It may be just the extra coax you are putting in the line between the
exciter and amplifier. As you said, the SWR goes up as the frequency goes up.
low frequencies, the amplifier and coax represents a small addition. At high
frequencies, (6 meters) it may be a significant addition.
Where is the SWR bridge? Is it in the exciter or at the output of the
amplifier? I suspect it's at the exciter. Does the SWR change to 1:1 if you
tune the SteppIR when the amplifier and extra coax are in the line?
Remember the articles on how your length of Coax will vary the SWR that your
exciter will see. One must consider the entire system from the SWR bridge
(in the exciter, amplifier, or outboard) to the antenna, regardless of the
fact that one might think the coax line is "flat."
In a message dated 12/7/2005 8:47:20 P.M. Eastern Standard Time,
When passing thru the Henry 4 K-2 amp, with the amp turned off, the exciter
sees an SWR of between 1.1 to 2.0 depending
on the band the exciter is set on (75M thru 10M). The SWR is higher at the
higher frequencies. The SWR is infinitely
high on 6M.
If connected directly to the antenna(s), the exciter sees 1.1 SWR on all
bands. I'm using a SteppIR antenna whose
elements can be tuned to present a flat impedance at any frequency between
40M and 6M.
With the amp turned on, the exciter sees an SWR of 1.1 on all bands (75M to
My question is why does the amp introduce a higher SWR in bypass and not
allow a 6M signal to pass thru without
introducing an infinitely high SWR?
In the off position, the signal passes thru an input bypass relay and then
to an internal SWR bridge at the output side
of the amp and then to the antenna.
With the amp turned on, the signal passes thru the input relay and to the
appropriate band input impedance matching
module. This explains the 1.1 SWR on all bands with the amp turned on.
The only components in the path, with the amp turned off, is the bypass
relay and the SWR bridge - all internal to the
amp. Can these be causing the exciter to see the higher SWR and infinite 6M
SWR? Is the internal SWR bridge the culprit?
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