Each winter I shift my primary operating from QRP in the Park to Boat Anchors in the Basement. Two of my favorite winter operating events are the AWA Bruce Kelley 1929 QSO Party and the AWA Linc Cundall Memorial CW Contest. Both of these focus on boat anchors running on 160, 80 and 40 meters. My permanent shack antenna is a trade off at best. I don't have a good way to get much height. For the past several years I've played around with a temporary/winter vertical.
This year I used 7 4' sections of military surplus
fiberglass tubing plus a 5' whip as a 40 meter quarter wave vertical. It is attached to the deck railing at the 9' level and guyed at 24'. I added a loading coil at 13' to get it resonant on 80. This coil is bypassed for 40 meter operation.
After looking at my 80/40 meter vertical I thought, "Hey, I like to operate on 20 also. Let's add a 20 meter quarter wave wire"; good on paper but bad idea. Both the 80/40 meter wire and the 20 meter wire are connected in parallel at the bottom of the vertical. The 20 meter quarter wave wire runs within an inch or two of the 80 meter loading coil. This wire couples into the loading coil changing the resonant frequency by 100-200 KHz...and the resonant frequency varies if the wire flops around in the wind at all. I could watch the
SWR shift as I held the key down. In addition this loading shift really ruins my 29 transmitter tone/signal. Solution: remove the 20 meter element. My winter vertical works fine on 80 and 40 meters, perfect for the AWA operating events.
Some might notice the knotted
rope and pulley attached at the 24' level. For the last two weeks of December and the first days of January my vertical is re-purposed for Christmas decorations. We run a lighted star up it with an attached "tree" of lights.
Thursday, December 10, 2015
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2 comments:
Interesting. I was looking at the fiberglass 4 footers at our surplus centre Monday.They wanted a buck a foot. I was thinking of building a 40M vertical. I already run a 20m vertical and have worked the world easily on a barefoot TS830SKNWD. using that Vertical last weekend in the BK. I checked my copy sheets and see I was copying you but unable to get my signal there.
donVE3LYX
Don, See http://www.freewebs.com/ai4wm/mastinformation.htm for a write up on these fiberglass poles. Mine are the heavier ones with the fiberglass reinforcing rings. Niel
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