Master Plan for PJ2T Antennas, Towers, and Feedlines
| Caribbean
Contesting Consortium Master Plan for PJ2T Antennas, Towers, and Feedlines |
|
|
|
Click here for Lot Layout Diagram
Click here for a photo (607 KB) of N8LGP on 14 September 2000 with his car attached underneath many of the parts of the two 20 yagis and one 15 yagi. Steve refurbished these antennas for shipment to PJ2T.
Antenna Complement (Red = Installed and Blue = Planned)
| Support | Band | Antenna | Height | Rotation | Status | Acquisition |
| Europe Tower (100 ft) | 20 | 5 el yagi, 34 ft boom | 95 ft | Fixed Eur | Installed | W0CG/N8LGP donated |
| Europe Tower (100 ft) | 40 | 2 el Cush Craft yagi | 107 ft | Rotatable on mast (T-2X) | Installed | W0CG/N8LGP donated and reinforced |
| Europe Tower (100 ft) | 15 | 5 el yagi, 38 ft boom | 85 ft | Fixed Eur | Installed | W0CG/N8LGP donated |
| Europe Tower (100 ft) | 10 | 5 el yagi, 24 ft boom | 75 ft | Fixed Eur | Installed | N8LGP home brew on W8AV platform |
| Europe Tower (100 ft) | 10, 15, 20 | 3 el Cush-Craft A-3S | 45 ft | Fixed SA and US long path | Installed | K8RF |
| US/JA Tower (80 ft) | 6 | Cush Craft 5 el yagi | 59 | Rotatable on mast (Ham IV) | Installed | W0CG donated |
| US/JA Tower (80 ft) | 20/15/10 | Mosley CL-33 | 85 ft | Rotatable on mast (Ham IV) | Installed | Antenna came with the QTH |
| US/JA Tower (80 ft) | 20 | 5 el yagi | 80 ft | Fixed US | Installed | W0CG/N8LGP donated |
| US/JA Tower (80 ft) | 15 | 5 el yagi | 70 | Fixed US | Installed | W0CG donated |
| US/JA Tower (80 ft) | 10 | 5 el Cush Craft XM-10 stack | 58/36 ft | Fixed US | Installed | . |
| Mult Tower (54 ft) | 17/12 | A-3WS yagi | 54 | Rotatable on mast (Ham IV) | Installed | W0CG donated |
| Mult Tower (54 ft) | 30 | Inv vee | 50 | Omni | Installed | |
| On 100 foot tower | 80 | N8VW three element wire loop | 80 | Fixed Eur | Installed | |
| On 80 foot tower | 80 | Inv vee | 75 | Omni | Installed | |
| Ground Mounted | 80 | K8RF vertical | Ground | Omni | On site | Planned for ridge top |
| Ground Mounted | 80/40 | HF-2V vertical | Ground | Omni | On site, not connected | |
| Ground Mounted | 160 | Inverted L | 54 | Omni | Installed | |
| Ground Mounted | 160 | Beverage - US | 6 | Fixed US | Installed | |
| Ground Mounted | 160 | Beverage - Eur | 6 | Fixed US | Planned | Antenna on site - not installed |
Coax Runs - Design Details
Each antenna will have its own run to the cable bulkhead at the rigs. This will provide for complete flexibility, even in a Multi/Multi situation. All feedlines at 7.0 MHz and higher will be Andrew LDF-50A Heliax. 6 meter feedline will be 1 inch Heliax.
Here (in the e-amil below) are the calculations we used to arrive at the final lengths for the Heliax.
I agree with all your lengths, pretty closely. I put my changes below in blue.
>(My lengths are from base of towers to the northeast corner of house. From there, we go 28 feet along side of house, turn left 90 degrees, go another 15 feet along porch, then go up and through the wall, 8 feet. Total of 51 ft from NE corner of house to the bulkhead inside at the rigs.)
>
>80 feet from 100 foot tower to house wall entry point 85 feet>30 feet from 80 foot tower to house wall entry point
25 feet>60 feet from 54 foot tower to house wall entry point
49 feet>>*******Note: Increased inside lengths to cover 10 feet up utility room
>wall to ceiling area, plus 35 feet to operating position for a total
>"Inside" length of 45 feet
>(previously this figure was only 25 feet)
>>******** 45 feet extra for each run: from wall entry point to inside
>end.
>>15 feet extra for two middle runs on big tower to reach to driven
>Elements.("DE")
>>15 feet extra for two middle runs on 80' tower to reach to driven
>Elements.("DE" = feet from tower to Driven Element of fixed beam)
>>Big tower has "Middle" beams at max height of 55 and 65 feet ( *****
>Note: Dropped these heights by 5 feet)
>80' tower has "Middle" beams at max height of 45 and 55 feet ( *****
>Note: Dropped these heights by 5 feet)
>>Calculations:
>(feet up tower) + (DE) + (feet from house to tower) + 45' inside = Total
>>So big tower has:
>>95' + 0' DE + 80' + 45' = 220' Top Runs (2 each)
>65' + 15' DE + 80' + 45' = 205' Mid-Top Run (Note changed this height
>to 65' from 70')
>55' + 15' DE + 80' + 45' = 195' Mid-Lower Run (Note: changed this
>height to 55' from 60')
>>80 foot tower has:
>>75' + 0' DE + 30' + 45' = 150' Top Runs (2 Each)
>55' + 15' DE + 30' + 45' = 145' Mid-Top Run (Note: changed this height
>to 55' from 60')
>45' + 15' DE + 30' + 45' = 135' Mid-Lower Run (Note: changed height to
>45' from 50')
>>54 Tower:
>50' + 0' DE + 60' + 45' = 155' Top Run (Note eliminated WARC Beam
>Heliax run)
>
>So Grand totals:>(2) 220'
(2) 231'>(1) 205'
216'>(1) 195'
211'>(1) 155'
150'>(2) 150'
(2) 151'>(1) 145'
146'>(1) 135'
131'>
>1575 Feet total
1618' totalThen maybe we should add 10" to each cut to make up for screwups and miscalcs, to give a grand length of 1708'.
If the members want to save money, the place to do it would be to feed the 40 yagis with regular coax (not much performance difference), saving 447'. Does the Heliax buy us that much advantage on 40??
If you just want a BIG signal, large stacked monobanders
are the way to go. With lots of antennas, a rotating tower
may be more economical than individual rotors.
For two towers, the 40 / 10 and 20 / 15 combination is a
good approach. 30 ft spacing works well for 5L10's. 35
to 40 ft spacing for 5L15's. 50 ft spacing for 3L20's or 60 ft
for 5 or 6L20's. 80 ft spacing with a pair of 2L40's has as
much gain as a wide spaced 3L40 with the added advantage
of waveangle and directional diversity.
It is tempting to just stack lots of antennas on tall towers.
W6QHS and K6LL among others have found that severe
interactions from closely spaced antennas for different bands
can destroy the added gain of multi element monobanders.
If you can't give your antennas lots of breathing room, you
may be better off with multiple tribanders.
With 2 or more moderately tall towers, suspended 2L 40
Delta Loops are very effective in performance and cost.
Two of them can be placed back to back sharing one reflector.
A 2L Delta loop has as much gain as a short (.25-.30WL)
boom 3L Yagi. I once suspended a 2L40 Delta Loop from
a 20 ft boom on my 130 ft tower. KILLER antenna but it
takes up a lot of space on the tower if you are looking to
stack other antennas.
Guy Designs from W8AV, 1 June 2001
100' tower
Guy point 1 (approx. 59 feet from the tower)
Bottom guy Philly length - 32.25'
Center guy Philly length - 63.25'
Top Guy Philly length - 94.5'
Guy point #2 (approx. 83 feet from tower)
Bottom guy Philly length - 44.25'
Center guy Philly length - 77'
Top guy Philly length - 106.25'
Guy point #3 (approx. 83 feet from tower)
Same as dimensions as Guy point #2
Tower guy levels used in calculations
Bottom guy - 30' level
Center guy - 60' level
Top guy - 90' level
80' tower
Guy point #1 ( approx. 69 feet from tower)
Bottom guy Philly length - 49.75'
Top guy Philly lenght - 81.5'
Guy point #2 (approx. 66feet from tower)
Bottom guy Philly length - 43.25'
Top guy Philly length - 80'
Giu point #2 (approx. 75' from tower)
Bottom guy Philly length - 53'
Top guy Philly length - 85'
Tower guy levels used in calculations
Bottom guy level - 40'
Top guy level - 75'
