I’ve been working on a 2 meter aprs digipeter/i-gate (more on that later) and was having trouble picking anything up with my ht antennas, so I put together a copper pipe j-pole this weekend.
The parts that I used were:
- 2x 5 foot sections of 1/2″ copper pipe
- 1x 1/2″ elbow
- 1x 1.2″ T junction
- 3x 1/2 end caps
There is a pretty good calculator here for finding the correct lengths for the antenna sections. The long side of my j-pole was 151cm. The short tuning stub was 49.7cm. The coax feed point was about 5cm from the bottom. I dry fit everything together to check the measurements.
Then I soldered everything up and tested it. I temporarily set it up with a small tripod to test everything. According to my HF SWR meter it is 1.2:1, but I’m not sure how accurate that meter is for 2 meters. I want to get a good swr reading before I permanently mount the antenna in case I need to make any modifications.
Overall, the antenna works great. I wasn’t picking up anything before with the aprs software, but now I’m getting non-stop packets. I’m a little hesitant to test it on transmit until I verify the SWR, but I suppose I could try a cheap Baofeng on it.