[AMRadio] Laws of Physics Repealed!


Jim Candela jcandela at prodigy.net
Fri Oct 23 17:06:20 EDT 2015


I wonder if the thing is similar to an OCF electrical 1/2 vertical dipole?  On 75m the BW is only 35 Khz suggesting the Q is high. Manual says the base must be at least 10' off the ground. If this thing were a dummy load, the bandwidth would be much broader. The bottom seven 49" "counterpoise" radials might not be radials at all. They are too short to provide much of a ground. The safety labels on each say these are hot as heck when RF is applied.
JimWd5JKO
 


     On Friday, October 23, 2015 3:51 PM, "oldradio at comcast.net" <oldradio at comcast.net> wrote:
   

 Cuscraft has a new owner, a Mississippi company of many products.

  http://www.mfjenterprises.com/

---------------------------------------

----- Original Message -----
From: "Donald Chester" <k4kyv at charter.net>
To: "Discussion of AM Radio in the Amateur Service" <amradio at mailman.qth.net>
Sent: Friday, October 23, 2015 4:23:53 PM
Subject: [AMRadio] Laws of Physics Repealed!


First there was the Gotham Vertical.  Then the infamous Max-Com automatic
antenna matcher.  Now, Cushrcaft is in on the action.

"R9" vertical.  Low angle radiation gives incredible, easy, world-wide low
band DX on 75/80m and 40m, plus it covers 30 through 6m with low VSWR on all
bands, with broadband matching transformer; no antenna tuner needed. Low
profile blends inconspicuously to keep your HOA happy.  31.5 ft tall.  Best
of all, NO RADIALS NEEDED!!!

Only $639. Just plug in your plastic radio and talk, talk, talk!

See November, 2015 QST, page 2.

Amazing that hams (or maybe I should say HAMs) swallow that crapola.  31.5
ft is only an eighth wavelength on 75/80m. The base impedance of a 1/8
wavelength vertical is about 12 ohms. No matter how much gimmickry such as
stubs, loading coils, toroidal transformers and porcupine spikes are added,
that thing will basically be a dummy load unless it is used with a
SUBSTANTAL radial ground system.  A couple of 8' ground rods won't cut it.

I had always considered Cushcraft, which has been in the antenna business
for decades, a reputable outfit, but this makes me wonder.


Don k4kyv
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