There is quite a bit of a search for an antenna and match-box for the QMX that work well. A great antenna is the one designed by Heinz HB9BCB. It’s designed for the KX2 and its built-in tuner. I have experimented a bit to make it work for the mid-band QMX. Turns out that the antenna is easily tuned with a L-match with an inductor of 0.5 to 7.5 uH and a condensator of 0-560pF, provided it can be switched from L-C to C-L. Matchbox directly coupled to QMX, no coax. Tuning is made easier by lengthening the wire a bit. The box can be very small and is tuned up fast. Simple and effective.
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Thanks Peter for the flowers, hi.
Note regarding the Elecraft ATUs KXAT2/3 and T1
The reduction in complex impedance achieved by the short antenna extension (in red) is not yet sufficient to achieve optimal impedance matching with the aforementioned ATUs at 14 MHz (at best, ~SWR 2.5).
Therefore, the design goal was unfortunately not achieved, and the 10.90 m inv-L multiband antenna must be used as before with an external matching aid at 14 MHz.
Nice side effects of the vertically mounted antenna extension
– A significant improvement in the vertical 14 MHz radiation pattern
– Trouble-free matching using a Kanga Pocket Transmatch (max. 10 watts).
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What is your setup while operating with emphasis on where the radials are connected?
If the radio and matchbox are laying on the ground, the connection should be simple…
With small radios (MTR3b, and QMX in the future) I operate sitting, with both radio and keyer on a small board in my lap, and I have no idea how to attach the radials directly without getting all tangled.
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I like to put the QMX and tuner on the ground, and have only paddle and logging equipment in my hand, mostly as in Paddle for screen logging. You can of course add a couple of meters of coax between the transceiver and the matchbox. Holding the transceiver, matchbox, and connections to antenna and radials doesn’t make for pleasant operating… I find this works only for an efhw without radials.
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