Past Longwave Messages - Aug. 2000
Addresses and URLs may become outdated over time.
construction
Posted by chris steele rm3squid aol.com on August 02, 2000
at 21:20:27: In
Reply to: Re: loop antennas 88
posted by Mick Reed on July 30, 2000 at 15:20:25:
mick, thanks for the help. how many times do i have
to wrap the wire?????? around the frame i choose..
Posted by Mick Reed bossmonkey altavista.net on August 06,
2000 at 13:20:39:
In Reply to: construction
97 posted by chris steele on August 02, 2000 at 21:20:27:
You can learn the most about making loops from the
LWCA member pages. Almost all of them have info on loops. For example, from
Lyle Koehler's page. The main page is: http://www.computerpro.com/~lyle/ and
check the Listening for Lowfers pages: http://www.computerpro.com/~lyle/listen/listn1.htm 1. The basic idea is to make a coil of large
size (30-48 inch diameter.) The coil can be round, square, whatever. Then
figure out the inductance of the loop. You can use the excellent free programs
from Reg Edwards's site to find the inductance of the coil. This is done by
entering the coil dimensions which you can measure easily. http://www.btinternet.com/~g4fgq.regp/ 2. Next, you need to put a capacitor in
parallel with the coil. The value of the capacitor is picked so that the
natural resonant frequency of the two is in the middle of the Lowfer band,
which is 175 Khz. 3. You can use the
calculated inductance that you got in 1. and get a capacitor which tunes the
loop to 175KHz. use the formula: 175KHz
= 1 / (2 * pi * sqrt(LC) ) Where L is
your inductance in Henries and C is the capacitance in Farads. 4. This will get you close to a tuned
antenna, but not all the way. Remember, the coil inductance was calculated, not
measured. The acutal inductance is bound to be off a little. To correct this,
you will need equipment. The minimum setup would be so: a.) Set up your receiver to about 175KHz and
listen to a 175KHz signal. Tune the capacitor for maximum signal. This may
involve trying different capacitors, or using a combination of a fixed
capacitor and a tunable capacitor. b.)
If you have more equipment, it is easier. You can loosely couple a 175KHz
signal to the coil and watch the output on a scope. This will allow you to tune
the coil too. 5. You now have a tuned
recieving coil for the lowfer band.
Re: LFCC Award
Proposal Update
Posted by Mike Troy, CA Carmelink aol.com on August 13,
2000 at 09:51:21: In Reply to: LFCC Award Proposal Update
48 posted by Les Rayburn on June 27, 2000 at 12:31:43:
For Lowfer work within our own club, I had in mind a
certificate for a confirmed or observed 2-way Part 15 contact...it declares the
honoree to be a Certified Low-Life. Figgered we'd start small.
antenna coupling
Posted by Mick Reed bossmonkey altavista.net on August 01,
2000 at 11:30:57:
Hello, I am starting on a lowfer setup here in
Salem, Oregon. Until next year, I am living in an apartment, and my space is
really limited. My main goal is to reach another beginning lowfer who is about
20 miles away. My question is about an
inverted L antenna that I want to build on the side of my building. I am
concerned that my top capacitive section is going to be too close to the rain
gutter on the top of the building. I am wondering if it is going to absorb
everything. I wondered also if it would be 'part of the antenna,' because the
gutter is much longer than 50 feet. I have thought about using a loop, but my
patio is surrounded by a chain link fence. Any suggestions? Thanks in advance Mick Reed
Posted by Bill Ashlock ashlockw hotmail.com on August 03,
2000 at 01:32:13:
In Reply to: antenna
coupling 93 posted by Mick Reed on August 01, 2000 at 11:30:57:
Mick, Just a
short comment on transmitting loops. In my experince they are very competitive
with std monopole Lowfer antennas and don't mind too much about the immediate
surroundings (easy to set up too). Twenty miles should be an easy trip if plane
of the loop, which must be vertical, can be oriented in that direction. I'll be submitting an article to the Lowdown
in the very near furture about my experiences with these antennas. Bill WA
Litz wire
Posted by Mick Reed bossmonkey altavista.net on August 01,
2000 at 11:46:35:
I want to use Litz wire for my base coil. I know
there is a theory for making the most efficient wire. I glanced at a research
paper online about designing it. My
question is, for lowfer wavelengths, can I simply weave my own wire? Also, is
there a preferred pattern. I have found the program 'awg-coil' very useful for
the form design. However, so far I haven't found much help online for making a
good litz for the chore. Thanks again
Mick Reed
Posted by Bill Ashlock ashlockw hotmail.com on August 03,
2000 at 01:13:45:
In Reply to: Litz
wire 94 posted by Mick Reed on August 01, 2000 at 11:46:35:
Mick, From
what I have read the optomin weave is fairly complex - not just a simple twist,
and this is fine enameled wire. I have yet to hear about anyone rolling their
own. Bill WA
Posted by Mitch Powell PowellM claven.fanshawec.on.ca on
August 08, 2000 at 11:07:14:
In Reply to: Re:
Litz wire 98 posted by Bill Ashlock on August 03, 2000 at 01:13:45:
I have a roll of 7/44 Litz. Can I take two lengths
of this wire, connect them in parallel and have 14/44 - and three lengths and
have 21/44 - or am I simplifying a more complex procedure of twisting, etc.
Found this in old junque box of wire, and would like to use, as haven't found
source / prices for Litz - is it still made ?\\Thanks 73 Mitch VE3OT
PC ISA slot VFO
Posted by Frank J. Lotito k3dz aol.com on August 02, 2000
at 03:16:41:
ref:
http://www.bytemark.com/waveguide/pcvfo.htm
Anyone have experience with this VFO? Or know of an impartial third
party tech evaluation? The VFO is supposed to cover 0.029 Hz to 54 MHz.
Posted by Bill Farmer fxfarmer erols.com on August 03, 2000
at 06:21:05:
In Reply to: PC
ISA slot VFO 96 posted by Frank J. Lotito on August 02, 2000 at
03:16:41:
I've been using the PC-VFO for a few years now. It
does all they claim and then some. I have a working program that uses PC-VFO,
and a mixer that gives me a panoramic display of the 10 kHz to 580 kHz
spectrum. Will be glad to send you some screen shots and further info. 73's
Bill
Litz Wire
Questions
Posted by Les Rayburn les highnoonfilm.com on August 04,
2000 at 12:15:12:
Several people have suggested that I wind a new loading coil (after viewing the photos
of my tall, skinny one!) My question is
what kind of litz wire should I use (10/40, whatever?) and also a good supplier
that I can order small quantities from.
I'm sold on litz wire, I just need the
practical application info.
Thanks! Les
Posted by Mick Reed bossmonkey altavista.net on August 06,
2000 at 00:21:37:
In Reply to: Litz
Wire Questions 101 posted by Les Rayburn on August 04, 2000 at
12:15:12:
I have found a web-based paper that I think is
important reading. This paper is about the use of litz wire for optimal
inductor design. I believe the equations given in the paper could give some
insights to some even better designs.
http://www.dartmouth.edu/~sullivan/litzwire/litz.html Thanks, Mick Reed
One source I have
found...
Posted by Mick Reed bossmonkey altavista.net on August 09,
2000 at 14:40:34: In Reply to: Litz Wire Questions 101
posted by Les Rayburn on August 04, 2000 at 12:15:12:
I ran across this source of some Litz wire while
searching.
http://www.surplusales.com/Wire-Cable/LitzWire.html Others must know of better places,
right?......
Posted by Eric Lawson elawson inficad.com on August 15,
2000 at 23:48:02:
In Reply to: One
source I have found... 108 posted by Mick Reed on August 09, 2000 at
14:40:34:
Amidon's price list shows litz wire for sale. Their
price, in the March 1998 retail price list, is 5 cents per foot for 8/42, 8/44
and 10/44 litz wire. While this price
list seems old, it is the that came with their Jan 2000 catalog Their web site is www.amidoncorp.com Eric
Long Wave Receiver
(200-400kHz)
Posted by Harry Joel organic fastlane.net on August 06,
2000 at 14:05:14:
I came across this site when searching through radio
related links. This is a shot in the dark maybe, I have a WWII vintage tube
type receiver made by Setchel-Carson (military model BC-1206c) for which I have
no use for. If anyone in this message forum would like to obtain it, I will
offer it cheap. It seems to be in near new condition and I have not hooked it
up for testing. There is no marking about the power requirements, but I assume
its 12V based on the filament voltage of the two tubes installed. I could send
a pic to any interested party. Thank you
XMGR Moves to
189.500Khz (CW & BPSK)
Posted by Les Rayburn, N1LF les highnoonfilm.com on August
10, 2000 at 14:12:37:
Using the new "All In One" transmitter
designed by Lyle Koehler, KØLR that transmits CW and BPSK. XMGR has moved to
189.500khz (where I promise to stay). Format is CW for the first half of each
hour, and BPSK (MS-100 10 Baud) for the second half of each hour. The clock on the transmitter is syncornized
to WWVB so the mode changes occurs
exactly on time. Signal strength is also
much improved, with antenna currents of over 200ma. We will be putting up a 32
radial elevated counterpoise for the Winter season soon, currently we are
testing with only a four wire system. (Antenna current is still around 175ma) Thanks to Lyle, Bill Bowers, and others who
have helped so much with this effort. Look for another remote beacon,
"1LF" also using the K0LR transmitter soon!
beacon BOB still
gg
Posted by bob hoffswell,BOB harvey prairienet.org on August
13, 2000 at 16:43:38:
Howdy, all!
I just wanted to say that BOB is still on the air, although the antenna
current is down, as it is every summer. (trees?) I haven't heard anyone, even the regular standard, BA, nor has
Brice heard me. Locally, I can get BOB on the portable RX pretty well at my
normal listening post about 20mi away, but QRN is a real killer! Looking forward to winter. 73 es dx
Ten Tec RX 320
Posted by Frank H. Reynolds reynoldsf rl.af.mil on August
22, 2000 at 13:53:27:
Can anyone point me towards a page with the mod that
makes this radio useful on LW?
Posted by Shaun P. Merrigan smerriga compusmart.ab.ca on
August 22, 2000 at 20:58:55:
In Reply to: Ten
Tec RX 320 115 posted by Frank H. Reynolds on August 22, 2000 at
13:53:27:
Sure Frank. Have a look around the AMRAD
site,specifically: http://amrad.org/projects/lf Shaun Merrigan
Posted by Frank Reynolds reynoldsf rl.af.mil on August 23,
2000 at 06:35:07:
In Reply to: Re:
Ten Tec RX 320 116 posted by Shaun P. Merrigan on August 22, 2000 at
20:58:55:
Thanks
Early season
propagation...
Posted by Les Rayburn, N1LF les highnoonfilm.com on August
23, 2000 at 12:49:50:
The last two nights have been very quiet here in the
Southeast with good LF propagation. I even picked up a couple of Iowa NDB's on
the Sony portable last night! Heard
traces of CW on a couple of lowfer frequencies (or was that narrow filter
ringing? Hi, Hi) But I suspect that most beacons are down or only on for
testing this month. Has anyone had much
success early in the Fall/Winter season before? Les Rayburn, N1LF
Low Frequency
Loop Article
Posted by Robert Bicking, W9RB bicking mwci.net on August
23, 2000 at 22:45:12:
The Sept. 2000 QST has an article (P.38) on a LF
loop built using a PVC frame with remote tuning to resonate it from 90 to 450
kHz.
Source of Litz
Wire
Posted by Robert Bicking, W9RB bicking mwci.net on August
23, 2000 at 22:55:25:
I purchased Litz wire (175 strand AWG 40) from MWS
Wire Industries, 818 991 8553, www.mwswire.com when building my LowFER loading
coil as described in the article in the LOWDOWN for Oct. '99. The article also
appears on my webpage www.qsl.net/w9rb/
LF Multicouplers
Posted by Shaun P. Merrigan smerriga compusmart.ab.ca on
August 25, 2000 at 17:37:21:
Hi Everyone,
LF multicouplers are hard to find, but I know that WJ Ford Surplus has
the following: Technical Material Corp
LMC-32 -one 50 ohm input -32 outputs -10khz-6Mhz -transistorized, active
outputs $150.00 Cdn + shipping I bought one of these about 6 weeks ago, and
it works extremely well for a multi-antenna, multi-rx setup. I have no
connection with WJ Ford except that of a very satisfied customer. Here is the
URL: http://www.falls.igs.net/~testequipment/radio_1.html
Lowfer TV
Documentary Update
Posted by Les Rayburn, N1LF les highnoonfilm.com on August
25, 2000 at 19:13:25:
Many have suggested that we should delay the editing
on the upcoming lowfer documentary until later this year due to relative
inactivity during the summer months, vacations, etc. With that in mind, I will
postpone final editing until at least October.
Another suggestion was that QSL cards be included in the video. Great
idea! If you have already sent in your tape or photos, please take the time to
scan your own QSL card and e-mail it to us. We suggest you write
"SAMPLE" on the card to prevent it from being copied or used for QSL
purposes. So far, we have tapes and
photos from about ten beacons but need many more to make the video a success.
Please take the time to tape your operation and send it to us soon: Les Rayburn, N1LF 4919 Cox Cove Helena, AL
35080
BPSK Eureka!
Posted by Les Rayburn, N1LF les highnoonfilm.com on August
29, 2000 at 13:02:01:
Happy to
report that XMGR is now fully active on BPSK! Just completed construction of
Bill de Carle's S-D interface board which allows reception of BPSK and CCW
signals on your computer. To say the
least, I am soldering iron challenged, which can make lowfering a pretty
frustrating hobby for me sometimes, but this kit (ordered for around $50 from
Bill) is very easy to build. Total construction time was about 2 hours start to finish (with a good 45
minutes of that being devoted to my paranoid checking and double checking) After completing construction of the board,
Lyle Koehler sent me a short .WAV file
of his own signal to use as a test. I simply played this file through the
Windows Media Player (in loop mode). This endless loop was recorded onto a
cassette tape for about 1/2 hour, so that I'd have lots to play with. I first tried the COHERENT program to decode
the BPSK, with no luck. (To be honest, Bill's instructions were a little confusing
for me) So, I printed out all 100 plus pages of documentation for all of Bill's
software and read it overnight. This morning I tried the AFRICA program, and
within ten seconds it locked into the audio signal and filled the screen with
LEK LEK LEK LEK LEK LEK! After having
this success, I rushed to try it with an "on-air" signal. Using an
older Kenwood TS-530S and an LF converter, I was able to rapidly tune in my own
signal using the "TUNER" utility. In no time at all, I had XMGR XMGR
XMGR XMGR filling the receive buffer!
------------------------- SUMMARY:
Thanks for Bill de Carle's easy kit, this mode is very easy to receive.
I'd strongly recommend that anyone serious about hearing distant Lowfers build
this before the upcoming season. Lyle's
"All in One" CW/BPSK transmitter makes it easy for any Lowfer to
transmit both CW and BPSK signals. In this way, you have the best of both
worlds. Again, if you're serious about having your beacon copied at good
distances, I'd recommend getting active on BPSK. Another use for Lyle's transmitter is as a "BPSK Frequency
Generator". For instance, I can set my own transmitter to the frequency of
"TEXAS AGGIE" and use the TUNER utility to carefully set my receiver.
Assuming that everything is stable, if I can copy my own signal in BPSK on that
frequency, all I'll need to do is place the software in TRACE mode and record
until I have copy on that beacon.
---------------------------- LESSONS LEARNED: All of this seemed very daunting to me, despite having read and
re-read Lyle Koehler's excellent tutorial on BPSK: BPSK Basics
http://www.computerpro.com/~lyle/watsbpsk.htm The first thing that is confusing (at least to me) is all the
various software packages that Bill
offers. Let me re-cap them in layman's terms.
COHERENT: This is the original software used to decode BPSK and CCW
signals. It will run on older, slower computers, though in my tests it can take
a very long time to "lock" on a signal. AFRICA: The state of the art decoder for BPSK. Takes a Pentium
class computer, but works great! Using this software, I was able to get locks
on my own signal and also the tape recording without any trouble at all. Start
testing your S/D board with this and a good source file (I'll be happy to
e-mail the .WAV files to anyone who needs them) TUNER: This is a utility program that makes it easier to set your
receiver for the correct 800hz tone that BPSK requires for decoding. You can
use WWV to set this just like setting a CW beat tone. TRACE: Is a mode of operation within the program called
"AFRICA". It allows you to set up your receiver and monitor a
frequency for up to 16 hours. Great for overnight monitoring while you
sleep. SEARCH: Is a great little
program that can scan your large TRACE files looking for the string of
characters that you're searching for. Makes it easy to pick out even a brief
opening when the beacon you're searching for might have been audible
overnight. All of this software is
Freeware and available from Bill de Carle's web site at: http://cafe.rapidus.net/bill1/bbs.htm You can also order the S/D board from Bill
as well. Just drop him an e-mail.
-------------- BOTTOM LINE: This mode is not as hard as it can seem. I don't even pretend to
understand how it works (Phase shifts, binary startbits, PLEASE! Beam me up,
Scotty!) But the fact is that this mode offers a 6db advantage over CW. Considering the extraordinary lengths that
we all go to just to get another db or so of increase in our signal strength,
then it just doesn't make a lot of sense not to be active on BPSK. This mode is not much more difficult than
CW, and if I can build it, I know that all of you can.
www.lwca.org