Homebrew T2LT dipole and 3el Skypper beam

[vkrules]

I'm making a T2 LT dipole and then going to convert it to a 3el vertical Skypper beam.

Stay tunned

First a t2tlt dipole can be easily mounted Vertical or Horizontal as the coax comes out one end Unlike conventional dipoles It uses part of the coax braid its self as half your ant and the center conductor ( or additional wire )as the other half It is most likely the simplest antenna you can make.It can be made completely out of coax, or as I have done ( to save some coax) 8 ft 6 inches of electrical wire and coax.

 

[vkrules]

Finished Dipole mounted fairly low for testing. Even at this height it is showing 70 ohms impedance. dont keep tuning for 1 to 1 swr it wont happen!

 

[vkrules]

Note the SWR 1.39 70 ohm J0 (reactance) Resonate on 27.140 as it should be.
Not 1 to 1 50 ohm as many on the forum think Dipoles are 70 ohm at resonance.Trying to tune it to 1 to 1 is counterproductive, tuning it away from resonance and a complete waste of time

 

[vkrules]

The choke is 16 turns on a 65 mm former ( you can use 5 turns on 90 mm , 4 1/2 former)

 

[vkrules]

Basic construction.
Wire is 8 ft 6 inch soldered to the center conductor an other 8 ft 6 measured off to the coil.If you use all coax construction than there is no need to solder, but the final length will be shorter due to the Velocity factor of the coax. A n other hint fold the wire back to tune don't cut it .

 

[vkrules]

Antenna as an inverted v .angle of the v is a little sharp.

 

[vkrules]

Note now the impedance is much lower and the resonance frequency has gone up.Angle of the V should be 110 deg or more for a better 50 ohm match. swr 1.o4 44 ohms res freq 28 mhz

 

[vkrules]

Now vertical

 

[vkrules]

Note swr back at 1.57 imp 80 ohms ( thats a little high and is most likely due to the close proximity of the metal rain gutter to the coil ) resonate freq 27.170 .Again not 50 ohm 1 to 1 ote

 

[vkrules]

T2LT Vertical Skypper on Fiberglass fishing pole.

 

[vkrules]

My mast is a 10 meter fiberglass fishing pole . Dont use the top 1m section it's to flimsy .
The boom is 2 fiberglass fishing poles joined at the centre using a section of aluminium tubing.


Dir 4.75 m
driv 5m
Ref 5.35m
Boom 4.3m
Ref to driven spacing 2,3 m
Driven to Dir spacing 2m
Wire used 1.5 mm insulated (house hold hookup wire)
If you use bare copper lengths will be 3 to 5% longer
Note : I had to shorten the T2LT both ends I did this by folding the wire over at the top. At the bottom I pulled some of the coax back around the coil. simple as long as you haven't tied off that coil to tight. ( if you just adjust one end the dipole becomes off centre fed and the impedance will rise , of course that could be advantages to some installations )

Note 2: I have ordered two telescopic fishing poles for the boom and will fit some sort off hook and eye fasteners to the ends so I can dismantle the whole thing and fit it into a backpack

 

[vkrules]

SWR after adjustment 1.19 57 ohm J0 at 27.380
1.5 points are 26.880 and 27.980

 

[vkrules]

Summary
The T2LT works well and vertical performs as well or better than other end fed half waves.Great antenna to have for difficult locations and can be used almost anywhere.

The 3 el skypper
works well horizontal with the gain only slightly less that a standard 3 el yagi. Does have a dovetail rear lobe and the pattern is not as tight as the yagi ,but only slightly! Has wide bandwidth due to the wide element spacing and the coupling affect of the bent elements.

3el Vertical T2LT skypper
Easy to make,light , easy to transport , same wide bandwidth.
Some thing I have noticed is it is not as directive as the same antenna horizontal , I don't get the same deep nulls off the sides when vertical . I am getting 3 s points difference front to back though so it is working .The T2 LT driven works and makes the portable fishing pole version convenient. If building horizontal .,stick with a standard dipole .


Come on those of you who have dipoles up. 1 stick and some wire and you have a beam.

 

[309hellinois]

Summary
The T2LT works well and vertical performs as well or better than other end fed half waves.Great antenna to have for difficult locations and can be used almost anywhere.

The 3 el skypper
works well horizontal with the gain only slightly less that a standard 3 el yagi. Does have a dovetail rear lobe and the pattern is not as tight as the yagi ,but only slightly! Has wide bandwidth due to the wide element spacing and the coupling affect of the bent elements.

3el Vertical T2TL skypper
Easy to make,light , easy to transport , same wide bandwidth.
Some thing I have noticed is it is not as directive as the same antenna horizontal , I don't get the same deep nulls of the sides when vertical . The T2Tl driven works and makes the portable fishing pole version convenient. If building horizontal stick with a standard dipole .


Come on those of you who have dipoles up. 1 stick and some wire and you have a beam.

It's snowing, well below freezing and I'm ready for spring.

 

[vkrules]

It's snowing, well below freezing and I'm ready for spring.

you can see the bad weather here in the photo come on you have got to turn that dipole into a beam its just begging for it( when the snow stops)