Yet no one has told a bad story or cautioned us about using the Force 12
yagis QRO at heavy duty cycles - right?? (I'm considering one for RTTY
contesting at power - I asked about this once before, and the responses
were 100% in agreement that the Force 12 yagis could take power and heavy
duty cycle.)
I'd like to know if others would worry about this.
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WA9ALS - John
mailto:jfleming@shelbynet.net
Tower Project Guestbook http://www.shelbynet.net/~jfleming/towerproject
Amateur Homepage http://www.shelbynet.net/~jfleming/amstart.htm
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On Friday, July 16, 1999 8:37 AM, Tom Rauch [SMTP:w8ji@contesting.com]
wrote:
>
> Hi Greg,
>
> > If it does not blow apart with the sound of a 12 gauge or steadily lose
> > power with a corresponding rise in SWR like all the W2DU type baluns I
> > have ever owned, then it's probably an ok balun. The only time I had
no
> > problem with the less expensive bead type baluns was with 100w or less.
> > You would do well to read "Baluns & UnUns" I have several of the
toroid
> > type baluns using the high power Teflon coax and the only problem I
have
> > with those is finding a suitable enclosure which is strong and
> > lightweight.
>
> The exact reason we need to know Rp of the balun, and do a little
> Ohm's law work with Rp.
>
> I've had exactly the same results as you, and a "paper review"
> predicts the balun should overheat just as it does.
>
> There are good applications for strings of beads, but QRO
> operation is not one of them because the string needs to a higher
> Q bead and MANY more beads than anyone would ever expect.
>
> Even 10 watts of bead dissipation will send the beads into 3 Mile
> Island effect unless it is a LONG string.
>
>
>
> 73, Tom W8JI
> w8ji@contesting.com
>
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