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[NO9E]

I have two beams at 20m and 30m, and a Spiderbeam at 13m. Nearly always the beams were up to 2 S better than the Spiderbeam, and the higher beam was better to DX than the lower beam.

Recently,  on 20m both beams were equivalent,  and the Spiderbeam was just a bit worse. On 15m, the lower beam was better than the higher beam.

A month ago, DF9BO of Optibeam fame operated on 80m. I talked to him earlier, and my signals with 4 square were the strongest by far. Last time,  G5RVs and low dipoles were heard well and my 4 sq was not. 

Are these signs of better propagation with higher angles of arrival?

Ignacy NO9E

[K2AR]

Very good possibility. I have seen on occasion during Sporatic-E on 6M where a full wave loop at 8 meters off the ground was 10 over S9 and the 5 element yagi at 25 meters above ground was only S3. 30 seconds to a minute later, the 5 element yagi was 20 over S9 and nothing on the full wave loop. I have also seen this happen on 160M between a Beverage on Ground versus a pair of phased Loop on Ground receive only antennas where high angle propagation will favor the BOG versus the phased LOG antennas. It's an interesting phenomena.

[KH6AQ]

The signal in question could have been in the takeoff angle null of the higher beam. VOACAP shows:


2 element Yagi (equivalent to the Spiderbeam) up 15m: gain within 2 dB of max at 14-40 deg.

5 element Yagi up 30m: gain within 2 dB of lobe max at 6-14 and 26-36 deg. plus a null from 18-23 deg.

If the arrival angle was 20 deg. the Spiderbeam has an 8 dB advantage. That is 1.33 real S-units or 2.7 S-units on many transceivers having 3 dB/S-unit.