[TowerTalk] (WAS) 4 Square for 80 and slopes; now mobiling and slopes

[Mike Smith VE9AA]

At the bottom of this email, John, NA6L makes some really good points.

I've been HF mobiling for decades and have often been surprised where the
best spot

was to work the DX.  My rig is on 20m CW daily. FT-857D @ 100w, 2009 MINI
COOPER, SD-330 antenna.

My older HS-1800/pro antenna was even better.

 

These days, unless I am on vacation, I pretty much do all my HF DXing in
motion.

As an example, as I drive along the undulating hills of NB, there are sweet
spots where the DX will usually be louder.

It's not always at the hilltop, but often just before it, in the direction
of the DX.

 

Yesterday I worked 3B9FR right over the top of a pileup of US, EU & VE guys.
I was listening to him

and as I drove along I could see the signal peaking as I 'neared' the tops
of small hills (probably 400' high (good for this area) )

One call on a really nice knoll (600-700'?) and he went into the log.  I
have seen this over and over and over. It's almost predictable.

 

There is a hydroelectric dam near my house and more often than not, if my
timing is right, I can usually get through a pileup to East Africa
(A6/A7/3B/5R etc.)

on a couple calls.  I have often (but strangely not always) seen Eastern
signals rise from 559 to well over 599 as I drive across it.  The path is
nearly due East/perhaps slightly SE off this 180' tall dam

with most of my signal funneled through the river valley to the E/SE.

 

If I had my choice though, I'd go park on a long pier over salt water !

 

Not sure where I was going with this, but I am sure N6BV's TA software will
tell you too , that it may not make sense to put your antennas right on the
'edge' of a cliff on a mountain, but perhaps back some distance.

If you have a favorite direction (EU?) then instead of putting your antennas
right on the pinnacle of a hill, place them down some distance, so part of
the hill can act like a reflector(?)

I don't think the hill is an ACTUAL reflector, but it sure seems that way,
as I drive along.

 

As an added tidbit, I have driven next to semi trailers, parked beside tall
bldgs. (like at my work) or driven between "rock cuts" and sometimes there
is almost no change at all in signal strength.

 

Whether that means the signal is arriving at very high angles or odd paths,
I don't know.  It just "is".

 

Like a mobile antenna range every day I go out, I get surprised.

 

YMMV

 

Mike VE9AA & VE9AA/m

 

 

 

On Wed,3/9/2016 5:56 AM, john at kk9a.com wrote:

 

> First, any thoughts as how the terrain where the antennas are located 

 

> will affect operation?  Also, any thoughts on how the big slope from 

 

> the antenna location to the ocean will affect the signal.  On HFTA it 

 

> is a big help on 80 with dipoles etc.  but I'm not sure how it will affect

a vertical system.

 

 

 

 

"N6BT gave a very interesting talk at Pacificon last fall (2015)) that

addressed something like this. He set up verticals (memory fails, I think it

was 20M) at three locations on a plateau with drop-offs on all sides. At the

edge of the plateau facing SA, he worked SA and no JA. At the edge facing

JA, he worked JA and no SA. In the center of the plateau, he worked neither.

He used a drone to measure the vertical pattern and found the field strength

increasing a bit below zero degrees elevation.

 

 

It's worth looking for his slides or having a chat at Visalia. He's usually

there. I just tried to find slides on the internet without success.

 

 

73, Jim K9YC"

 

 

My HF mobile mountaintopping experience (using a vertical) supports exactly

what Jim K9YC related. 

 

 

As the mobile moves toward the slope that faces downhill in the direction of

the DX there is a huge positive gain in signal strength. Interestingly the

very edge of the hill is seldom the best location for the best signal but

usually it is found farther back and away from the edge. On some flattop

mountains or hills I would drive the vehicle toward the desired edge facing

the DX (say NE for EU) and found that I may have not heard anything in the

center of the flattop but as I headed toward the NE edge the signal started

getting stronger. Once I got toward the edge and the signals weakened I

would back up until they got loud again and work to the NE from there.

Driving toward and back away from the edge of the hill side was almost like

rotating a beam for the best signal -- the difference in signal strength was

night and day. 

 

 

Prior to hilltopping I always thought that the best signal would be at the

very edge of the slope but it seems like it is 20' to 50' back from the edge

-- at least with the mobile. 

 

 

Best, John NA6L        

 

 

 

Mike, Coreen & Corey

Keswick Ridge, NB