What's a good receive antenna for lightning season?

[WB2EMS]

Just got pinged by one of the remote users of my SDR-IQ receiver about it being off the air today. Tornado went through about 1/2 mile north of me and took out the power last night and I guess the Shuttle PC that runs it didn't reboot properly, I can't reach it via VNC. But I was telling him that even if it was up, that I often have the antenna disconnected during this season because of lightning in the forecast.

I've been thinking for a while about what to do for a summer lightning season antenna for it. I have a couple of loops, some dipoles and a C3 beam up, but disconnect them all from the rigs when any storms are forecast, even though they only materialize about 30% of the time. But I would like to have the SDR on line, both for my purposes and for others to use. So I'm thinking what kind of 'hardened' antenna arrangement I might be able to make for it.

I've already put a partial protection circuit in front of the input, a couple of hefty power supply diodes back to back behind a grain of wheat light bulb. I mostly did that for protection from the KW on one of the other antennas if I forgot to disconnect things when transmitting, but it should provide some lightning protection. But I'm thinking what kind of antennas would be least affected by nearby strikes? (I figure with a direct hit, all bets are off). I do have my station ground tied to all the other grounds via #4 wire and have tried to move things towards a ground window entrance, though I'm not done with that yet)

Loops seem like they might be more robust than dipoles or verticals - they are often more noise immune and seem that by their design they would tend to reject electrostatic fields more. I've thought about a bush height small loop just as a general receive antenna. Or possibly a small receive loop of the type often used to null out interference, but I don't want it to be too frequency specific.

The other thought I had was my small beverage. I have a short little beverage aimed NE that about 6 foot high. (just tall enough for the deer that frequent the area where it's set to get under it) The interface box has some spark gaps in it, and I could put a polyphasor out where it enters the building, but those are geared to let transmitter power (250 watts) out, which means more than enough energy coming in to zorch the front end would be available without tripping one. I've always thought of those kinds of lightning protectors as being much more about keeping your insurance in force than keeping the rigs behind them safe. But with the low antenna, the two layers of lightning protection and my little protection circuit, maybe that would be robust enough.

What do other folks do if they want to be on the air during lightning storms? For our 2 meter storm nets, I just use the HT.   

[Pete, WA2CWA]

What do other folks do if they want to be on the air during lightning storms? For our 2 meter storm nets, I just use the HT.   

Lots of life insurance 

[KM1H]

A BOG...Beverage On Ground.

I have one that is about 660' long and it hears well to the SW which is right at a noisy yuppie neighbors house. Noise is generated by 5 kids, wife and money is no object toys, appliances, entertainment, etc. It runs anywhere between ground and 12" high mostly thru the woods.

The 900' 2 wire reversible one at 6' high about 5' away hears better for DX after they are in bed.

Carl

[K5UJ]

what frequencies do you want to listen on?

[WA1GFZ]

I was on 160 Tuesday night with real bad static. Everyone was having trouble hearing signals. I was on my KAZ loaded loop 30 foot base apex at about 16 feet. load 1000 ohms. 1:4 transformer to 75 ohm coax. I have 2 phased to the east and one to the west. I copied at least 80% of transmissions. It works well up to 15 MHz. RX cubic R3080
K9AY is also good but I hear it isn't that good on 40 meters

[WB2EMS]

what frequencies do you want to listen on?

Well, DC to daylight would be best, but I'd be pretty happy with 75-10 meters. If I had to narrow it down, 40-20 or higher would probably make the most sense for summer. In the fall and winter when 75 is more useful, I can use the regular antennas.

I hadn't heard of beverage on the ground. Is that a real thing? Is it appreciably better than a regular beverage for rejecting megawatt signals of microsecond duration? 

Pete, I don't know if the life insurance will help. It's when I'm not here that the antenna needs to work well!

[K5UJ]

so you want a low profile to lightning antenna.   Frank has the right idea I think--something small near the ground for receiving only.    You can also try small coax loops for 160 and 80--put the 80 loop in side the 160 loop with both of them vertical on a PVC cross frame and jammed down into a tripod on the ground,  Each loop tuned with a capacitor and connected to coax.  There are designs for them all over on the internet.  Google "magnetic loop" or "small receive coax loop" and you'll probably find them.  For 40 and 20, hamstick dipoles?  Higher bands use full size dipoles on fishing poles. Mount everything five to 10 feet off the ground.  You can probably parallel everything to one feedline since it is for rx only.   Actually for rx, you probably don't need a separate dipole for each band; just one cut for 20 m. and wrapped on fiberglass fishing poles and the low band loops will probably be enough.

[Jim, W5JO]

Try a Flag, Pennant or rotatable loop.  Usually the upper frequencies will be relatively quite except when the storms are nearly upon you.  When that happens, throw the coax out the window and close it.

[KA2DZT]

It would depend on how much lightning you want to capture

For the most strikes/hour rate, I would use a long wire held up by a balloon.  We had just such an antenna up one FD.  We were getting static discharges 3 inches long from it.  I finally had to order the morons who put the thing up to cut it loose.

For the least amount of static a loop alway works better.

Always helpful,

Fred

[KM1H]

Most of those compromise small antennas are single band affairs wheras a Beverage is non resonant. For just 40M and up Id try a 130' BOG which is a full wave. A preamp may be needed for 17-10M depending upon how deaf your radio is. If you have real good ground a 450-500 Ohm to coax transformer and termination will be fine and if its real bad ground around 250-270 Ohms. The ARRL ON4UN Low Band DXing book 5th Revision has a lot of good info on all the popular receiving antennas, grounds, matching, etc in a dedicated chapter. Earlier revisions had several errors.

Carl

[W1RKW]

are you trying to receive lightning?

[WB2EMS]

Try a Flag, Pennant or rotatable loop.  Usually the upper frequencies will be relatively quite except when the storms are nearly upon you.  When that happens, throw the coax out the window and close it.

The problem is the radio and antenna may be unattended at the time the storm shows up. This is for a radio that is online 24/7, whereas I may not be here during the work day, though I do stop by from time to time. We get a lot of forecasts that include the potential for thunderstorms, though I'd say only about 30% of the time do they show up as forecast. So if I cut the radio free on all the forecast days, there's a lot of unnecessary downtime. Or if they miss a forecast and the radio is connected when a pop up storm occurs, it's at risk.

Sounds like my existing beverage, or a beverage on ground (BOG) make the most sense so far. The small loops might be a possibility for a specific band.

are you trying to receive lightning? Wink

Hell no! 

More like trying to receive around lightning. Just trying to have a receiver on line most of the time with a usable antenna that will survive nearby strikes when storms pass over.

Also looking into the possibility of a remotely controlled antenna relay. Anyone know any apps that let you control a remote relay from a network connected PC (maybe even connecting from an android device to send the commands?)

[Jim, W5JO]

Had a small loop at one time with a K9AY controller.  It worked very well up to 40 meters and compared to the beverage I had.  The advantage was the small footprint compared to the beverage.  It, too, was non-resonate therefore worked the same as the beverage.  Much less to maintain and can be made to rotate electrically or physically whereas the beverage is fixed in one or two directions.

[KM1H]

Why do you care about whats on if youre not home?

[Fred k2dx]

I have been using a small shielded non-resonant loop from a company in Colorado, Pixel Technologies.
http://www.pixelsatradio.com/PDF/RF_PRO-1A_Cut_sheet.pdf
It isn't inexpensive but it is general coverage, ftom LF through HF. The preamp seems to be pretty strong and I'm satisfied with the overall performance. It is mounted close to the ground, Mine is at 12', and hears well. I've been using it with my Harris RF-590 and Racal 6778c receivers. It has a built in T/R circuit if you transmit close by, it's about 35' from my transmit antenna. My T-368 running full power hasn't harmed it. They say it isn't directional on skywave but for local QRN rotating the loop nulls the source effectively. I haven't put a rotor on it yet, it's oriented with the null in the general direction of my multipile sources of noise.

[WBear2GCR]

Not sure but a DC grounded antenna might help...?

Also the other question is what sort of ant is best to listen with during lightning season...

                    _-_-bear

[KX5JT]

Why do you care about whats on if youre not home?

Ever heard of Short Wave Listening?  I enjoy listening remotely when I'm bored at my night job.  Although I'm not setup to listen to my home station remotely, I do use globaltuners.com and other remote setups. 

Not all of us just chase awards!  Some of us actually enjoy casual SWLing and operating.

[Fred k2dx]

Kevin, Is your receiver available to the general public or 'closed'? What is your opinion of it? I had been looking at one online but haven't heard many comments from owners. I am unfamiliar with SDR but had looked into remoting one of my three premium rx's, the two mentioned above or my Watkins Johnson 8718-15. I abandoned the idea as it was looking more complex than I wanted to get into - with the 3d party software, interfacing, difficulty locating a suitable rx site with broadband internet available, etc.

Your comments would be welcomed.

73, Fred

[KM1H]

Ever heard of Short Wave Listening?

Yep, decades before you were born and it would have helped to explain your application in the first post.

[WB2EMS]

Fred,

My receiver is an SDR-IQ from RFSpace and it's on server software by the same fellow who wrote ham radio deluxe. Simon's web site for the software is http://sdr-radio.com/ and the download includes both a server and client.

The client can be used directly on the SDR-IQ and several other receivers, including the softrocks, or to talk to receivers running the server, as mine is. The server software is a small piece of software that runs on my case on a shuttle PC (40 watts, no fan) with the SDR-IQ connected by USB. It just boots with the machine and runs in the background.

From the client, when you start it up, you can choose to use a local, or remote, receiver. If you choose remote, you can choose to browse the web for available receivers reporting to the system. Mine should be listed under my call as I leave it open for others to use when I'm not using it. When I want to use it, I log into the pc it's running on and boot off the current user and then connect myself. There are a couple of people who who tend to log on and stay on for hours, and I try to discourage them from time to time by taking the receiver down or grabbing it and holding it till they go away.

Feel free to download the software and give it a try. It's on most days, and since I've started this discussion it's been on the 210 foot beverage oriented NE as my best bet for a safe antenna. The reason I started this discussion was last year I took the receiver off whenever there was lightning in the forecast for the day, which made for a lot of down time and I'd like to reduce the amount of time it's unavailable.

I think it's a pretty good little receiver. I don't know how it compares to the other receivers that were mentioned, but it seems to hear about anything I can hear with the TS-2000 or Flex on the same antenna. It didn't do very well with a short piece of wire when I first tested it, but with a real antenna it does fine. I was able to run it stand alone with the software it comes with (spectraview) on a simple netbook computer, an HP mini-1000.  It has a frequency coverage range of 500 HZ, to 30 mhz. Some folks connect ultrasonic transducers to it and listen to bats.     I'm pretty well pleased with it and it gave me enough of a tasted of SDR to get me to take the next step of getting an SDR-1000, and then a Flex 5000. Beware, you might get hooked too.

KM1H asked

Why do you care about whats on if youre not home?

I use it remotely. I like to listen to 75 meters late in the afternoon to see what's going on. Listen to 20 and 17 meter HFpack and other frequencies. Listen to local and remote AM broadcast stations from time to time. Listen to special events on HF of one sort or another. And when I'm not using it, make it available to other users to do similar things. Just because I'm not *at* my station doesn't mean it has to sit idle.    Besides, this little box (about twice the size of an altoids can) doesn't have any knobs, just a couple of LEDs, so there's no point in sitting in front of it anyway. It's in a closet with it's PC host.

[Fred k2dx]

Kevin, I had looked online at the Winradio Excalibar a few weeks ago. http://www.winradio.com/index.htm It looked to be a very decent rx and very simple to set up. Once I get done with this tower and antenna array refurbishing project I will look into the possible remote rx site...

I will give it a shot to listen to your rx... my problem is local QRN and loss of access to the woods where I used to have a stealth NE beverage. The last time I had listened online was to Keith LaMonica's set up but had computer issues, I'm sure the problem was on my end.

If you were closer to me I would let you try out my Pixel Technologies loop, it does a decent job up to 10m. http://www.pixelsatradio.com/PDF/RF_PRO-1A_Cut_sheet.pdf It's not an inexpensive antenna, but I'm happy with it. Pixel does offer a 30 day trial... I found it to perform well enough to keep. I wouldn't compare it to a big beverage but all things considered: performance, small profile, and frequency coverage 100kc - 30 mc, I'm pleased. It outperforms the small single band loops I had built. 

[Fred k2dx]

OK, after trying several receivers it was working out FB. I spent some time listening to N3UJJ's rx this evening. The synchronous AM was very good on 75m. I was impressed with it but unable to find what his rx antenna was.

I think I see a remote internet rx in my future!

 

[WB2EMS]

That pixel technologies loop looks interesting. I wish I had enough details to try building something like it. I don't think the budget will support the acquisition of a new one just now. I may try mocking up something from Dr Baum's original notes to try. Going to need something for a balanced preamp though.

N3ujj has the same receiver I do. Something seems to have gone wrong with my server software. I can log into and use the receiver, but it's not showing up on the server website as available. I will look into this and see if I can get it fixed.