Wednesday, November 30, 2016

Interested in AM Operation?

If you're interested in working the AM mode on HF, you'll find lots of conversations to listen to on the AM spot page. The AM Spot page is set up to allow AM operators to find each other more easily. The link is: . You'll find routine conversations and round tables to listen to and join in on, and you can spot other AM QSOs on the AM Spots page as well. AM is an interesting mode, and you'll find folks operating everything from vintage & home brew rigs to the latest flex radios on AM. Enjoy!


Sunday, November 27, 2016

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!


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

Monday, November 21, 2016

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 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...