Sunday, 19 June 2011

QRP Fun and portable antenna musings

Operating with low power QRP is amazing.

Today I spoke to Chris 9J2RI in Zambia some 1600 km distant on SSB and much later in the afternoon I heard Chris on 14.060 MHz this is the QRP calling frequency. He was not awfully strong I guess a RST 559. I decided to turn the power all the way down and gave him a quick report. I honestly did not think he would respond. The output power meter on the rig did not move at all. I will have to measure to be sure, but I suspect the power was only a few milli watts.

I was pretty pleased when Chris responded with ZS6?  Once we were in QSO I noticed his signal was also quite a bit weaker and down to 539, maybe he also dropped to QRPp levels.

I have been contemplating the portable antenna setup again. I must be honest I am a big fan of the simple link dipole. The only disadvantage is that one needs a feed line. Maybe I could consider using a short piece of twin flex (rip cord) of about 7 metres as a balanced feed line the followed by a small 1:1 balun then a very short piece (2 or 3 metres) of RG58 coaxial cable.

The reason for the twin flex is weight saving and portability. The RG-58 does not like being coiled up and has a mind of its own. 10 metres is normally the minimum practical feed line length. I think the losses on a 7 metre piece of twin flex should be minimal even on 14 MHz?

I had better build and test such an antenna before my trip. I guess I should really consider doing A/B comparative tests with a standard coax fed dipole before making up my mind.

Has anyone else tried the same antenna system  ??

1 comment:

  1. Hi Pierre,

    Was great working you as well... I dropped power from 100W to about 3 or 4W for the QSO.