Topband: 8 element antenna - Amplifier placement

Gary Smith Gary at ka1j.com
Sun Sep 25 01:22:21 EDT 2016


A little follow-up with my life in the 
fast lane...

I move slowly, all considering, kind of 
like Ahab with a pair of shoes. I've been 
spending the better part of the last two 
weeks putting up a HI-Z 4-8Pro array.

If it were open space with good soil, all 
would have been done after the first 1-2 
days. But no, I live in New England, the 
place where the Glacier's Gall Stones came 
to rest after it encountered Global 
Warming.

The place I have to put the array in is 
like a Louisiana Bayou minus the standing 
water. It's a salt marsh and just a bit 
above sea level. I don't have an option 
where else to put it, this is it.

We're known for Lyme disease, Lyme, CT is 
10 miles west of here so tick protection 
is mandatory. Worse, this is Bambi's 
frolic-land and deer sign is everywhere. 
More, we're blessed to have West Nile  and 
of course Zeka is getting all kinds of 
press. So pyrethrin and DEET 40 is the 
cologne de jour.

You can't imagine the scale of the rocks 
here, it really boggles the imagination. 
So much stone 5" below the surface and 
muck on top of them. Some boulders above 
ground are the size of Volkswagens and 
most showing are like an iceberg with the 
greater mass underneath.

This place has one other unusual issue in 
that in a storm surge, at high tide, salt 
water can get in there and will ruin 
everything. So to outwit the tide, I moved 
the amplifiers up inside the PVC tubes and 
used a rubber cap to hold the amp high 
enough that if the water rises, it won't 
reach the electronics as there will be an 
air pocket inside to keep everything out 
of harm's way. I posted this pic earlier 
of what I did:
doctorgary.net/Hi-Z-8-Pro-3.jpg
It will work just fine to keep the amps 
safe..

Of course there are the briars, brambles 
everywhere that are strong enough to stop 
an Iron Man in his tracks, not to mention 
the bittersweet vines that make walking in 
a straight line impossible.

I staked out the proper placements for the 
8 antennae, 4 times, before I found an 
acceptable spot rock-wise but the trees 
were unforgiving and ended up cutting down 
7 rather large trees to make room.

Of course the Poison Ivy is everywhere and 
the last spot I had to deal with branches 
& rock-wise had a hairy 5" root of Poison 
Ivy going up the tree with branches 
hanging out right in the way of the 
antenna. The Oak was too thick for my 20" 
chain saw so I had to remove the tree 
branches and the poison ivy. 

I couldn't reach the branches 20' up and 
my extendible saw/pruner could only reach 
the poison ivy. Ended up slicking the vine 
at knee level and leaving it die for a few 
days. I tried a rope saw but it got stuck 
1/2" in and was useless. Then I remembered 
the extra elements I ordered from DXE and 
connected the large ones & duct taped the 
pruner to the aluminum and was able to 
reach the branches. Between the tree 
sawdust and the poison Ivy Sawdust, it was 
a glorious time.

Finally , success! The local metal shop 
cut my aluminum angle for the 
ground/support rods, so today I hoped to 
sink all the angles, using a Stainless 
Steel angle as a probe to find what 
worked. Great success, I get to the last 
place I had marked out as correct, put the 
knapsack with all my tools down, pull out 
the SS angle and pound in the Aluminum and 
there it was, the sound like small Harley 
Davidsons on a mission from God, the 
ground wasps that I had put my knapsack 
down on their entrance were angry and knew 
I was to blame.

Give me three good Honey Bee stings, one 
yellow Jacket sting but nothing inch for 
inch is more painful than these guys, they 
are just mean. They stung me several times 
and I proved Ahab can still run if the 
prize is worth enough. I couldn't get my 
tools, there were constantly 3-4 dozen of 
these in the air swarming everything I had 
laid down.

Some Hornet killer later and I could get 
close enough with a stick to wrangle my 
tools out but the damage was done 
time-wise, I couldn't finish before dark. 
So I finished assembling the antennas, 
have them ready to connect to the 
controller and tomorrow I get to connect 
up all the coax, the terminals, everything 
outside and I'm good to go.

My ear is the size of a Cauliflower but at 
last count it was Wasps 5, Gary 100, that 
wasp stuff really works... Looking forward 
to hearing with this marvellous Antenna 
system.

Oh, and I left out so much more of the 
saga... ;)

73,

Gary
KA1J

 
> I'm so close to being done with putting 
> this together. I have all 8 antennas made 
> @ 23' each the tip section is .5" and the 
> base is .850" I'm using a 3/4" fiberglass 
> rod as an insulator 
> 
> doctorgary.net/Hi-Z-8-Pro-1.jpg
> doctorgary.net/Hi-Z-8-Pro-2.jpg
> 
> I am having a conundrum with the placement 
> of the enclosure for the preamp mounted at 
> each antenna and need some advice. The 
> problem is I am at sea level and the 
> antennas will be mounted in a location 
> that will possibly get a storm surge 
> during a Hurricane, it ruined my remote 
> coax switch during Sandy from this very 
> reason. The preamp does have a silicone 
> gasket but if the amp gets submerged in 
> salt water, I'm sure it will get past the 
> terminals and ruin the amp. I have no 
> alternate choice, this is the location 
> where I have to put the array.
> 
> Seeing the photo of the end cap on the PVC 
> tubing with the zip tie holding the amp in 
> place (to protect from rain & Snow), gave 
> me an idea for the solution; At the top of 
> the PVC tube, make two opposing holes, run 
> a loose loop of thin wire through and 
> twist together. Run the coax up & over the 
> wire to hold the amp elevated inside the 
> tube, all the way to the top. Use a rubber 
> cap with radiator clamp to secure the top 
> and make it truly airtight. Now if the 
> tide water from a storm surge encroaches, 
> there will be a pocket of air inside and 
> will be unable to push high enough to 
> reach the amplifier. I tried this with a 
> Mason jar and the water did not get very 
> high in the upside down jar.
> 
> doctorgary.net/Hi-Z-8-Pro-3.jpg 
> 
> So here's the dilemma: As a further hedge 
> against water damage assuming there are 
> strong winds making waves (they would not 
> be breakers, just waves in the marsh) at 
> this time, I'd like to raise the placement 
> of the amplifier so it would be another 
> foot higher than standard placement which 
> is on the base below the insulator. This 
> would require me to clamp the PVC on the 
> antenna instead of the base. Can anyone 
> see how this might be a problem with 
> operation?
> 
> Also, I'd like to spray camo paint on the 
> elements so they don't stand out. When the 
> leaves come down, I'd prefer the neighbors 
> not see the elements, they're nosy enough 
> as it is. I think I remember reading a 
> layer of paint on the element shouldn't 
> cause a problem, is this correct?
> 
> Thanks & 73,
> 
> Gary
> KA1J



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