Re: [TenTec] Eagle problem?

["Bob McGraw - K4TAX" <RMcGraw@Blomand.net>]

Why?  I bring mine all the way to the tuner sitting on the shelf above the 
radio.  If the line is operating anywhere near a balanced condition there 
will be little to no radiation from the feed line.
Ground?   Someone said use one for lightning protection.  Why?  All 
lightning protection should be OUTSIDE of the house and never inside.  I 
operate from the 2nd floor of the house.  No ground from the station to the 
outside is ever needed.
I still question why connect the data audio into the mike input.   The 
signal to the radio from the computer needs to be 20 to 30 db higher which 
will improve the signal to noise ratio.  Thus the level of RF will be 
effectively reduced 20 to 30 db.  There is no magic here, just math.
Yes, one can change the feedline length which will move the voltage point, 
perhaps further from the radio.  Still, that is not perceived to be the best 
solution.

73
Bob, K4TAX





----- Original Message ----- 
From: "Mike Schatzberg" <cherokeehillfarm@earthlink.net>
To: "Discussion of Ten-Tec Equipment" <tentec@contesting.com>
Sent: Wednesday, May 14, 2014 6:16 PM
Subject: Re: [TenTec] Eagle problem?


> Hello Carter,
>
> Why not eliminate the balanced line near the house?
>
> Install a 4:1 current balun on the balanced line well away from the house, 
> and connect from the balun to your tuner with 50 ohm coax. Bring it thru 
> the wall and have nothing radiating in the shack.
> A line isolator can also be installed right before the Eagle.
>
> I sit under a fan dipole and have no issues with 100 watts portable.
>
> Naturally, a good single point ground with a short low impedance ground 
> connection is desirable, but I operate at the beach from the second floor 
> without it.
> Leave the RF outside.
>
> 73,
>
> Mike
> W2AJI
>
> Sent from my iPhone
>
> > On May 14, 2014, at 6:43 PM, "Rick - DJ0IP / NJ0IP" <Rick@DJ0IP.de> 
> > wrote:
> > Actually James hit on an important point here:  feedline length.
> >
> > Actually it has nothing to do with impedance matching but everything to 
> > do
> > with the behavior of common mode current on the feedline.
> > Unlike the transmitted RF current which is the same for the entirelength 
> > of
> > the feedline, common mode current is not the same at all places along the
> > feedline.  It varies constantly.
> > It is worst a half wavelength away from the feedpoint and minimum a 
> > quarter
> > wavelength away from the feedpoint.
> > You must consider the vf of the feedline (but not its transmission line 
> > vf,
> > rather the vf of the individual wires - which is probably about .97 our
> > .98).
> >
> > G3TXQ reports measured data on this on his web site at the bottom of his
> > page on RF chokes:
> > http://www.karinya.net/g3txq/chokes/
> >
> > You didn't specify which band(s) the problem is on.
> > A quick try would be to insert 1/8 wavelength of additional feedline 
> > between
> > the existing feedline and the JV Matchbox.
> > Of course it you are on 80m, this is not going to be an option.
> >
> > I still suggest the dual RF choke as per my previous email.
> >
> > 73 - Rick, DJ0IP
> > (Nr. Frankfurt am Main)
> >
> >
> > -----Original Message-----
> > From: TenTec [mailto:tentec-bounces@contesting.com] On Behalf Of TTMaven
> >
> > Have you tried different lengths of feed line - window line and coax,
> > respectively?  I won't recite all the reasons here, but you know how 
> > various
> > lengths of feed line matter to impedance matching, etc.
> >
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