I live in the Los Angeles metro area on a small lot but have wanted to try out 160 meters for years. I have considered building or constructing various types of antennas that will fit on the property and even purchased a coil loaded sloper that I was going to suspend from a palm tree in my back yard. The palm tree was taken out because it became a hazard to the power lines that run along the property border in the back yard, so that plan was gone with it.
I've had a deluxe Buddipole kit for years, which I use mainly while RV'ing in places that won't let you put up wires. Last year I was looking for my Buddipole low band coil for 80 and 40 meters and when I couldn't find it, I assumed that I loaned it to someone and never got it back. I ordered another and of course, promptly found the one I already had. This led me down a path trying to figure out what to do with two 80 meter Buddipole load coils...and the 160 meter Buddipole vertical experiment was born.
My idea was to stack the two coils to create a pseudo 160m coil. I stacked two arms on the versa-tee and then the two coils. Then I used a 12' MFJ telescoping whip on top of the coils. I ran a single 160m 1/4 wave (roughly) ground wire out around the property for counterpoise and hooked up the Buddipole Triple Ratio Switch Balun at the feedpoint using the 1:1 setting. Using a Rigexpert AA-600 was absolutely critical for helping me understand the tuning of this arrangement. I figure that stacking the two inductors might cause them to interact in unexpected ways, but was hoping that the proximity of the two would make them act more like one big coil. I was wrong about the latter.
Ultimately what I found is that I could adjust the lower coil tap to find the best SWR on the frequency I wanted, and then adjust the top coil to affect the SWR curve and bandwidth while making the SWR dip even more. I expected that the bandwidth for a low SWR on this band would be very narrow. Making small adjustments and then sweeping with the analyzer helped me quickly understand how to adjust and it wasn't long before I had something reasonable. Next I decided to replace the telescoping whip to get more metal in the air, so I took it off and put a Chameleon shock cord whip and extended base on top of the load coils to make the whip a total of 17' above the coil. I extended the Buddipole tripod up just a little bit to get the coils about roof eave height, but not so high that it would tip over. The antenna is sitting right outside my shack so the coax run is less than 20 feet.
A quick retune of the coils, a bit of shortening on the ground radial, and I got an SWR of 1.8:1 at 1.915 Mhz. The antenna is under 3:1 SWR between 1.860-1.945 Mhz.
The 160 meter band isn't that wide, so the tuner in the Elecraft K4D easily tunes up the antenna at any frequency I've attempted. With such a short coax run, the coax loss using the tuner in this manner is small. So the real question: Does it work? Yes! Obviously this not a very efficient antenna. The noise floor in the big city is HUGE. In the short time I've played with it at night, I haven't come across many strong SSB stations, but I've heard a few weak ones...I will continue to listen when I have time on the weekends to see if I can make some phone contacts. I decided to try some FT8 - there is quite a bit of activity there. Currently my 100 watt station is heard better by others than I can hear - likely due to the high noise and local interference. But I have made more contacts than I expected in North America.
Here's a screen shot of my transmit activity last night and the stations that heard me over the course of a couple of hours:
I'm not done experimenting with this antenna - a local ham is gifting me a Chameleon cap hat that I am going to integrate to see if I can eliminate the top coil. I will also experiment with different RX antennas while using the Buddipole as the TX antenna. When I started this journey, I googled around to see if anyone had come up with a way to use the Buddipole system on 160 meters and came up empty. I'm pretty happy that I was able to accomplish even this much, so stay tuned while I see what else I can do with this setup on 160 meters on a postage-stamp sized lot in the L.A. metro area!
Edit: See Part 2 where I add a capacity hat.
I've had a deluxe Buddipole kit for years, which I use mainly while RV'ing in places that won't let you put up wires. Last year I was looking for my Buddipole low band coil for 80 and 40 meters and when I couldn't find it, I assumed that I loaned it to someone and never got it back. I ordered another and of course, promptly found the one I already had. This led me down a path trying to figure out what to do with two 80 meter Buddipole load coils...and the 160 meter Buddipole vertical experiment was born.
My idea was to stack the two coils to create a pseudo 160m coil. I stacked two arms on the versa-tee and then the two coils. Then I used a 12' MFJ telescoping whip on top of the coils. I ran a single 160m 1/4 wave (roughly) ground wire out around the property for counterpoise and hooked up the Buddipole Triple Ratio Switch Balun at the feedpoint using the 1:1 setting. Using a Rigexpert AA-600 was absolutely critical for helping me understand the tuning of this arrangement. I figure that stacking the two inductors might cause them to interact in unexpected ways, but was hoping that the proximity of the two would make them act more like one big coil. I was wrong about the latter.
Ultimately what I found is that I could adjust the lower coil tap to find the best SWR on the frequency I wanted, and then adjust the top coil to affect the SWR curve and bandwidth while making the SWR dip even more. I expected that the bandwidth for a low SWR on this band would be very narrow. Making small adjustments and then sweeping with the analyzer helped me quickly understand how to adjust and it wasn't long before I had something reasonable. Next I decided to replace the telescoping whip to get more metal in the air, so I took it off and put a Chameleon shock cord whip and extended base on top of the load coils to make the whip a total of 17' above the coil. I extended the Buddipole tripod up just a little bit to get the coils about roof eave height, but not so high that it would tip over. The antenna is sitting right outside my shack so the coax run is less than 20 feet.
A quick retune of the coils, a bit of shortening on the ground radial, and I got an SWR of 1.8:1 at 1.915 Mhz. The antenna is under 3:1 SWR between 1.860-1.945 Mhz.
The 160 meter band isn't that wide, so the tuner in the Elecraft K4D easily tunes up the antenna at any frequency I've attempted. With such a short coax run, the coax loss using the tuner in this manner is small. So the real question: Does it work? Yes! Obviously this not a very efficient antenna. The noise floor in the big city is HUGE. In the short time I've played with it at night, I haven't come across many strong SSB stations, but I've heard a few weak ones...I will continue to listen when I have time on the weekends to see if I can make some phone contacts. I decided to try some FT8 - there is quite a bit of activity there. Currently my 100 watt station is heard better by others than I can hear - likely due to the high noise and local interference. But I have made more contacts than I expected in North America.
Here's a screen shot of my transmit activity last night and the stations that heard me over the course of a couple of hours:
I'm not done experimenting with this antenna - a local ham is gifting me a Chameleon cap hat that I am going to integrate to see if I can eliminate the top coil. I will also experiment with different RX antennas while using the Buddipole as the TX antenna. When I started this journey, I googled around to see if anyone had come up with a way to use the Buddipole system on 160 meters and came up empty. I'm pretty happy that I was able to accomplish even this much, so stay tuned while I see what else I can do with this setup on 160 meters on a postage-stamp sized lot in the L.A. metro area!
Edit: See Part 2 where I add a capacity hat.
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