Recent content by The DB

Putting together some quick models, here is the radials and bottom dipole element all attached compared to a standard 1/4 ground plane at the same height. The results aren't even comparable, so it is definitely not wired as it appears at first glance... So to continue I need more...

For a model, the question is, how is this antenna wired inside. Typically you have a dipole layout, or a ground plane layout. I wouldn't assume both as the ground plane layout would effectively render the dipole bottom half effectively useless if they are wired together... Perhaps if you can...

As someone who has two air tents that use the same principle in that picture, I think we have the technology to make such a tower, but it would be so damn heavy it wouldn't be worth it... One of my tents is 10' by 6', and weighs about 60 lb, the other is 13' by 10', and weighs about 150 lb...

If your trying to measure the low angle lobe you see in models, neither will be of help. In a base antenna at height, 200 yards isn't enough for the lobe to formed yet at, and six miles, even if it is formed, it will be to far above your head (more than a half mile if you have a 5 degree angle...

My suggestion would be a modification of bob85's. To test a mobile setup I would put up an antenna at the house attached to a usb based spectrum analyzer, then with either remote access on the computer set up or perhaps streaming to a youtube or twitch account. This would let me test in...

This quote is from years ago when modeling the imax 2000 antenna and given a new piece of information... That was from 10 years ago on this very forum... Unfortunately the models and such that I posted aren't there anymore... I will have to see if I still have them laying around somewhere...

During the rare free time I had at work today I read through some of the earlier posts in this thread. The old days where several of us were dissecting these antennas and others trying to figure out how they actually worked... I learned a lot doing that, and learned modeling as well. Me and...

Sounds pretty complicated, if I get some more time this week I might try and get it into the modeling software... No guarantees though, I can't say translating that into a model will be easy... The DB

The ocf and fan dipoles are really two different antennas, and there really isn't much that is directly comparable. A few things I noticed while modeling these antennas. 1) With the fan dipole, it is easier to predict the radiation pattern. On some frequencies, the pattern of the ocf is...

I never could get the DDRR to model well, even if I used the double variant of it and mounted it in any number of locations. The Super Sinner would be great if most of what he wants to do is DX. It is horizontally polarized. There is a bug in both Nec2 and Mininec programs that appears to...

I've been playing with ground mounted antenna models just to see what I can find out. This is something I couldn't do with the nec2 engine as even with the best real ground, you could only get so close before it became inaccurate. As I now have a license for the nec5 engine, I don't have that...

Its actually not the connection to the earth itself that is causing that, its just that the connection to the earth changes things in such a way that that happens to have that effect. The same thing can be done without any earth present. Here is a hint that you likely don't need, what change...

So here I will start with a base model that shows a half wavelength antenna in a worst case scenario. In this case, the circle is the feed point. Everything above it represents the antenna, and everything below it represents the feed line. The green curved line is the current distribution...

That would have been me, I don't think anyone else used that name anywhere, at least radio related. It would have been years ago. All of the other forums I did anything I left for mostly lack of use. I have said many times that the optimal place for a choke on a 1/2 wavelength antenna is 1/4...

The only time an electrical half wavelength multiple lengths of coax have to come into play is using older models of antenna analyzers. Many newer designs have the ability to calibrate out such things, so in that case length doesn't matter so much. Also, such coax lengths are only good for one...