[TowerTalk] DX Engineering Horizontal Receive Antenna

[Rick Karlquist]

I tried this antenna last year and found it to be unusable due
to BCB interference (I am 6 miles from a 50 kW AM station).  You
would think being horizontal that it simply wouldn't pick up
ground wave, but the feedline decoupling is inadequate.  I know
it was the feedline because the antenna was mounted on a crankup
tower and the QRM got worse as the tower was cranked up.  There
are some front end filters which can be selected by jumpers.  This
is just a band aid, and, while it helped, it wasn't sufficient.
It was possible to get it to work on 40 meters and up by selecting
the highest cutoff filter (thereby making it useless on low bands). 
However, I found it to be fairly deaf on 20 meters and up.

As an experiment, I put up two of these antennas, but on one of them,
I replaced the DXE electronics with a simple broadband transformer.  In
A/B tests, the modified unit had as much or more sensitivity compared to
the stock unit, but of course it didn't have BCB QRM problems.  The
electronics in the DXE unit is simply a source follower FET; no rocket
science.  So I wasn't surprised that my transformer could replace it.
Another advantage of a transformer is that you get extreme feedline
decoupling.  There is no DC feed choke to limit the decoupling.

When you turn a CB whip horizontal, it sags a LOT.  If I was going to
keep the DXE antenna, I would have redrilled the holes to tilt the whips
upward somewhat to partially alleviate the sag problem.

Another gripe I had with the DXE antenna is that it isn't weatherproofed
very well.  The box is folded up from sheet metal and the seams aren't
sealed.  It is also much heavier than it needs to be.  For some reason,
the whip mounts are made of brass, not lightweight aluminum.  Not sure
what they were thinking when they chose brass.

I am currently assembling a MonstIR which will be mounted at 110 feet.
I am installing relays on the 70 foot passive elements to allow me
to use them as phased low band receive dipoles.  I will again use simple
transformer coupling.  This should give me the functionality I wanted
with the DXE dipoles.

Rick N6RK







Richard Thorne wrote:
> I'm working on my home stealth antenna installation.  Currently I'm using
> a
> 29' vertical mounted on my fence with 2 radials fed with an SGC-239 tuner
> at
> the base.  For transmitting it works extremely well.
>
> On receive its picking up all the noise in the neighborhood.  I ran a
> quick
> test with a dipole running along the fence line cut for 20 meters and the
> noise was dramatically reduced on that band.
>
> The Active Horizontal Receive Antenna - DXE-ARAH-1P looks very intersting.
> I could mount it on my chimney with a small tv rotor and use it for
> receive.
>
> http://www.dxengineering.com/Parts.asp?ID=888&PLID=163&SecID=79&DeptID=12&PartNo=DXE%2DARAH%2D1P
>
> Has anyone tried one of these yet? results?
>
> Thanks in advance.
>
> Rich - N5ZC
>
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