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Buddi pole5/16/2023 ![]() Scott Andersen, NE1RD, I estimate that my shorting tap at about 16 turns from the base means I’m using about 39-40 uH of loading to achieve resonance at 80m. Next step of course is to make some contacts or at least activate the antenna on WSPR or JT65 to get an idea of whether the signal gets over the fence.įrom checking the chart on page 146 of the ‘Buddipole in the Field’ book by B. It’s hard to do but I managed and it will throw your readings. One thing to be aware of with the Buddipole hardware is not to accidentally short out adjacent turns of the coil with the coil clip. The 1.0:1 bandwidth was 10 kHz while at 1.5:1 it was in excess of 65 kHz.įrom readings at the other possible coil tap points my guess is that at this frequency range each face of the coil moves the resonant frequency by about 4 kHz. My target frequency was 3535kHz and this is a chart of the SWR readings I had when the coil tap was set at what I calculate to be 15 3/4 turns up from the base of the coil. It’s actually more confusing reading that sentence than understanding it in practice! It took me a few measurements to realise that as I progressed left (from my point of view) I was decreasing the amount shorted out and hence increasing the loading inductance and so lowering the resonant frequency. You appreciate the value of being able to tap at 1/8 of a turn increments. The adjustment is too coarse on a turn by turn basis. This means I was shorting out the bottom 16 turns of the coil. ![]() I used the iP30 SWR analyser to narrow it down to a spot 16 turns up from the base of the coil. Background noise level rises as you get in the zone. The next step is to simply drag the fly lead across the coil turns to identify the best spot to tap the coil. I also connected a 1:1 balun between the Versatee and the iP30 SWR Analyser. Then carefully attach that assembly to the top of the Versatee. Attach two 22 inch antenna arms to a long whip antenna fully extended. Leave the red fly lead loose for the moment. Attach the Versatee horizontally to the top of the mast. Set up the tripod and mast with only bottom two sections telescoped out. The Buddipole Low Band coil showing the coil tap for 80mĪssembly was straightforward. The adjustment wasn’t as fiddly as I expected such a short antenna for this band would be, and it appeared to give a usable bandwidth. I was surprised how easily it all went together. Here’s a list of the items used along with the counterpoise: The purpose yesterday was to establish how speedily the antenna could be assembled and adjusted for a frequency of interest such as a net. The counterpoise doesn’t follow the recommended dog leg arrangement and is higher off the ground than the 2 feet suggested. Buddipole components don’t lend themselves to permanent installations. The idea is to connect a short fly lead to connect the hidden counterpoise when the antenna is deployed and then disconnect when it’s all packed away. I installed a counterpoise wire a few feet shy of 66 feet length hidden on a timber fence that runs down the side of the property. Plan for 80m vertical made from Buddipole components While I have dreams of a magnetic loop for 80m, the vertical is more in reach now. The back garden space here is barely 4 metres by 4 metres and for the moment the chimney is out of reach. I spent the pleasant sunny part of the final day of autumn testing a vertical antenna for 80 metres using Buddipole parts for home.
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