M0IAX

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Not a review of the Icom AH705 Automatic Antenna Tuner

Posted: 24 Mar 2021 03:48 AM PDT
https://m0iax.com/2021/03/24/not-a-r...antenna-tuner/



A long, long time ago (everything seems to be a long time ago these days)
Icom announced the AH-705 Automatic Antenna Tuner for the excellent new
IC-705 and on Friday 19th March 2020 Icom UK sent out a press release that
it was now available to buy here in the UK. I got my order in to Nevada
Radio as soon as I could and waited.




It arrived on the 23rd, less than 24 hours after being dispatched well
done Nevada Radio and Parcel Force.








So enough of the pre-amble you all want to know more about it Im sure, as I
dont do reviews this is not a review of the AH-705 but its a little more
info about it and my first thoughts.




What does it do?




You can see the Icom brochure here
https://icomuk.co.uk/files/icom/PDF/...5-brochure.pdf but
basically it will tune a long wire to 1.8mhz to 50Mhz with a 30m or longer
wire, or 3.5Mhz to 50Mhz with a 7m or longer wire. but thats not all it
will also allow you to attach a standard pl259 and tune your coax fed
antenna which means its as versatile as it could be. I suspect that its
best suited to a long wire antenna because as we all know the best place
for a tuner is at the end of the antenna not the end of the feeder line
from the antenna, but I intend testing it with as many options that I can
find, including some things that maybe wont work very well like barbed wire
fences and things




Whats in the Box?




Opening the box we find the instruction leaflet not sure what thats for
the the AH-705 tuner, control cable, coax terminated in BNC connectors, a
small bracket to attach a strap to for mounting the tuner to a pole, a
terminal post adapter for long wire and a power plug so you can make up a
12volt power cable.








Power




Power for the AH-705 is provided by 2xAA batteries. These are fitted easily
by removing the flap on the back of the tuner. There is also the option
making a cable to connect to your 12volt radio battery (the plug is
supplied) but as my soldering skills leave a lot to be desired and I want
to keep the number of cables to a minimum I will probably stick to using
the batteries.












External Connections




As you can see from the power connector picture above, on the bottom we
have the BNC connector for the feeder to the IC-705, control cable
connector and the 13.8 volt power socket. Its worth noting that the
supplied Coax feeder and control cable are the same length so its good to
see that someone was thinking logically about how this works








On the top we have a standard SO239 connector and a terminal for the
ground. Ground can either be some wire radials/counterpoise or a connection
to a ground spike.




Connecting to the radio and control




Connecting to the radio is simple enough, after connecting a suitable wire
or antenna to the AH-705 connect coax feeder to the AH-705 and to the radio
Antenna BNC and connect the control cable to both.








Open the FUNCTION screen, navigate to the second screen and touch the TUNER
option to tune it on. this will cause the AH705 to tune the antenna, you
will hear the latching relays click into place it should take a second or
two if you have set up correctly.




Using the AH-705 Automatic Antenna Tuner




Once set up if you change frequency simply transmit a carrier and the
AH-705 Automatic Antenna Tuner will do exactly what it claims to do. It
will automatically tune to the frequency you are on. For my quick test last
night I laid a long wire across the garden and raised one end about 2.5m
above the ground sloping down to the tuner which I hung on the back of a
chair (dont tell the wife!) I also attached some ground wires 3 or 4
measuring about 5m long for each one.












I was able to quickly tune on 3.5 to 28Mhz (1.8 did not tune as the wire
was not long enough) excellent results on receive, you can see from the PSK
Reporter map that with 5W using a mixture of JS8Call and FT8 the results
form my TX was quite acceptable.








Portability




Weighing in at just under 600g or 1lb 5oz (including feeder/control cables
and 2xAA batteries) its light enough. Its not tiny but can be held in the
hand and more importantly fits into the LC-192 backpack.












In Summary




Initial thoughts are I am very happy with this tuner its well designed and
well made although not rugged it feels like it can take a bit of
punishment. In use its simple to operate and works very well.




I intend using this tuner to complement my exiting antennas giving me
additional scope for experimentation and more options for lightweight
antennas. I never thought that the IC-705 should have had an internal
tuner, normally internal tuners wont deal with SWR higher than 3:1 which I
feel isnt too useful.




If you always use resonant antennas then you dot need this tuner. If you
want to make your radio more versatile when it comes to antennas I would
recommend the AH-705.




Look out for more about this tuner and the IC-705 in the next few days.
Video of it in use coming as soon as I can find the time.




73




Mark M0IAX




https://m0iax.com/findme