Friday, August 13, 2010

No improvement

I know that one of the purposes of my website is meant to be to demonstrate that you can play ham radio even if you can't have outside antennas. But sometimes the frustrations of not quite being able to achieve what you want to make become almost too much.

On Tuesday I replaced my home made ribbon cable Slim Jim 2m antenna with a commercial dual band colinear from Moonraker. I wasn't sure the home made antenna was working as well as it possibly could. Originally I planned to replace the Slim Jim with a single band 5/8 wave Sirio, but after a month waiting for Radioworld to deliver it I cancelled the order and gave up. Then I got the Kenwood TM-D710 which is a dual band transceiver, so I decided I should have a dual band antenna to give me the option of running a public Echolink node on 70cm.

During the last few days I have been searching for signs of improvement in my 2m receive capability, but the signs haven't been good. I'm hearing a frustrating number of APRS "braaps" that are just not strong enough to decode.

The antenna certainly works. I'm getting almost end-stop signals from the repeaters GB3DG and GB3LA, whilst GB3AS is about S5 with a bit of noise on it. I have had a couple of solid contacts using the antenna but nothing to form a basis for comparison until today, when Noel G4PEW drove past.

On the left of the screengrab you can see his track on Monday, when I was still using the Slim Jim. On the right you can see today's track, received using the new antenna. It's a lot shorter. I certainly heard a lot of packets after the last one shown by the grey blob, but none were strong enough to decode.

If only I could have the antenna outside the attic, up above the apex of the roof, I'm sure that extra little bit of height would make all the difference.
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