Welcome to Amateur Radio Station K6ATZ  •  ex KQ6MM, KD6ALY and WN2SWQ  •  First licensed 1973, relicensed 1991
QTH Cupertino, CA USA  •  Santa Clara County   ARRL Section SCV   CA QSO Party SCLA  •  CQ3   ITU6   Grid CM87xh


Antenna project articles
  MA-40 tubular tower
  Farm 3: slanted roof «
  Farm 2: flat roof
  Flagpole antenna
  AEA Halo-6 Loop
  Farm 1: peaked roof

Cabrillo contest log info
  California QSO Party

Shack software
  DXLab New site
  DX Atlas New site
  WSJT-X New site
  JT-Alert New site
  Contest Log Checker New site
  Romac Equalizer New site
  CW Skimmer New site
  CW Decoder New site

Ham sites I depend on
  Contest Calendar New site
  QRZ.com New site
  eHam.net New site
  LoTW New site
  eQSL New site


Antenna Farm III:
The Slanted Roof

Here's One Way to Keep Antenna Masts Straight
in Tripods Mounted On a Slanted Roof

Most passerby can guess what my OB6-3M beam is for, but they are often confused by the little loops and eggbeaters sticking up over the edge of the solar array. They were even more confused at first, because the masts were mounted at a very strange angle!

This is because the roof is slanted by several degrees. But after a few false starts I solved that problem, and in the picture below you can see that only one of them is leaning to the right now.

Antennas peeking over the solar array

I stood on my roof for these photos; you see a lot less of this from the street or the neighbors' yards. In the next picture, we're looking down on onto the rear roof during construction, after the tar paper was on but before the final roof layer was installed. The tripods were screwed into roof joists, and the roofers waterproofed them in the same manner as vents or the solar array mounting frame posts.

Waterproofing antenna tripod feet before laying roofing

After the final white bitumen roofing material was installed, I had the roofers lay walking pads on top, as I planned to spend a lot of time tromping around up there. For one thing, it took a lot of experimenting to figure out how to straighten the masts.

Antenna tripods after roofing and walking pads

To compensate for the slanted roof, before installation I asked the general contractor to raise one foot of each tripod with a wedge of some kind, but the roofers said they wouldn't trust the waterproofing if we did that. So, what to do, what to do...?

Radio Shack rotor mounted inside tripodTurns out a cheap Radio Shack rotator did the trick. Lots of those are being abandoned around the neighborhood lately, but I have a permanent home for a few!

Because the lower half of those things are sort of shoe-shaped, I was able to slide them along the tripod support arms to a good angle, and then strap them down with hose clamps.

Haven't figured out how to mount a bearing at the top opening to actually use these as rotors yet...

As you can see in the picture below, I managed to angle the 2m eggbeater on the left OK without doing anything to the mast, but the other two are standing straight and proud in those rotors.

V-UHF loops and eggbeaters

I plan to replace these antennas with beams one at a time over the next few years. First up is six meters, so I did not mount my trusty AEA Halo-6 six meter loop. I have a small InnovAntenna LFA Yagi on order for that band. Meanwhile, in the picture above from right-to-left you can see:

  • an M2 EB-144 mounted above an Icom AG-25 preamp at about 28', on an angled pole but the antenna's OK,
  • a stacked pair of Olde Antenna Labs Mini-Wheel 23 cm loops hanging off an Icom AG-1200 preamp at about 28',
  • a stacked pair of KU4AB 222 loops at about 25', and
  • an M2 EB-432 mounted above an AG-35 preamp at 31'.

You can find close-ups of some of these on the page describing my previous antenna farm: the flat roof challenge. Notice anything missing? This time I replaced all my 2m-23cm J-poles and other verticals for FM and D-STAR with one single Diamond D220 mobile discone mounted above the beam on my MA-40 tower, and it's working really well at that height.


QRZ K6ATZ on QRZ     Twitter @K6ATZ on Twitter     Envelope Contact

"You see, wire telegraph is a kind of a very, very long cat. You pull his tail in New York and his head is meowing in Los Angeles. Do you understand this? And radio operates exactly the same way: you send signals here, they receive them there. The only difference is that there is no cat." — Albert Einstein