Am I wrong to expect to
find kindred souls in the eme community? I know my status is still
"wanabee", but I'm working toward joining you all. After I master the
proven approach(es) to eme, I'd like to explore some new frontiers. Hoping
I'll find others out there will a similar inclination!
P.S.
Proud owner of eleven Alaskan Huskies and a dog musher for 20 years. Prior
to that, a Nordic skier for 10 years and an alpine skier for 20 years,
until badly breaking an ankle in 1978. Some day I may have to retire to a
machine...or a rocking chair!
73, AL7EB, Ed
===================================================
50-144-432-1296
Analog Satellites: RS, AO-10, FO-29, AO-27...QRV very soon.
2m-eme: FT-847-MGF1302-4xM2xpol-20 (V/H)...building 8877
23cm-eme: DEMI xvtr & preamp-K9EK(7211)-OE9PMJ(TH328)=500w
...building power supplies and 5m dish (Summer 1999)
21cm-Radio Telescope: under design for 5m dish
13cm & 3cm: 2.5m dish...Rx for 2401 & 10,368 (Fall 1999)
===================================================
ARRL-AMSAT*-SETI*-SARA...*Alaska Coordinator
Just a simple proposal : given that the EME subband doesn't seem to suffer from
overcrowding problems, why not reserve a slice of it for experimental modulation schemes
other than CW ?
This way, both the romantic fascination of decoding by ear a faint murmur coming from
the silver lady of the night and the sensation of self-accomplishment deriving from
tackling a technical challenge could be both preserved.
73, Alberto,I2PHD
On Sun, 20 Jun 1999, Ian White, G3SEK wrote:
> Also, as I3LDI has said, for most of us the modulation/detection method
> is part of the basic choice we have already made about the style of
> operating. The present "EME" sub-bands belong to that style of
> operating, as well as to the EME path.
Hm, if the modulation method is really optimized for the path, I doubt
that you can even detect these (hypotethical) signals (low power, wide
bandwidth). Lets not worry about problems before there are problems. I
think the same frequencies can be shared like gentlemen and solve any
conflicts if they become real.
Please go ahead with experimenting, after all, that's what ham radio is
for!
Cheers, Kaj, OH6EH
From:
Koellner Guenter Guenter, DL4MEA
DL4MEA's WEB Page
Hi there,
I read last messages of Leif (SM5BSZ) and Juergen (DL8OBU) and I strongly
appreciated the technical opinion of Leif (his proposal of "coherent" CW on
base of high frequency stability and a loop of 3 frames of the same message
- I still use a ECC83 xtal oscillator + triplier with a large amount of
freq. drift but this don't prevent me to explain my opinion - I'pe!) and
the ideas of Juergen, particular:
1) Understanding the importance of EME and MS procedures (simply to obtain
the maximum fun in the radio ham activity, i.e. a great number of C QSO!)
2) Freedom in the choices of activity (don't mean that I can transmit on
beacon sub_bands or other damaging acts!) like use or misuse of a PC to
have maximum performances, QRP or QRO (matching EME ARRL rules or for
terrestrial qso),etc.
Really I think that everybody want improve his EME performances (increasing
G/T of antennas, noise figure of receivers, quality of analogic or digital
filters - last but not least power output), it's true that everbody use own
ears to solve a QSO but it's also true that there is'nt any kind of natural
activity by using radio equipments (even if analogic) and some (or many)
accessories to send a "low rate of information" by the moon!!
Maybe I'm biased to digital techniques (so I wrote this message) but maybe
also that freedom is the key to continue this funny experience.
73 Claudio, I4XCC
WOULD ANYONE MIND CHANGING THE NAME OF MOON NET??
MAYBE "AS THE WORLD TURNS"
BOB TAYLOR, W5LBT
Subject: Re: EME procedure
On 1296 sometimes signals were peaking 30 dB over noise , but very much
distorted. i could not find out if it was OE9XXI or OE9ERC. The only way to
discover who it was, was to call him on SSB.
I would like to see a computer in such a case.
GL, 73 Paul, WA6PY
"Charles R. MacCluer" wrote:
> In regards to the following"
>
> "But you must realize that, in spite of any advances in DSP or other
> digital techniques, a majority of attempts at EME communication will
> still fail."
>
> I strongly disagree. Most EME QSO's (at least on 432 & 1296) are made
> just like on 20M you call CQ and answer whoever come back. On 1296 a
> significant number of QSO's are made on SSB.
>
> Steve, K1FO
Kaj Wiik wrote:
>
> Hm, if the modulation method is really optimized for the path, I doubt
> that you can even detect these (hypotethical) signals (low power, wide
> bandwidth).
There's no worry about detecting them on the downlink from the moon -
it's about detecting the *uplinks* from stations up to 50 miles away, or
more. Even if they are 10dB down from "EME power", those signals are
STRONG, and capable of causing a lot of wide-bandwidth QRM.
The other problem with the under-the-noise modes that rely totally on
computers for decoding is that operators have no reason to actually
listen on the band. Nobody should ever transmit unless they know that
the frequency is clear... but if a station hasn't got the "ears" to copy
weak CW on the EME downlink, how can they know that? The only answer is
to wait for up to 2 or 2.5 minutes in case a local uplink signal
appears, and I don't think most operators would do that.
> Lets not worry about problems before there are problems.
Having some practical experience in band planning in Europe, where VHF
population densities are extremely high, I fear that's bad advice. It's
true that the first few experiments cause little QRM to existing users
of the same frequencies, but if the experiments are successful and lots
of people get involved, it's already too late!
> I think the same frequencies can be shared like gentlemen and solve any
> conflicts if they become real.
The European VHF band-plans always keep a frequency area where new modes
can start up, so that they can avoid conflicts with existing uses of the
band.
> Please go ahead with experimenting, after all, that's what ham radio is
> for!
Absolutely - but only with complete respect for other band users.
73 from Ian G3SEK
Editor, 'The VHF/UHF DX Book'
'In Practice' columnist for RadCom (RSGB)
G3SEK's Web Page
From:
Leif Asbrink SM5BSZ ( remove .sm5bsx from address )
To:
MOON-NET@VM.STLAWU.EDU
Hi all,
I have to admit that my previous posting on this subject was strongly
biased. My interest is RANDOM contacts, and there are underlying
assumptions because of that.
Taking a pro sked attitude just for once I would like to propose a sked to
some Oscar Class -6dB station, for example Stewart, KK7KA with
appropriately reduced power. I suggest 75 W to compensate for my use of
four yagis rather than one.
I suggest the following procedure:
My sked partner suggests the day, the hour and a 10kHz frequency band and
sends the proposal to me.
At some 1 minute interval within the first 10 minutes of the hour my sked
partner starts by transmitting a full minute of continuous carrier,
starting the first second of the selected minute.
If I can "hear" the signal I will respond during nearly 3 minutes by
transmitting call signs and OOO at the frequency I received with a
polarisation that is optimum for my sked partner. It will take some time
for me to adjust the frequency and polarisation so one minute is not
enough. Two minutes is no good in case my partner likes to make a second
attempt.
If my sked partner can hear my answer on the frequency he calculates from
the doppler shifts, he should transmit one minute of continuous carrier at
a new frequency somewhere between 0.5 and 1.5 kHz away from the first
frequency (up or down).
If I can "hear" the confirmation I will answer by transmitting calls and
RRR at the new frequency I have received during nearly 3 minutes.
If my sked partner can hear my confirmation he should transmit a
confirmation by transmitting a 1 minute carrier without frequency change.
I will record the signals and make the recording available as a gif file
and some spectrum graphs that allow determination of bandwidth and S/N.
If the "QSO" is successful my sked partner will know for sure that I can
actually detect him. I will have no chance to select correct minute and
frequency just by luck or by detecting something else. (Actually this
procedure is far more safe against mistakes than the standard procedure as
any station that has some experience in listening to other stations skeds
must know)
This test "QSO" must be done without ground reflections at both ends to
make the result really interesting. Any suitable time with degradation
(loss + sky temperature) below 3dB and the sun 20 degrees away or more is
fine.
Stewart, KK7KA wrote:
>4) We are comparing "once in a lifetime" conditions with "good" ones.
In my experience with cross yagis there is no such thing as exceptional
conditions. Unless something is wrong, the signals are always the same.
The bandwidth changes from time to time but the maximum S/N is always
nearly constant if the degradation according to popular programs is
subtracted. Things that may go wrong are mainly:
1. Local QRM.
2. Thick ice layer on antennas.
3. Error in azimuth or elevation.
4. All other possible (and impossible) operator errors.
5. Very strong aurora.
The EL2RL signal was in fact weaker than it was during the first attempt.
I failed to work them then because they disappeared (due to extremely bad
weather making it impossible to track the moon as I learned later)
In my collection of QSL cards I have the following:
call date time(UTC) single ant pwr degradation
K1FJM 02 oct 94 1328 17M2 280W 1.3dB
W7OE 19 oct 97 0418 2M8WL 350W 3.7dB
SP2JXN 15 nov 97 1957 17M2 4CX250B 3.8dB
F8ZW 16 nov 97 1830 17B2 600W 3.8dB
These were regular random contacts during contest. There was some
contribution from ground gain. K1FJM was before I had any digital
processing at all, just analog filters and polarity switching in 45 degree
steps. The other three were DSP aided, but only adaptive filtering and
polarisation, no coherent processing.
By use of ground gain at both ends, medium power single yagi stations can
already work each other (but it takes patience and good understanding of
EME) Add 4dB for ground gain for K1FJM, one more for lower degradation and
increase the power by 1dB to 350W to get the signal level I had in our qso
using a normal analog filter. It is generally accepted that a qso is
possible at lower signal levels by use of skeds so take that as a bonus!
73
leif.asbrink@sm5bsz.MBOX300.SWIPNET.SE ( remove sm5bsz from email address )