[TowerTalk] Stacking question - another data point

[n1rr at comcast.net]

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 at k3lr.com> 
To: john at kk9a.com, "TowerTalk" <towertalk at 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 at contesting.com] On Behalf Of 
john at kk9a.com 
Sent: Friday, August 19, 2016 1:33 PM 
To: towertalk at 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 

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