Mobile shack

Happened to be in W4 (Florida) this winter so I took my FT817 with me. Thanks to reciprocity between Canada and the US, I can operate using my Canadian callsign while in the US.

Being in a car country, it looked sensible to me to set up a mobile shack. My VE3 elmer has had a great success with MFJ miniature hamsticks mounted on the trunk of his car so I started looking in that direction too.

After quick research on what’s available at HRO online, I ordered two versions of MFJ hamsticks: miniature 3′ and longer 7′ hamsticks for the most popular bands. For the base, I ordered a mighty MFJ-336T mag mount with 3/8″ mount.

The first one to arrive and to install was MFJ-1620 – 7 feet tall antenna for 20m. The fiberglass base is about 4 feet long and is hollow inside. A stainless steel whip that screws on top is adjustable.

MFJ-1620

When fully extended, it resonated nicely on 13.540 MHz (perfect 1:1 match!) which was way too low… After shortening the whip by about 4″ the center of resonance shifted towards 14.060 QRP CW frequency (with the lowest SWR about 1:1.2). Could not get it match 1:1 anymore.

The whip is very hard to cut. After some trial and errors, the best tool happened to be a triangular file. Cut through the steel half-way then snapped it easily.

While busy with all this hard work, I did not notice it got really dark outside and the 20m band faded away. After scanning back and forth, a weak but workable signal of ZL3GA emerged and my tiny 5W signal just barely made it across the Pacific (7,220 nautical miles!) . Not bad for QRP with a mobile whip!

The 40m was alive and kicking so the next one to install is a 7 MHz hamstick.

The length of the whip makes driving a bit difficult – have to watch out for clearance, low hanging tree branches, etc. Also, at speeds of more than 45 mph, the whip starts buzzing in the wind.

Photo of my new mobile shack:

Mobile QRP

Hope to see you on the air!

73s,
Paul

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About va3paw
Ham radio enthusiast, software developer

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