Wednesday 09 September 2009 07:30pm
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Over the last couple of weeks, I have been racing along with the development of my amateur radio station. Starting off with the purchase of a HF/6m whip aerial, through to buying my first HF transceiver (Yaesu FT-450) to setting up the IT side of things. It is here that I have hit a snag.

The modern radio shack isn't complete without a computer. Whether it is used for logging, decoding digital signals or just looking up callsigns; it must be said that it is a pretty indispensable piece of equipment. Because my setup is in the living room of my flat, I needed a solution that was low profile and quiet.

Fortunately, I had access to an old laptop (IBM Thinkpad R50e) which has a broken LCD screen. Perfect I thought. Connect up an LCD monitor, keyboard and mouse and there's my solution. I've attached some brackets to my desk so that the machine is out of the way and today I connected up the peripherals.

Being quite sure the machine worked, I wasn't to worried about the big switch on but I do have a record of things dieing at this point so I was pleased to see it all spring to life even just running off the battery which hadn't been charged for a while. I did of course connect the mains adaptor too.

And it is this that is the problem. When connecting the mains adaptor to the laptop, it wipes out my radio with +20dB of noise making most (if not all) signals unreadable. To confirm it was the power supply; I unplugged it (after which the signal meter fell to a much more reasonable S3), tuned about on 20m until I found a signal and then plugged it back in again. Lo-and-behold, the noise floor rose and the signal dissappeared.

So now I'm on the search for a solution that doesn't involve me giving up on the laptop and putting in a desktop computer. I can charge the laptop battery when not using the radio and then unplug it when I'm operating but that's a little inconvenient.

I did get to wondering whether the laptop would run from my DC power supply at 13.8V. I checked the laptop's power block which is rated at 16V 4.5A. No problem providing the amps, but I'm a little short on the volts. However, the battery is rated at 10v. I'm thinking that perhaps running without a battery, I could get away with it. However, I'm also wondering if there is a chance of damage to the laptop or power supply.

I'm going to have to do some more research.
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