New T2FD Antenna Construction and Performance

[Pigmeat]

Any one remember the old "El Toro" antennas hams made out of ladder-line with the high point on the TV mast on the roof? The bottom end of the ladder-line would be hooked to the center conductor of the coax and the outer braid soldered and clamped to the outdoor spigot as a ground. The center of the ladder-line would be pulled as far from vertical as the postage stamp lots of those post-war developments allowed.

Those guys got out. Oddly, regulations on rf output filtering came along about the time interest in antennas like the "El Toro" peaked.

[Stretchyman]

Drone survey complete but because of the angle of vision my drone pilot failed to get it over the very top so will try again today.

I have a very 'Tree congested' garden and the far side of the tree is a childrens playground so definataely inable to take off/land in either.

Will take off from my roof top, flu over the tree top, dip down 20' and then turn and land in the lane to the side of the tree.

Tricky manoeuvre!

The monofilimant line must trial from a weight suspended under the drone otherwise the line will get caught in the props, again, tricky business...

Str.

[ChrisSmolinski]

Drone survey complete but because of the angle of vision my drone pilot failed to get it over the very top so will try again today.

I have a very 'Tree congested' garden and the far side of the tree is a childrens playground so definataely inable to take off/land in either.

Will take off from my roof top, flu over the tree top, dip down 20' and then turn and land in the lane to the side of the tree.

Tricky manoeuvre!

The monofilimant line must trial from a weight suspended under the drone otherwise the line will get caught in the props, again, tricky business...

Str.

Thanks for the update!

I was wondering if using a weight to keep the fishing line down below the props would help. Let us know how things go, I'm considering getting one of the kids to try using their quadcopter to take some line over a tree.

[Stretchyman]

I'd make a video but am too busy guiding the pilot and feeding out the line from a multiplier reel...

Str.

[Stretchyman]

3rd time lucky and after a few attempts and having gained a bit of experience it was quite simple. Flew up some 12lb monofilament, followed by some 80lb. However the rope I've tied to the 80lb won't go through the branches. Will have to use wire rather than rope?

The tree is an 80'+ eucalyptus, growing 5' a year.

Str.

[ChrisSmolinski]

Congrats!  Any tips on the technique you used to lift the fishing line over the tree? Maybe some step by step instructions?

I've found that when a rope won't go through a tree (I use a sling shot to shoot the fishing line over), it is often because a knot is hitting a branch, Often pulling back and forth a bunch of times will allow the knot to eventually slip past the obstruction.

[Stretchyman]

Fly drone over tree and land on other side!

A small weight is suspended 12" below with the line off that to keep away from props as drone decends.

I've smoothed the knots out and the transistion from line to rope with much insulation tape, still no good..

I'm going to get some dacron to smooth the transition.

Str.

[ChrisSmolinski]

Perfect, thank you, I got it now 

[Stretchyman]

Cool. Definitely the future of wire antenna deployment!

Str.

[i_hear_you]

it is often because a knot is hitting a branch

In cases like these I send a "carrier wave oscillation" up the rope orthogonal to the plane of the branch and rope.  This can "jump" the knot over the branch, however these operations have always been within 40'.  I doubt I could get the wave to travel all the way up 80' with enough amplitude to jump the knot over. 

[Stretchyman]

Indeed I had the same thought and tried it from the open window but not enough oomph on it. I'll have to get out on the roof at weekend, will hopefully be cooler as I burned my hand and rear cheeks as it was so hot! Somewhat rare for the UK!

Str.

[refmo]

For the drone deployment, I highly recommend going up 2 times the height of the tree plus the width of the tree.
This should prevent a situation where the drone can't make it back down to the ground if the line gets snagged in the tree.
Also, make sure the attached weight is centered, so that the drone isn't trying to compensate (drift) for the unbalance. (especially if flying in close proximity to tree limbs).

[Josh]

This is droning on and on!

I want to see specs on noise floor and signal levels for each antenna at casa del smolinksi!

[ChrisSmolinski]

I repaired the T2FD after some storm damage. I replaced the generic ham radio balun I was using with a custom 12:1 version of my Cyclops potted matching transformer, fed into 75 ohm RG-6 it provides an ideal 900 ohm feedpoint impedance. Also a potted 850 ohm termination resistor.

Works great, I am hearing my semi local (I suspect they are about 5 or 10 miles away) pirate on 1620, WEDG The Wedge, playing Christmas Music. Heck, they might even be a Part 15 station, or close to it.

https://www.blackcatsystems.com/rf-products/cyclops_rf_ham_shortwave_radio_matching_transformer.html

[syfr]

Zombie thread I know but antenna discussion are always undead!

Chris, I notice that your Kiwi is noted as a 120 T2FD ... did you change from the short one to the big version ?   I've been using your kiwi on and off for the last  week or so and am really impressed with the results.  I have  an acre of trees out back , some of which are probably pushing 100'. The usual issue is there's too many trees and it's a struggle to find an antenna path.  On the other hand, I own a Stihl chainsaw......

WIth your 59 foot version of this antenna, did you scale the wire to wire spacing to the new shorter length? I'm guessing yes, but I wanted to confirm before I get out the soldering iron and tape measure.