Because you're using a shunt capacitor. This in conjunction with the inductive
reactance forms an L-network. As I said before, you need a series capacitor.
Move the tap to get 50 +jX and then add -jX.
Wes N7WS
On 10/15/2019 1:30 PM, Marty Ray wrote:
Thanks for the response Herb. I can
Marty,
You may be seeing errors in your readings due to broadcast pickup. This is
common when modern R+Jx measurement tools are connected to large antenna
structures. Others have described ways around this problem before here on the
topband chat.
Lee K7TJR OR
Thanks for the response
On 2019-10-15 4:30 PM, Marty Ray wrote:
I can obtain a good match using the 65 ft tap point, but my question
> is why my analyzer is measuring a change in the feedpoint resistance
> (real component of R + jX).
Because the *shunt* capacitor creates an L network with the impedance
(R +/- jX) at
FWIW, I had a shunt feed on my 97-foot Rohn 25 with stacked tribanders
and a shorty forty on it. I spent a long time trying to find a 50-ohm
tap point on the tower and was never successful, so I changed to an
Omega match, which was very easy to adjust once the local broadcast
station on 1550
Marty:
Did you mean it literally when you wrote you added the shunt capacitor,
that is, did you put the cap from the shunt wire/coax center conductor
junction to ground? The cap in a "shunt-feed" arrangement goes in series
between the coax center conductor and the shunt wire up the side of
Thanks for the response Herb. I can obtain a good match using the 65 ft tap
point, but my question is why my analyzer is measuring a change in the
feedpoint resistance (real component of R + jX).
Regards,
Marty
> On Oct 15, 2019, at 3:19 PM, Herbert Schoenbohm
> wrote:
>
> Best to use a 3
Best to use a 3 or 4 wire cage feed and you will find the match easier.
You should tap the tower at 50 feet and work down till you find the sweet
spot. A 500 to 750 vac variable will take care of any measure inductive
component.
Herb, KV4FZ
On Tue, Oct 15, 2019 at 3:10 PM Marty Ray wrote:
> I
