Topband: Topband DX/NVIS

W3HKK at roadrunner.com W3HKK at roadrunner.com
Fri Aug 25 16:21:22 EDT 2023


Tnx for the many replies on NVIS.

My last qth had a 95 ft tall Buckeye tree. On a lark I stealthily shot
a 135' wire over top ( sort of an inverted J) and had a ball on 160m
in the contests . 

Modest Antenna: 

Then I retired to three acres with one small 15 ft tall tree. (I had
previously sold my tower and large yagis due to deed restrictions.) So
I gave it a shot with a 1/4 wave INV-L ( 15 ft up and 120 ft sloping
back to the ground) and fed it against a single ground rod. It loaded
great. During that first winter I worked all over the US. I even
started to hear some DX, and worked a few, running 100w.

One magic night I heard an LZ2 Cqing, gave him a call, and almost fell
off my chair when he came back. A while later I heard a 4z4, and
worked him as well, getting a 579. About a month later I heard my
first JA - and worked him!!

So with 100w to a 15 ft tall Inv-L I had three juicy contacts on
topband. What a life!

Ive since added radials, and raised my antenna's peak .... as the tree
grew.... to a respectable 52 ft!
 DXCC is now approaching 200 worked, but the rate is slowing down. 

I added a SAL30 about 6 yrs ago, since I dont quite have enough room
for a decent Beverage.

The SAL 30 has given me plenty of help - and laughs in the TB
contests. Its directionality has me guessing which way to point it.
And Propagation at times seems to alternate qsos in opposite
directions, so I have to almost continuously flip directions in order
to copy a guy. He is faint, just above the noise, then I reverse
directions and hes 599. Trouble is, every other qso is from a
different direction. If I were on SSB you could hear me laughing at
how silly it can seem! 

Best NVIS ht = 0.25 wavelengths- Yes I totally agree if you have a way
to engineer an antenna for that ht youd have the best NVIS signal
possible on a particular band. 

Note: A friend is convinced that a low wire just a few ft off the
ground, on land adjacent to a freshwater lake will produce booming
signals for NVIS purposes. My approach has been to hang a sloping loop
from the three nearest trees as high as you can get it. This usually
produces good results.

Another friend had managed to hang a horizontal loop at 50-70 ft high.
We worked the world on every HF band, and in some cases ( like on 40m
ssb WPX) absolutely dominated the band with it.

All antennas are fun. Some more than others.

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