Friday, December 5, 2014

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.

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