I need to make on of these too. Repeaters are going to be vertically polarized, your dipole is mostly horizontal. hang the wire vertically and see if it does better with the repeaters. Also, your VNA was most likely correct. a meter is a bit over 3', so if you have two lengths of 3' 6", that's about a full wave length. it should be about 3' 6" total, not each. cut them a little long and check that with your meter. then trim in small increments until you get it perfect. by the way there is a NTX horizontal 2m net on wedensday nights at 8:00 on 144.250 SSB. Good Luck
Your lengths for quarter wave 2 meters is way off why your SWR is way up. a 1/4 wave 2 meter would work much more awesome with a vertical polarized 1/4 wave antenna. For a 1/4 wave vertical, Just remember 234 divided by Frequency which say 147 MHz would be 15.9 feet multiplied by 12 is 19.1 inches. So the vertical copper wire part would be 19.1 inches and the four copper wire radials would be another 19.1 inches. You can use copper wire or welding rods to solder on your center pin of your SO-239 chassis connection and then screw your other four radials on the chassis with lock washers and screws by using some needle nose pliers to bend a small loop to fit on your screws.. Then when you finished get you some 3/4 inch PVC pipe which your coax will fit through pipe and your vertical with chassis mount can fit perfect on other end. Clamp it on a mast or even use least 10 foot PVC pipe as your mast clamped to a pole or fence post.
Love the video, as you are getting in there and having a go. Your antenna is a few inches too long. Use your VNA to scan from 140 to 150 MHz and find the resonance point. Then start trimming it back, equally, a little at a time until there is a nice dip in the 2m band. An SWR of less than 1.5:1 is best for everything including the radio. Use your chopping board and paracord to make a skyhook to hang one end in the tree, and to run the coax horizontally for a few feet. The higher the better, but it will work to some degree even touching the ground. There's a loss of about 20dB going from vertical to horizontal polarization, so once you and the repeaters are on the same polarization, you'll be booming in. Antennas are fun and easy to make. Having a vna is the best and cheapest tool out.
Your first calculation was correct for 3 feet 6 inches which is the TOTAL length of the antenna. Cut that in half (19 inches or so) and use that for each side of the dipole. Your SWR will be where you want it. KN8N
SWR between 1:1 and 1.5:1 is good, but anything 3:1 or higher is bad and can blow your finals. I think VHF transmitters are more forgiving than HF, but still it can damage or shorten the life of your finals. The best thing to do is to get the antenna up as high as possible. When I'm portable I use a Spiderbeam 40' mast along with a vertical N9TAX roll up J pole antenna, and at 40 feet I can hit repeaters all over the Houston area. I noticed that in the video you were on 146.52 while the antenna was horizontal. That frequency is typically used on FM with a vertical antenna. The horizontal antennas would be good for 2 meter sideband. Another thing that would help is to use a Yagi antenna. That would give you more forward TX/RX and more attenuation off of the sides and rear. I heard a Canadian station on 2 meter SSB during a Field Day event years ago while my antenna was inside the house, but he could not hear me. 73 KD5YOU
I live in the Houston area, and 2 meter repeater activity is almost constant. Simplex is not used so much except for occasional area simplex nets. 73 KD5YOU
Tnx, cool video :) I had to go back and watch again as I noticed the cables was to long, and as stated in previous comments they should be about 50cm each, a 1/4 wave on each element. Feeding the radio a full wavelenth as you have dome will get an impediance of 2500-4000ohm and not the desired 50 ohm, so thats why your analyzer not shows any dipp. that will be good for a part2 of this antenna :) 73´s
I need to make on of these too. Repeaters are going to be vertically polarized, your dipole is mostly horizontal. hang the wire vertically and see if it does better with the repeaters. Also, your VNA was most likely correct. a meter is a bit over 3', so if you have two lengths of 3' 6", that's about a full wave length. it should be about 3' 6" total, not each. cut them a little long and check that with your meter. then trim in small increments until you get it perfect. by the way there is a NTX horizontal 2m net on wedensday nights at 8:00 on 144.250 SSB. Good Luck
Your lengths for quarter wave 2 meters is way off why your SWR is way up. a 1/4 wave 2 meter would work much more awesome with a vertical polarized 1/4 wave antenna. For a 1/4 wave vertical, Just remember 234 divided by Frequency which say 147 MHz would be 15.9 feet multiplied by 12 is 19.1 inches. So the vertical copper wire part would be 19.1 inches and the four copper wire radials would be another 19.1 inches. You can use copper wire or welding rods to solder on your center pin of your SO-239 chassis connection and then screw your other four radials on the chassis with lock washers and screws by using some needle nose pliers to bend a small loop to fit on your screws.. Then when you finished get you some 3/4 inch PVC pipe which your coax will fit through pipe and your vertical with chassis mount can fit perfect on other end. Clamp it on a mast or even use least 10 foot PVC pipe as your mast clamped to a pole or fence post.
Love the video, as you are getting in there and having a go. Your antenna is a few inches too long. Use your VNA to scan from 140 to 150 MHz and find the resonance point. Then start trimming it back, equally, a little at a time until there is a nice dip in the 2m band. An SWR of less than 1.5:1 is best for everything including the radio.
Use your chopping board and paracord to make a skyhook to hang one end in the tree, and to run the coax horizontally for a few feet. The higher the better, but it will work to some degree even touching the ground. There's a loss of about 20dB going from vertical to horizontal polarization, so once you and the repeaters are on the same polarization, you'll be booming in.
Antennas are fun and easy to make. Having a vna is the best and cheapest tool out.
Your first calculation was correct for 3 feet 6 inches which is the TOTAL length of the antenna. Cut that in half (19 inches or so) and use that for each side of the dipole. Your SWR will be where you want it. KN8N
SWR between 1:1 and 1.5:1 is good, but anything 3:1 or higher is bad and can blow your finals. I think VHF transmitters are more forgiving than HF, but still it can damage or shorten the life of your finals. The best thing to do is to get the antenna up as high as possible. When I'm portable I use a Spiderbeam 40' mast along with a vertical N9TAX roll up J pole antenna, and at 40 feet I can hit repeaters all over the Houston area. I noticed that in the video you were on 146.52 while the antenna was horizontal. That frequency is typically used on FM with a vertical antenna. The horizontal antennas would be good for 2 meter sideband. Another thing that would help is to use a Yagi antenna. That would give you more forward TX/RX and more attenuation off of the sides and rear. I heard a Canadian station on 2 meter SSB during a Field Day event years ago while my antenna was inside the house, but he could not hear me. 73 KD5YOU
You need 50cms of wire. What you created was more akin to 6 metres antenna than 2 metres. With a few snips it should get into the band quite easily.
People don't really talk on 2 meters in my experience I have stopped calling to and from work but I still scan
I live in the Houston area, and 2 meter repeater activity is almost constant. Simplex is not used so much except for occasional area simplex nets. 73 KD5YOU
Tnx, cool video :) I had to go back and watch again as I noticed the cables was to long, and as stated in previous comments they should be about 50cm each, a 1/4 wave on each element.
Feeding the radio a full wavelenth as you have dome will get an impediance of 2500-4000ohm and not the desired 50 ohm, so thats why your analyzer not shows any dipp. that will be good for a part2 of this antenna :)
73´s
I’m trying to follow the math on this one. I’m also thinking this is why the SWR is off…