|
Subj: Re: LF: Eclipse Monitoring
Date: 99-08-30 08:36:25 EDT
From: rikstrobbe fyskuleuvenacbe (Rik Strobbe)
I just received a preliminary report from the eclipse-experiment of UBA
(Belgian amateur radio society) and KMI (Belgian meteorological institute).
They received a lot of reports for the 160, 80 and 40m band but only very
few for LF/VLF.
Therefore I would like to ask everybody who did measurements during the
eclipse and wants to help UBA and KMI with the eclipse-experiment to
contact the co-ordinator of the experiment, John Devoldere (ON4UN) via
e-mail :
john.devoldere village.uunet.be
73, Rik ON7YD
Subj: IK1QFK Home Page
Date: 99-08-29 04:55:12 EDT
From: reromero tinit (Renato Romero)
To all Long Wave researchers,
Yesterday I have published my home page, on Radio Waves below 22kHz.
http://space.tin.it/scienza/rromero/
The site has been written in english (at least in my intentions and with
big difficulty) to reach the greatest number of interested people. Comments and critique are appreciated.
Many thanks.
Bye, Renato.
Subj: OK
Date: 99-08-28 23:27:17 EDT
From: okbill brightok (William Bowers)
Well, after tornadoes and lightning strikes, LowFER "OK" is back on the air at 189.950 KHz.
Subj: National RBL-6 receiver users
Date: 99-08-24 18:53:23 EDT
From: Mike Perry
Anyone use the old National RBL-6 Receiver, shipboard or shore-station, regen. TRF, 15-600 kHz in 6 bands? I just got one off of Ebay for $36, luckily it was close to home, this baby weighs over 60 lbs!
Anyone out there use one of these gems for LW monitoring? If so, let me know how it performs for you, and if you can give me any info on it, I'd appreciate that too!
I got an online schematic for the beast from a good military site. Try this one for Milspec gear & old war boatanchors....
http://hereford.ampr.org/millist/milidx.html
Happy monitoring... 73
Mike N2COD hotmail.com Forestville, NY
Subj: AM broadcast stations in LW band
Date: 99-08-19 10:57:33 EDT
From: emond1 globetrotter (Electronique Emond)
Hi!
I'm trying to catch some signals in the LW band but, at night, I'm receiving US AM broadcast stations. I have a Sangean ATS-818CS (Radio Shack DX-392). I know that this is not the most selective receiver but, for now, I can not afford buying a better one. Maybe there is somekind of filter circuit that I can connect between my antenna and the receiver. Can you give me some advice about this. I'm living near Quebec city in Canada. I have for now a 100 feet long wire antenna. I'm planning making a loop antenna in a near future.
Thank you.
Sylvain.
esnaud globetrotter.qc.ca
Subj: LF: Solar Flares
Date: 99-08-19 08:13:53 EDT
From: mikedennison rsgb uk (Mike Dennison)
For those wanting to correlate solar flares with enhancements in
sky-wave reception at LF, may like to look at:
http://moondog.astro.louisville.edu/flares/info.html
Mike, G3XDV (IO91VT)
http://www.dennison.demon.co.uk/activity.htm
Subj: Whistler and SID receivers
Date: 99-08-16 23:42:40 EDT
From: evogel flash (Eric Vogel)
Folks interested in Whistler and/or SID receivers might enjoy checking out
my home page at http://www.flash.net/~evogel/
I have included PDF files of the current schematics and some construction
details. I also show some results from my Stokes gyrator-tuned VLF receiver
monitoring NAA at 24KHz.
Subj: Back in the saddle.
Date: 99-08-14 10:44:20 EDT
From: iguana usit (Doug Williams)
Well, after a two year period of almost complete
inactivity in the amateur radio and longwave hobby, I
have again caught the bug and decided to get back into
the hobby. I just ordered a Kenwood TS-850 (used) from
AES and some narrow CW filters from INRAD. I chose the
850 for three reasons: (1) I used to own one and know
it's a good rig. (2) The receiver is one of the few
(possibly the only) in a modern ham rig that is
sensitive down to 100 kHz. (3) Have you seen the prices
on new rigs? ;-)
Hopefully, come winter, I'll have some Lowfer beacon
loggings to report here. I'm also going to try to log
some BPSK beacons.
Is everyone as excited as I am about the proposed LF
ham band(s)? We here in the USA are behind the times.
Several other countries already have LF allocations and
are having a blast experimenting with LF. I have
tremendous respect for our part 15 Lowfer experimenters
here in the US that are able to put out a decent signal
using 1 watt input into a 50 ft antenna. I had an LF
beacon going for a couple of years and know how hard it
is to put out a decent signal. I was happy when I could
here my own beacon ten miles away. I think an LF ham
band will be a good thing for the hobby. It will bring
in new people with new ideas. We will start to see more
construction articles, etc. in QST and CQ. Raising the
power limit and getting rid of that infernal 50 ft
antenna limitation will mean more of us will actually
be able to have QSOs on the band. By no means do I
foresee LF ever becoming a "turnkey" aspect of amateur
radio, the way 2 meters and even HF is now. It will
always require some effort to get a decent signal on
the air. It being a ham band will not change the laws
of physics. Antennas will still be the most difficult
to overcome limitation.
I'm excited to be back in the hobby and am now looking
forward to winter.
Best 73 to everyone,
Doug-KB4OER
Subj: RE: Re: Thanks & my DX observations
Date: 99-08-14 00:29:32 EDT
From: jasonevans28 hotmail (Jason Evans)
Thanks again for your quick response & info. I certainly have
encountered the beacons. In Australia aeronautical beacons alone occupy
from exactly 200 kHz to about 480 kHz, although the ones above 400 kHz have
only appeared gradually since the late 80's, & they aren't crowded. At
night more than half the 200 to 420 kHz region has co-channel interfernce
from other beacons.
It seems that the govt. made a change to some rules in the early 90's
'cos many beacons that used to only xmit 2 morse letters endlessly, now xmit
3. For ex., Devonport's was DV but is now DPO. Devonport is about 20000
people living at the middle of Tasmania's northern coast. The govt. must
have made another rule change late in 1997 'cos most of the beacons below
about 270 kHz are now a lot weaker (7dB I guess).
Our beacons are spaced 3 kHz apart, starting from exactly 200 kHz. Some
are modulated at near to 400 Hz; the rest at 1 kHz which is stupid 'cos
often a beacon will be heard with a constant 1 kHz beat from a faint
entertainment broadcaster's carrier. Broadcasters are spaced differently
from beacons; I think they are on multiples of 9 kHz. A bit of arithmetic
will reveal the potential for 1 kHz beats which will make such a morse
tone indistinguishable.
In the last 2 years have I seen the appearance of new types of
xmissions: from 305 to 318 kHz the are some RTTY-type xmissions; & from
around 410 to 440 kHz are a few RTTY-types that are interruptedd in a rhythm
that is always di-di-di-dihhh di-dihhh. In the middle of these are some
blank carriers that are so close that they produce an odd futuristic musical
chord. Remember, I'm using a 3 valve (tube) regenerative set with a 50 foot
wire 9 feet in the air. So I can resolve SSB and normal AM.
Usually every week late at night I can JUST detect similar beacons in
the rgion from 1620 toabout1800 kHz. Two are MH, & KUB. I've also
discovered some really crazy types of beacons at around 4.300, 6400,
8400kHz, 13 to 14mHz, & roughly near 17 mHz. These are STRANGE 'cos they
send a carrier that is modulated with a 50 Hz tone for 3 secs then goes off
the air for 3 secs, does this again about 12 times, then sends a blank
carrier that is switched on & off as 2 or 3 morse letters. Each such beacon
sends only the same letters. The whole weird cycle then repeats.
If I have ever heard MARITIME beacons, I can only guess that they must
be exactly the same format as aeronautical ones.
I have never heard anything below 14 kHz, and I can tune down to 10 kHz,
which suggests that 14 kHz is Australia's (& the Pacific's?) lower limit.
Subj: Re: Thanks & my DX observations
Date: 08/13/99
From: LWCANews
To: jasonevans28 hotmail.com
Very interesting observations. I'm not sure if the electric utilities "down under" use power line carrier systems for peak load control as they do here, but that may account for some of the unmodulated carriers you encounter. Other signals (mainly military) are modulated with extremely narrowband frequency or phase shift keying, so that the modulation is not apparent with a detector that responds to amplitude variation.
Longwave broadcasters do roll off their frequency response rather seriously. The maximum modulating frequency permitted by most countries is 4.5 kHz. This has to do with the 9 kHz channel spacing, plus the fact that LW broadcast assignments are geographically different from those on mediumwave. Adjacent channel interference becomes more likely at LW, even when stations are many miles apart, simply because groundwave attenuation between them is so much less than it is at MW. There's also the technical problem of making the transmitting antenna system pass a sufficient bandwidth at those frequencies. They tend to resonate rather sharply at carrier, reducing modulation depth as sidebands spread farther from carrier frequency, even if the modulation percentage in the transmitter itself is 100%.
The latter problem doesn't exist in the tropical bands, of course. I've often been puzzled about the poor audio quality I hear there myself (although poor engineering practice, or very old equipment, may account for it).
Have you encountered any of the aeronautical or maritime beacons between 200 and 400 kHz, by any chance?
Regards,
John
Subj: Thanks & my DX observations
Date: 99-08-13 03:04:58 EDT
From: jasonevans28 hotmail (Jason Evans)
Thanks for your very quick reply. I can only guess that all Australian
LW ham work is outside the SE part of Australia or is far too weak for me to
hear. Below 200kHz I can receive: a few faint blank carriers between 60 &
200kHz; some RTTY-like xmissions between 170 & 200 kHz & another of them at
17kHz. This last at 17kHz is accompanied by a morse xmission about 3kHz
lower. It sends a meaningless jumble of letters for 20 minutes then spends
over 20 minutes sending nothing but a series of 4-digit numbers! This goes
on throughout each day.
Until late 1997 there were two foreign entertainment stations near 170
& 185 kHz. I could hear them after midnight in mid-year. They played
semi-classical & easy listening music a lot. I could not hear the speech
clearly to try & guess the language 'cos of the static; and their
modulation had a deliberate amount (about 4dB/octave) of de-emphasis of the
mid & upper audio frequencies, making the tone quite muffled; and they
obviously only used 50% modulation depth! I've noticed that all
entertainment stations in the 3 to 4.5 MHz also use reduced modulation depth
& a lot of treble de-emphasis. Why the heck anyone would WANT to make their
signal easily buried by noise is a mystery of life to me.
Subj: Re: Australian dx-er
Date: 99-08-13 01:03:59 EDT
From: LWCANews
To: jasonevans28 hotmail.com
Hi Jason,
Ham activity on LW is only a few years old. Ironically, although American experimenters have had very low power, unlicensed privileges at 160-190 kHz for decades, we still don't have a regular licensed amateur radio allocation here.
The first big push for LW ham activity came from your part of the world! Papua New Guinea and New Zealand have regular ham bands on longwave now, and Australia has ham activity between 100 and 200 kHz by special license, with a regular allocation likely in the near future. Over the past year and a half, much of Europe has acquired a narrow ham band around 136 kHz.
As you have discovered, static is a big nightmare at longwave. It originates from power mains as much as from nature. To overcome static, most longwave communication systems these days use narrowband transmission modes, which means receivers need superb frequency stability, plus narrow crystal filters and/or digital audio filters at the output.
At the receiving end, careful choice and orientation of aerials can also help reduce static enough to enable reception of signals that would otherwise be buried in noise. Loops are very popular, although amplified whip antennas located at a quiet spot on one's lot are also effective sometimes.
As you get a chance to explore our Web site, you'll probably find more about these topics in our LF Ham page and our File Library section, particularly the Receiving Files library.
If you have more questions, we'll be glad to post them in the LW Message Board and see if anyone can clarify matters further.
73,
John Davis
LWCA Webmaster
Subj: Australian dx-er
Date: 99-08-13 00:24:18 EDT
From: jasonevans28 hotmail (Jason Evans)
I was actually searching for stuff about guitar amplifiers when I
discovered someone's page of links that included one to LWCA. I was quite
shocked 'cos in all the years I've read books & mags about radio &
electronics (including ARRL ones) I have NEVER seen or heard ANY mention of
amateur longwave. Since when has there been regular ham activity at LF?
Is this a uniquely American thing?
I live in a coastal town of 19000 in Tasmania, Australia. My main
receiver is a three valve regenerative receiver that uses plug-in coils to
cover from 12kHz to 40mHz. The aerial is a 40-foot lenth of wire 9 feet
above the ground. This works well enough even at VLF to bring in all the
static clearly. So I find that noise, not poor receiver gain, is what
limits how weak a signal I can hear.
Subj: Lowfer topics
Date: 99-08-10 13:07:17 EDT
From: W3HMS aol
Hi John.....I am rather new to low band DXing but have been licensed for 48
years and worked many facets of ham radio.
I believe the Lowfer could help others get acclimated to low band easier by
runing some basic info on where to get tech info. and parts/rcvrs. Example: I
want to buy a Datong or other good LF converter. At the Dayton Hamfest 99, I
asked many top line vendors for Datong or equivalent...no one had even heard
of Datong and no one had LF converters and I was ready to buy!
In the fine article by John Lauerman, WB7TQT (in The LOWDOWN) this month, he says receivers and
converters are easily purchased! Now I won't say the gentlemen is wrong but I
do wish he would articulate with some info, HI!
He mentions his three transistor rcvr for 3-30 KHZ...boy would I like to see
that in the Lowfer! I suppose it has been there so question remains...where
can I get/buy the article.
In the interim, can you give me an EMAIL/phone number or two where I might
buy a converter.
I use a R2000 and IC 706 with 80 m half-wave loop or 40 m dipole and I hear
NOTHING on LF but strong aviation beacons and BC interference and QRN from
30-400 khz..........and I am sure from the reports of others that there is
more there than just that.
Feel free to quote me if it will springboard an article.
73,
John Jaminet
W3HMS
Subj: New Success with a Transmitting Loop Antenna
Date: 99-08-09 13:45:42 EDT
From: WilliamAshlock edwardsboc (Ashlock,William)
I have always been up against a wall, so to speak, in trying to get the
antenna system losses for WA down to reasonable values. The 'apparent'
ground resistance in the summer season can run as high as 150 ohms and as
low as 60 ohms in the winter season. I have proven conclusively that this
high value is due, not to the ground, in which I have buried many $$ of
copper but to the close proximity of the trees surrounding the antenna. The
'tree loss' lowers the Q of the system and looks electrically the same a
ground loss.
Over the last 2 months I have been experimenting with transmitting loop
antennas as a way to get around the high loss from the trees and this
Saturday I was able to copy WA at a distance equal to my best record in the
winter season - 96 miles (reception site is mountainous terrain having poor
soil). This was in spite of a atmospheric noise level ~ 3X of the winter
levels, and also lacking, of course, the advantages of frozen ground.
From my local field strength measurements I have shown that the
characteristic that best predicts the performance is the Q of the loop.
I'd appreciate hearing from anyone who has experimented with LF transmitting
loops or anyone that would like more details of my experiments.
Bill Ashlock
Beacon WA
Andover, MA
Subj: R390
Date: 99-08-08 13:30:10 EDT
From: Poulsen (David L Quinlan)
I have a Collins R390 which goes down to 15kHz, or so it says, but I
have never got much use of it. Mostly what I hear is noise. Perhaps I
don't have the correct antenna for the rig. Could you suggest what
antenna or antenna tuner I should be using?
Regards,
David Quinlan
Subj: revised webpage
Date: 99-08-08 00:03:54 EDT
From: livvi digital (Olivia Hattan)
To: webmaster lwca.org
Congratulations on the new web page. My patience paid off as tonight it seems to
be all that was promised. I am reviving an old interest in natural radio and recently
joined the LWCA as it seemed to be a "natural" for the new interest. Keep up the
good work.
73 de Carl K0BZV
Reply 1: Thanks, Carl. We've still got a ways to go before everything works again, but we're getting there!
- JHD
Subj: VLF receiver
Date: 99-08-07 12:12:06 EDT
From: febend impopbellatlantic (faith & erich bender)
I watched a show on TLC or Discovery about lightning and the sound it
produces world wide at the 0.1 to 10 kHz band. I am looking for plans or a
kit to build a receiver. I am an automobile tech and have also repaired
copier machines. After building RC cars and planes, this seems like a
good hobby to get into. I did not know that VLF could be used for
transmitting voice on. I would be thankful for any information anyone
could give me.
Erich C. Bender
E-mail: eb714 netscape.net
Reply 1: Actually, it's not practical to transmit voice at VLF, but both Mother Nature and various manmade devices fill the electromagnetic spectrum with a variety of signals at audio frequencies.
In the Natural Radio and Propagation page of the lwca.org web site, you'll find links to the site of Steve McGreevy, who used to sell receivers; and our own library has plans for a high-performance unit based on integrated circuits.
- JHD
Subj: Geophysical Research Letters article of interest
Date: 8/4/99 12:05:58 PM Eastern Daylight Time
From: ericvogel eds (Vogel, Eric S)
The new Geophysical Research Letters site (http://earth.agu.org/GRL/) has an
article that may be of interest to LWCA members, "Poleward-displaced electron precipitation from lightning-generated oblique
whistlers."
ARTICLE - HTML http://www.agu.org/GRL/articles/1999GL900374/GL768W01.html
ARTICLE - PDF http://www.agu.org/GRL/articles/1999GL900374/GL768W01.pdf
Subj: RI
Date: 99-08-01 12:31:28 EDT
From: pthomson bruderhof (Pierre Thomson)
I was just dusting off the RI beacon, which has been off air since April,
to make a few improvements for the coming season. The stimulus for
this came from an email from Jacques D'Avignon, who mentioned that
they will be doing DX camps again this winter. I have materials and a
site for a much better antenna this season; details will follow when I
have it up!
Also, I have just updated the whole
Canadian NDB database, with about a dozen changes since the last
update 6 months ago. It is found at:
http://frodo.bruderhof.com/ka2qpg/
Looking forward to COOLER weather!
Pierre Thomson KA2QPG/RI
Rifton, NY FN21
|