Clint,
You can make a multi frequency element using the cage method. Just make each
wire a slightly different length. Then it will tune across a larger
bandwidth. I have built multi-band dipoles using antenna rotor cable. This
method is found in some of the older Handbooks. The more the spread, the
easier it is to tune each wire for the desired resonance.
The best way to tune these type antennas is to build it for the lowest
frequency and keep two opposite wires the full length to hold the spreaders
straight, Then cut off some of the elements to cover different higher
frequencies. You will need a spreader to support the end of each wire
element.
My tower guy wires are cut as slopers. One of these is a two wire sloper on
the same feed point at the top of the tower. It covers 3.5 to 4.0 mhz. with
less than 3:1 over the entire range. It is optimized at 3850 and is less
than 1.3:1 between 3750 and 4000. I just use a spreader at the end of the
shorter wire.
There are lots of ways to skin the cat and provide a ladder for the
squirrels. Good luck.
* 73's Jim W5IFP *
.
>-----Original Message-----
>From: towertalk-bounces@contesting.com
>[mailto:towertalk-bounces@contesting.com]On Behalf Of W5CPT
>Sent: Sunday, December 07, 2008 10:59 PM
>To: Dick Dievendorff
>Cc: towertalk@contesting.com
>Subject: Re: [TowerTalk] Cage Vertical ideas wanted.
>
>
>Dick,
>Thanks for the "heads-up". I never have figured out how to
>model an antenna. I really didn't think I could cover both the
>75 & 80M bands. I had hoped to broaden the bandwidth enough
>that I didn't have to re-tune every 40 KHz. I guess I could
>use the tie-wrap idea on a larger circle but don't have a clue
>what I could use to make a 24" diameter spreader, though it is
>intriguing.
>
>Clint - W5CPT
> ----- Original Message -----
> From: Dick Dievendorff
> To: 'W5CPT'
> Sent: Sunday, December 07, 2008 4:35 PM
> Subject: RE: [TowerTalk] Cage Vertical ideas wanted.
>
>
> Is a 6" cage going to give you enough bandwidth? I have a
>bunch of circular
> plastic spreaders for 4" in diameter, and after a little
>modeling I decided
> that they weren't going to be much help for a 75/80 meter
>dipole. I think I
> need spreaders that are on the order of 2 feet long for a
>four-wire cage
> that went from 3.5 to 4.0.
>
> 73 de Dick, K6KR
>
>
> -----Original Message-----
> From: towertalk-bounces@contesting.com
> [mailto:towertalk-bounces@contesting.com] On Behalf Of W5CPT
> Sent: Sunday, December 07, 2008 2:30 PM
> To: Jim Hargrave; Tower
> Subject: Re: [TowerTalk] Cage Vertical ideas wanted.
>
> Thanks Jim,
> That is exactly the kind of solution for which I was looking!
>
> Clint - W5CPT
>
> ----- Original Message -----
> From: Jim Hargrave
> To: Tower
> Sent: Sunday, December 07, 2008 3:51 PM
> Subject: Re: [TowerTalk] Cage Vertical ideas wanted.
>
>
> Clint,
>
> You can use the thin drain pipe and drill the attaching
>holes through the
> side of each ring. Then you can attach the antenna wires to
>the ring by
> using small nylon cable ties. Pass them thru the hole and
>out one end
> clamping each wire in the same manner. This will keep the spacing
> consistent. if you drill the holes near one end of the
>ring, the ties will
> be short and hold the wire tight enough to keep the ring
>from sliding down
> the antenna. You can even wrap the cable around the ties
>before closing it
> to provide a little more friction to better hold it in place.
>
> * 73's Jim W5IFP *
>
>
>
> >-----Original Message-----
> >From: towertalk-bounces@contesting.com
> >[mailto:towertalk-bounces@contesting.com]On Behalf Of W5CPT
> >Sent: Sunday, December 07, 2008 7:14 PM
> >To: towertalk@contesting.com
> >Subject: [TowerTalk] Cage Vertical ideas wanted.
> >
> >
> >I have decided to build a Cage Vertical. I can get about 80 to
> >100 feet straight up by suspending it from a catenary strung
> >between two of my taller trees.
> >
> >
> >
> >Two points:
> >
> >
> >
> >1 The wire I intend to use is Fishing Line. I tried to post the
> >link but it ends up being 3 lines long, so go to cabelas.com
> >and search for item number wt-12-1511. I built a dipole out
> >of this stuff and it solders and crimps well and appears to
> >last for a long time.
> >
> >
> >
> >2. I need ideas on what to use for spreaders. The 45 lb. test
> >line is .037" which is too big to use a thin slice of 6" PVC
> >drain pipe as I cannot drill holes edgewise into the pieces
> >large enough to accept the wire and small enough to not
> >compromise the strength of the slice of PVC. I am considering
> >5 or 6 wires in a 5 to 6" diameter and need some suggestions on
> >what to use.
> >
> >
> >
> >Suggestions about the spreaders and other comments are
>always welcome.
> >
> >
> >
> >Clint - W5CPT
> >
> >
> >_______________________________________________
> >
> >
> >
> >_______________________________________________
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> >TowerTalk@contesting.com
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> >Date: 12/6/2008 4:55 PM
> >
>
> _______________________________________________
>
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