Building a sliding mount for my in car radio - Part 4

Now that I have my car back after its accident, I was able to attach the fixed plate that makes up the mounting point for my slide mount. I may trim the screws so that they fit flush but they don’t get in the way at the moment. The plate fits well giving a sturdy base to slide the radio onto. When the radio is in position it is very accessible and doesn’t interfere with my driving position or getting in and out of the car. The next  job is to run the power lead from the battery through the bulkhead. The end of the lead will then be stored in the dropdown tray behind the radio. I will then do something similar with the antenna lead so that it is always available at the radio end and easy for me to connect the lead from the mag-mount at the other.

Top of the bracket fitted to the car. I’ll remove it and give it a coat of matt black paint so that it blends in better.

 

 

The radio slid into position.

 

 

Building a sliding mount for my in car radio - Part 2

The main part of the bracket has now been drilled and the holes countersunk. I cut down four screws and will be using both flat and crinkle washers. The preformed channels have had one end folded over and silver soldered. The next job is to clean up the brass and position the first channel ready for soldering. I plan to hold the channel in place with some bent paper clips. Hopefully this will do the job without the parts moving about. Once the first one has been soldered in position I’ll arrange the second channel so that the top part of the bracket slides in without binding. After both have been soldered I’ll have the fun of cleaning it all up.

Building a sliding mount for my in car radio

Now that the weather is getting better, I am looking to fit my mobile radio into my car. I don’t want it to be a permanent fixture as it could be stolen if left in unattended. I have decided on where I want to fit the radio and have devised a bracket design that will allow me to slid the radio in and out. I’ll still have to connect the power and antenna but this will only take a few seconds. I am going to make the brackets out of various pieces of brass soldered together. I have cut out the bits I’ll need and a photograph of these is shown below. My next job is to fabricate the channels so that they are blocked at one end. These will then be soldered onto the larger sheet of brass which I’ll attach to the radio mount. The small sheet of brass will be mounted in the car where the radio bracket will slid over it. When I get some spare time to do the drilling and soldering I’ll post the next set of pictures.

Yaesu FT-1900

As a diehard Yaesu fan, I couldn’t resist getting one of their mobile transceivers for the car.  Now to spend a few days programming in all the local repeater offsets. With any luck I'll post some more details of this rig in the next few weeks.

 

 

My new 2m Power Amplifier

Now that I am using my Wouxun handheld unit in my car, I feel that its 5 watt output is a little on the weak side. Recently I spotted a 2m amplifier on eBay and decided to try a few bids. The device was described as untested but the seller said the lights came on and there was a circuit diagram available on the Internet. I kept my fingers crossed as the minutes ticked away but I eventually won the amplified for just over £30. It soon arrived so I set about making up some new patch leads so I could test it.

This amplifier produces around 30 watts of output from 5 watts in. It also has an adjustable RX amplifier. The unit is made by "Tokyo Hy-Power" and the model number is HL-37Vsx. I first decided to power it up and ensure it didn't do anything strange such as smoke or draw too much current. In its idle state all seemed well. I then connected it to my rig and antenna so I could test the RX amplifier. I found a suitable signal which was a conversation on the local Cambridge repeater. As you will see from the short video below, moving the sliding potentiometer adjusted the signal strength. This RX amplifier can be left at a suitable level or turned off altogether. As I tend to use the Cambridge repeater when mobile, I will probably set this to a reasonable level as it'll be hidden away and not accessible whilst driving.

Next on the "todo" list was to check the SWR whilst transmitting 5 watts into a dummy load. I did this with the amplifier switch off and then switched on. With the unit off the SWR was about 1.3:1 and with it on it was just about 1:1.

The final test was to see if the amplifier was living up to its name and actually amplifying. My transmitter was configured to output 5 watts. With the amplifier turned off and my power meter set to 20 watt fsd, the meter showed an output of just over 3 watts of FM.

I then changed my meter to display 200 watts fsd and switched on the amplifier. The meter showed an output of 40 watts of FM.

The manufacture's specification says I can expect an output of around 20 to 35 watts with a maximum input of 5 watts. With my meter showing an output of 40 watts I am happy that this is probably about right, give or take a few watts. At this point my dummy load was getting rather warm so I completed my basic testing. The next test will be to try some on-air contacts to see that the audio isn't being distorted etc. I will then need to buy some additional coax to enable me to set this up in my car. So far this amplifier seems like a good purchase.

Going mobile

It has taken a while to finally get this far but at long last I’ve put together my mobile setup. I checked the SWR between the antenna mounted centrally on the roof of my car and my Wouxan handheld. It is very close to 1:1 across the frequencies I plan to use so no extra adjustments were required. I plan to build a proper mounting bracket so that I can more easily access the controls of the transceiver. So far I’ve just been listening to see what the reception is like on my journey to and from work. I seem to get a reasonable signal on a couple of the repeaters and the one at Danbury seems to pick-up my signal, even though I’m only pushing out 5 Watts. As long as the reception is acceptable I may look into the possibility of making a 2m amplifier to boost my output.

Here are some pictures of my current in-car configuration.