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Unadilla Pre Show

Posted on Aug 14, 2009

Unadilla Pre Show

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Back in the early 1960s I used a trap dipole made with the old Reyco traps – essentially the same as the modern version - and it performed well despite being in a lousy location and not very high (about 15’ at the center) and with part of one leg bent. Also, in those days it was supplied without the W2AU voltage balun which meant that the antenna was unbalanced. I expected the modern version to be at least as functional and I have not been disappointed. I did modify the design a bit by making the wire elements longer than recommended in the data sheet (32’ inner & 22’ outer). Since I operate 100% CW on HF I made the inner sections 33’ and the outer 24’ and as expected this lowered the resonant frequency on 80 & 40 meters. 640-460 Overall length of the wire is now 114’ instead of 108’ and the 80 & 40 meter minimum VSWR points are 3560 and 7085 kHz respectively, with 2:1 VSWR bandwidths of approximately 90 and 180 kHz on the two bands. VSWR on 30 meters and above is quite a bit higher but my MFJ-929 IntelliTuner is able to achieve a reasonable (VSWR 1.5 or less) match on the CW portions of all the other bands. I should note that the built-in tuner in my IC-756PRO easily tunes to 1:1 VSWR on the CW portions of 80 & 40 meters. 350-029 80 & 40 meters is where this antenna really shines. With the W2AU balun to achieve better (although no doubt not perfect) balance the pick-up of vertically polarized noise by the vertical portions of the coax feed is significantly reduced and the extra wire length definitely improves sensitivity over my 82’ Alpha-Delta DX-DD (which is slated to become my low-mounted 80/40 meter NVIS antenna). The trap dipole is about 28’ high at the center and has yielded very nice signal reports on the two lower bands. Even though it will load on the higher bands I don’t expect superlative performance although sensitivity on 20 meters seems to be quite good and back in the ‘60s I worked a fair amount of DX on 20 with the old trap dipole, a Viking II (120-watt output) transmitter and a surplus BC-348 receiver. 650-393 This is a good general-purpose coax-fed wire antenna for multiband use but will require a tuner on the higher bands and on portions of the two lower bands that are outside of the 2:1 VSWR region. Some have reported trap failure problems with high power but I've always been a 100-watt kind of guy and this antenna is definitely a winner under these conditions, and I would expect that 200 watts is likewise not an issue.

Looks like Bailey, sounds like Bailey, moto-savvy like Bailey...I say put Hamblin on TV, but only when he can't be on the track. Hurry up and get back on a bike Hammy. We miss you.

Hello friends.

Brasil yes, south america. Antonio Balbi, good.
32 i has this nomber plate.

My best wishes.

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