Re: Now Peter ^^Tsk, Tsk, Tsk
Hello Fellow LOWfers, and monitors: John I appreciate the time and effort you took to post an answer to my question. Yes, it is a lot to absorb, but NOT TOO DIFFICULT TO DO SO. Re: Nice to hear from you
Peter; ease up just a smidgin there, remember this; most, if not all the guys who are, and allow me to use the phrase: " DOWN HERE " are technically competent enough, to get a grasp of " teckie type " articles. We're constantly talking about " ERP " vs " EIRP " "Isotropic"( imaginary ) radiator vs. " Actual physical radiator ", " dB " & " dBm ",
radiation in free space ( vaccum ) vs that of radiation in and through a physical conductor. Frequency matters, conductor circumference matters, wire spacing matters. That's why we study, ask questions, experiment, etc. We never get too old to learn. My engineering mentor told me many years ago that the mark of a good engineer, was not so much what he knows, but how quickly he can find out what he dosen't. Soak up what you can, squeeze it out, then soak up some more. 73, and by all means; everyone have fun!! Andy
Posted by Andy - KU4XR on June 02, 2008 at 09:13:42.
In reply to Re: Reception of " MP " in Friendsville, Tn. posted by KG4ENB on May 30, 2008
Hey Bryan; nice to hear from you. Yeah I get a kick out of this LF stuff. I wonder if we have possibly talked on 10 meters before ? your call dosen't go " Ding " with me, but that don't mean we haven't QSO'ed before. Technically, I,m in Friendsville, but as far as I'm concerned, I'm in Maryville. I live off Morganton Rd. on Ratledge Rd. before you get up to the water tank. I'm sure you know where that is. I'm only about 10 minutes from Foothills Mall; if that ain't Maryville, you can't get no closer. ( hi hi ). Email me straight through, and let's chat awhile. Might get together and experiment some. 73, for now: Andy - KU4XR
John: - A new vertical question
Posted by Andy - KU4XR on June 02, 2008 at 09:40:53.
Thinking about the heigth of the feedpoint above actual ground, the question comes to mind; " how high is high ? " 3' - 6' - 12'; how high above ground would the feedpoint need to be at these frequencies for ground losses to diminish somewhat. This thought just came to mind today; What about a Rhombic style vertical with a short tophat ?? In the olden days, the low frequency BC stations would use the " diamond shaped " tri-leg towers to physically shorten the towers height, but still be almost the same electrically. In LOWfer cases, say a 40 foot leg ( 20' X 20' ), with a 10' tophat. The wider the spreaders,( to a manageable extent of course ), the shorter ( physically ) the antenna. Using lightweight PVC pipe and strong wire to maintain tension, the shorter antenna could be mounted on a metal mast ( insulated of course ) say 10 feet above ground, the " ATU " or " Doghouse - if you prefer " mounted directly underneath, and grounded to the mast, all the transmitting components could be mounted inside the box, by now you get my idea. - - - - NOW; for the theorectically arguable question; Would the 10 foot heigth of the feedpoint make any difference in ground losses in your opinion ?? What say Ye ?? 73, Andy - KU4XR
Re: John: - A new vertical question
Posted by John Davis on June 03, 2008 at 08:48:18.
In reply to John: - A new vertical question posted by Andy - KU4XR on June 02, 2008
Certainly do-able, if I understand correctly what you are proposing. In such a case, though, the pole elevating the transmitter has to be counted as part of your ground connection and taken into account in overall length. However, it's not going to cost you anything, radiation-wise, for reasons we'll discuss shortly.
(I notice on the QTH reflector there's been some talk about not taking that term "length" too literally, but that IS the word used in the Rules.)
There are advantages in making the conductor of the radiating element as large in diameter as possible, mainly related to increasing the capacitance to ground and thus requiring a smaller loading inductor. However, a top hat has this same effect -plus- increasing the effective height.
The diamond taper of old-time broadcast towers was not a good solution to skywave control (its purpose there, rather than achieving resonance) and is no longer used commercially. In an electrically VERY short situation such as we face, its main drawback is that the wide part in the middle causes partial electrostatic shielding of the upper half of the radiator from the ground. This increases current somewhat in the lower portion, but decreases it further out toward the end... not the result we're after. Much better, IMO, to concentrate on the top hat.
As for elevating the transmitter/tuning components, effectively making them part of the antenna, that strikes me as a good idea. In an electrically short vertical, the electric field dominates the near-field region. It is strongest around that part of the radiator on the "hot" side of the loading coil because, at resonance, that's where the voltage is highest. If you move that region up and away from vegetation and other objects that interact with the electric field, you should reduce losses from power absorbed by those objects.
It's somewhat like what we discussed earlier about having loading coils midway up the antenna, but without the potential awkwardness of having to count wire length in the coil as part of the antenna rather than transmitter.
Now, about that bottom 10 feet of mast: it becomes your ground system connection for the transmitter, but that's OK. It radiates too. Remember, the same current flowing from the transmitter into the base of the antenna is flowing through that ground connection--and in the same direction. Furthermore, that mast is on the "cold" side of the tuning coil and has very low voltage with respect to ground. Stuff in its immediate vicinity will thus have very little effect on losses or tuning.
John
Beacon identification
Posted by Ted on June 04, 2008 at 04:27:06.
Hello, I'm very ignorant about longwave. I'm living here in Phnom Pehn Cambodia and recorded a morse code being broadcast on 378khz. I was wondering what it says and if anyone can tell me were it's coming from and what it's purpose it. If you're interest in hearing it please send me your email and I'll attach the short audio recording for you. Thanks! Ted
Re: Now Peter ^^Tsk, Tsk, Tsk
Posted by Peter B on June 04, 2008 at 09:10:59.
In reply to Re: Now Peter ^^Tsk, Tsk, Tsk posted by Andy - KU4XR on June 02, 2008
Hmm, John it does seem someone has taken to being the (your?) nexus to this List as well as a finger wagger. Appointed? Seems to exhibit nascent illusions and possessive inklings, to wit, "an answer to >my question<...."
May I remind this poster that This is a public forum where personal pronouns can become tiring and divisive, a subtly lost to some?
Additionally, speaking for ALL: "Peter ... remember this; most ... the guys are 'DOWN HERE' are technically competent enough." Wow, had not a clue there.
Then by what measure, Mr.? And so by implication, never a curious newbie, a budding novice will open these pages for a look see, an intro into the rare world of LF--and be lost in hypertext? Wow again. My, how prescient an observer.
But rather than bluster on about "ERP' vs 'EIRP' " and ‘Isotropic’..." it might be a worthy exercise to flesh out the nuance of the paragraph at issue. Com' on, let's hear your take.
My take
Posted by Andy - KU4XR on June 04, 2008 at 10:51:08.
In reply to Re: Now Peter ^^Tsk, Tsk, Tsk posted by Peter B on June 04, 2008
Hey Peter; ( and anyone else who may read this ) I don't have a clue as to what " my take " refers too. I guarantee everyone that I'm not interested in a " Spittin contest " in any form. Made that mistake before, will try not to again. " snippets " are dangerous little bits of part statements, rather than the whole comment. My main point in the last post was " You never get to old to learn " Your very profession in trade should be a testament to that. If I'm not mistaken, I believe your are a college professor??, and yet your words seemed to discourage in-depth discussions on topic! And you certainly don't use small words in your posts either, ( very confusing choices in wording at times ).In real life, If I don't understand a word, or concept; I use whatever resourses are at my disposal to learn about it. *** I asked a question, John was the only one who took the time to give an answer, and quite in depth. Your followup post wasn't even an answer to my question. So, possibly consider going back to my original post, reading it, and for the sake of the " Newbies " by all means, if you can, Condescend, and post a Novice level answer - ON TOPIC -. If your choice is rather to be verbally combative towards me directly; Keep it off the list !!! I have an email address, contact me direct. I will listen to your opinion " Once " , and will give you mine " Once ", and then drop it! After one time, it becomes argument / debate, and no longer opinion. Words strike harder than a fist, and once spoken, or written, can't be taken back, I try to choose mine carefully. Have a great day, and enjoy the hobby: 73, Andy - KU4XR
Re: Beacon identification
Posted by Andy - KU4XR on June 04, 2008 at 11:17:54.
In reply to Beacon identification posted by Ted on June 04, 2008
Hello Ted: try going to this web address and reading some. It might tell you what you want to know: " http://en.wikipedia.org/wiki/Non-directional_beacon " Copy and paste it into your address bar in your browser, hit enter and it should go there. If the morse code seems to be the same sounds over and over, with short pauses in between the transmissions, it's likely to be an NDB. If this dosen't help you, then post back again and someone may be able to help you find out. 73, Andy - KU4XR
Re: Vertical Antenna Questions (long)
Posted by John - AB4MS on June 09, 2008 at 07:21:00.
In reply to Re: Vertical Antenna Questions (long) posted by Peter B on May 31, 2008
Sorry,I've been away for a few weeks. I just can't go anywhere without all Hell breaking loose. Sheesh! ;)
BTW Peter, I thought John did an excellent job explaining short vertical antenna theory, in a nut shell. Basically the "Cliff Notes" version but, it works for a discussion group concentrated around a hobby.
Next time John, throw in some of Maxwell's equations to keep the intellects happy. I'm sure you're all too "fimiliar" with them.
Regards Re: Beacon identification
John
Posted by Michael on June 10, 2008 at 01:27:42.
In reply to Beacon identification posted by Ted on June 04, 2008
Hi,
Most likely you were listening to an NDB (nondirectional beacon) transmitting from Phnom Penh on a frequency of 376 kHz. It's callsign is PNP which in Morse Code looks like .--. -. .--.
Does this match your recording?
vy 73 + gd DX,
Michael
Question about decade counters
Posted by Andy - KU4XR on June 12, 2008 at 11:21:24.
Hello Fellow LOWfers: - Would someone explain the difference in a Decade Counter, and a Johnson Decade Counter ( 4017 series ), such as, how it performs its job in the circuit. I am gathering the parts to build a Kohler special, and he uses the 4017 series. Will any type of decade counter work, or does it really NEED to be the 4017 or equivalent chip ?? Thanks for the info; Andy - KU4XR
Re: Question about decade counters
Posted by John Davis on June 12, 2008 at 20:18:17.
In reply to Question about decade counters posted by Andy - KU4XR on June 12, 2008
A Johnson counter is a "ring" counter. It can have a separate output for each count up to the maximum for which the device is configured. For a decade counter, there would be 10 outputs, each of which goes high (or low) in turn as the count travels around the ring. That is, the first output changes state at the first clock cycle; at the next clock, the first output returns to normal while the second output changes state; at the third clock, the third output changes state while the second one returns to normal and the first one remains normal...all the way to the tenth output, when it starts all over again with the first output.
Not all ring counter ICs make all count outputs available to the user, of course, depending what they're designed to do. But that's the principle on which they work, rather than, say, outputting Binary Coded Decimal from J-K flip-flops configured to give the same division ratio.
If one's goal is simply to divide a frequency by 10 and it makes no difference what the duty cycle is, then one decade divider is as good as another (within the same logic family, of course). I'll have to look up Lyle's circuit and see if that's the case there or not.
Re: Question about decade counters
Posted by John - AB4MS on June 13, 2008 at 13:41:53.
In reply to Re: Question about decade counters posted by John Davis on June 12, 2008
My take is Lyle used the 4017 because it's a CMOS device and Vcc can be +12VDC. Other devices such as TTL will use +5VDC and would require a regulator or separate supply.
It simplifies matters when your logic and final can use the same supply. Towers of former Public Emergency Radio of the United States
Posted by Harald on June 16, 2008 at 04:01:51.
Do the towers, which were built for the Public Emergency Radio of the United States at Ault, Colorado and Cambridge, Kansas ( http://en.wikipedia.org/wiki/Ault_Public_Emergency_Radio_Tower ) still exist? Re: Towers of former Public Emergency Radio of the United States
Where are/were they exactly located?
If yes, for what purpose are they used? Were these towers ever used for GWEN?
If these towers do not exist any more, when were they demolished.
Posted by Scott on June 17, 2008 at 07:37:05.
In reply to Towers of former Public Emergency Radio of the United States posted by Harald on June 16, 2008
Harald,
I'm sorry I have no further information on this system for you, however it does sound quite intriguing. At first I thought you were referring to the GWEN system, but on reading the Wikipedia article I see it was not the same. The article's comment: "The system was determined to be impractical and never implemented" is open to debate. The European utilization of LW for broadcasting to an entire continent seems to be working quite well, say for the last 80 or so years, to present! Please post us if you learn anything more about this system. Scott NM8R Michigan, USA Re: Towers of former Public Emergency Radio of the United States
Posted by John Andrews, W1TAG on June 17, 2008 at 10:16:28.
In reply to Re: Towers of former Public Emergency Radio of the United States posted by Scott on June 17, 2008
Scott, Harald,
This topic keeps coming up. If you do some keyword searches on "WGU20" or "DIDS", you will find plenty of information. The latter acronym stands for "Decision Information Distribution System". As Scott points out, it was not related to the later GWEN network.
I am not a fan of the Wiki site, as it contains a large amount of misinformation and speculation. In this case, I can find no other source claiming that those two towers were ever built. The only DIDS operation that any of us ever heard was from WGU20 in Maryland on 179 kHz, about 30 years ago. I don't believe that the "network" was ever created.
The Wiki article is quite correct in saying that the system was impractical as it was conceived. Without that long history of LF broadcasting, there were very few LF radios in the U.S. in the 1970's. The plan was to build LF warning radios into TV sets, but I suspect that the planners found some difficulty in integrating CRT-type TV's and LF receivers with self-contained antennas. Buzzzzz...
Anyway, do the web searches and don't be overly reliant on the Wiki articles. Some of their authors have probably lived in underground bunkers since the 1950's.
John Andrews, W1TAG
Re: Towers of former Public Emergency Radio of the United States
Posted by John Davis on June 18, 2008 at 00:58:58.
In reply to Re: Towers of former Public Emergency Radio of the United States posted by John Andrews, W1TAG on June 17, 2008
John A. writes: "I am not a fan of the Wiki site, as it contains a large amount of misinformation and speculation. In this case, I can find no other source claiming that those two towers were ever built."
Same here...and as I presently happen to be very close to Cambridge, Kansas, specifically to research this very matter, I'm beginning to have even more doubt of their existence. We do know that WGU-20 was the only one ever to place a transmitter on the air; and despite some of the odd things our government has been known to do, building multimillion dollar broadcast towers on the off chance they might someday be needed is not one of the more common occurences.
PER was definitely not practical for its intended purposes, for the very reasons John states. In addition, it would have been very susceptible to outage from nuclear attack. The towers of GWEN, by contrast, were scarcely a quarter of the height and were hardened to withstand anything but a direct strike.
John Re: Towers of former Public Emergency Radio of the United States
Posted by Harald on June 18, 2008 at 15:43:39.
In reply to Re: Towers of former Public Emergency Radio of the United States posted by John Davis on June 18, 2008
What facts speak against the possibility that the towers were sold to broadcasting companies after one stated that the LF emergency system was impracticabel? Re: Towers of former Public Emergency Radio of the United States
These companies would have transformed this towers into FM-/TV-broadcasting towers.
Posted by John Andrews, W1TAG on June 18, 2008 at 18:43:38.
In reply to Re: Towers of former Public Emergency Radio of the United States posted by Harald on June 18, 2008
1. The towers you referenced were never built.
2. Had they been built, they would have been owned by the federal government on government-owned land. It's highly unlikely that the land and tower would have been sold to a private company.
John Andrews, W1TAG
simple beacon transmitter
Posted by Rick KA2PBO on June 19, 2008 at 20:49:03.
Hi ALL,
Does any one have a copy of Mike Mideke,s "simple beacon" schematic? I found articles on how to modify it but would like to find the original.
Re: simple beacon transmitter
Thanks
Rick KA2PBO
Posted by jim vander maaten on June 22, 2008 at 16:56:52.
In reply to simple beacon transmitter posted by Rick KA2PBO on June 19, 2008
I found what you are looking for in '1750 meters western update #53' dated March 1, 1988.
I'll be glad to scan it and e-mail to you.
73 jim Re: simple beacon transmitter
Posted by Webmaster on June 23, 2008 at 19:03:26.
In reply to Re: simple beacon transmitter posted by jim vander maaten on June 22, 2008
Thanks to Jim's generosity, we have been able to archive the article as a compact PDF file for your convenience:
MidekeSimpleXmt.pdf
Re: simple beacon transmitter
Posted by Rick KA2PBO on June 25, 2008 at 18:31:21.
In reply to Re: simple beacon transmitter posted by Webmaster on June 23, 2008
Thanks much Jim!!And thanks to the webmaster and everyone else who makes this great site possible.
SAQ Copied At Scituate,MA
Rick
Posted by Kevin Norton N1NQC on June 29, 2008 at 10:39:43.
SAQ copied at Scituate,MA at 29 0900Z JUN 08.
Heard EXTREMELY weak bits and pieces, but definite copy . Thor was VERY angry, so the static crashes were HORRIBLE.
When the tape was played back and cleaned up w/ two graphic equalizers in series, copy was "better" but still weak to very weak. Some letters "sort of" picked out , with an especially clean and clear example of the letter O.
There seemed to be just few minutes of sending, then nothing else was heard.
Overall VERY rough going. Antenna was a 2000 ft. longwire in the shape of the letter J laid out along the dune base. Counterpoise was about 500 ft long down the salt water with about 50 or 100 ft of bare copper actually in the ocean .
Receiver was an Icom R-70 quad conversion set at 4.017.2 using an LF Engineering L-111 up converter.
Using my "monster" loading coil didn't really make much difference (oh well).
Also the use of coupling cap from ant to L-111 input made no difference either.
No broadcast QRM and no local QRM from 150 watt field day transmitters (which about 300 to 500 ft from the far end of my antenna).
Many thanks to my host Dale and all the boys at the event.
de N1NQC
potrzebie