My Grey-Hoverman Antenna

NARODs for VHF

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The term NAROD stands for: Not A Reflector Or Director, as coined by the inventor, 300ohm. These additional elements boost the gain of a Grey-Hoverman for VHF to usable levels, while minimally effecting the antenna's gain over the UHF band. The result is an antenna optimized for channels 7-51, the majority of TV transmissions now in use. In the unlikely event that you have VHF-Low (Real RF Channels 2-6) transmitting in your area you will have to get a separate antenna to receive these frequencies.

In addition to the NARODs themselves it is necessary to add NAROD reflectors. These are one piece rods, unlike the collinear reflector rods on a G-H, and are located far behind the elements.

Here are the NAROD dimensions.
And the details of attaching them...

(As always, clicking on any of the photos will open a larger version in a new browser window.)

For the full story of the Grey-Hoverman antenna click here

Tophat_NAROD_dim03.jpg
NAROD dimensions

NAROD-Supports.jpg
NAROD support dim's

29-complete_set.JPG
One Complete set

22-scribing_tophat_support.JPG
fig 1

23-scribing-tophat_support.JPG
fig 2

I started making the NAROD supports when I cut the Lucite for the element supports of the G-H on the table saw, but they came out a bit ragged being such thin material. I clamped all 4 pieces together and smoothed them out on a belt sander. I used the scribe & snap method for the Tophat supports and they came out much nicer without the extra effort. (fig's 1, 2 & 3)

24-setting_length.JPG
fig 3

25-finished_supports.JPG
fig 4

The finished supports are shown in fig 4. All holes were laid out with a caliper for accuracy, centerpunched and drilled. I clamped all 4 pieces together and drilled thru all: The small holes for the element & NAROD wires and also a pilot hole using the same size bit for the larger holes for the reflector rods. I then finished with the 5/8"spade bit individually to minimize the chance of cracking.

NOTE: While the .136" dia is a little loose on the #8 wire used, it facilitates fitting around the Tophat wires after bending, and generally eases assembly. (I had the notion of drilling .128" dia & putting these on before bending, but this was a pipe dream - the wires were tough enough to bend with nothing in the way! LOL)

27-tophat_bending-jig.JPG
fig 5

So I'm all ready to bend the NAROD wire around a piece of scrap 1/2" PVC, as it has an O.D. of .845" and is almost perfect to the .838" required to get the 1.0" centers out of #6 wire - when I look at the wire and realize it's not that thick! Turns out I've been working with #8 all along!!! (Smacks self in head, as in a V-8 commercial) No biggie, a piece of 3/4" copper pipe is .875 O.D. and almost perfect for the .128" dia wire. So to sum it up, I used the same #8 AWG copper wire for the NARODs that I used for the driven elements. And these should be the same size - whatever size that might be. LOL (And I did correct the other pages ; )

26-tophat_bending_jig.JPG
fig 6

Fig's 5 & 6 show the bending jig I made from a scrap of 1"x4" several feet long screwed to a scrap of 2"x4" with a 7/8" dia hole drilled for a scrap of 3/4" copper pipe - it was clamped in a vice. I marked a line down the center of the pipe with a sharpie to help keep my locating marks on the wire in the center of the 180 degree bends when forming the wire. Scrap wood was used to back up the wire and make bending easier.

30-assembled.JPG
fig 7

Figs 7 & 8 show the NARODs and reflector rods assembled on the antenna. The NAROD reflector rods are the same 1/2" copper pipe used for the collinear reflector rods. The plastic supports will be glued to each other and to the rods & wires to secure.

As the support plates are the pieces that determine the spacing and location of the NAROD elements and reflector rods, the PVC pipe that takes the weight of the NAROD reflectors aren't glued, and are just a pressure fit.

32-assembled.JPG
fig 8

It took a little tap-atty-tap persuasion with a small hammer to adjust the seating of these so the rods lined up with the holes in the support plates, but it wasn't a big deal. I made sure to cut the pipe that connects the tees a little short to allow for adjustment. Once everything is aligned a couple of small brass screws up in the floating tees at the collinear reflector rods hold everything solid. (The NAROD reflector rods themselves are also held permanently with a small brass screw.)

Next I have to assemble the bottom half and get this bad boy mounted to a mast ~10' above the roof and do some testing!


Hope this was of help to someone!

Hooper

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The Gray-Hoverman antenna designs, schematics, and diagrams on this site are Copyright 2008 and are free: you can redistribute them and/or modify them under the terms of the GNU General Public License as published by the Free Software Foundation, either version 3 of the License, or (at our option) any later version.

These designs, schematics, and diagrams are distributed in the hope that they will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details.

For your complete copy of the GNU General Public License to go along with the designs, schematics, and diagrams, see:

http://www.gnu.org/licenses/gpl.txt

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All done just for fun,

And to see if I can produce something that performs...

And if I can ditch Dish Network in the process, all the better! :-)