80 Meter Antenna up!

Boy, this project is really dragging out.... this is the tower seen in previous blogs, that was torn up back in April of 2016 in a storm. It's now the end of November, and I'm just beginning to install some temporary antennas. I expected to be finished with the tower by now but work, storm damage repairs to our home, and remodelling of our home took priority. I've been operating with only a 30m sloper at about 68' on the west side of the tower, but it's a pitiful performer on other bands. On the bright side, I'm almost at DXCC on 30m, a band I almost never worked before :-)

A photo of the side arm, current choke, and low-end 80m Inverted V installed at about 65' on the east side of my tower. You can click on any of these photos for a larger view...
 

The tower is currently at about 70', and I have another 50' to install. Since it's late November, I realize the total rebuild likely won't happen before spring. With the winter months being the time I operate most, I decided I needed to get busy with some antennas. The antennas I install will be done with extra feedline included and built in a in a way that will allow me to simply cut the tape securing the coax and raise the mount once the remaining tower is installed.


A photo of the insulator used on the low end of the south leg of the next low-end 80m Inverted V.

This is the first of these antennas. I cut an inverted V for 3.550 mhz , to allow operation from about 3.500 mhz to 3.600 mhz at QRO without a tuner. The two wires were cut to 67'2", and this allows 9" for attachment to the strain relief at the feed point, and 6" for wrapping at the insulator. The tower side arm & current choke assembly from the previous blog was installed at about 65' up on the east side of the tower. It included a mount for a vertical antenna, but I haven't decided on that, yet. I attached the inverted V to the dipole feed point installed on the arm, with the antenna pulled north-south. While an inverted V is mostly omni-directional, this will allow for the lobes of strongest radiation to be east & west. The feedpoint was designed and fabricated to allow multiple dipoles to be attached, and more be added soon.

A photo looking up the south leg of the low-end 80m Inverted V antennas. Since the far ends are anchored to trees, I always leave a bit of sag in the wires.

 The antenna resonates about 3.550mhz, and is still less than 2:1 swr at 3.500 and 3.600. It was fed with CQ-1001 Flexi X-4xl RG-8 size coax from the Wireman. That feedline's loss properties are about .4db loss per 100' at 10mhz, and about .75db loss per 100' at 30mhz. I got a chance to test it out in the CQWW CW contest on Saturday night, and was very happy.At only 65' up at the apex, I was busting pileups all over Europe, some into Africa, South America, and later into the South Pacific. That'll hold me through the winter months, and I can't wait to get it up to at least 100' in the spring!

Dave WB4IUY
http://www.WB4IUY.net


A look up the tower, the side arm and 80m Inverted V is seen on the RH side of the tower in this picture.

Assembling a Low Band Dipole Support....

Well, winter is upon us, and my tower still isn't finished. With lots to do, and cold weather coming fast, I decided I should probably get something up for 80 & 40 CW...fast. I'll still be working on my tower over the coming weeks, but have been in a bad way for antennas since the tower damage on 4/28/16, operating on 40 through 6 meters with my 30m sloper & a tuner.

This is one of the side arms I was able salvage from the tower wreckage. Dipoles for 160m and 80m are heavy, and the previous mount was destroyed, so I needed to fabricate something pretty stout for the job. This side arm looks up to the chore, and will push the antenna feed point about 3 feet away from the tower.

I located a heavy phenolic bar to use as the center insulator, drilled it in the center for a support rope, drilled a pair of holes on either side of the support for stainless steel bolts to be installed to attach the dipole leads, and a hole on either end to anchor the dipole elements to as a strain relief.

I wound a current choke from 8 turns of feed line, about 6 inches in diameter, and attached it to the side arm. A heavy portion of rope hangs the center insulator from the sidearm to support the #14 stranded & insulated wire I'll use for the dipoles. There will be 3 pairs of dipoles (over 300' of wire!) pulling down on this, so the center insulator must be strong and the support must be robust. In addition, the loading goes way up when we have a heavy wet snow or ice storm, not uncommon for our area in January & February.

I use long stainless steel bolts in the center insulator to allow additional dipoles to be easily attached to add more bands and/or bandwidth to this antenna. Initially, it will support two 80 meter dipoles and one 40 meter dipole, in a fan dipole arrangement. This will provide resonant points at 3.525mhz, 3.885mhz, and 7.025 mhz. I'll post more on this, once installed. Here's a few pics of the sidearm, current choke, and dipole support thus far...

This is the phenolic bar I chose to make the center insulator from. I used heavy stainless steel bolts & nuts, and hot dipped galvanized washers to allow attachment of additional dipoles/

Common mode current choke wound from 8  turns of feedline @ 6" in diameter

Choke attached to side arm...

Center insulator hung from the side arm with rope, coax attached to the dipole attachment points

Ready for coax connector to be installed, and be hoisted up to the 70' point on the tower that I have errected thus far... 

More Tower Work at WB4IUY

I finally had time to make a little more headway on my radio tower rebuild. I finished cold galvanizing the rest of my tower sections (I had previously used rust converted on them in preparation). I've gotta get this done before cold weather hits, I still have a lot of antenna work to do, once it's up. Here's a few pics...

Here's a few pieces of tower after the rust converter was applied... Kinda makes them look like a  sloppy whitewash was smeared on :-)

A 6el Force 12 HF yagi, awaiting installation. I've got to get busy and do this before winter sets in!
 

More tower awaiting rust conversion and cold galvanizing.

The top section with bearing, ready for the last cold galvanizing application. 

Another pile of antennas awaiting me to make repairs and  reinstallation on the tower. This is a pair of  17el 2m yagis.

My 5el 6m Cushcraft that was  converted to "CrushCraft" in the storm. I have another to replace this with, though I may repaid this one and re-use it...

A pic of 70' of tower that is currently erect and awaiting more to be stacked.

Almost finished with the cold galvanizing compound...

Another shot of the tower at 70'...
 

Right here is where the rest of this tower is going :-)
 

This is GOOD stuff. I've got some tower I did this to over 23 years ago, and it still looks great. It takes about 4 cans per section of Rohn25 to do the job correctly. 

Ready for installation!

 Dave WB4IUY
http://www.WB4IUY.net

More lightning strike damage...

What a summer... the nastiest in 23 years of living here, for lightning strikes and storm damages. I found another piece of lightning strike damage by accident. We recently had a storm that was nasty, and when I returned home I found all the breakers in my home workshop tripped. Didn't really find any damage in the shop, until now. I noticed the 2 meter rig (VHF radio) in the workshop wasn't receiving very well, so I decided to put the SWR meter on it and check the antenna. It sits on a grounded, wall mounted, metal shelf. I reached for the feed line connector near the radio and had to break it away from the shelf. Ruh Roh...

Check out the spot on the connector where it welded itself to the shelf...
 

It blew right through the powder coating on the shelf!
 

I haven't removed the antenna to inspect it, yet, but the SWR is about a zillion : 1  on it now :-( . I don't know if it's a direct strike, or a near strike, as there was a tree about 50 feet away that was struck. Whatever the case, this is a real eye-opener for what can come in on the feedline!

Dave
http://www.WB4IUY.net

JarsFest Benson NC Coming Soon!

The image below says it all. GREAT local hamfest in Benson NC. Be there!!

Dave WB4IUY
www.WB4IUY.net