Hello and welcome to xtract 13 of the HX files.
In this issue I would like to talk about the new mobile unit I am making .
After operating /m for many a time I decided to make a new mobile unit, It was taking the fun out of setting up /p when I had to connect the tx unit to the amp, the monitor, and their dc leads, and having to disconnect the aerial and connect it to the rx .As you /per’s know the cables seem to have a life of their own and seem to knot together, and by the end of the experimenting, and that you would have a ball of wires at the end of the day.
This unit would be an all in one; it would have a transmitter, receiver, and a small monitor installed, also I would be installing a 25 watt amp as well.
This unit will save me a good bit of time as when I get to the site all I have to do is connect the aerial, camera and the dc, and I am good to go. And when the fun is over I would be on the way home in a few minutes, and not spending ages taking everything down and packing it away while the base station I just worked only has to switch off and head for the tea.( the lucky #*!>*<^<).
I was looking for a suitable project box in a Maplin store, and the ones they had were a bit too pricey for the size I wanted (and my pocket). So I had a look in my own stores, aka the shed, and after a while of digging in the shed I found the one you see in this issue. The first job was to make chassis for the parts, (this was made from some of the computer panel’s I had cut up that I mentioned in a previous issue) and to layout the parts for the best use of the project box and that the layout was as serviceable as it could be so I could improve on the design by adding other parts in the future. (Like a pre amp) laying out the parts took a few tries as I had to make sure the parts would be easy to get to adjust if needed and I would also be able to add or remove a faulty unit on it’s own and not have to a complete teardown.
The first job I did on the project box was to fit the monitor, speaker, led’s and switches to the front, (Photo 1) a few pages were used in drawing the mock-up for this.
The next job was to checkout how the heat sinks would perform under test. I had a small slab of aluminium plate that could be mounted on the back panel (Photo 2 below) or one that was much bigger and this one had fins as well.
The amp was mounted on to the heat sink, after some compound was used as this was only a test I held the amp onto the plate by cable ties. After only 5 minutes the temperature rose to 44 degress, way to hot, and when second heat sink was used (photo 3) this was the best, as after 35 minutes this was only 33 degrees
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It was only when the connections were been rechecked and tightened that it was noticed when the coax was held that the RF power dropped. When I decide to install the pre-amp and a different relay I will be making a new chassis out of metal again as the prototype one was getting like a sieve, and I will paint it to match the outside of the unit, or it could be made from a piece of Perspex .
As a point of interest the tools I used in constructing this project were, a cordless drill, various drill bits, including a stepped one that is shaped like a cone, a hole punch, various files, and a tap and die set, most of these tools are available in your local hardware store. And finally
Thanks to Michael EI-5-GG for his help in some of the drilling and taping on the project and of course his years of experience in the construction field.
73's and may all your signals be P5.
After operating /m for many a time I decided to make a new mobile unit, It was taking the fun out of setting up /p when I had to connect the tx unit to the amp, the monitor, and their dc leads, and having to disconnect the aerial and connect it to the rx .As you /per’s know the cables seem to have a life of their own and seem to knot together, and by the end of the experimenting, and that you would have a ball of wires at the end of the day.
This unit would be an all in one; it would have a transmitter, receiver, and a small monitor installed, also I would be installing a 25 watt amp as well.
This unit will save me a good bit of time as when I get to the site all I have to do is connect the aerial, camera and the dc, and I am good to go. And when the fun is over I would be on the way home in a few minutes, and not spending ages taking everything down and packing it away while the base station I just worked only has to switch off and head for the tea.( the lucky #*!>*<^<).
I was looking for a suitable project box in a Maplin store, and the ones they had were a bit too pricey for the size I wanted (and my pocket). So I had a look in my own stores, aka the shed, and after a while of digging in the shed I found the one you see in this issue. The first job was to make chassis for the parts, (this was made from some of the computer panel’s I had cut up that I mentioned in a previous issue) and to layout the parts for the best use of the project box and that the layout was as serviceable as it could be so I could improve on the design by adding other parts in the future. (Like a pre amp) laying out the parts took a few tries as I had to make sure the parts would be easy to get to adjust if needed and I would also be able to add or remove a faulty unit on it’s own and not have to a complete teardown.
The first job I did on the project box was to fit the monitor, speaker, led’s and switches to the front, (Photo 1) a few pages were used in drawing the mock-up for this.
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| Photo 1 |
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| Photo 2 First test |
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| Photo 3 |
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| Cool running |
(Photo 4 on the right) These tests were done without any cooling fans this heat sink was drilled and cut to size and was used as the back panel of the unit. A small piece of metal was used to make a panel to mount onto the back of the heat sink; this would be used to accommodate the aerial socket (N type) and audio/video sockets (phono) and the 12v dc line (a gland would be used for the cable to go through safely).
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| Photo 5 |
(Photo 5 on the left).The first couple of layouts of the parts (Photos 6 ) were setup with some wires and coax attached, in photo 7 you can see more of the cables and leads, and I decided to put as many of the wires under the chassis as this could make the unit look tidy .
Photo 8 shows some of the parts in their final location, but as always this could be changed as the project developed as this is photo type 001 and who knows what would happen when the unit was up and running.
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| Photo 6 |
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| Photo 7 |
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| Photo 8 |
Photo 9 on the left shows the finished back panel but without the fan guards and the dc leads. After a few hours of transmitting both into a dummy load and on air, I did some modifications of the parts, one been the relay, it was running hot so it was mounted on some heat sink, (see photo 10 before I found the right bolts) the other been the coax from the N type to the relay. It was decided to use some hard-line coax as the transmitter was losing power, the original seemed to be intermittingly loosing power and if it was not for the watt meter I would not have known, and who knows I could have let all the smoke out in a few weeks of usage.
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| Photo 10 |
As a point of interest the tools I used in constructing this project were, a cordless drill, various drill bits, including a stepped one that is shaped like a cone, a hole punch, various files, and a tap and die set, most of these tools are available in your local hardware store.
Thanks to Michael EI-5-GG for his help in some of the drilling and taping on the project and of course his years of experience in the construction field.
73's and may all your signals be P5.
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