[ICOM] ATU Mobile
Edward Dickinson, III
softblue at alltel.net
Fri Mar 10 17:25:55 EST 2006
I operate 40m through 10m...as described.
-----Original Message-----
From: icom-bounces at mailman.qth.net [mailto:icom-bounces at mailman.qth.net] On
Behalf Of Paul Gates, KD3JF
Sent: Friday, March 10, 2006 5:03 PM
To: ICOM Reflector
Subject: Re: [ICOM] ATU Mobile
Good grief .... You are going through a lot to operate on 40. If I am using
a ham stick I have a portable tuner up front with my rig. But, usually I am
not too lazy to tune the antenna by itself. When I use a van and hustler I
have a 3 ft mast to get the antenna above the van. In the 60s I had 2
hustlers on the rear of the van or car and nobody had a better signal than I
did. Now I use one antenna in the center of vehicle off the trailer hitch
which I no longer use as a hitch. I have the old Atlas matching network if I
can't get a 500hm load for some reasonl. K.I.S.S. is my focus.
Paul, KD3JF
EX: WA4JGI, WA8TER
Central Maryland
FM19qd (Map Grid Square)
----- Original Message ----
From: "Edward Dickinson, III" <softblue at alltel.net>
To: ICOM Reflector <icom at mailman.qth.net>
Sent: Friday, March 10, 2006 1:26:53 PM
Subject: RE: [ICOM] ATU Mobile
David,
I don't know if this will help, but you might give it some thought.
While mobile, I operate 40m through 10m. In my mobile installation, I run
an AH-2 remote antenna tuner and a 40m Hamstick type antenna with a special
provision. Icom has current units which are very similar the the AH-2.
The ATU is mounted on the underside of the trunk lid. The business end of
the ATU is mounted facing towards the front of the car and the forward edge
of the trunk. I use a 3 magnet mag-mount for the antenna. I place the
mag-mount on a spongy rubber pad (toolbox liner from Harbor Freight) cut to
size. The feed from the output of the ATU to the base of the antenna a
jumper (insulated center conductor from RG-X, I think) with a banana plug.
A banana jack is installed at the feedpoint on the magmount. The jumper is
less than a foot long and passes through the edge of the trunk lid when
closed. The ATU is strapped to the underside of the trunk lid with small
bungee cords for easy removal. The banana-jack/plug allows for easy removal
of the mag mount. The toolbox liner protects the painted finish on the
trunk. I also use a small bungee cord to hook the mag mount to the edge of
the trunk for extra security.
Now, the special provision. I took a 4' rod, which is about 3/32" diameter
and attached a Claw Clip (beefier than aligator clips, but I don't know the
official name of them) to each end. They are attached with springs slipped
over the ends of the rod and anchored to the screw terminal of the Claw
Clips. The springs allow for flexing of the antenna system. The length
matches the length of the base section. When using 40 meters I do not use
this special provision, but when I want to operate above 40 meters it is a
10 second add on. Easily done at a quick (and careful) stop on the shoulder
of a suitable roadway.
With the special provision clipped on, the 40m coil is bypassed and I
suspect (my ignorance may be showing) the remaining affair looks somewhat
like a 102" whip to the ATU.
I have used older radios such as the IC-751A, and 745 and 735 with this
basic setup. The AH-2 has a control head that goes with it. It was not
required with rigs newer than the 735. It works fine with the 751A and 745
and I suspect it will work with my 730 and 740 as well. A feature on the
735 that is not found in the 4 other rigs mentioned, is a provision to
automatically turn down the power on the rig when tuning. When using the
751 or 745, etc., on must first manually turn the power down to tune. There
is an odd advatage that comes with this manual power cut-back. If one 1st
pre-tunes at low power to obtain a nominal 1.5:1 match, power can be turned
up and the system re-tuned for a near 1:1 match. If initially tuned at high
power and there is a significant mis-match, the tuner may 'kick-out' or
refuse to tune. After pre-tuning at low power, it will usually successfully
retune at a higher power and better match.
I find the on-air performance of this system on 40m and above satisfactory.
In your case, I don't think you don't have to be concerned about the control
head or power levels as that circuitry is built into your 706.
I hope this diagram helps (and formatting holds up)!
*
|
|
|
| <- Top Whip
|
|
0 <- Top Furl =? <- Claw Clip on Spring
I |
I | <- Steel Rod (+/- 3/32")
I <- Loading Coil Area |
I |
I <- Clip to Furls <---|
I |
I |
___0___ <- Base Furl =? <- Claw Clip on Sping
=^= =^= <- Mag Mount
---------------------- <- Trunk Lid
Happy Mobiling!
de Dick - KA5KKT
-----Original Message-----
From: icom-bounces at mailman.qth.net [mailto:icom-bounces at mailman.qth.net] On
Behalf Of David J. Ring, Jr.
Sent: Friday, March 10, 2006 12:13 PM
To: ICOM Reflector
Subject: [ICOM] ATU Mobile
Can anyone recommend a solution to this?
I want to use multiple bands while mobile. I have an IC706, it has no
automatic tuner, but it feeds Hustler whips quite well.
Is there anything as efficient as the Hustlers on 80 and 40 meters (or
better?) that I can use an automatic tuner (ATU) with a standard 102 inch
whip?
I know one manufacturer makes a whip that has two antennas inside it, one
that is helically wound for use at lower frequencies (40, 80) and a standard
no coil whip inside that. I've not heard if these are worth the money.
They are expensive because of the dual antennas in one package.
Any suggestions would be helpful.
73
David N1EA
n1ea at arrl.net
----
Your Moderator: Dick Flanagan K7VC, icom-owner at mailman.qth.net Icom Users
Net: Sundays, 1700Z, 14.316 MHz Icom FAQ: http://www.qsl.net/icom/
----
Your Moderator: Dick Flanagan K7VC, icom-owner at mailman.qth.net Icom Users
Net: Sundays, 1700Z, 14.316 MHz Icom FAQ: http://www.qsl.net/icom/
----
Your Moderator: Dick Flanagan K7VC, icom-owner at mailman.qth.net Icom Users
Net: Sundays, 1700Z, 14.316 MHz Icom FAQ: http://www.qsl.net/icom/
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