Antennas seem to be the most poular topic

[K4AVL]

Following the threads here, antennas seem to be the most popular Q&A topic. From my limited experience I do seem to have a usable configuration now, a stationary ladder-line fed doublet with a matcher that works pretty well.

I saw this "clothes line" pulley idea on the ARRL site, and that looks like a great one to try, since some of you guys mention you have limited space and may need "stealth". It tunes by moving the feed point:
http://www.arrl.org/members-only/tis...df/9807056.pdf

On my end, I'm wondering if "lengthening" my doublet/dipole which is about 66'4" per leg will help bring in weaker stations, since I can't get it up much more than 30' or so. Most of the trees here are very tall and their lowest boughs are way up there 60' or more, beyond a stones throw.
Would I have to lengthen both sides evenly to keep it symmetric so as not to cause an imbalance in the feed line? If so, I would have to make a 90 degree turn at the south end to not get too close to the power line by the road, and then another 90 degree turn in the opposite direction at the extreme other end, so it would end up being as "S" like half a swastika. If those ends were higher or lower relative to the ground than the rest of the antenna (I'm on a steep mountainside as well) would that make a difference? They say that really the center portion carries most of the power so maybe this idea won't offer much improvement.

[AI4IJ]

Generally speaking, more wire in the air = stronger signals. #But, one thing that adding more wire to a horizontal doublet doesn't really change is the take-off angle. #That is going to be primarily influenced by the type of antenna and the installation height.

So, yes, lengthening the antenna is going to give you stronger signals - but, at a price. #The gain is going to show up in the form of additional radiation lobes with increasingly narrow beamwidths, as you go up in frequency.

In your case, I think that raising your antena higher in the air will help far more than adding length to your antenna.

In fact, you might consider adding another doublet mounted at 90 degrees from the first. #That way, you can switch between the antennas to find the strongest signal.

If you want to do this, you might consider a pair of Extended Double Zepps for your favorite band. #For 20M, you would need a doublet about 88 feet long for maximum gain, and about 82 feet to improve the side rejection and reduce the size of the "ears" on the sides. #Any longer than this, and the major lobes begin to shrink and the "ears" get bigger - eventually, becoming the major lobes. #

The big advantage to the EDZ, apart from it being a high gain simple wire antenna, is the fact that you know where your gain is pointed on the design frequency and below.

At one wavelength above the ground, you can expect a takeoff angle in the 15 to 17 degrees range and gain in the range of ~10dBi in a pattern that is bidirectional broadside to the wire. #Lower height = lower gain and higher takeoff angle. #The quality of the ground beneath the antenna is largely irrelevant for the EDZ. #

An EDZ is just a doublet with 5/8 wavelengths of wire on each side of the feedpoint.

The antenna you already have is an excellent multi-band solution, as is. #You don't need to add length to it, unless you want to be able to work efficiently on lower frequencies than 80M. #Just get it as high as you can. #That will help more than anything else.

73
Richard
AI4IJ

[AI4IJ]

Quote[/b] (k4avl @ June 19 2007,16:56)]On my end, I'm wondering if "lengthening" my doublet/dipole #which is about 66'4" per leg will help bring in weaker stations, since I can't get it up much more than 30' or so. Most of the trees here are very tall and their lowest boughs are way up there 60' or more, beyond a stones throw.

Oh, and consider yourself lucky to have such a "problem." #There are ways of getting wire antennas up in those tall trees without throwing any stones! #You could use one of those EZ Hangs (see leftside of this page), which is just a sling shot with a fishing reel attached. #I use one of those with great success to get my wire antennas up 60ft., or more, with ease.

You could also use a crossbow and string. #Or, you could use a tree man's toss bag and string (often a bean bag filled with lead shot and a string attached). #You just swing it around a couple of times to gain some momentum then let it fly.

73
Richard
AI4IJ

[AI4IJ]

(duplicate post removed)

[KL7AJ]

And I'm GLAD that antennas are still the most popular topic. Twas always the case and twill always be!

[ND6M]

Quote[/b] (ai4ij @ June 19 2007,17:52)]

Quote[/b] (k4avl @ June 19 2007,16:56)]On my end, I'm wondering if "lengthening" my doublet/dipole #which is about 66'4" per leg will help bring in weaker stations, since I can't get it up much more than 30' or so. Most of the trees here are very tall and their lowest boughs are way up there 60' or more, beyond a stones throw.

Oh, and consider yourself lucky to have such a "problem." #There are ways of getting wire antennas up in those tall trees without throwing any stones! #You could use one of those EZ Hangs (see leftside of this page), which is just a sling shot with a fishing reel attached. #I use one of those with great success to get my wire antennas up 60ft., or more, with ease.

You could also use a crossbow and string. #Or, you could use a tree man's toss bag and string (often a bean bag filled with lead shot and a string attached). #You just swing it around a couple of times to gain some momentum then let it fly.

73
Richard
AI4IJ

[QUOTE]

i was thinking the same thing...... LOWEST bough 60 feet!!!..... YEE HAW!

[AG3Y]

The slingshot works best for me. Tossing a bag, in my case, often results in the thing whizzing over my head and almost beaning someone standing behind me ! Not a good thing !

In spite of the EZ-Hang™ being one of the fine sponsors of this forum, I will mention that if you have an old fishing reel and a little ingenuity , you can purchase a slingshot for around 6-10 dollars that will work just fine! I have gotten lines up 50-60 feet very easily with my setup!

73, Jim

[KL7AJ]

Quote[/b] (AG3Y @ June 20 2007,12:18)]The slingshot works best for me. #Tossing a bag, in my case, often results in the thing whizzing over my head and almost beaning someone standing behind me ! # Not a good thing ! # #

In spite of the EZ-Hang™ being one of the fine sponsors of this forum, I will mention that if you have an old fishing reel and a little ingenuity , you can purchase a slingshot for around 6-10 dollars that will work just fine! # I have gotten lines up 50-60 feet very easily with my setup!

73, Jim

On the other hand, I'm all for supporting hams who run businesses. I bought an EZ hang, just because it is a cool thing, and the "perpertrator" thereof ought to be patronized. \\

For the same reason, if I run across a cool piece of software, even if it's freeware, I'll send the guy a donation. I know what it takes to come up with something original...it's HARD work!

"The good laborer is worth his wages."

eric

[K4AVL]

Thanks Richard, very excellent info. I will have to eventually do the "higher up" scheme, pretty much was a no-brainer, just thought there may be other tricks I hadn't heard of.
Also maybe use all copper wire, rather than the galvanized #18 fence wire I'm using now. Some folks say it doesn't matter, others say copper is the only way to go. I still have 2/3 of a 500' roll of #14 stranded & insulated THHN that may be put to good use soon. Will look more into your Zepp idea as well.
I'm more interested in the rx than the tx, as my outbound signal using a Heathkit SB-200 can take up to around 600ma drive, at up to 2750 volts depending on my power company (1650w PEP?), so that's pretty respectable and I really don't usually even push it that far except on bad hair days (the RF output on my Drake matcher usually shows 600-800 watts.)
So no need to work 'em if I can't hear 'em. Sometimes I'd probably best run my barefoot 100 watts, as in the case today, I heard a few guys 1000 miles away from me that would blast out my eardrums, but then would have to turn up the AF gain from like 3 to 8 to hear who they were QSO'ing with, and woe to my eardrums if I didn't turn it back down when they came back on, especially with my headphones.
Thanks again.

[AI4IJ]

Check out this site:

L.B. Cebik (W4RNL)'s web page

This is one of the best antenna sites on the web. #A tremendous wealth of information is available there for FREE. #Click "Tales and Technicals."

L.B. Cebik has been a long time contributor to the ARRL and amateur radio, in general. #He's an "Uber Elmer!"

I also highly recommend you pick up a copy of the ARRL Antenna Book. #It comes with a cd with all the text in PDF format for easy reading on your computer screen and a host of accessory software programs for modeling antennas and such.

73
Richard
AI4IJ