Hello and welcome to Xtract 031 of the HX Files.
In this issue of Echo Ireland I would like to talk about
some of the aerials used /portable (and at QTHR) and the means to fix them in
place when out /p.
In photo 1 above, you can see some aerials mounted on a small
portable mast that has been used many times, all the aerials on it are for
23cms (1.2ghz) the top one is a vertical and the others are various types of
beam aerials such as what would be classed as a regular type of beam, the
others are a loop Yagi, and a circular polarization type. In use there would be
some coaxial cable used to connect the transceiver to the aerial but on some
occasions the transceiver is screwed direct to the aerial and a remote lead
carrying the power, audio, video and TX/RX switching from the car to the mast
mounted transceiver.
Photo 2 above shows one of the stands used, it works on the
fact that you drive over the base of the stand and the weight of the car holds
it in place and it does not need any stays to hold it in place. This base unit
was the mk1 type; it was made when I had a 5 door sierra, and made as a fixed
item. It became awkward to transport in the boot model car I got next and the
base unit was left aside for a few years. The latest car is a hatchback and is
well able for it, but not long after using the base for a few times I got
someone to modify it, firstly he had to separate part of the base frame and
make it wider by inserting an extra
piece of box metal so some hinges could be wielded in place, also the rigid
support arm on its right side was cut away and its ends modified so that each
end was held in place to the base by a bolt and when one of them was removed
the unit could be folded flat for transporting and storage, the base can be
seen again in photo 3 below along with some of the mast bases that were bought / made over
the years.
In photo 3 above you can
see the various ways the aerials are used /portable whether attached to the car
or being held upright by other stands. Some of the masts would take a couple of
people to erect safely, but others could be attached to the towing eyes or the
tow bar. You should take care when you are on your own working /portable, you
could end up with some damaged aerials, or car as the pole with the aerials
attached could be to long and will be top heavy for you to manage the assembling
of the aerials and mast, and their dismantling, the dismantling part can be the
most dangerous regardless of the weather, as fatigue could set in after a long
day and with possibly cold / wet hands you
could lose your grip and have to repair a boom and a few elements on an aerial
or two, and remember if you are on a height you do not need a skyscraper of a
mast, if you are on your own just bring something you can safely manage by
yourself.
In photo 4 above you can
see some of the other aerials that did not make it onto the mast, these bow tie
aerials can be used individually or some of them could be placed into the panel
aerial case you see them resting on. (The panel aerial is for use between
195-197 MHZ.) When it comes to connecting your aerials to your transmitter other
than coaxial cable, the range of fittings can be bewildering as can be seen in
photo 5 below.
Photo 6 above shows a dish and on the bottom right of it is an
aerial that looks like a can, and it could be used as is for some local use, or
it can be used as a launcher and lined up to feed a dish like the one it is
sitting on, but some framing, and exact measurements would have to be done to
attach the can to the dish at the right distance but that is a job for another
day.
That’s it for this issue of Echo Ireland and indeed for
this year.
I would like to wish you all a Happy Christmas and a
Prosperous New Year.
And that all your signals are P5.
73
Pat