File Attachment 1: QRSS_WSPR2_22_m.jpg
KiwiSDR WSPR2 Received Spots Distance Map
Attached is a KiwiSDR WSPR2 received spots distance map. These stations over the course of a day provided >90% reliable reception for my 22 m WSPR2 propagation beacons. It's generated using wspr.aprsinfo.com and I did editing using Adobe Photoshop (the free GIMP equivalent is good, too). K3SIW's WSPR2 beacon overlays the same areas but I suspect that his would be received farther south, but I'm only interested in where mine signal is "landing" ;)
There aren't many KiwiSDR's north of the US/Canada border so I have no idea if I flip the curve and assume it's symmetrical on the north side, too. My sloping dipole signal really improves and gets stronger when the terminator is between me and VE7 land and reception continue's on until VE7GL's local sunset when it abruptly cuts off. Reception starts on the east coast after my local sunrise.
I have noticed that when K3SIW is strongest, I'm weakest (fade out) and when I'm strongest K3SIW is weakeast (fades out). But sometimes were are neck and neck. We both transmit our WSPR2 beacons in the same time frame and have very close longitudinal solar times so I can objective comparisons with the SNR with the distance being the only real variable difference.
Since I still have a small dataset, I'll need a few more months before I can do a proper model but VOACAP has been pretty spot on using my virtual 20 m WSPR2 100 mW model (I model with isotropic antennas and use the actual daily SSN. Then that's scale to my real-world sub-5 mW WSPR2 signal on the 22 m band and so far, it seems to work. I haven't had any days in January where I couldn't monitor my signal during the daylight hours most of the time using a remote KiwiSDR in this map.
73.
73.
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File Attachment 1: QRSS_WSPR2_22_m.jpg
Re: KiwiSDR WSPR2 Received Spots Distance Map
Oh, forgot to mention that the line I've drawn seems to be the "sweet spot" corridor where any station along it or close to it should receive and decode my WSPR2 signal. But if you are too far north or south -- "no joy" -- as we say in Upper Canada. The reception pattern may wander a bit north/south but most of the time it seems to sit in this reception "sweet spot" corridor. If I didn't know any better, I'd say that it's flowing with the Jet Stream weather patterns over the Central US!
73.
Hifer VAN off air until further notice
Posted by jimvm on February 03, 2021 at 19:56:32.
My Hifer beacon will be off the air until I can repair my backyard fence that blew down two weeks ago.
Re: KiwiSDR WSPR2 Received Spots Distance Map
Posted by Ed Holland on February 03, 2021 at 21:03:08.
In reply to KiwiSDR WSPR2 Received Spots Distance Map posted by Robert, VA3ROM on February 03, 2021
Hi Robert,
Nice Work in making some objective observations. I will keep an ear out for ROM, but there seems to be a lull in reception at the moment. Last weekend was rather quiet, according to the data I collected.
I am interested in getting a WSPR signal added to PVC, but this would need quite a bit of thought and learning on my part. The signal generator I use as a master oscillator is programmable, so the potential is there, but I lack the knowledge of how this would be achieved in practice.
73
Ed
Reminder: Lowfer net +/- 3927Khz Saturday morning 0800 California time
Posted by Jerry Parker on February 05, 2021 at 15:17:19.
Reminder: Lowfer net +/- 3927Khz Saturday morning 0800 California time
Or listen online at kfs:
http://69.27.184.62:8901/?tune=3927lsb
or
KPH Point Reyes:
http://198.40.45.23:8073/
or
Utah Web sdr:
http://www.sdrutah.org/websdr1.html
If you cannot get into the net on 80 meters you can listen on KFS and participate by sending net control your thoughts to wa6owr@gmail.com
73
HF Radio w/ decent LF receive
Jerry
Posted by Brian on February 07, 2021 at 17:47:24.
What in everyone's opinion is the best HF Radio with decent LF/MF receive for 2200,1750 and 630 meters?
Re: HF Radio w/ decent LF receive
Posted by John Davis on February 07, 2021 at 20:58:25.
In reply to HF Radio w/ decent LF receive posted by Brian on February 07, 2021
A potentially loaded question! :) By "HF radio," do you mean ham transceiver? If so, ICOM, Kenwood, and Yaesu all have what could be described as decent LF receivers, provided you can give them an electrically quiet antenna at 50 ohms impedance; but my own personal preference that I'm hoping to acquire very soon is a Kenwood TS-590 with the OCXO option.
Re: HF Radio w/ decent LF receive
Posted by Robert, VA3ROM on February 07, 2021 at 22:52:15.
In reply to Re: HF Radio w/ decent LF receive posted by John Davis on February 07, 2021
Loaded and how!
Do you want a traditional analog receiver or an SDR receiver? Do you want it a stand-alone SDR or computer controlled only? It's really 80% antenna and 20% receiver.
I like my RSPDuo SDR but a lot of people don't like to have to tie up a computer with SDR's. My CCW small active half-wave vertical does a good job for VLF at 25 kHz or so and up to 14 MHz. My active small loop is better above 14 MHz.
The other option is an upconverter and SV1AFN makes two excellent VLF/LF upconverters DC-120 kHz (for the listening to the natural sounds of lightning, VLF beacon and time signal stations like WWVB) and DC-520 kHz (for what you want and very popular with the NDB chasing crowd). Normally, the LO output is 10 MHz (10.147 MHz = 147 KHz) and so you can feed any old frequency stable decent analog receiver with the upconverted signal. You can change the LO but I'm not inclined to open the thing up while it's under warranty. See www.sv1afn.com for all the technical details.
I have the DC-520 KHz version and use it with my FT857D. For the money and features, it can't be beat. SV1AFN also sells a 10 MHz bandpass filter (which I also have) so you can feed the upconverter 10 MHz LO into it and then into your receiver for even better performance. I'm far enough away from both WWV and WWVH that there's no issue with them mixing in with the upconverted signals. Again, I use the CCW active small half-wave vertical (it has an Owen splitter feeding two separate antenna out ports.
I'm sort of on the fence with computer-only controlled SDRs and so I have a mix of each but I'm more analog by nature and still prefer the sweet smooth even harmonic audio of tube amps.
73
73
Re: HF Radio w/ decent LF receive
Posted by Robert, VA3ROM on February 08, 2021 at 14:40:35.
In reply to Re: HF Radio w/ decent LF receive posted by Robert, VA3ROM on February 07, 2021
CCW = Cross Country Wireless. Great products, too.
T 13563.45 and KFS Omni Ant.
Posted by Bill Hensel on February 08, 2021 at 16:29:11.
At 1628 utc T is blasting into KFS Omini Antenna sometimes reading S2
Re: HF Radio w/ decent LF receive
Posted by John Davis on February 08, 2021 at 23:04:50.
In reply to Re: HF Radio w/ decent LF receive posted by Robert, VA3ROM on February 07, 2021
Robert adds some other thoughts to the mix, Brian. Perhaps what we need to know before we throw too much information at you is, what else do you want to do with the radio, beyond listen to the longwave ham bands? Are you in general more digitally or analog inclined? And, are you wanting a radio that's pretty much self-contained and all-purpose in nature, or will it be just one part of a more elaborate (existing or planned) setup? What price range? New only, or is used gear an option?
With knowledge of these factors, we can all probably offer more relevant or specific suggestions for your situation.
2200 meters 136.450 khz QRSS 30
Posted by Lee on February 09, 2021 at 22:05:42.
Getting ready to go to intermittent / by request on air duty till next season. Thanks to all who spent time looking. If you want to make sure I'm up for a receive session send me an e-mail. Lee KE6PCT.
Daytime EAR
Posted by Rick KA2PBO on February 09, 2021 at 23:30:59.
The T-storms in the gulf have been making a mess of things for normal nighttime monitoring so thought I would park on EAR's frequency for a few days. We are only 300 plus miles apart so I expected signals to be little better but I did get copy yesterday and today.
https://www.dropbox.com/s/s9fx7nquf2r3285/ear%201%20pm%20feb%208%202021.jpg?dl=0
Rick
Re: HF Radio w/ decent LF receive
Posted by Ed Holland on February 10, 2021 at 02:00:06.
In reply to HF Radio w/ decent LF receive posted by Brian on February 07, 2021
I've experimented with a few conventional receivers for LF/MF Three things I have noted:
1) Receivers with vacuum fluorescent displays often suffer internally generated interference. JRC NRD 525 and NRD 535 are both prone to this, but technically are only specified to 90 kHz, and the "quirk" is most notable in this range.
2) Overload from MW broadcast can affect 630 m and 2200 m, depending on the quality of preselector circuitry, and first mixer performance. This can be overcome with a little ingenuity.
3) Stability (and precise tuning) will be important if you are interested in very slow modes. I have no real experience here beyond some basics, but temperature compensated (TCXO) or temperature controlled oscillators would be preferred.
When experimenting with 2200 and 1750 m listening, the biggest issue has been noise. I have found isolating transformers on feedlines to be very helpful against self inflicted noise from the house wiring, but there is still some neighborhood interference from things like switching supplies, dog fences etc. that are picked up by the long wire antenna. More experimentation in that department could improve results.
Cheers
Ed
Re: T 13563.45 and KFS Omni Ant.
Posted by Ed Holland on February 10, 2021 at 21:46:38.
In reply to T 13563.45 and KFS Omni Ant. posted by Bill Hensel on February 08, 2021
Thanks for the update Bill,
I'll add T to my checklist for the weekend's listening.
Re: Daytime EAR
Posted by John Bruce McCreath on February 12, 2021 at 15:40:03.
In reply to Daytime EAR posted by Rick KA2PBO on February 09, 2021
Hi Rick....sorry for the late response. My iMac was at the service reps yesterday getting more RAM added.
Thanks for the nice daytime Argo screenshot. The signal strength seems consistent across the screen.
73, J.B., VE3EAR Re: hifer now
Posted by swlem3 on February 12, 2021 at 17:34:54.
In reply to hifer now posted by swlem3 on January 31, 2021
Propagation again looking good at time of writing. Hifer wspr2 SIW just decoded here at a -12 db.
QRSS Knights Winter 2020
Posted by Robert, VA3ROM on February 13, 2021 at 17:49:57.
The QRSS Knights group has put out an annual QRSS Compendium for the past 3 seasons.
The 2020 issue has a blurb on 22 m HiFER; a simple up-converter circuit using a 10 MHz LO and mixer, a couple of 2N3904's and VLF/LF filter; low bands antenna design and so on.
There are other excellent articles in the previous 2 years. I downloaded 2018 and 2019 but forgot I had them on my HD until I was doing some housekeeping today. Can't even remember downloading them!
They can be found together here at the top of the list.
https://qsl.net/g0ftd/other/misc/
Even learned a few more new things about the QRSS world, too!
Re: QRSS Knights Winter 2020
Posted by Robert, VA3ROM on February 13, 2021 at 17:56:15.
In reply to QRSS Knights Winter 2020 posted by Robert, VA3ROM on February 13, 2021
Also from Scott, AJ4VD's QRSS PLus Grabber website with more QRSS info.
https://swharden.com/qrss/plus/index.php?style=big
Re: HF Radio w/ decent LF receive
Posted by Paul N1BUG on February 14, 2021 at 01:42:33.
In reply to Re: HF Radio w/ decent LF receive posted by Ed Holland on February 10, 2021
I will concur with regard to frequency stability. The slow modes (best for DX) often require very low drift. For example, for the new FST4/W modes I believe drift during a 30 minute period should be less than 0.01 Hz for optimum sensitivity using the 1800 second transmission length.
Stability is a subject not often discussed and I was not fully aware what would be needed to satisfy my LF interests when I built my first 2200 meter station. I ended up starting over with ifferent equipment after I learned more about it.
Paul N1BUG
SDR utah
Posted by Lee on February 15, 2021 at 02:39:04.
It seems that SDR Utah is down. Anybody else noted this.
Re: SDR utah
Posted by John Davis on February 15, 2021 at 04:46:14.
In reply to SDR utah posted by Lee on February 15, 2021
Seems to be OK now. It's at a remote site, so brief power or internet outages can be expected there from time to time.
Re: SDR utah
Posted by Lee on February 15, 2021 at 06:57:58.
In reply to Re: SDR utah posted by John Davis on February 15, 2021
Thanks John. It came back for me. I suspect my browser was part of the problem.
Re: Hifer VAN back on the air
Posted by jimvm on February 16, 2021 at 18:37:35.
In reply to Hifer VAN off air until further notice posted by jimvm on February 03, 2021
Fence fixed and HIFER VAN back oh the air 24/7.
COIL 3.96
Posted by Brian on February 18, 2021 at 10:42:42.
The 96th revision of my Windows coil calculator has improved accuracy for self-resonant frequency and proximity effect. Results are much more accurate for short coils. N6LF is using the program to optimize high-efficiency loops for 2200-meter receiving arrays.
COIL calculates inductance and Q for solenoids made of solid or Litz wire. It models a number of copper and aluminum alloys and form dielectrics. The program handles dielectric ribs (Air Dux) or ridges (steatite), axial or radial leads, and U.S. or metric units. COIL can automatically maximize coil Q while keeping inductance constant. It can provide results as an RLC model for wideband circuit or antenna analysis. To validate accuracy, the documentation compares calculated values with hundreds of inductance and Q measurements made with an HP 4342A Q meter on dozens of coils.
http://ham-radio.com/k6sti/coil.zip
Brian
Re: COIL 3.96
Posted by Rick KA2PBO on February 18, 2021 at 23:29:05.
In reply to COIL 3.96 posted by Brian on February 18, 2021
The link is not working for . Anyone else able to use it?
Rick
VO1NA in PA
Posted by Rick KA2PBO on February 19, 2021 at 01:00:55.
Lots of static last night but was able to pull VO1NA out...somewhat. Sorry about the contrast settings. I usually use ARGO but was playing around with Spectrum-lab capture. I will try and grab a better shot in the next few days.
https://www.dropbox.com/s/mj1xkyyn3qvzzwk/vo1na%202%2018%2021%20TEXT.jpg?dl=0
Rick
Re: VO1NA in PA
Posted by John Davis on February 19, 2021 at 09:40:41.
In reply to VO1NA in PA posted by Rick KA2PBO on February 19, 2021
Hi Rick. Does the ptd.net address replace the verizon.net one?
Just a reminder, if you use a # followed by your Authenticated Author password, URLs in your post are automatically converted to clickable live links.
73, John
Re: VO1NA in PA
Posted by Rick KA2PBO on February 19, 2021 at 10:19:36.
In reply to Re: VO1NA in PA posted by John Davis on February 19, 2021
Yes John; the ptd.net address is the new address.I notified Kevin last month and have received HQ mail at the new address.
Thanks for the tip. I will do that next post.
Rick VO1NA : take 2
Posted by Rick KA2PBO on February 19, 2021 at 10:47:30.
VO1NA was copied all night here in PA. I will try for a daytime grab over the next few days.
Here is a much better screenshot than the previous night .
https://www.dropbox.com/s/a2k953a3ah61ox9/vo1na%20%202%2019%2021.jpg?dl=0
Rick
T
Posted by Ed Holland on February 21, 2021 at 19:43:17.
T booming in today (11:40 PST) fading up to very good audibility here in Bay Area CA
Re: COIL 3.96
Posted by John Davis on February 22, 2021 at 17:20:51.
In reply to Re: COIL 3.96 posted by Rick KA2PBO on February 18, 2021
I think the problem came from having to copy-and-paste the link. Browsers don't interpret Zip files, and won't just automatically download them from the address window either, out of security concerns.
[EDITED 27 February:]
A live (clickable) link would allow the user to right-click and choose "Save target as..." or "Save Link As..." (wording varies by type of browser) to download the file. I manually converted the URL to a live link, which made it accessible to more users. (Unfortunately, not to Rick until he discovered his security software was blocking the download.)
However, Brian subsequently objected to the link conversion, so as of today it's back to the original plain URL that you'll have to copy and paste.
Word of Caution: While I trust Brian's software implicitly, never ever allow your browser to Open any Zip file directly! Always choose the Save option and scan the file before trying to do anything else with it, just as you would for an .exe or similar file, just as if it were of unknown provenance. I'll talk more about this in a later post, but for now let it suffice that Zip files appearing to contain HTML pages and JPG files can actually be sources of ransomware attacks. Caution is always warranted.
John
Re: COIL 3.96
Posted by Rick KA2PBO on February 23, 2021 at 02:44:52.
In reply to Re: COIL 3.96 posted by John Davis on February 22, 2021
I gave it a try John but it wouldn't work. The problem is on his website. I went to his website directly using Firefox and Internet Explorer and couldn't download the file.
Rick
Re: COIL 3.96
Posted by John Davis on February 23, 2021 at 05:50:16.
In reply to Re: COIL 3.96 posted by Rick KA2PBO on February 23, 2021
Sorry, Rick, I'm not clear what you mean by "went to his website directly." I've now downloaded the file twice from the live link today myself, once with IE and once with Firefox.
Re: T
Posted by Bill Hensel on February 23, 2021 at 16:20:56.
In reply to T posted by Ed Holland on February 21, 2021
Ed, Tuesday HiFERs
Glad you caught it...today Feb 23, it has been blasting into KFS omni antenna peaking S3...boy that KFS antenna system is super.
Posted by John Davis on February 23, 2021 at 20:25:01.
From 11:30 AM CST to 1:00 PM, 22 meters was getting off to a slow start! Initially, nothing was audible except the mid-band ISM, which was so weak it didn't register on the S meter. WWV was nice and strong at +20 on 10 MHz, but only WWVB could be heard on 15 MHz, and only about S2 maximum.
NC was good at first, 7P and EH were fair, RY was weak, JB was good, WV was fair, and PLM varied from poor to fair. Mo VAN or FRC...and in fact, nobody above mid-band until finally ODX began showing up intermittently, after which KAH came in faintly from time to time also.
Later, ROM suddenly appeared at 12:32 but was mostly gone by 12:40 PM. 7p and RY were both good copy most of the time by then, and MTI turned up at the end of the lunch hour. Am leaving the receiver on until dark in hopes of seeing short-hop openings if the anticipated G1 storm shows up by then.
(Won't be any WSPR decodes, though. Something's haywire with my WSPR-X today.)
Re: Tuesday HiFERs
Posted by Mike N8OOU on February 24, 2021 at 01:50:39.
In reply to Tuesday HiFERs posted by John Davis on February 23, 2021
John;
I have been capturing screen shots of the WA5DJJ Super Grabber 22m page all day. It has been a while since I last tracked the WM beacon on his site. I have read a number of conversations of how propagation has gone down in the past couple months. I copied those screens up to my website if you would be interested in comparing them to your captures. His screen image covers from 13555240 to 13555620. NC has been in and out all day. WM has been weaker and less frequent. Other beacons in between have been seen thru the day.
You can access them at ===> n8oou.meekfarm.us/ArgoCaptures/
That URL will show the individual files. They are timestamped with my local time. I will put up the additional overnight files after I stop the captures tomorrow morning.
Mike 73
Re: COIL 3.96
Posted by Rick KA2PBO on February 24, 2021 at 03:04:06.
In reply to Re: COIL 3.96 posted by John Davis on February 23, 2021
Well; when the live link didn't work for me, I went to K6STI's website (http://www.ham-radio.com/k6sti/)where not only is the coil.zip file located but also lots of good info for the FM stereo enthusiast . I was able to open up all the links on his page and was also able to download another .zip file he has there (HP4332 A Utilities). So the problem was just the coil .zip file. Well I came to find out that my antivirus program was blocking it because it contained a URL:Blacklist so I had to make an exception in my antivirus program . Now I can download it no problem
Rick
Re: Tuesday HiFERs
Posted by John Davis on February 24, 2021 at 09:26:50.
In reply to Re: Tuesday HiFERs posted by Mike N8OOU on February 24, 2021
I can't speak to band trends as this was the first time in 19 days that I was able to get to the farm to do HiFER listening. It'll be interesting to compare my results with the grabber, though. Thanks, Mike.
After 1 o'clock, everyone whom I mentioned at the watering hole earlier settled in fairly solidly for a couple of hours, except ROM was never present again for more than a few seconds at a time. RY exhibited dogbones. After about 3:00, MTI faded and NC became intermittent, and EH was back to being just fair. JB held on for another half hour then also began declining.
By 5:00, it was mainly 7P and RY with a little EH. Nobody else was visible or audible elsewhere on the band except K6FRC, who would have been fair to good copy except for what appeared to be SWBC sidebands in the upper half of the band.
No sign of the CME that was supposed to maybe bring a G1 magnetic storm, so consequently the first skip zone remained both closed and quite large in diameter...no WM, SIW, MN, T, or PBJ. By 5:30 I gave up and went to 1750 meters. Last night on 1750, I had excellent results with EAR during the first half of the night, but only snippets of JH during the second half. Tonight when I switched over, WM and SIW were already present on groundwace and did even better as skywave took over. SJ and WH2XND have also done well tonight. I'll report on those receptions in detail later.
John
Re: Tuesday HiFERs
Posted by John K5MO on February 26, 2021 at 01:56:25.
In reply to Re: Tuesday HiFERs posted by John Davis on February 24, 2021
Interesting report John, thanks very much for the log of JB. It'll continue to be 100% solar for another few weeks till the leaves come back in the woods. It needs about 3 hrs of sun a day to keep the battery pack going.
Glad to hear its still getting out!
Re: COIL 3.96
Posted by Brian K6STI on February 26, 2021 at 09:54:10.
In reply to Re: COIL 3.96 posted by Rick KA2PBO on February 24, 2021
Glad you were able to resolve the problem, Rick. I don't check here often, otherwise I would have spoken up. False positive virus detection is common, and as you found, it can be inscrutable. If you suspect a file may have a virus, submit it to VirusTotal to have it checked by over 100 virus checkers. Often there are one or two false positives from some obscure virus checker. When I did this for COIL.ZIP last week, there were no detections.
I discovered a minor optimization issue and I've posted 3.97 to fix it. Check my website every now and then to see if there's an updated version.
Brian
1750m progress- time for the worms
Posted by Ward K7PO on February 27, 2021 at 04:19:59.
Work has been slow but steady on the 7P Lowfer. The keyer (I went old school and used an eprom) is built along with a TX design by K0LR. I went with a custom chinese TCXO and divide by 64, so it's more stable than my ability to measure such things. The thought process here was reliability and stability. My intention is to have it on 24/7 for as long as I'm around. I scored about 20K feet of wire for radials at a swap meet back in Dec. Not sure how much and how many I'll put down yet. Got some ground rods at the same swap meet. A concrete base is in the ground, along with a tilt bracket with 3 insulators that just happen to match the dimensions of Rohn 25 tower. I have 4 sections left over from the great K7PO cleanup of 2020. Here's where the worms come in. Actually a whole can of worms. Given 40' of tower, wait for it, how much top loading could I use and still have any chance of defending the Part 15 legality if it was ever questioned? Radius or diameter? Spokes, with or without skirt wires? I thought long and hard before posing this question, mainly because it has been cussed and discussed many times already. I had all but decided to just find another tower section, trim it for 15M total length and walk away. Then I calculated the loading coil, and thought about where the current would be, and ended up here, posting an old question yet again.
I welcome any and all opinions on the question. In the meantime, WH2XXP is on 185.305 all the time except when I'm using the antenna for 160/630/2200M.
Ward K7PO
Re: 1750m progress- time for the worms
Posted by John Davis on February 27, 2021 at 08:03:39.
In reply to 1750m progress- time for the worms posted by Ward K7PO on February 27, 2021
If by skirt wires, you mean ones running around the top hat spokes (not a skirt along the outside of the vertical run), then tying the spokes electrically into a single structure would probably let you defend a 9+ foot radius.
Up 40 feet + out 9 feet ≤ 15 meters. That used to be the view of meticulous old-timers like Z2, HDO, and OWR, at any rate.
(Apologies to Mike and Jerry if they run across this post. I'm not being pejorative with the OT label, as I'm not that many years behind them according to the calendar.)
As has been noted in prior discussions of this sort, it is simultaneously too bad, and at the same time possibly fortunate, that we don't have more specific FCC guidance to go by. But I would note that in a case involving wannabe Part 15 AM "broadcasters" a few years back who were using large non-traditional conducting surfaces as radiating elements, the FCC defined "total length" to include the longest diagonal measure of the structure. On that basis, if no other, 40 feet of Rohn and a top hat of 9 or 10 ft radius should fit comfortably within 15 meters.
Bottom line, of course...our opinions are only that and nothing more. It's always up to the individual operator to be ready to justify his own choices in case of an official visit.
John
Re: 1750m progress- time for the worms
Posted by Ward K7PO on February 28, 2021 at 03:30:56.
In reply to Re: 1750m progress- time for the worms posted by John Davis on February 27, 2021
Thanks John, I appreciate your response. My thoughts are basically the same as you outlined. I think I'm letting the FCC's "guidance" or lack thereof in Part 15 worry me a bit too much. After several hours of math I'm going with the 40' plus 9ish feet radius on the top loading and move on. I'd like to believe that if it ever came down to it that I could show that there was a "good faith" effort made to comply with the rules, as I understand them, rather than a blatant effort to cheat. I also think strict adherence to input power limits and spectral purity would go a long way towards strengthening that argument.
That's my story and I'm sticking to it.
Re: 1750m progress- time for the worms
Ward K7PO
Posted by John Bruce McCreath on February 28, 2021 at 18:10:58.
In reply to Re: 1750m progress- time for the worms posted by Ward K7PO on February 28, 2021
In my twisted way of thinking, the top loading of the vertical element, if it's symmetrical in construction, will not radiate,
as the current distribution will cause phase cancellation from one side, to the side 180 degrees opposite it. If it doesn't
radiate, it can't be considered as part of the antenna. As Ward said, that's my story and I'm sticking to it.
73, J.B., VE3EAR Re: 1750m progress- time for the worms
Posted by John Davis on February 28, 2021 at 22:13:56.
In reply to Re: 1750m progress- time for the worms posted by John Bruce McCreath on February 28, 2021
If it doesn't radiate, it can't be considered as part of the antenna.
An interesting theory, but possibly harder to defend. A transmission line doesn't radiate either if properly terminated, but its length is required to be included in the total if used. So, I suspect the not-radiating argument (despite being technically correct) could prove ineffective if one encounters a literal-minded, by-the-book radio inspector.
Re: 1750m progress- time for the worms
Posted by John Davis on February 28, 2021 at 23:32:23.
In reply to Re: 1750m progress- time for the worms posted by Ward K7PO on February 28, 2021
In your hours of math, Ward, did you happen to calculate antenna capacitance for all three options, by any chance? Namely, 50 feet unloaded, 40 feet unloaded, and 40+9ish top load?
I absolutely concur with your assessment that careful compliance with the unambiguous rules and good-faith efforts to comply with the more "biguous" ones will stand one in better stead with the FCC.
During my 30-some years in broadcasting in Georgia, I was inspected four or five times by regular FCC engineers and five times by the very scary Chief Engineer of the Sixth Radio District, Angelo Ditty himself. (There was also an "informal and completely unofficial" stopover at the TV station one day when he was returning to Atlanta from a golf trip, during which he nonetheless glanced at the operating log and waveform monitors, and rather thoroughly perused the bulletin board where the licenses, EANS procedures, and other required items were posted.)
Seldom was anything amiss at any of the stations. The few times there ever were (such as a frequency tolerance glitch during the 1976-77 winter natural gas shortages), the fact that we were visibly on top of everything else and made a conscientious effort to correct errors quickly, resulted in no adverse actions or fines.
Re: 1750m progress- time for the worms
Posted by Ward K7PO on March 01, 2021 at 14:53:07.
In reply to Re: 1750m progress- time for the worms posted by Ward K7PO on February 28, 2021
John,
Yes, it was the capacitance numbers that made the decision for me. I'm not home now and my notes are there, so I don't have the numbers with me. I gave up a long time ago trying to pin down exact capacitance by calculation. Every one of my antennas has shown a different measured value vs. the calculated one. Now I just use the same method for each antenna and use that for comparison. I don't even try to get very detailed in computing the top loading, I just go with 10*r for a rough guess. FWIW, I think the 40' Rohn 25 bare tower value I used was 200pf, based on my about-to-start-receiving-SS memory.
Trying to get that coil as small as I can!
Ward K7PO
/Savannah GA
potrzebie