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SQUALO Revisited – an Antenna for 2 Meters

posted Oct 8, 2018, 2:30 PM by L Gray   [ updated Oct 8, 2018, 2:34 PM ]

This is a continuation of the previous 6 meter Squalo effort utilizing the leftover parts from the chair to 
fabricate an antenna for 2 meters. In keeping with the theme I dubbed this a “Squalo Revisited”; however, this is NOT a true Squalo – it is simply a U shaped dipole. 

I kept the square shape overall as it makes stacking the 2 & 6 meter versions a little easier (see end). The antenna pattern will not be circular, it will favor the direction of the feed point hence the pattern will be somewhat elliptical. This is due to the current distribution with a half wave dipole; current is maximum at the center and zero at the endpoints. This is not an antenna for 2m FM as it is not vertically polarized, it is intended for the low end of 2m where most of the CW and SSB operations are horizontally polarized.

The section of chair I had available was a little short for 2m. End to end a dipole should be about 39 inches, the section I had was 34 inches. I improvised and added the short ‘tails’ visible in the picture along the horizontal section of PVC to adjust the antenna resonance. I placed the pipe mounting clamp off center so the antenna would be balanced, it also provided space for the RF choke. I fabricated the RF choke from a section of RG58 cable, 7 turns close wound on the PVC mount as shown. 

I tried a hairpin match but found the overall length would interfere with the pipe mount. I 
ended up with a small inductor across the feed point for matching, 8 turns of #16 copper wire, 1 inch long. I used a screwdriver shank as a form to wind the inductor. Tuning is relatively easy – trim the tails for resonance while spreading or compressing the coil for the best match.

So, does it work?  Back at the WA1GPO antenna test range VSWR and antenna Z results looks reasonably good – VSWR is 1.1:1 at 144.29 and the Z is very close to 50 ohms (resistive).

WA1GPO Test Range
VSWR and Z

I operated during the September VHF contest from a Park’n’Ride located in Mattapoisett on Saturday night. I only operated for an hour or so and the number of contacts were limited. . .

 Squalos on a 20 foot mast, ready to go up
 Antennas in position

Just another fun project. I have parts available (a couple of spare chairs) if anyone is interested in building antennas for 2 or 6 meters.