AV-640 Vertical is Up

My Hy-Gain AV-640 vertical is finally up!

This article is really about the assembly and erection of the antenna.  I will cover my operating experiences in a later post.

In the adjacent photo you can see it next to my house.  That’s my wife’s 2001 Toyota Tacoma in the photo (boy that is a great little truck).

First, this thing has a bazillion parts. A long time ago I had a GAP Challenger DX and this AV-640 seems like it has 20 times the parts to be assembled. And Hy-Gain is owned by MFJ Enterprises and has seemingly adopted the same policy of leaving the last ten percent of Quality Control to the buyer. Hoping to save some future buyer of the AV-640 some grief, here is a list of my discrepancies:

1. Instruction Manual: Pages 10-15 , page number missing
2. Instruction Manual: Pages 16,17 are numbered ‘1’
3. Instruction Manual: Pages 19- end, page number missing
4. Instruction Manual: Task VI refers to Figure G for mounting location of Matching Unit, It’s really on Figure H.
5. Parts Bag #1, 705-1032S Should contain 10-32 nuts. They were 8-32 instead.
6. 6 Meter stub 810-0640-19 incorrectly threaded.
7. Hole in one Single Stub Insulator 737-8100 drilled too small

It’s amazing to me that I’m reading reviews that are several years old complaining of a mis-threaded 6 meter stub, and they have not corrected the problem. Having inherited my late father’s tap-and-die set, I ran a 10-32 die down the 6 Meter stub and corrected the mis-threading problem. The missing 10-32 nuts were no big deal except that it was a 50 mile round trip to Ace Hardware.

There are times during the assembly when a second pair of hands would have been helpful.  Specifically when adding the rods for the capacity hat and counterpoise. One pair of hands could hold the end of the rod into the rings while the other pair of hands tightens the screws/nuts.

The footer is a concrete-filled hole that is 15×15 inches and 30 inches deep. The Hy-Gain support guy said that 2-3 cubic feet of concrete would be a sufficient footer, so mine is a little bit of overkill. The ground here is HARD. I could dig about three inches at a time.  I would then fill the hole with water that would take about 4 days to soak in.  Then I could dig another three inches. I therefore spent weeks digging the hole.

Embedded in the concrete is a 4-foot steel pipe that is 2 inches in diameter.  I then attached a Hy-Gain ATB-75 tiltover to it.  I’m getting too old to be climbing to high places to adjust antennas.  The AV-640 is mounted on top of a 15 foot mast that also is 2-inch diameter steel pipe.  The result is that the top of the antenna is at 40 feet.

Quick initial SWR measurements with my MFJ-269C analyzer:

7.2 mhz: SWR 1.4
14.1 mhz: SWR 1.8
21.3 mhz: SWR 1.5

I coud ‘easily’ tilt the antenna back to horizontal and tweak the 20M length but for now it’s good enough. (The tuner in my TS-590s seems to have no problem with it.)