Sunday, 27 January 2013

New 144MHz antenna

Last summer I erected a YU7EF dual band 4/6m five element yagi on my mast. A few month's ago I asked Colin, G4ERO, if he would also make me a 5m boom 144MHz YU7EF yagi.

Yesterday I took delivery of the new yagi at the monthly Codger's breakfast meeting, courtesy of G4BAO and his delivery system!

Taking advantage of the mild weather today, I assembled the yagi and put it on my mast, ready for testing.

After normalising the cable I was able to check the match direct at the yagi feedpoint, using my HP 8753C network analyser.

This showed the best match to be slightly low in frequency at 142.8MHz at 25dB, rising to 16dB ( about 1.3dB VSWR) at 144.3MHz.
I didn't have time today to play with the match, but suspect that the coax balun is slightly too long.

Next time I have the mast down I will shorten the balun by a few mm and check the match.

Listening around on 2n there wasn't much activity today, but the usual beacons were all there and about their normal strength, although a longer period of listening is required to see if their level is better or not. My 'old' Cushcraft 145B2 ten element was quite good, but it is not an optimised design, so I would expect marginally better performance on terrestrial and a fighting chance at single yagi 144MHz EME.

73 de Sam

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  2. Thank you. You didn't give your callsign?