Lee W0VT
Tune up with a BITX has always been problematic because there is no low power output mode suitable for use with restive SWR bridges.? I use an audio source that? can be adjusted for very low RF output.? With around 8 millivolts AF into the mic jack I get around 100 milliwats RF out to safely drive a resistive SWR bridge.??
Others have devised thier own approaches to this, including very low duty cycle CW.??
There are alternative RF sources that include their own SWR bridge for optimizing antenna adjustments before connecting the BITX.
Arv. K7HKL?
_-_
Sent from my Verizon, Samsung Galaxy smartphone
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-------- Original message --------
From: "Alan de G1FXB via Groups.Io" <g1fxb@...>
Date: 7/30/18 6:24 PM (GMT-07:00)
Subject: Re: [QRPLabs] QCX & Ant Tuning
I would investigate building
A resistive type SWR Bridge
if they perform as "advertised"?
As always there are other solutions......
Alan
On 31/07/2018 00:57, Leland L. Bahr
wrote:
If one
was going to use a random wire antenna matching the antenna to the
QCX through the use of a tuner, how does one avoid hurting the
finals until the tuner has a match?? I am assuming the radio will
see a high SWR until this condition is met and would suspect a
temporary high SWR would hurt the finals over time.? There is no
low power setting for the QCX. ?? So how do you use a QCX with an
antenna needing a matching device without damaging the finals??
Must the tuning be performed prior to putting the QCX "in line"?
Lee, w0vt
