Vertical Antenna 160M-10M
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| May 12th 2020, 11:01 | |
donavangaffneyTotal Topics: 0 Total Posts: 0 |
I am looking for a Vertical Antenna. I live in a house in the country, I have no trees around just open area. I am thinking of getting a antenna and I think a vertical one would probably be a better one unless someone else has a better option. I have a ICOM IC7300 and what I want is a Vertical that will do 160 meters to 10 meters, without being 100 feet in the air or taller. I am looking for something that isn't going to cost a ton of money but work great. I have seen some that require radials, tuning, etc, and some that don't. I want this to be around maybe 15-20 feet something manageable that I can do by myself and secure it so it doesn't get blown away. I live in the south and we are always have hurricane threats. What are some options, what are some mounting hardware without having to get a an actual tower. If this cannot be done I would be happy with a 80 meter to 10 meter. Also want this antenna to be able for me to go to another band on the fly without me having to take the antenna down and do adjustments to make it happen. I know this sounds like a lot, but I know someone out there that has a great idea that would be awesome to help. I am willing to come off the price if it means I can get everything I want just don't want to sink thousands and thousands of dollars into a antenna. Any Ideas? |
| May 12th 2020, 12:12 | |
W1VTSuper Moderator Total Topics: 0 Total Posts: 0 |
Typically you don't want to go below about 2/3 the size of a normal resonant antenna length. This is about 20 feet for 40 meters. This is for an antenna with radials. The antenna is a resonant quarter wavelength with either ground mounted radials or elevated quarter wavelength radials. Now, there is a way to get rid of those pesky radial, or at least make them more manageable. You can shorten them to just five feet or so. What you are doing is similar to an off center fed dipole, in which one end is much shorter than the other. But, if you do this, remember the 2/3 rule? Well, it is now 2/3 of a half wave and not a quarter wave. So, for 40 meters the size should be five feet plus the antenna height should now be twice 20 ft or 40 ft. But what if it is shorter? The antenna gets less efficient. The digital mode FT8 will allow contacts with a less efficient antenna than you need for voice. Zak Lau W1VT ARRL Senior Lab Engineer |
| May 21st 2020, 20:34 | |
gw0nvnTotal Topics: 0 Total Posts: 0 |
Hi, The ARRL website has a number of antenna articals from QST which may be suitable. Also design articals for HF verticals. Have a look at:- http://www.arrl.org/hf-vertical Build this Novice Four Band Vertical https://www.arrl.org/files/file/Technology/tis/info/pdf/7806016.pdf If you wanted to 'remote' the band change switch. I would suggest you use some relays and a multi-core cable back to a multi-way switch in the Shack. If you wan't hi tech, a micro controller and a wifi link. Or better and simpler is 'A Multiband Groundplane Vertical Antenna with tuned Feeders by K4TP from QST. This is a simple vertical with radials fed with 450 Ohm Ladder Line balanced feeder to the shack. The balanced feeder is connected to a Balun and then to the Auto ATU of the transceiver. The length of the vertical isn't critical. They used 16ft 5ins (5m) for operation from 40m -10m. I use this arrangement for doing IOTA portable. I use 33ft (10m ) for operation on 80m - 10m. Make the radials the same length. My vertical is on the shore edge, with the radials over the sea. By mounting it on a post, a few feet off the ground, it is easy to connect the radials, the ladderline and make measurements. It has low loss with high VSWR on the feeder. The materials are easily and cheaply obtainable from Hardware Stores. The inductors and capacitors you can make or purchase off the Internet. The good thing is that you can use materials to suit your local conditions. Extra guying as you see fit. You could even make you own ladderline. Bring the ladderline from the antenna back to the shack. It should not be lying on the ground and no right angle bends. You will need a balanced to un-balanced transformer ( Balun ) to connect to the unbalanced antenna connector on your transceiver. Again the ARRL website has articles on building ladderline and Baluns. If you want a commercial antenna, a Butternut HF9V at 25ft is a good multiband antenna. I would ask the suppliers about the guying arrangements and survivability at you location. The choice of antenna and feeder will depend on what you want to do. Is it for local working, DX or to a specific target area? I would suggest you do some reseach on the properties of hf antennas and Hf propagation. So that you choice the best antenna for your use. All the articles I have suggested appear in the ARRL Antenna Anthology by WB1FSB. A collection of articles from QST. It is an old book and will be available secondhand on the internet. The articles are separately on the website. Whatever antenna you build, record any measurements and observations. So that you can diagnose any future issues, or compare with another antenna. If you can, Use a Field Strength Meter close to the antenna to show how well it is radiating. Also use an online SDR to both give you a signal report and a recording of your modulation. A poorly performing transceiver with a good efficient feeder and antenna system will perform much better than a 'State or the Art' working transceiver with a poor in-efficient feeder and antenna system. best regards 73's Simon GW0NVN N1XIH |
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