Shack at 02/05/14

Shack at 02/05/14

Thursday, 26 January 2012

Been messing about with various modes and antennas today. Noticed yesterday that the 3o metre band was the most active overall, re weak signal modes, so today I resolved to get something working antenna wise so I could grab some action.

I had managed to tune the Pro Whip on 3o, but wiped out my freeview signal in the process. I also tried a long wire, but that had the same effect. The 80 metre 1/4 wave magmount on the metal roof had no effect on the tv however, so 'Thinks!' I have various mobile whips in the shed, but infortunately not one for 30. Could I rig something up with them?. After returning from town and grabbing an 'Ocean Pie' for lunch, I reasoned that joining the base (helical) sections of a ten and twenty whip together, with the standard whip on top, I might get close enough to 10 megs to try inserting another coil section that would take care of the other missing whip section. Sounded logical, even if electically it's not the done thing.

Anyway, I joined said sections together and fitted the base to a tri magmount on the metal roof. To my surprise, after connection the MFJ analyzer, the swr was 2.1. Amazing!, and I hadn't even compensated for the missing whip section yet. Well!, if it's happy as it is so be it. Sometimes antennas just defy logic Hi!.

I replace the 80 whip with this new one and went back in to the shack. On connecting the analyser now however the swr was well out. In fact the antenna now resonated on 7 megs instead on 10. All through basically changing to a longer lengthg of coax feeder. That's silly, it shouldn't be anywhere near 40 metres. Oh well, I thought, in for a penny. I connected the feeder to the atu, tuned the radio to a quiet spot on 30 metres and fired 5 watts into it anyway. A bit of twiddling of the inductance, tx'er and antenna controls and I easily had the swr down to 1.1 and an apparent power out of five watts. The ft-897 was set at 5 watts (the minimum) in the menu.

As I have since been received in Moscow and Germany, I suppose there can't be a lot wrong with my signal. Also I'm not freezing my Freeview signal at all, so I think I'll leave it at that for the time being.

As I'm now on qrv on 30 hf I can't play with jt65 as there is no allocated frequency for it. However, there is one for ROS, so I might have a go at that tomorrow.

No comments:

Post a Comment