[TowerTalk] Fw: SCREWDRIVER ANTENNAS DE K0FF

[K0FF]

Howard, I have tried a few of the full sized screwdrivers and can attest
that they are all very good performers on HF, and yes they are all a problem
to  mount. Let me comment on the Yaesu ATAS100 in particular, since this is
the only one I know of that also covers VHF frequencies (the theme of our
reflector).  Used with the Yeasu FT847 or FT100/D the ATAS 100 will operate
on all ham bands between 40M and 432. This in itself is an amazement to me.
Secondly, it;s without a doubt the smallest and lightest weight antenna in
the group. It accepts a standard SO239 type mount, and is small enough to
mount smack in the middle of the car/van roof, and all I use is a long
chassis mount so239 on mine, and have tested it at 75MPH in Oklahoma winds
with no problems.

No extra control wires, control boxes , switches or anything needed. The
radio tunes the antenna with a panel button command, and sends the info and
voltage up the coax cable. Very slick.
Performance wise, you would naturally expect a smaller antenna to be lacking
over the monster size screwdrivers, and it no doubt is, but I'm convinced
that the ability to roof mount it makes up for a lot of that. I was very
successful working even DX on 40CW from the mobile, and even broke a few
pileups during my winter mobile activity.

When used on 6M it's a full size 1/4 and the performance is about as good as
you can get with any other full size vert. On 2M and 432, the antenna is
fully nested, and no further tuning is done across both bands. By selecting
the length just right, the antenna becomes an odd number of quarter waves
long, and the SWR is quite low. Of course the trade off on these two upper
bands is that you really want a horizontal antenna, but this thing does
work, and ever cross-polarized will give some surprising contacts.

Another use that I have put the ATAS antenna to is portable from motel
rooms. When mounted on a simple single Magnet base (ALA MFJ 5") and stuck on
the airconditioner unit, the antenna still performs remarkably well.
 After 35 of mobiling, and using most of the schemes available, I  can say
that I'm very happy to see a multi purpose antenna like this available.
Again, any antenna this small is a compromise, you can't fool he laws of
physics, but for a single package that will give reasonable performance on
10 bands, it can't be beat.

Now there is an after market outfit selling a control box that allows the
ATAS100 to be used with any radio (in the manual tune mode).

I'm looking forward to future non-mobile trips , with the FT100D/ATAS100
/mag mount and MFJ tiny switching power supply.  This whole outfit can be
tucked away in the corner of a suitcase, with a total weight of about 11
pounds.
73 and have fun, K0FF


-----Original Message-----
From: Howard Gorden <GORDENH1@westat.com>
To: vhf@w6yx. stanford. edu (E-mail) <vhf@w6yx.stanford.edu>
Cc: Howard Gorden <GORDENH1@westat.com>
Date: Wednesday, June 21, 2000 9:07 AM
Subject: SCREWDRIVER ANTENNAS


>Hi All,
>
>I know that this reflector is primarily for VHF, but with the current
>upgrades going on, I
>thought this question might be relevant.
>
>If any one has a problem with this e-mail as to content, and wants to Flame
>me, my
>phone number is: 301-294-3824
>
>Has anyone done a comparison on the currently available SCREWDRIVER
Antennas
>??
>
>Ease of assembly (mounting)
>User friendly operation
>Accessories (things that are really needed for operation)
>Accessibility to the MFG if problems arise
>PRICE ?/
>etc.
>
>Have a nice day...
>
>73 de Howard W3CQH
>Pres. MADRAS
>DRO Montgomery County, MD, RACES
>------
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