I think what some are missing is that the 40M numbers from Tim are based on HIS
location in W.PA /OH border and his terrain.
The numbers for W1 are much lower. We see higher angle propagation to EU more
often, hence the lower heights.
The 40M heights for your QTH will vary from either of these.
These differences can be read about in Dean Straw's All-The-Right-Angles.
A typical W1 has a 2L40 @ 90ft to 110ft and might switch to an EU wire beam at
50 to 70 feet
Another standard combination that yields good DX pattern without a high angle
lobe is the Stacked 402-CD and the
height over flat ground would be 135ft/55ft a la N2RM.
This would be varied based on your terrain and angles to your target audiance.
Again S=80ft
K1RX uses 130ft / 60ft S=70ft
K1EA/K1AR used a 3L40 at 110ft
KC1XX uses a 4L OWA at 140ft
K1LZ Monster-IR on 40 150ft / 80ft S=70ft
My terrain near Rhode Island with two 3L40's on 40 to 48 foot booms likes 150ft
/ 75ft S=75ft
-Charlie N1RR
>From Tim K3LR's website: 40 meters Station #1
4L/4L/4L = 12 element stacked array (15 meter booms- each antenna weighs 370
lbs.) full size OWA Yagi's.
One 4L at 80 meters / 262ft with a K7NV large Prop Pitch rotor,
one at 59 meters/ 193 ft on a K0XG Ring Rotor and
one at 36 meters/ 118 ft on a TIC ring rotor. S = 75ft
PiRod 24 inch face tower.
Switching allows operator choice of TOP only, MIDDLE only, LOWER only, all
THREE, Top TWO, Bottom TWO or HIGH and LOW feed.
**Interlocked with** 40 meters Station #2
2L/2L = 4 element stacked array W6NL Moxon design (7 meters boom)
at 57 meters/187 ft (TIC ring rotor) and 37 meters/ 121 ft (TIC ring rotor)
mounted on the 20 meter tower.
S = 66ft
Switching allows operator choice of TOP only, Both In Phase, BOTTOM only or
Both Out of Phase.
RX Ant: Comtek ground mounted full size 4 square vertical array with 10,000
feet of radials. Used for receive only.
----- Original Message -----
From: "Tim Duffy" <k3lr@k3lr.com>
To: john@kk9a.com, "TowerTalk" <towertalk@contesting.com>
Sent: Friday, August 19, 2016 1:52:52 PM
Subject: Re: [TowerTalk] Stacking question - another data point
Hello John,
The K3LR stack has been optimized as a 3 high in phase array for best
pattern control (both AZ/EL). Optimizing for best rear rejection (over 180
degrees)and eliminating high angle radiation (lots of noise up there) takes
some doing. HFTA was also used to determine best heights.
As W6NL says "Experience trumps theory".
The 3 high stack at K3LR works very well for DX Contest work.
73,
Tim K3LR
-----Original Message-----
From: TowerTalk [mailto:towertalk-bounces@contesting.com] On Behalf Of
john@kk9a.com
Sent: Friday, August 19, 2016 1:33 PM
To: towertalk@contesting.com
Subject: Re: [TowerTalk] Stacking question - another reality data
That is a good question Jim. 72' stacking distance works well with small
40m beams however K3LR's 4el OWA antennas are anything but small. I
believe that he has three which puts the top one at 262 feet. I too
would think equally spacing them down the tower would be better but I
have not modeled this scenario.
John KK9A
[TowerTalk] Stacking question - another reality data
from [Jim Thomson] [Permanent Link][Original]
"Tim Duffy K3LR said:
I have 41 years experience in stacking 2, 3 and 4 Yagi's high.
After many hours behind the HFTA and NEC model engines - then putting
Yagi's
up in the air and using them for many years here at K3LR - these are the
stacking distances that have worked very well at this Western PA QTH:
Lowest Yagi height:
40 meters - 118 feet
Then - stacking distances by band:
40 meters - 72 feet
## How did the 118 ft for the lowest height for 40m come about ? That
and the
72 ft stacking distance on 40M ? That would put the upper 40m at 190 ft.
72 ft spacing on 40m is like 36 ft spacing on 20m.
## I would have thought that a 95 / 190 stack on 40m....with 95 ft
spacing
would
have been the ticket.
Jim VE7RF
_______________________________________________
_______________________________________________
TowerTalk mailing list
TowerTalk@contesting.com
http://lists.contesting.com/mailman/listinfo/towertalk
_______________________________________________
_______________________________________________
TowerTalk mailing list
TowerTalk@contesting.com
http://lists.contesting.com/mailman/listinfo/towertalk
_______________________________________________
_______________________________________________
TowerTalk mailing list
TowerTalk@contesting.com
http://lists.contesting.com/mailman/listinfo/towertalk
|