Hello and welcome to Xtract 025 of the HX files.
In this Xtract I would like to talk about a couple
additions made to one of the 10 GHz dishes used when out portable.
This would involve somehow attaching a block of metal to
the back of one of the dishes. The metal would be shaped to the same profile as
the dish and it would have a telescopic sight and a laser fitted to it.
These attachments would (I hope) help me line up with the
other station in the qsl The telescopic sight to help line up the other
station, and the laser would hit the spot of their location or at least very
close to it.
New toy
Before talking about the project in this issue of Echo
Ireland, I was wondering what project was going to finish first as I was moving
from one project to another as the stock pile was missing a few parts for some
of them, and not wanting to remove parts from other projects made in earlier
issues what was one to do, then just what I needed, a new project came to the
top of the list that pushed the others to the back burner; I decided to change
my car. I had a friend looking out for a car for me and in the last couple of
days of February he found what I was looking for and a new toy was bought. One
job was to take the radios out of the other car and into the new car, (new to
me that is) the ATV gear had to be removed and installed also, although not
fully installed into the car yet, some of the ATV equipment is in place and
just waiting to be connected, as with some cars there are not too many hiding
places to place the parts, and it is getting harder to get cables from the car
battery to your equipment. For now only one hole was drilled in the roof for
the 2m/70cms aerial and now it is a waiting game to see if a tow bar or a roof
rack is purchased to attach anything else. Play time was brought to an abrupt
end when our editor let it be known that the deadline was only a couple of days
away as I had not noticed the time, so words like gosh and darn were uttered
and something had to be finished for Echo Ireland.
The sight
The telescopic sight (photo 1 above) was bought at a rally in
the UK, the trader who I know for many years said that I had the wrong accent
to be buying this sort of thing over hear, he did not know what to think when I
asked him if he had anything to go under the sight ( a rifle).
Some details
The sight is to be mounted above the centre of the dish,
and the laser is mounted below the sight.
Lining up the sight and laser would not require any high
tech equipment, the high-tech thing done in a friends yard was to fire the
laser (switch it on) at the wall, mark that spot on the wall with a felt pen,
and then using a spirit level I marked a spot on the wall the same distance as
the sight is mounted above the dish centre, so in theory the spot on the wall
would show were the rf is heading for.
Anyway back to the start of the construction, using a
piece of wood a template was cut out to match the metal, firstly using a fret
saw and then finishing it off with some files and sandpaper to get it right.
With that job done it was time to get the shape marked out onto a piece of
metal fit enough for the job.
After a bit of a search the block of aluminium (photo 2 below )
was found in the parts bin, and the wooden template traced onto the metal
block.
Using a small
angle grinder, fitted with a cutting disk, a lot of the unwanted metal was
removed and the cutting disk replaced with a grinding disk, this would remove
most of the metal and leave a small amount to be filed to the final shape.
Ooops
It was while grinding the last of the metal that some of
the aluminium dust was sucked into the grinder through the cooling ducts and in
an instant the dust ignited and there was a flash and the mains power tripped.
When the power was turned back on I found out two things,
one that the grinder no longer worked as the aluminium dust had gotten into the
workings of the grinder and wielded to them, and two, new underwear needed.
It was while
grinding the metal that the dust was hitting the guard behind the vice and
unknown to me, some of it was bouncing back towards the grinder and being
sucked into its cooling ducts.
With the curve finally right some grooves were cut into
both sides of the top of the block so that the sight would slide onto the block
of metal for fitting. The laser was to be clamped to the block using some
fittings from another project until some were made for it, but the drill bit
jammed, snapped and followed by the drill with me holding it and the metal
fitting broke. So some changes had to be made for this issue, and not
having similar brackets in stock yet, I am
just using the smaller laser, or as the trader said, it is an astronomy aide, When the bracket was finished it had to be
attached to the dish but how, not wanting to drill any holes into the dish or
the wave guide after a chat in one of my local hardware stores with members of
the staff some adhesive was used and that adhesive is so strong that you would
bend the dish rather than break its hold on the parts.
As you can see in photo
3 above, there is a difference in the sizes of the lasers;
the larger of the two is
from an old laser printer/copier.
Photo 4 above shows the sight in position and the
laser just placed on top of the wave guide,
it or the larger one will be
attached to the plate when the parts are got.
That’s it for this issue; may your
signals be P5.
73 de Pat.
