[IRCA] More array testing

[neilkaz <neilkaz@xxxxxxxxxxxxx>]

A few days ago I turned my Broadside Double KAZ Array around to aim towards the east by switching the ends that the feed xfmrs and termination resistances are on. Now I have nice back nulls to the west and a narrow beam towards the east. Last night was quite interesting and again proved the array concept and shows the benifits of a narrow beamwidth and good side nulls. 

On 1410 I have a big pest and a near local WRMN 14.5 miles away at 215 degrees. This is off to the side of the best area of back null, but a single antenna does help reduce it. However, the array seems to clobber this station and I was getting CKSL mixed with CJWI's mostly Haitien stuff (new for me) with WRMN a very distant 3rd.

With a side by side spacing of only 260 ft (all my room here) most of the beamwidth reduction effects and good side nulls are only noticed on the upper part of the band where the wavelengths are shorter. Also, low angle skip and groundwave is affected more than high angle skip since the phase difference between signals arriving from the sides (N and S) isn't much from high angles when only 260 ft apart.

Being NW of Chicago, many of my local and fringe pests are located SE of me or SSE. The array clearly gets less WRDZ 1300 than a single element leaving WOOD dominant and clearly less WGRB 1390 which resulted in WFBL 1390 from Syracuse being in last night. Additionally, the more narrow beamwidth of the array (calculated at about 65-70 deg for GYs) definately improves the clarity of what is heard on the GY channels. 

1640 provided a great illustration of beamwidth, side nulls and back nulls when I tuned by and had a  weak TIS atop occasional traces of normally heard Disney from Milwaukee. I could barely copy the TIS on peaks above distant T-storm noise but there were several Strongsville ments and www.strongsville.org from this community info stn. in a Cleveland burb. There was little trace of Milwaukee in the north side null, no trace of WTNI in the south side null, and no trace of OK or UT stations in the cardioid back null caused by the resistive terminations.

I urge other DXers who have access to a decent amount of land to try arraying two cardioid type loop antennas. To get good broadside array effects it isn't necessary to take the time to build the more complicated double loop type antennas I use for a permanent home situation. Simply using a tree for each support for a delta flag and having them 300 ft (better 400 ft) apart would yield very nice patterns.

73 KAZ Barrington IL
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