Re: Help - Finally got a SLM - Having trouble using it...
Thank you, Alan!
The original response, to Alan, BTW, was that I was thinking of buying the more expensive Kiwa Low-Pass Filter to try (instead of the PAR Electronics version I currently use). Another LW hobbyist mentioned that it had better specs than the PAR unit I have.
And I thank Alan very much, again, for the input re: this.
Good DX,
Al
The wooden radio towers of KWG in Stockton, California
Posted by Herbert Klein on November 03, 2005 at 05:24:37.
KWG in Stockton, California used until the Mid of the ninties two wooden towers approximately 60 metres tall. The basements of the towers are still there. Has someone more informations (and pictures)?
Re: The wooden radio towers of KWG in Stockton, California
Posted by Jim V. M. on November 03, 2005 at 12:46:52.
In Reply to The wooden radio towers of KWG in Stockton, California posted by Herbert Klein on November 03, 2005 at 05:24:37.
Looks like the towers are gone. LOWFER YTN BACK ON
Check Google Maps 37 57.567N, 121 15.466W
73 Jim
Posted by AL on November 06, 2005 at 15:37:31.
Lowfer YTN ON 161.2KHZ has been rebuilt and is now running QRSS 3 24/7 from
Central Fl Had to change freq and put up new antenna after latest Hurricane.
Later may run QRSS 30.Please email me if you hear it.
Thanks
Al
VLF transceiver
Posted by Hank.Lewin on November 10, 2005 at 00:56:35.
I am in need of two VLF tranceivers 30 to 200 KHZ with a variable wattage from 10 to 200 watts. I cannot find what I need. Any sugestions would be welcomed.
HBL
Re: VLF transceiver
Posted by John Andrews on November 10, 2005 at 06:55:56.
In Reply to VLF transceiver posted by Hank.Lewin on November 10, 2005 at 00:56:35.
Hank,
I doubt that anything like that is commercially available. There may be military gear, but it would be extremely expensive if purchased new, and I've never seen radios that fit your description on the surplus market.
What would be the application?
John Andrews
Carrier at 13.566?
Posted by af0h on November 10, 2005 at 22:01:34.
Has anyone picked up a steady carrier on 13.566 or thereabouts? It was a steady carrier picked up between 1:00am and 2:00am CST on 13.566. It was a weak carrier, possibly part 15, but continuous - not a beacon. Although I picked up a small bit of drift between those times, it was definately there.
Anyone else pick this up, or was it possibly local noise?
af0h - Rob
P.S. - I threw the main breaker in my house and still got it...
Re: VLF transceiver
Posted by af0h on November 10, 2005 at 22:04:21.
In Reply to VLF transceiver posted by Hank.Lewin on November 10, 2005 at 00:56:35.
There are WWII surplus rigs that are capable of this, although rare. The rigs were used in submarines. Although the rigs are around, power supplies are extremely rare and usually have to be homebrewed. Balashikha Transmission Mast - Europe's second tallest tower!
Posted by Herbert on November 13, 2005 at 01:48:57.
Balashikha Transmission Mast is the radio mast of the 13th broadcasting centre at Balashikha near Moscow, Russia. It is a 460 metre high guyed radio mast, which is guyed in 6 levels. Balashikha Transmission Mast weighs 421 tons and is of triangular cross section with a side length of 3.6 metres. A weather radio can help people survive
Further information on http://www.stako.ru/HOME_RAr_V.htm and on http://www.skyscrapercity.com/showthread.php?t=265786&page=1&pp=20
Posted by Mike Terry on November 13, 2005 at 03:40:00.
November 13, 2005
Curtis Hawk
Bloomington
The early November storms that left death and destruction across western
Kentucky and southwestern Indiana are a reminder that tornadoes can strike
in any month and at any time. Most were sleeping when this severe weather
struck and heard no warning.
Get a NOAA Weather Radio for a first alert to changing weather conditions.
If your home has a smoke detector, it should have a weather radio. It will
provide the initial warning message letting you know to take action to
protect your life and property. Today's weather radios can be programmed to
provide alerts for selected counties and are especially valuable when
individuals are asleep.
Dangerous winter weather is just around the corner. The good news is that
the same weather radio you'll depend on for tornado and severe thunderstorm
warnings will also keep you informed when it comes to inclement winter
weather.
Consider a NOAA Weather Radio as a holiday gift for an older parent a child
away at school or any loved one. Consider it as a gift to the rest of your
household.
(The writer is director, McLean County Emergency Services & Disaster Agency WWVB decoder problem
http://www.pantagraph.com/stories/111305/let_20051113005.shtml ).
Posted by Chris Waldrup KD4PBJ on November 13, 2005 at 22:31:32.
I am building the Hagtronics WWVB decoder from Steve Hageman's website and am having trouble. The receiver I'm using is a Rohde and Schwarz frequency selective microvoltmeter, and I get a great carrier on 60 Khz, giving full scale deflection with the range switch at the 1uV full scale setting. I am a little concerned since I hear no audio/digital mode at all when listening with the speaker and see nothing on my scope when connected to the output. For comparison I tune to 100 Khz and hear the LORAN station and can see pulses with my scope. Any thoughts?
Thanks!!
Chris Re: WWVB decoder problem
Raleigh, NC
Posted by John Davis on November 13, 2005 at 23:32:56.
In Reply to WWVB decoder problem posted by Chris Waldrup KD4PBJ on November 13, 2005 at 22:31:32.
I would not expect to hear very much from WWVB. Remember that the carrier level is shifted twice each second. That's the only modulation...no pulses or anything else in the audible range.
It looks to me as if the kit in question is expecting to see a rectangular wave of 200 mV-4V pk-pk amplitude, changing state between low and high and vice-versa each second. This would be the direct AM detector ouput of the receiver, which is probably not available to you with the R&S meter.
Anyone else have a good solution for Chris? Re: WWVB decoder problem
Posted by Chris Waldrup on November 14, 2005 at 07:51:41.
In Reply to Re: WWVB decoder problem posted by John Davis on November 13, 2005 at 23:32:56.
I have connected the decoder to the headphone output of the R&S meter. Is this not a detector output (I can hear AM BCB and shortwave when at these frequencies with my dipoles connected)? Thanks.
Chris
Re: WWVB decoder problem
Posted by John Davis on November 14, 2005 at 12:55:55.
In Reply to Re: WWVB decoder problem posted by Chris Waldrup on November 14, 2005 at 07:51:41.
I would expect that the headphone output is buffered by an audio amplifier that is capacitor coupled (possibly with one or more transformers in the path, too). It will easily pass audio frequencies, but not what amounts to a DC level that is shifting twice per second. That's what the WWVB modulation is, and it's what the decoder kit appears designed to trigger from.
It really would have been helpful if Mr Hageman had been more explicit about the output circuitry of his homebuilt WWVB receiver, or at least clearer in his description of the required input. He calls the inputs "analog," which I think is misleading. The first op amp is a buffer, while the second is a transition detector to give the PIC a cleaner, constant amplitude, conditioned version of the detected time code...which is, by any definition, a digital signal.
I'm not at all sure how you will get something like that out of your R&S by itself.
If it has a BFO (or if you can inject a signal near 60kHz that would serve as one), then you would get an amplitude-varying audio signal at the headphone output. Perhaps you could then rectify and filter that audio to achieve a slow rectangular wave of adequate amplitude to be passed to the kit.
John Re: Help - Finally got a SLM - Having trouble using it...
Posted by Christopher Gross on November 14, 2005 at 15:25:37.
In Reply to Re: Help - Finally got a SLM - Having trouble using it... posted by Al on November 01, 2005 at 12:43:56.
I bought a CE-24A on eBay recently, and I haven't had any trouble picking up signals with it. Did yours come with the BNC adapter and attenuator? Mine picks up MW and SW stations (up past 6 mHz, which surprised me because it isn't supposed to tune that high) with a simple whip antenna connected to the BNC adapter. A simple loop antenna in the attic picks up plenty of NDBs when hooked up to the attenuator. The only problem I'm having is downward drift; for the first hour or so after starting it up I have to keep retuning it, but after that it begins to stabilize. That apart, I'm very happy with it-- I hope you'll be able to get yours going as well.
Chris Gross
Re: WWVB decoder problem
Posted by chris waldrup on November 14, 2005 at 15:36:59.
In Reply to Re: WWVB decoder problem posted by John Davis on November 14, 2005 at 12:55:55.
I see one problem now- I am using a transformer as impedance matching/isolation on the headphone output of the receiver. I got a mild AC bite once when touching one of the output terminals and the chassis, plus the receiver is tube based so I wanted to have some isolation between this and my 8 ohm headphones that I usually use with this receiver for LF beacon chasing.
I do have an AAVSO gyrator that I built a while back and I am using a resonant loop for 60 Khz so I may have better luck with this (if I go back and short across the blocking cap). Thanks.
Chris
vlf.it update
Posted by Renato Romero on November 14, 2005 at 17:46:57.
An update of www.vlf.it is on line, with two new articles:
-ADA: AN ACTIVE DIFFERENTIAL ANTENNA FOR 5Hz – 500 Khz By I1RFQ, by Claudio Re
-LUMINOUS PHENOMENA IN THE HESSDALEN VALLEY AND VLF EMISSIONS, by Renato Romero and Jader Monari
73, renato romero
strange results from loop antenna
Posted by tom on November 15, 2005 at 10:44:39.
I have a late model PC with sound card and I've been reading about vlf reception with SpectrumLab. The websites say to make a loop antenna and connect it to the mic input of the snd card. This I did, but I noticed that I get a much stronger signal with only 1 of the mic leads connected to the antenna. When the antenna is connected only to one mic lead (the one thats connected with the tip of the jack, not the base of the jack) this gives a strong signal, when the antenna is connected to both leads, or only connected to the base of the jack (that goes into the mic input) the signal is virtualy nonexistent. Another odd thing is that it makes no difference if only one lead from the antenna or both leads from the antenna are connected to the tip, the signal is the same. When one lead from the antenna is connected to the tip and the other to the base of the jack that goes into the mic input, there is no signal --- but the diagrams all seem to show this as the way that it is supposed to be. I tried putting series inductances (transformer) and resisters in series and parallel to no avail. I am very confused by this and would appreciate any help from anyone more knowledgable.
Just to remove any ambiguous references, the mic input has 2 leads: tip and base (of jack that goes into mic input) and the loop antenna has 2 leads coming from it: a1 and a2.
Strong signal:
tip connected to a1, base unconnected, a2 unconnected.
tip connected to a2, base unconnected, a1 unconnected
tip connected to a1 AND a2 simultaneously, base unconnected.
Weak signal: Re: strange results from loop antenna
tip to a1 AND base to a2
tip to a2 AND base to a1
Posted by John Andrews on November 15, 2005 at 14:36:30.
In Reply to strange results from loop antenna posted by tom on November 15, 2005 at 10:44:39.
Tom,
With only one connection to the loop, you effectively have an e-field probe, and that will certainly pick up more "stuff" than the loop. "Stuff" in this case refers to mostly unwanted noise, digital hash from the computer, signals radiated from nearby power lines, and so forth. An antenna like an e-field probe must be placed in a clear location such as a rooftop, well away from nearby conductors. Such a "whip" antenna usually requires a high-impedance input preamp right at the antenna.
The loop (with both connections) will be much quieter, hopefully raising the ratio of desired to undesired signals. While the loop should also be kept away from nearby wires and electronic equipment, you may be able to use it inside of a house.
So, don't be surprised at the lower levels from the loop. Focus on trying to identify desired signals, and be thankful for the inability to detect if a TV set two houses away has been turned on!
John Andrews
Re: strange results from loop antenna
Posted by Tom on November 15, 2005 at 19:40:27.
In Reply to Re: strange results from loop antenna posted by John Andrews on November 15, 2005 at 14:36:30.
You can see the difference between spectra samples taken with each configuration:
http://ftp.shaw.ca/cyberhun/0_22khz_10_turn_magloop.jpg
and
http://ftp.shaw.ca/cyberhun/1_11khz_floating_magloop.jpg
The antenna is a 35cm square loop with 8 turns.
apparant lack of significant signals
Posted by Tom on November 16, 2005 at 10:30:12.
I don't think I'm receiving anything significant. Here's a link to a screencapture of Spectrumlab made with a 30cm/side square loop antenna with at least 10 turns of wire on it:
http://ftp.shaw.ca/cyberhun/allband_magloop.jpg
I'm living in a basment suite and my antenna isn't very high, but so what --- VLF is supposed to reach subs underwater, isn't it? Repositioning my antenna would be a huge hassle but I'll try it if anyone thinks it'll really help. Also, how about the number of turns on the antenna --- will increasing the turns enable me to receive stuff that I'm not getting at all now, or will it only help to marginally improve the reception of signals that I would already be getting with 10 turns?
Re: apparant lack of significant signals
Posted by John Andrews on November 16, 2005 at 11:27:37.
In Reply to apparant lack of significant signals posted by Tom on November 16, 2005 at 10:30:12.
Tom,
I am not able to access your screen shot, but that's a very small antenna at VLF. You should consider something larger, with more turns, and possibly tuned to your frequencies of interest. The VLF.it site has VLF antenna information that should help.
John Andrews
Re: apparant lack of significant signals
Posted by Warren K2ORS/WD2XGJ on November 17, 2005 at 10:35:26.
In Reply to apparant lack of significant signals posted by Tom on November 16, 2005 at 10:30:12.
Tom,
As John pointed out a 30cm loop is way too small at vlf. Also 10 turns is not nearly enough if you are shooting for vlf coverage. From inside your house you are likely to only pick up electrical noise from the power line and appliances.
In addition to the www.vlf.it website I recommend looking at the LWCA antenna library pages with articles by Will Payne:
http://www.lwca.org/library/rcvg-lib.htm
Good luck with your experiments! Where can I buy a long wave radio?
73 Warren K2ORS/WD2XGJ
Posted by Karen on November 17, 2005 at 16:35:25.
I am not very familiar with long wave radios, but I would like to buy one for my father-in-law. Can anyone tell me where I can buy one?
XDW HiFer Good Copy MI
Posted by T. Kennedy on November 17, 2005 at 16:53:06.
Copied XDW Bartlesville, OK on 13.554920 MHz strong signal at 1630Z into Michigan. Using HP3586C with dipole antenna and ARGO software. Even with the very low sunspots there are still surprises to be found on HF. (Cant do LF anymore thanks to the neighbors "Invisible fence" dog transmitter which has harmonics up through the lower AM broadcast band.) Re: Where can I buy a long wave radio?
73,
T
Posted by Warren on November 17, 2005 at 17:38:05.
In Reply to Where can I buy a long wave radio? posted by Karen on November 17, 2005 at 16:35:25.
I'd have to answer your question with a question or two.
Where does your father in law live?
What does he want to listen to on longwave?
If he lives in the Europe or Asia he can pick up local longwave broadcast stations and most any radio with the longwave band is o.k. for that. Sony and Sangean make a number of portables that would work.
In the U.S. it tends to be more of a hobbyist thing. There are no longwave broadcast stations in North America. You can pick up airport beacons, amateur type experimenters and some government data transmissions which unfortunately are encrypted. If all he wants to do is pick up some local airport beacons then a Sony (or equivalent) is fine. More serious listening would involve a bigger investment in a radio and an antenna. A good longwave radio for the serious listener is the Icom R-75, which retails for somewhere around $600, with used ones available for about $400.00
Good Luck!
Warren
Re: XDW HiFer Good Copy MI
Posted by Laurence on November 17, 2005 at 23:11:01.
In Reply to XDW HiFer Good Copy MI posted by T. Kennedy on November 17, 2005 at 16:53:06.
thanks for the report T - first one for a few weeks. A few milliwatts from an HP3336b into a low, firing North/South dipole - around 18 ft agl. Cheers - Laurence XDW EM26AQ
MedFER slow CW audio frequency and dot/dash durations?
Posted by J. Jason Wentworth on November 18, 2005 at 09:11:59.
Hello All,
I'm going to use a stock, unmodified Part 15 AM realtor transmitter as a ready-made MedFER beacon. The Talking House and TalkingSign transmitters have built-in auto-repeat digital audio recorders that can record up to 5 minutes of audio. I will record slow CW on the recorder.
For best results, what audio frequency should I use to record the dots and dashes, and how long should the dots and dashes be?
Many thanks in advance to anyone who can help. -- J. Jason Wentworth
Re: MedFER slow CW audio frequency and dot/dash durations?
Posted by John Andrews on November 18, 2005 at 09:42:49.
In Reply to MedFER slow CW audio frequency and dot/dash durations? posted by J. Jason Wentworth on November 18, 2005 at 09:11:59.
Jason,
I would not go any slower than QRSS3 (3 second dots), and you will want to verify that the audio recorder produces something understandable on an Argo (or similar) screen. Typical timings for that speed would be:
Dots = 3 seconds
Dashes = 9 seconds
Space between successive dots or dashes = 3 seconds
Space between characters = 9 seconds
Space between words = 18 seconds
As to the choice of audio frequency, it's up to you. You will be transmitting full-carrier AM with two sidebands. Listeners will have the choice of tuning either sideband. If you use a 1 kHz tone, the sidebands will be 1 kHz above and below your carrier. For listing purposes, you should probably pick one sideband and measure its frequency within 20 Hz to be sure that it will appear on a QRSS3 screen.
Of course, the down side to running AM instead of CW is power. For a 100 milliwatt carrier, each sideband at 100% modulation (assuming the real estate box is capable of that ) will only have 25 milliwatts, which is a 6 dB penalty. That's a significant loss, made worse if the modulation is less than 100%.
John Andrews
loop antennas
Posted by Ed on November 18, 2005 at 11:35:36.
Spiral versus edge wound receiving loop antennas: comments, opinions, theory or speculations appreciated. Some of the WWW sites show the null directions of the two types of windings to be 90-degree apart. This seems odd, since the physical dimensions of both types of loops are not that far apart, particularily when the number of turns is small. Could a handful of edge-wound turns flip the null direction by 90-degrees from the same number of spiral-wound turns? Is there a preferred loop style (windings, size, shape, etc) for NDB Dxing?
Re: loop antennas
Posted by John Andrews on November 18, 2005 at 13:09:13.
In Reply to loop antennas posted by Ed on November 18, 2005 at 11:35:36.
Ed,
Small loops, which at LF even includes my big 480 foot perimeter loop, have their maximum pickup in the plane of the loop. If they have multiple turns, the manner of winding is unimportant. If there are web sites that claim otherwise, then something is wrong with the author's thinking, or perhaps with our understanding of it!
Large loops, such as those that are 1 wavelength or more in perimeter, have the opposite response: The maximum is on the axis of the loop. So you may see some HF-oriented articles that correctly claim the "reverse" directionality. "Quad" antennas are an example.
I do not believe that there is a significant difference between edge-wound and spiral-wound loops at LF. The constant area of an edge-wound loop does make it a little easier to predict the terminal voltage, but unless you are making field-strength measurements, that's not an issue.
Endless experimenting has shown that the best LF receiving loops are balanced with respect to ground. Shielding is not necessary for a balanced loop. Either series or parallel coupling may be used, or you may inductively couple to a tuned loop through an extra (perhaps smaller) turn. Size (area of the loop) does matter when using DSP techniques to dig signals out of the noise. Just because you can hear or see the noise does not mean that you can receive a signal buried 30 dB into it. A lot of successful LF DX-er's use loops around 2 meters in diameter, or 2 meters on a side if square. If you space the turns fairly widely, you can get more turns and a wider tuning range.
John Andrews
Re: MedFER slow CW audio frequency and dot/dash durations?
Posted by J. Jason Wentworth on November 18, 2005 at 18:59:44.
In Reply to Re: MedFER slow CW audio frequency and dot/dash durations? posted by John Andrews on November 18, 2005 at 09:42:49.
Thank you, John. I don't have the modulation percentage specs for the Talking House or TalkingSign, but I believe they're either 95% or 100%. I've worked with other Part 15 AM transmitters that had considerably less, and you can hear the difference.
The built-in audio recorders in these transmitters have a high sampling rate, and the audio has good fidelity. -- J. Jason Wentworth
KPH Reception Report
Posted by Ray W2RS on November 19, 2005 at 21:07:06.
KPH was RST 579 on 500 kHz here in Green Valley, AZ, about 25 miles south of Tucson, on a 130-foot end-fed wire 30 feet high. This was my first MF reception of KPH. Back in New Jersey I could only hear them on HF.
I don't yet have the LF loop back up, but all in good time....
73,
Ray
NDB List in Wikipedia
Posted by Harald on November 21, 2005 at 10:50:40.
On http://en.wikipedia.org/wiki/List_of_NDBs there is a list of NDBs.
Re: NDB List in Wikipedia
Posted by Warren K2ORS/WD2XGJ on November 21, 2005 at 17:20:43.
In Reply to NDB List in Wikipedia posted by Harald on November 21, 2005 at 10:50:40.
Looks like the list is being considered for deletion from Wikipedia.
73 Warren K2ORS/WD2XGJ NVIS at Long Wave frequencies?
http://www.w4dex.com/wd2xgj.htm
Posted by J. Jason Wentworth on November 23, 2005 at 11:50:34.
Hello All,
Does NVIS (Near-Vertical Incidence Skywave) propagation work at Long Wave frequencies?
Ham operators can communicate out to 300 - 500 miles with just 3 - 10 watts at HF frequencies, using NVIS. NVIS generally favors the lower ham bands, all the way down to the 1800 kHz - 2000 kHz 160 meter band. Since there are no groundwave path losses with NVIS, LowFER beacons using this mode of propagation might more easily be able to contact each other.
Many thanks in advance to anyone who can help. -- J. Jason Wentworth
Re: NVIS at Long Wave frequencies?
Posted by John Davis on November 23, 2005 at 14:14:16.
In Reply to NVIS at Long Wave frequencies? posted by J. Jason Wentworth on November 23, 2005 at 11:50:34.
Well, as a broadcast engineer, I wouldn't regard 300 mile or greater skywave propagation to be "near vertical incidence" at all. It's just plain old everyday (or every night) skywave, which LowFERs have been using for a very long time.
True near-vertical launch angles are easy with dipoles, which are practical at HF but not at all feasible for LowFERs. Remember also that groundwave path losses are a lot less at LF than HF, so the kind of distances (100 miles or so) or rough terrain that would require NVIS for QRP operation in the ham bands are not much of a problem at LF.
John
NVIS
Posted by John Andrews on November 23, 2005 at 15:13:35.
In Reply to Re: NVIS at Long Wave frequencies? posted by John Davis on November 23, 2005 at 14:14:16.
Just to carry John Davis' comments a little further, those of us running vertical loop antennas send a significant amount of RF up at high vertical angles. With ground wave coverage out to 200 miles or more, this actually results in increased fading at night within the groundwave zone, as the reflected and surface waves combine vectorially. This would be an undesirable thing for broadcasting. We tolerate it for Lowfer work because a loop may be the best transmitting antenna on a tree-infested lot that would otherwise produce high dielectric losses with loaded verticals.
John Andrews
Re: NVIS at Long Wave frequencies?
Posted by alan G3NYK on November 23, 2005 at 17:54:42.
In Reply to Re: NVIS at Long Wave frequencies? posted by John Davis on November 23, 2005 at 14:14:16.
I think the other problem is that if you convert the 5 to 10 watts on 5 or 7MHz into 5 to 10 watts ERP on LW then you would certainly have a good ground-wave range, but you would need a PA generating several kW or a big antenna. Antenna efficiencies are around 0.1% at LF (if you are lucky !)
In general at LF the skywave only exceeds the ground wave in strength at distances in excess of about 700km (abt 450 miles) ref. ITU Reports 1990. This is not quite true of LowFer signals where the small antenna does not normally allow efficient low-angle take off. If you fire something directly upwards on LF (not an easy project!) it probably won't come back down again. The higher the angle, the deeper the penetration of the ionosphere, and the greater the absorption.
In fact NVIS is not particularly good even on 160m.
Cheers de Alan G3NYK Re: NVIS at Long Wave frequencies?
Posted by J. Jason Wentworth on November 23, 2005 at 22:21:05.
In Reply to Re: NVIS at Long Wave frequencies? posted by John Davis on November 23, 2005 at 14:14:16.
Those NVIS ranges at HF have been achieved with antennas mounted at chest-height and below, sometimes even lying on the ground. Antennas that low don't radiate ground wave signals--that's why the military uses them to evade direction finding equipment.
This also makes the antennas very quiet for receiving, as thunderstorms outside of the near-vertical NVIS lobe aren't heard. That is also why low power achieves long ranges on NVIS, because the signal-to-noise ratio is higher. -- Jason
unknown beacon
Posted by karl on November 24, 2005 at 05:55:33.
I was hearing a beacon? sending NAETE on 396 on 11/23 at around 0200 GMT. Does anyone know where it is?
Re: NVIS at Long Wave frequencies?
Posted by John Andrews on November 24, 2005 at 09:53:23.
In Reply to Re: NVIS at Long Wave frequencies? posted by J. Jason Wentworth on November 23, 2005 at 22:21:05.
Jason,
You are quite correct that a low horizontally polarized antenna will not radiate much ground wave signal at LF. And since chest height is 0.0005 wavelengths at 190 kHz, there probably won't be much difference if the antenna is on the ground.
So, try it! We would appreciate reports of your results here, or in an article for The Lowdown.
John Andrews
Re: unknown beacon
Posted by Brian Wingard N4DKD on November 24, 2005 at 14:14:46.
In Reply to unknown beacon posted by karl on November 24, 2005 at 05:55:33.
I copied the same NAETE on 11/18. Haven't found any info yet.
Brian
N4DKD
Southern Avionics TX
Posted by Murray ZL1BPU on November 24, 2005 at 17:39:22.
Hi folks,
I've been able to catch a used but damaged high power commercial LF transmitter, a Southern Avionics SC1000 DGPS USCG. I think it should be possible to make it operate on two or more of the 136, 180 and 500kHz Amateur bands. I am hopeful of also getting the manuals for it.
What I really need is some inside advice on how to go about the conversion, and of course since it's not a commercial installation, I can hardly pester the manufacturer directly! Do any of you work at Southern Avionics, or a service agent, or know someone who does or did?
Any advice would be very welcome. Re: NVIS
73,
Murray Greenman ZL1BPU
Posted by Scott Tilley, VE7TIL on November 25, 2005 at 03:41:46.
In Reply to NVIS posted by John Andrews on November 23, 2005 at 15:13:35.
Steve, VE7SL and I discovered last summer that at short range (<100km) and in a mountian valley could not hear his beacon at all during daylight, no groundwave signal at all. However, as soon as darkness decended his beacon burst out of the noise and we could conduct CW crossband QSOs 599 all around. We tried this with me in various portable QTHs in the mountians and noted the same thing every time. All at distances under 200km. This has lead us to plan more focused experiments into enhancing NVIS like antennas on LF this coming summer so stay tuned...
73 Scott VE7TIL Re: NVIS
Posted by J. Jason Wentworth on November 25, 2005 at 09:37:42.
In Reply to Re: NVIS posted by Scott Tilley, VE7TIL on November 25, 2005 at 03:41:46.
Scott, the results you described sound like classical NVIS. It may be very surprising what only 1 watt can do in this mode on LF with an NVIS-optimized antenna.
I recently corresponded with a ham who tried out his 150 milliwatt Pixie II 80 meter transceiver with a chest-high dipole hung on bushes (and no matching network between the dipole and the transceiver). He clearly heard and was clearly heard by hams up to about 250 km away.
He said that he heard no hash or static, and at first he thought there was something wrong with his radio--then he realized that his low dipole simply couldn't "hear" noise sources outside the upward-pointing lobe. With NVIS, the signal-to-noise ratio is more important (up to a point) than the output power. -- Jason
Re: NVIS
Posted by John Davis on November 25, 2005 at 12:07:31.
In Reply to Re: NVIS posted by J. Jason Wentworth on November 25, 2005 at 09:37:42.
Indeed, Scott's results over a span of 100-200km are characteristic of NVIS. However, most LowFERs are not positioned in locations where such coverage is that difficult by groundwave. I would thus not expect a lot of "surprising" results.
And while NVIS can be a useful tool at LF in non-average circumstances such as mountain valleys, bear in mind that at these frequencies D-layer absorption is still a significant factor in the daytime. This generally limits the usefulness of high-angle LF ionospheric propagation to hours of darkness...which Scott and Steve also observed.
Then there's the matter of the antenna. No vertically polarized antenna can radiate significantly within a few degrees of the zenith, which is what one would need for NVIS at distances appreciably less than 100 miles. (Short verticals have enough high angle radiation for the first hop to land at or about that distance, but not much less.) Horizontal antennas are notoriously poor radiators at LF, groundwave or skywave. The reflection from the earth directly beneath the antenna is almost exactly 180 degrees out of phase with the antenna radiation, thanks to the miniscule fraction of a wavelength separating the two.
Under the Part 15 limitation of a 15m total length of wire, I'm more than a little skeptical of overcoming that drawback; however, hams and Part 5 stations have more room for experimentation. Re: unknown beacon
Posted by John Davis on November 25, 2005 at 12:23:10.
In Reply to Re: unknown beacon posted by Brian Wingard N4DKD on November 24, 2005 at 14:14:46.
Excess letters in the identifier, especially when those are 'short' letters consisting of a relatively few dits and dahs, sounds very much like what's called negative keying. This is an unintentional fault in the beacon.
Check out Chapter 9 of Sheldon Remington's On The Art of NDB DXing for a technique for sorting out the correct ident.
This article is just one of the resources available to beacon hunters listed on the LWCA Longwave Home Page. Re: unknown beacon
Posted by karl on November 26, 2005 at 09:34:36.
In Reply to Re: unknown beacon posted by John Davis on November 25, 2005 at 12:23:10.
The N and the A sounded good, but the E-T-E were "unusual" sounding. Thanks for the info lowfer beacons
Posted by Steve Hobensack on November 26, 2005 at 15:55:54.
I am hearing lowfer beacons on 137 and 185 khz. How does one obtain an email of the operator to send a report? Thanks. Re: NVIS
...Steve...N8YE
Posted by Alan G3NYK on November 26, 2005 at 18:18:36.
In Reply to Re: NVIS posted by J. Jason Wentworth on November 25, 2005 at 09:37:42.
Hi again Jason dont get so hung up about a few milliwatts at 80...do some calculations. Chest height...say 1.5 metres ... at 80 metres is the equivalent of a wire at 90feet on 136kHz, higher than most lowfer or part 5 tops. This will radiate very well, but you will have to put several hundred watts into it to RADIATE 150mW ERP upwards. It will not radiate upwards very efficiently at LF. It will however put out a bruising strength ground wave. It will probably be out at a range of about 300 miles before the skywave aproaches the groundwave strength, then you will get deep fading.
My appreciation of "NVIS" is as a daytime mode and uses frequencies close to the LUF where absorbtion is less important. You wont hear much daytime NVIS on 160m.
Yes at night you will get LF reception by skywave close in as the absorbing D-layer disappears (unless there is geomagnetic disturbance). But unless you are heavily screened from the transmitter, the ground wave should be much stronger. Many operators use "poor" antennas for receive on 160m because it is not necessary to have a sensitive antenna....loops can be very popular and they are about 20dB down on a dipole, or Marconi.
I can receive a "beacon" station 500 km away here on my grounded counterpoise, 6 inches above ground, at a strength which is only 20dB down on my Marconi (450 foot meander top at about 45 feet). BUT the ground "skin depth" could be as much as 15 to 20 feet at 136kHz.
73 de Alan G3NYK
"Ground dipoles" do work as a sadly now deceased amateur in the UK proved many years back. He got reports over ranges up to 100 to 150 miles, with relatively low powers (50-100 W I believe).
Re: lowfer beacons
Posted by Webmaster on November 26, 2005 at 18:42:43.
In Reply to lowfer beacons posted by Steve Hobensack on November 26, 2005 at 15:55:54.
Steve,
If the operator has an e-mail address, you'll find it in our Operator Contact Info data.
From the Longwave Home Page, click the Low/Med/HiFER link, then Operator Info in the menu at the bottom of that page.
John Re: lowfer beacons
Posted by John Andrews on November 26, 2005 at 18:48:12.
In Reply to lowfer beacons posted by Steve Hobensack on November 26, 2005 at 15:55:54.
Steve,
The best resource is the Operator List on the LWCA site: http://lwca.org/sitepage/part15/index-call.htm
If you regularly access this Message Board, use http://lwca.org/lobby.shtml as your entry point, and you will see the various options for the beacon and operator lists. Be advised that some of the frequencies may change and not be reflected on the list. You should see links to the various web pages of the operators, however, and they usually keep their information up to date. In my case, WD2XES has been on three different frequencies in the past three days, but those have been reflected on my web site.
John Andrews, W1TAG/WD2XES
Re: unknown beacon
Posted by Michael Oexner on November 26, 2005 at 18:49:36.
In Reply to Re: unknown beacon posted by karl on November 26, 2005 at 09:34:36.
The following was recently posted on the NDBLIST reflector:
"NAETE" is XEN-395 miskeying. It has been doing this for several
weeks now. Its keyer has obviously departed for a better world.73,
Andy Robins KB8QGF
Kalamazoo, Michigan USA
vy 73 + gd DX,
Michael
NDB's
Posted by Steve/N8YE on November 27, 2005 at 09:44:58.
Across the NDB beacon area of the low frequency band, my Argo viewer shows carriers that seem to be spaced at 500 cycle intervals more or less. Some carriers are strong, some are weak. My viewer showed lowfer yho just a couple cycles away from one of those carriers. Without the bfo, there is just a steady drone of 500 cycle noise mixed with the NDB's. Where do these carriers come from? Are they part of the NDB system? Why do they extend well below my lowest logged NDB beacon DIW? I don't think it is intermod/overload as my Sony2010 has it in the boonies. Re: NDB's
Thanks
Steve
Posted by John Andrews on November 28, 2005 at 16:17:05.
In Reply to NDB's posted by Steve/N8YE on November 27, 2005 at 09:44:58.
Steve,
The carriers must be some sort of local interference. I don't have any experience with the Sony 2010, but am curious what you are using for an antenna with it, and whether you have tried relocating the antenna away from other electronic equipment.
John Andrews
DI2AG on 440 kHz
Posted by Frederick Raab on November 28, 2005 at 21:06:43.
Walter Staubach DJ2LF has an experimental license to transmit on 440.044 kHz. He has reception reports from all over Europe, but so far none from North America. His license expires on Dec. 31 so he invites you to listen for him before then.
DI2AG transmitts 24/7. Usually the ERP is 0.4 W and he has recently been transmitting PSK-31.
During December, he will be transmitting QRSS30 with 4W ERP from 2300 to 1000 GMT on friday/saturday, saturday/sunday, and sunday/monday evenings to facilitate Trans-Atlantic reception.
You can contact him at .
73 de Fritz W1FR Re: NDB's
Posted by Jacques d'Avignon on November 29, 2005 at 11:16:27.
In Reply to Re: NDB's posted by John Andrews on November 28, 2005 at 16:17:05.
Good morning:
Those carriers might be coming from a tape recorder or a VCR or a fax machine on standby. I have had the experience of a 2010 being badly interfered by a Sony tape recorder being on standby.
Jacques
Re: unknown beacon
Posted by karl on November 30, 2005 at 06:09:32.
In Reply to Re: unknown beacon posted by Michael Oexner on November 26, 2005 at 18:49:36.
thanks for that info Michael. that is so funny how the keyer broke up the original letters into new ones. karl
Re: DI2AG on 440 kHz
Posted by Walter Staubach on November 30, 2005 at 08:12:39.
In Reply to DI2AG on 440 kHz posted by Frederick Raab on November 28, 2005 at 21:06:43.
Dear friends, Anyone looking for a Braun T1000
please let me add: The licence for DI2AG is now valid to Dec.31 2006, so there will be enough time for experiments and hopefully crossing the atlantic.
Locator is JN59NO, 15Kms north of Nuremberg. I will begin 4W ERP Dec, 2nd at 2200Z. You can also use DI2AG@fen-net.de
73 Walter DJ2LF
Posted by dennis stallt on November 30, 2005 at 11:42:45.
Hi,
I just wanted to spread the word that I have put my Braun T1000 on e-bay today(Nov 30 2005).
My selling name on e-bay is dalphabet but I’ll bet just entering T1000 will show the auction (there aren’t too many of the around!).
Below is some info about the radio. I hope my posting this doesn’t upset anyone, I just wanted to match a radio lover with a radio. Thanks.
This radio is in great shape, it works great and it'll look great in your abode, be it humble or a mansion. Icom R75, Palstar R30CC and AOR 7030+
I have tried to photographically show any scratches or blemishes but they maxed me out at twelve pictures. Everything is very minor as you can see.
It comes with the owners manual, a schematic of the electronics a guarantee card, the stub from the warranty card (I assume it was sent in) and some other piece of Braun papework
Unfortunately I can't find the a/c cable or the olive drab cover that came with the radio. You should be able to get a cable somewhere online or Radio Shack (I took a close up photo to show you what size you need. The width between the plugs is 7/16ths of an inch) and I will make you a promise: When I finish my final exams on the Dec. 19th, I'll tear the garage apart and do my best to find the cover. If I can't find it, I'll keep your address and send it to you someday when I do find it (it needs a little repair, I think I remember some of the seams had become undone- I don't think there were any tears though). I definitely have it somewhere so you will get it oneday.
Thanks.
Posted by Al on November 30, 2005 at 14:08:56.
Folks,
This may sound crazy (to some) but I am considering selling my Kiwa modified R75 and recently purchased Palstar R30CC - and getting an AOR 7030+ instead. I've been less than happy with the ability of these radios to DX NDBs.
Going by all of the currently available lab tests, it looks like the 7030+ would give me an edge for NDBs. I thought I would try to get some comments before I start the process of putting these on e-bay.
Any opinions would be appreciated.
Thanks,
Al
Re: Icom R75, Palstar R30CC and AOR 7030+
Posted by John Andrews on November 30, 2005 at 15:13:38.
In Reply to Icom R75, Palstar R30CC and AOR 7030+ posted by Al on November 30, 2005 at 14:08:56.
Al,
What sort of antenna are you using, and what is the problem you have been having? I don't know anything about the Palstar radio, but am pretty familiar with the R75.
John Andrews
Re: Icom R75, Palstar R30CC and AOR 7030+
Posted by Al on November 30, 2005 at 15:54:11.
In Reply to Re: Icom R75, Palstar R30CC and AOR 7030+ posted by John Andrews on November 30, 2005 at 15:13:38.
Mostly, I use a GMDSS antenna on the roof and various longwires (< 100 feet). The GMDSS antenna is made by RF Systems and uses a helical element and magnetic transfer technology. I usually use an antenna tuner or a good balun (by I.C.E.) with the various "long" wires. I also have an active loop that, to be honest, I haven't used all that much yet. It is designed for the longwave band. Re: Icom R75, Palstar R30CC and AOR 7030+
And my problem is: I just can't seem to hear distant beacons. For the average (low power) beacon, a couple of hundred miles seems to be my limit. I know that living in a (fairly)urban environment makes low band DXing practically impossible; but it's one of the reasons that I'm thinking the AOR7030+ will help.
Posted by karl on November 30, 2005 at 18:21:15.
In Reply to Re: Icom R75, Palstar R30CC and AOR 7030+ posted by Al on November 30, 2005 at 15:54:11.
I have been DXing NDB's using an R75 and a Kenwood R5000 and a Kenwood TS450S. I have found the R75 can hear as well as the other radio's. I have 8 antenna's and switching between them sometimes makes a ton of difference especially with man made RFI problems.
potrzebie