The wife was having a girl's day out with her sister & our oldest daughter, so I was left to my own devices (not always a good thing ...).  

Just for fun, I decided to see if a 10m cage dipole would show a low SWR across the whole band.  I had a spool of 17 awg aluminum fence wire lying around & some old corrugated drain pipe, so the raw materials were at hand.  

The drain pipe was used for the spacers, just cut between the ribs & drill holes through the rib sides for the wire.  I used six wires on each side.





Feed point & pull point tabs where fabbed from a 3/8" thick cutting board that has been source material for quite a few builds...

Wire was pulled tight in bundles, measured & cut then threaded through the ring spacers.  The whole assembly pulled tight, measured & adjusted as needed.  I pulled it up with some pull lines left un-used except for hoisting test antenna, attaching RG8x to an outside coax connection.  Just connecting direct to coax.

 
The camera angle show a corner of the 294' horizontal delta in the background.

Testing showed it a bit long, so  did an initial trim & added a 1:1 current balun to the feed point.  Once it was up, it hadn't shifted enough, so I did one more trim & checked again.  The end result:


(the shaded band area on the chart runs from 28.000 to 29.700)


I don't think it will out perform either of the two horizontal loops (550'  & 294' delta), but no tuning is necessary prior to use...
I probably won't leave this up for any great period of time, just enough to play with it a bit.

Nick

I'm not sure I'm reading that correctly... It's under 2:1 for everything above 60MHz?

Seems like you could make one for 160 and either have a great dummy load, or a great antenna, heh.

Not sure, but a guess is that the RG8x is soaking up the higher frequencies.  There is about 120' or so between rig and antenna.  Had to use two lengths with a barrel connector in between to accommodate the pull height.   If I had some ladder line around, I would have preferred that for the trial  ...

This is what was seen on the first scan, no balun, original build length and about 40' less coax (it was pulled tight).





Nick

ETA:  in retrospect, it was kinda silly to do a half wave dipole, short as 10m is, shoulda' just gone ahead & done a full wave ...

There's certainly nothing wrong with that!  1.7:1, max, and lower over the rest of the band.

Looks great to me!  That experiment was a big success!

Antenna looks good, coax not so much...


My quick calculations show about 48% signal loss or about 53 watts/100w power out.  Not bad, not great.  Certainly better cable would help turn that into a more respectable number.

http://www.arrg.us/pages/Loss-Calc.htm

Agreed.  Just used what was on hand to see what the numbers looked like.  I have become a real fan of ladder line & would probably at least give that a shot if I was leaving it up for real.   It is currently occupying a "test' slot with regard to the pull points used & the outside coax connector.

Nick

Antenna looks cool to me!   How high is it above ground level?

Interesting to use drain pipe as spacers

Should be nice and light

I would suspect it will hold up in the sun

currently about 40' (guesstimate).  Received signal about the same as the 294' delta and maybe a hair less than the 550' loop - but a couple of times it was higher than the delta (flipping back & forth with the A/B switch). No info on xmitted signals yet...

Nick

Cool!

The pic posted wasn't too clear, so here's a crop/closeup



Nick

What if you made a "fan caged dipole".

The wider bands would be larger diameters and narrower bands smaller.

How's it working today? 10m is WIIIIDEEEEE open.

Actually used it for a Ukraine contact this morning @ 5000+ miles.

Nick

Too bad I don't speak the language of most of them.