Hello and welcome to Xtract 023 of the HX
Files.
In this xtract I would like to talk about a handy little project that
was made a short time ago, its main use is to be a quick setup when first
arriving on site, and it would get you on air in a few minutes by using the
tripod, a slot aerial and coax you would be on air whilst the main station was
being setup.
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The unit in receive mode |
In photo 1 above you can see the finished project,
top is the transmitter, on the left side is the receiver, in the middle is an N type socket, on the middle right is a TX/RX switch, a red and green lights, and a red and black DC sockets. In the lid of the box is a monitor and on the top left of the lid is a camera with sound.
Case history
The case for the project was bought at a nearby car boot sale, it was
originally a vanity case and the main reason it was bought was (not for the
fiver the seller was asking or the hair dryer in it but) the fact that the lid
was deep as it would accommodate a monitor for a project when I got a monitor
small enough to fit, and there the case lay, languishing in the stores
department, (as seen in the last HX Files) for a couple of years. Maybe some
time I will feature the stuff in that department/shed in a future issue when/if
I have to take everything out for some stock taking.
The build
The first thing I noticed was that the case had a couple of narrow
metal brackets riveted to the sides to form a support for something when the
case was brand new. These brackets would be used as a support for the main
panel and for a change the panel was cut from some of the mesh sheets that were
bought in Friedrichshafen this year. The panel had holes of 8mm in it and after
measuring the internal dimensions of the box a piece was cut out with some tin
snips and made to fit the case. You would think that having a piece of metal
with a couple of hundred holes in it that it would make for an easy time but
they were never in the right location but with the snips and some files the
parts could be fitted to it, but as the holes were not in line it meant that
when cut out the panel had a lot of sharp edges to it, although the panel would
be recessed into the case a lot of filing still had to be done which took a
while and I was almost sorry I did not pick a piece of solid sheet metal
instead. Knowing the case was a small and that the components would be close to
each other I could not be to fussy unless I wanted to made my own case, and
also having the 12v battery as a primary power source installed in the case, things
would be cramped and some compromising would have to be done. With that in mind
the laying out of parts followed, and then with the aide of a file one of the
holes was widened to the size of the SMA fitting on the TX board, and with a pair
of snips some of the metal was removed to let the phono and DC sockets protrude
trough the mesh, some fine tuning was done with the use of various files to
smooth the edges and to make the parts fit nice and tight.
The same method was to fit the RX board next and most of the rest
of the parts were able to be fitted as they were small enough to be installed
with no need for the holes to be touched, with the exception of the N type
connector the file was used to remove the excesses metal. With the TX/RX boards
and other fittings in place, but as the transmitter’s output power was 50mw I
decided to use a 2 watt amp, it was connected to the TX unit with a small SMA
patch lead on one end of the amp and the previously mentioned N type panel
mount to the other end, and as the amp was mounted under the panel, and the
transmitter’s SMA fitting was above it, one of the holes in the panel was
widened to allow the patch lead through it and connect the transmitter to the
amp. The fuse holder was mounted on the top of the panel, as if there was a
power issue the fuse could be checked out quickly without the need for a tare down of the unit. The use of the DC sockets are two fold, their primary use
are to allow the recharging of the units 12v 5 amp internal battery, and they
would also be a handy source of 12v.
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| Photo 3 |
The monitor was attached to the lid of the
case with the use of some small brackets to leave a space for the audio to be
heard, as the monitors internal speakers were mounted in the back of it, it
also had a headphone socket so you could use the headphones or a set of active
speakers depending on the location, in photo 3 to the left of the monitor you
can see were the camera is fitted.
In use
To use the transceiver the
toggle switch is moved from its centre off position and pulled towards the
operator, and to receive the switch is pushed away from the operator from the
off position. There is no separate power cut off switch, but this toggle switch
has a locking system, to use it you have to lift a spring loaded shaft and move
the switch to the position you want, when the shaft is released it locks the
switch in that position and it cannot be moved until the shaft is lifted.
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| Photo 2 |
As
you can see from photo 2 on the left (a close up of photo 1), a small aerial is attached to
the receiver for self monitoring if I decide to leave the unit in TX mode I
could use another DC lead and connect the receiver to the DC sockets, to the
right of that aerial you can see an SMA to N type adapter that will allow the
main aerial to be connected.
In photo 4 below, you can see the kit ready for assembling on site, the aerial used is a slot type and above it is its protective sleeve( removed for the picture) which is made up of a piece of plastic waste pipe.
When not out and about with
this project it can be used as a test piece for checking out other receivers
and transmitters like the one featured in issue 08 of the HX Files as seen
photo in photo 5 below.
And finally
This project has reminded me that somewhere in the deepest part of
the shed is a much larger case so if get brave I will go exploring and locate
it.
That’s it for now and may all your signals be P5
73 Pat.
