Hi Jim,
I used a piece of 75 ohm coax 1/4 wave in electrical length to feed each of
the five elements, running each one to a band select relay box mounted about
a foot below the quad. Works excellent with good swr across all bands.
-----Original Message-----
From: towertalk-bounces@contesting.com
[mailto:towertalk-bounces@contesting.com] On Behalf Of Jim Lux
Sent: Thursday, April 20, 2006 8:58 AM
To: Jim Rhodes; denis coolican; towertalk@contesting.com
Subject: Re: [TowerTalk] Lightning Bolt Quad
At 04:43 AM 4/20/2006, Jim Rhodes wrote:
>I asked the Lightning Bolt guy about that once and he got very
>defensive about his feed system. Said the tuning would be all off and
>he wouldn't be responsible. Others have said the opposite, that
>quarter wave lengths to a switch were needed. I am sure there are
>many opinions on this.
This is a question that could be answered by modeling it. (that is, what's
the sensitivity of the design to this change) There are some tricks to
accurately modeling quads (the corners), but I think that Cebik's web pages
cover it. You also need to choose segment lengths that line up nicely.
>At 12:02 AM 4/20/2006, denis coolican wrote:
> >This four element Lightning Bolt Quad covers 20, 17, 15, 12 and 10
> >meters. It is fed by a common balum. (one input PL259 and 5 output
> >pairs of conductors)
> >
> >Does anyone know what type of balum this is and what would be the
> >replacement for it?
> >
> >I imagine the driven elements for each band has an impedance of
> >about 80 to 100 ohms. The feed into the balum is 50 ohms.
> >
> >If a person provides a 2:1 balum for each feed, would the unused
> >balums be terminated in 50 ohms or left open?
> >
> >Any more thoughts on this antenna?
> >
> >Denis Ve6aq
_______________________________________________
_______________________________________________
TowerTalk mailing list
TowerTalk@contesting.com
http://lists.contesting.com/mailman/listinfo/towertalk
_______________________________________________
_______________________________________________
TowerTalk mailing list
TowerTalk@contesting.com
http://lists.contesting.com/mailman/listinfo/towertalk
|