Antenna Dipole placement

[KC4KFC]

I would appreciate some advice.

I live on the side of a hill in a fairly deep little valley here south of Nashville. Hillside is completely wooded with trees about 60 to 80 feet tall.  I have an 80 meter dipole strung up 70 feet or so very close to the house. Its fed with  about 90 feet of 450 ohm ladder line.

300 feet or so up the hill is a ridge at a much higher elevation still wooded.  Would I get noticeable improvement in lower angle reception if I hung my dipole up at the top of the hill and fed it with so much more ladder line?

Would the improvement to hassle factor make it worthwhile?

Also, I've never seen the topic covered in the handbook. How do trees effect antenna performance? At hf, do trees block reception?  I have no choice except to get above the trees. The whole property is wooded.  I have only once seen the antenna handbook mention that verticals need to be in the clear.  Will a vertical work in the woods?

Finally raining in Nashville,

KC4KFC   Mark

[W8EJO]

My 2 cents:

An additional 300 of ladder line @ 3.8mc only adds .16 dB of loss to your system which is truly negligible.

 So the question becomes:

Where is the better (best) place to string up your dipole?

If its me, I'm placing it at the top of the ridge. You'll be much higher & you won't have the slope absorbing the signal in one direction.  You should see noticeable improvement.

Having said that, at 70' off the ground it will still be too low to be a GREAT DX antenna on 75. You'll need more low angle radiation for that (Vert. or Inv L)

Terry
W8EJO

[Steve - WB3HUZ]

Trees do have some attenuation at HF but it's very minimal. I wouldn't worry about it. Terrain can have a big effect on the pattern of an antenna. Placing your dipole at the edge of a very steep slope will make it "look" and act like an antenna that is much higher, at least in the direction of the slope. Your 70 foot high dipole might act like a 150 foot high dipole in the direction of the slope.

The effects of terrain have not been covered much until recently. But there are now several terrain modeling programs out there (at least one is included in recent versions of the ARRL Antenna Handbook) that will show changes in antenna pattern over real terrain. Check it out.

I did some modeling about 10 years ago on a dipole at the edge of a steep slope. The takeoff angle was lowered significantly in the direction of the slope.

[K3ZS]

A better receive signal-noise ratio will probably be gained moving the antenna away from the house.    You will get less noise pickup from things in the house such as digital cable noise, computers, etc.

[Todd, KA1KAQ]

I have a similar situation here except my house is on the top of a steep bank. The dipoles for 40 and 80 literally hang in amongst the branches and work fine. Green vegetation is more of a sponge for RF when you get up into VHF and above. Besides, the leaves are all falling off this time of year.

Go for the elevation.

[flintstone mop]

The height of a dipole that most of us Ham folks use are "cloud burners". The magic number may be 120 feet high, not sure here.
The direction your signal goes starts probably on the 40M band and up. Prolly 15M to 10M you will have many lobes and distortion of the radiated signal using a dipole. That's why a Yagi is better for those bands.
Keeping the antenna away from noise sources is a very good idea.
Fred

[W9GT]

A better receive signal-noise ratio will probably be gained moving the antenna away from the house.    You will get less noise pickup from things in the house such as digital cable noise, computers, etc.

This good advice!  And....it works both ways...you will have less problems with RFI/TVI if you keep the antenna some distance from the house.

73,  Jack, W9GT

[KC4KFC]

Thanks for good advice.  As soon as the leaves drop, I'll climb the hill with my fishing pole.  Anybody have favorite techniques for hanging antennas as high as possible in trees?

[w3jn]

Wrist rocket, couple ounce sinker, and some fishing line 

[Todd, KA1KAQ]

Wrist rocket, couple ounce sinker, and some fishing line 

I need to get one of those! My days of transformer and water-shutoff-cover slinging are getting annoying. Takes too damned long, too!

[K6IC]

RE how to put the antenna into a tree,

Have had very good luck with the BigShot -- a very large slingshot,  and 12 oz shot bag.  The BigShot can alunch this shotbag about 200 feet vertically and about 200 ft horiz..   If therre is wind it may take a couple of shots.  My usual error it to get the bag too high,  and the hang time allows the wind to carry the shot off course.   This device could be made,  but is about $ 90. mail order from Arborist supply houses.

YMMV   Vic   K6IC

[WD8BIL]

Recurve bow and aluminum arrow rigged for bow fishing.
Instead of the barbed fishing tip I use a field/target tip blunted with a file.

I'd dis-courage the use of a compound bow unless you enjoy digging your arrows out of the neighbors roof. (Don't ask me why..... please!)

[WA1GFZ]

Bud I use a 75 pounder and put a 3/8 bolt at the end. Chevy manifold bolt works good. I sent one across the neighborhood a few years ago and never found it. I bounced one off my new 50 year roof with no problem

[W8EJO]

Recurve bow and aluminum arrow rigged for bow fishing.
Instead of the barbed fishing tip I use a field/target tip blunted with a file.

I'd dis-courage the use of a compound bow unless you enjoy digging your arrows out of the neighbors roof. (Don't ask me why..... please!)

I concur. Ive used everything from wristrockets to compounds to a straight spinning rig to my current set up a 35 pound draw "youth" recurve. It gives me terrific accuracy & enough power to go 150+ feet. Spinning rig works great if you are in the clear up to heights of about 60'. Heights greater than 60' go with a bow.



Also a few tips I've found helpful:

1) Use at least 12 pound limp monofilament.
2) Weight the tip of your arrow with a little lead tape so it will tip down fast after reaching it's apex or unscrew the broadhead and screwin a bolt & a few washers in its place for weight.
3) Tape your monofilament to your arrow toward the tip.
4) Use a brightly colored arrow. Cammo arrows can be tough to find in the foilage.
5) I use weedeater string to hoist the antenna up & as a permanent tie down. The stuff is tough as nails & doesn't seem to age.







 

[KB2WIG]

I've been using a pipe wrench and that black ant stuff....   weed eater cord works ok and is cheep... if you have old cast iron window wts., they've got a hole at the ends......  ( bow/arrow probably the best bet )  klc