[Hallicrafters] Sloper and SX-71 (was) Re: An AM antenna

[Philip Atchley]

Bill, Bob et al,
I too have used the Alpha Delta DX-B (60 footer) sloper antenna for a number
of years.  It's intended to resonate at 160, 80, 40 & 30 Meter ham bands.
However, due to real estate size restrictions (mobile home park with almost
no yard), mine is mounted over the sheet metal roof (about 1200 Sq/ft with
awnings) it resonates below all bands, about 1550, 3490, 6700 & 9700 kHz  if
I recall correctly.  This makes it GREAT for BCB and SWLing and does the ham
bands with a tuner!  I have not attempted to re-cut it to frequency.   The
high, coax fed end is perhaps 28 feet above the roof sloping to about 5 feet
above the roof on the South end.   It DOESN'T appear to be as directional as
one would expect, perhaps due to the proximity of the teetotal roof that is
also grounded.

Using that Sloper I have the Christian Voice BCB station (530KC) out of the
Caribbean verified and it is also my PRIMARY antenna for longwave beacons
below 530KHz.  With it I've heard beacons from Easter Island, Brazil,
Ecuador, Guam, Japan and far too many more to list here!  So, it's a good
all around antenna, though on some bands like 15 & 17, 21  MHz etc either
the 1/2 sized G5RV Inverted Vee, 15M Inverted Vee or Hustler 6BTV vertical
"may" outperform it (the G5RV is usually my "quietest" antenna).

SX-71 on the BCB band.  Mine was nearly dead on that band with very poor
performance, even after re-capping and overhauling it.  It turned out the
BCB input coil was fried.  For the BCB I replaced BOTH the antenna input
coil AND the RF amplifier interstage coil with a set of ADJUSTABLE universal
coils from AES Arizona.  The results was that I was able to adjust the
tracking of both coils for the BCB with GREAT results.  The set is one hot
firecracker on he BCB band now!

73 from the "Beaconeers Lair".
Phil, KO6BB



> Bill... for years i have used an alpha-delta sloper (the 60ft version from
> Universal Radio), with the feeder end at about 25ft and the other end at
> about 10ft. I also live near Puget Sound (Maple Valley WA) and can hear
> trans-pacific MW DX with this antenna and one or other boatanchor (I
usually
> use an HQ-180 with digital readout)
>
> I like the antenna so much i recently bought a second one, and am mounting
> it at 90degrees to the original. Eventually i hope couple them through a
> phaser, probably a Quantum.
>
> These antennas also work up a storm on the commercial HF bands. My guess
is
> that the SX-71 should be as hot as the HQ-180, if you can figure out how
to
> get the front end aligned on MW :-)
>
> hope this helps
>
> Bob Bennett, Maple Vly, WA