Everything you know about dipole (calculators) is wrong ...

I use 4 wires w/ X-shaped spreaders (24" x 24"), as an inverted vee. The free design program on smeter.net (http://www.smeter.net/antennas/wire-cage-dipole.php) sez 2:1 VSWR bandwidth is 318 kHz but, my measured BW is 500 kHz. I later reconfigured it to also function as a vertical w/ top-hat on 160m.

Most of the parts came from Davis RF, DX Engineering, and the local box store. I can't imagine ever BUYING an antenna as simple as a dipole.

Bryan WA7PRC
Photos + info: http://www.tinyurl.com/wa7prc-80m-160m

 

One day, I came home from work to find the front of my '69 Barracuda dangling from a bumper jack, and the RF wheel/tire missing. The lug nuts on the left side were piśś tight.

 

I wonder how my mother was able to give birth to me 73 and some years ago with out a computer ? Whow ?. Well blow me down, I'll be darned

 

Toilet flanges... clever!

Hope it don't mean my signal is in the crapper.

 

468/frequency (in MHz) = Length of dipole in feet. Each half of the dipole would be half this length. Add or subtract as needed for each antenna. For example, my favorite net on 7.153 MHz, use 468/7.153 = 65.43 feet or 65 feet 5 inches. Each half of the dipole would be 65.43/2 = 32.715 ft or 32 feet 8 1/2 inches. It's a total no-brainer that has worked for me since I put up my first dipole in 1972.

 

re: " sez 2:1 VSWR bandwidth is 318 kHz but, my measured BW is 500 kHz. "

Soil composition?

 

ALL he has to do to really make it efficient is ... reduce the ground loss!

Do you know how much of the E-field ends up in the 'earf' from a horz dipole?

 

I stated the design program is for a dipole (with no input for the soil under it or how high AGL). I also stated I'm using the antenna as an inverted vee. The good news, instead of having to trim it to fit ≈ 100 kHz BW (for a single wire) to the band segment where I want it, the thing is so broad that it mostly doesn't matter:

I constructed it a few feet long, and the low VSWR point is low. But, since I spend most of my time below about 3900 kHz, I left it alone.

The soil is "glacial till" (lotsa rocks).

 

88

 

Why didn't they make the title "Now, for the next can of worms"!

 

A length of isolated house wire has a velocity factor similar to coax.
i keep making antennas out of it though.. one ham says if you need an antenna
a little shorter because you don't have the room this is the ticket, but bottom line
whatever formula you use it will be too long.
those out there that use bare antenna wire do not have this problem.
Try .85 for a velocity factor for plastic insulated wire and see if it tunes right.
Rich

 

Meh, humor I guess?

 

Yes he opened a can of worms on this one,,
a whole lot of things can screw with an antenna, roof flashing, metal roof jacks etc etc..
plus if your using plastic coated wire it will be shorter.
If anyone thinks im full of BS try it, make an antenna by the formula out of plastic coated house wire
and see.. then do the same with bare wire.. or better yet strip the house wire and put it back up
exactly the same place and see what its center frequency is.
Rich

 

The "newer generation" wasn't taught the skill sets that the older gen did.. I'm guessing that computer skills or interacting with social media wasn't taught then either and where not the norm in the 50's or earlier either.. Just a different set of skill sets.. Rock on new comers!