Topband: Sloping Ground

[Sam Josuweit]

Thanks Steve,

 

I ran a very similar analysis using the data from Low Band Dxing and HFTA plots. It’s good to hear your real world experience. I think some trenching is in my future.

 

Sam(N3XZ)

 

 

From: VE6WZ_Steve [mailto:ve6wz at shaw.ca] 
Sent: Sunday, June 21, 2020 11:26 AM
To: Sam Josuweit
Cc: topband at contesting.com
Subject: Re: Topband: Sloping Ground

 

Sam,

Yes…I think it would be worth it!

My purpose built low-band remote QTH is on a prominent hill surrounded by farmland in all directions.  My QTH at the crest of the hill is about 300’ above the surrounding land and it slopes gentle in all directions.  Also my Beverage arrays mostly all slope down the hill in each direction.

Anecdotally the QTH seems to perform very well fro DX.

 

Here is a somewhat qualitative analysis of my hilltop QTH using some data from the ON4UN low-band DXing book where he talks about verticals on sloping terrain. I make some comparisons to my QTH.

https://drive.google.com/file/d/1UP45c5MWaWvA0T9no4DHW060FSgC-3Pk/view?usp=sharing

I think its reasonable that some exceptional low-angle take-off angles can be achieved when located on a hill.  It may be even possible to approach the low-angles seen from sea-side verticals…but NOT the gain seen by a saltwater location. The “vertical over sloping terrain” data from Johns book would suggest low-angle gain that would be almost impossible to achieve on flat land. (up to +11 dB at 3 deg angle)

The caveat to this is whether the long-haul DX wave angles really do arrive as low as predicted.

 

73, de steve ve6wz

 

 

Looking for some advice from some of you who have been there and done that
before. I'm looking at moving my 160M inverted L to a new location that
would be approximately 100 feet ASL higher and be on top of a hill with
nearly perfect sloping ground in all directions. This would change my coax
run length from 130 feet to 620 feet. I'm looking at LMR400 to meet my loss
and budget needs. Is the move to sloping ground worth the extra work and
coax loss??