Date
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Loop construction
Rob Q
I've found a 10 foot section of electrical conduit that can be bent to a circle. (extra conduit will be cut off)
Trying to go for something like this... (see picture)
My question is, does it matter if....
- the wire is touching a metal bolt that is attaching the mast to the conduit?
- the wire is not exactly 8 feet long, it might be longer/shorter by a couple of inches?
- it's not a perfect circle as the ends of the conduit aren't flush?
This will be "loop antenna - version 2". "Version 1" is an inverted delta loop.
Trying to go for something like this... (see picture)
My question is, does it matter if....
- the wire is touching a metal bolt that is attaching the mast to the conduit?
- the wire is not exactly 8 feet long, it might be longer/shorter by a couple of inches?
- it's not a perfect circle as the ends of the conduit aren't flush?
This will be "loop antenna - version 2". "Version 1" is an inverted delta loop.
Mark Scudder
Hi Rob,
Is the bolt attached to anything else metal? If not it shouldn't cause an issue.
I think the difference between almost round and perfectly round is likely to be so minute it would be inperceivable.
Regards,
Mark.
On Sat, 10 Dec 2022, 15:08 Rob Q, <robman501a@...> wrote:
The final outcome should look like this.
Rob Q
It didn't work, I ended up tossing that PVC conduit. I've made a diamond shaped loop. It works quite well. The FM BCB is outstanding. HF is an improvement as well. Since it's made with wood, I'm going to change it to a hula hoop so it's more light weight. I've also ended up using thicker gauge wire. Lost one of the washers in the snow but Chris said it's M6 and A2 graded stainless steel. So, I can get that at the hardware store anyway.
Chris Moulding
Using thicker wire or tube lowers the inductance of the loop and allows more RF current to flow in the loop for a given field strength.
It also increases the self-resonant frequency of the loop. The typical 1m diameter loop is quite close to being resonant around 30 MHz so to cover the full HF range up to 30 MHz thicker wire or tube is used.
We use the same principle in the new v4 loop. This uses two 1m lengths of S400 coax cable 50 mm apart connected in parallel to make a very low inductance loop that gives similar performance to the 1m diameter wire loop. It also raises the self-resonant frequency above 50 MHz allowing the v4 loop to cover the lower VHF frequencies and the 6m amateur band.
Regards,
Chris
It also increases the self-resonant frequency of the loop. The typical 1m diameter loop is quite close to being resonant around 30 MHz so to cover the full HF range up to 30 MHz thicker wire or tube is used.
We use the same principle in the new v4 loop. This uses two 1m lengths of S400 coax cable 50 mm apart connected in parallel to make a very low inductance loop that gives similar performance to the 1m diameter wire loop. It also raises the self-resonant frequency above 50 MHz allowing the v4 loop to cover the lower VHF frequencies and the 6m amateur band.
Regards,
Chris
