Just thought I would share one of my antenna projects. It has been something I have wanted to try for a long time now and I am very pleased with the results.
Living in a mobile home, you don't have a lot of space. My Ham Shack is out in the yard more than 50 feet away and when it's cold out at night I don't much feel like heading out there to check-in for the weekly net or a quick QSO.
So I installed one of my Dual band 2m / 440 radios in the house close by for my convenience.
I wanted to have a vertical dual band antenna for all around general reception and beam antennas to get out over the hills for maximum transition range.
I also have a 220 MHz hand-held and thought it would be nice to include an antenna for that band as well.
So how do I go about this with minimal cost and maximum effectiveness?
I decided to use a 2m / 440 J-pole that I had lying around as my omani-directional vertical.
It has always worked well at Field days and other outings.
Next for the Beams I had a 5 element 2m Yagi beam that we used last Field Day for the 2m SSB station and a 9 element 440 Yagi beam that I had put together when the 440 Box Springs repeater was moved and a bit harder to hit from my place.
I also put together a 220 - 4 element Yagi beam to hit the Box Springs Mt repeater awhile back when we thought we would have an ARES net on 220.
The J-pole I would put on top of a 5 foot mast and a 50 foot piece of RG8x runs to a 2-position antenna switch connected to my Dual Band radio. I always put in a loop or coil type of choke near the feed point of the antenna to reduce emissions on the feed line. (usually 4-4" turns of coax )
Next I mounted the 2m and the 440 Yagis on the ends of a 56 inch long horizontal boom with the antennas in vertical polarization. I mounted this to the mast so the longest element of the 2m antenna, (the Reflector) was 2 inches below the J-pole. Checked the SWR and it was a great 1.2 : 1 on both beams.
Works for me!
The 2m and the 440 beam antennas are both connected to a UHF / VHF Duplexer that is mounted in a water proof bag and zip-tied to the mast. From the duplexer a 50 foot piece of RG8x runs to the antenna switch on my Dual band radio.
Now I can switch from the vertical J-pole to the beams no problem.
Both the beams have about a 9 - 10 DB gain on their respective bands. This is nice. Once I get the beam pointed in the direction of my contact I switch from the vertical to the beams and can really see the difference in the signal strength. Typically an S-5 jumps to S-9 or more.
Next I added the 220 beam to the mast just above the rotor. I was worried about not quite being below the elements of the 2m beam, but after testing and SWR checks it really didn't seem to matter. The SWR on all the antennas were very good.
The 220 beam is fed with 50 feet of RG8x coax and connects to my 220 HT via sma to BNC quick disconnect adapter.
The antenna array is mounted on top of a 30 foot mast screwed to the side of my mobile home. I added 3 guide lines on it to prevent it from swaying in the wind. All those elements do create a bit of drag when it gets breezy.
With this antenna array I have no trouble hitting the club 2m machine and the 449.300 repeater that was moved from Box Springs.
I can also get good simplex com into Moreno Valley from my place, so for me it is all worth it!
All the antennas except the J-pole were home made using the Yagi Cad program.
You can download it free from the web.
Please feel free to leave a comment or show us your own projects here on this Blog!
Dipole, Inverted V and Ground Plane Antenna Calculators