[IRCA] Vertical antenna position

["Craig Healy" <bubba@xxxxxxxxxxxxxxxxxxxx>]

A few days ago I moved the vertical antenna
http://www.am-dx.com/vertical.htm from one room to another in my house.  It
went from the east corner to the south corner of the house, maybe a 45'
(15m) move.  This was to try to get it further from my computer equipment
and where the AC power feed is in the house.  Just a noise reduction
experiment.

Well, the noise didn't really drop, but the directionality went nuts.  It
appears that stations to the WSW are severely nulled while stations to the
WNW are enhanced a lot.  Examples:

550 which is to the NW is now the strongest station in the MW band by about
5db.  Even beats out WPRV-790 which is 5kw and closer but to the SW.

600 is usually dominated day and night by WICC in Bridgeport, CT with Cuba
also being there at night.  WICC was not heard.  Last evening all I heard
was country music fading up and down.  It also sounded like SS between the
songs.  Cuba doing Country???  That would be weird.  The noise level makes
it difficult to hear.

660 and other NYC stations are either inaudible or have significant
interference.  WCBS-880 had some music station fading up above their
residual signal occasionally.  Usually WCBS is darn near a local when it
comes to listenability.

WGY-810 is usually unlistenable day or night.  It is much better now.

Some locals that are trashed at night are now decent.  990, 1240 are two
examples.

930 is now dominated by WBEN nights.  Normally WBEN shares the frequency
with others.

1080 is very weak while CHOK-1070 is much stronger.

WNBH-1340 in New Bedford is inaudible days with weak ESPN (probably WGAW)
noted.  WSAR-1480 is also much weaker.  So, there is a SE null as well.

And similar results throughout the band.  What is odd is that some stations
that are nulled are in similar directions to ones that are enhanced.  810
and 1080 for example.  There's really not that much difference in azimuth.

Doing an A/B switch to a loop antenna showed conditions are pretty normal.
Stations heard on the loop are there as expected.

What it didn't do was kill a pest noise.  It sounds like a bad streetlight.
It buzzes for about 30 seconds and is quiet for a minute and only after
dark.  It's audible on all my antennas, inside or out.  So, it trims my DX
time by a third.  The buzz is loud enough to over-ride the IBOC noise of
some stations.  Ironic...

This is pretty interesting.  Positioning an antenna can have some useful
effects.  I'll move the vertical to another corner of the room and see what
changes.  By making this simple vertical other may find similar results.
Next is to try some phasing with another antenna to enhance or modify the
nulls.

Craig Healy
Providence, RI


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