Continuing from here…
So now I have an 1:1 transformer balun based on these instructions (using 20 gauge thermostat wire and an FT-140-43 ferrite toroid) at the feed point of the antenna, and while I'm getting less noise when receiving than before, the SWR plot still looks pretty bad. :(
Some ideas going forward:
- Since the bad SWR might simply be "uneven" (multipath) reflections from the stucco walls of my balcony, I'm thinking it might help to have a Yagi-Uda style reflector on the balcony side of the dipole, as shown in the attached diagram.
- Just fucking build the J-pole and save the dipole for later. :(
What do folks think?
Neil E. Hodges
in reply to Neil E. Hodges • •Comrade Weez
in reply to Neil E. Hodges • • •Neil E. Hodges
in reply to Comrade Weez • •SWR has a local minimum at 49 MHz, but it's still 14. :(
Wondering about that tuned reflector idea in my original post.
zl2tod
in reply to Neil E. Hodges • • •Shortening the elements until the antenna resonates at the frequency of interest will also reduce the huge loading from the walls at either end.
I'd avoid looping the ends back on the selves or tying knots in them, but I think that's not the biggest problem.
You'll likely have more luck with higher bands where there will be less proximity effect.
With radical experimentation you may find a way to resonate the balcony space.
It's a very difficult location.
@weezmgk
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DD8SF
in reply to Neil E. Hodges • • •What happens if you connect a 50 Ohm resistor to the BalUn instead of the antenna?
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Neil E. Hodges
in reply to DD8SF • •DD8SF
in reply to Neil E. Hodges • • •I use often screws or banana connectors even on 2m antennas and had not that much problems with it.
I read some more of the older thread and saw that there are maybe more general problems with your setup because of the walls etc. : What happens if you fold the ends of the dipols down, so that they are not so near to the wall?
If nothing like that works because of the disadvantageous environment. You may have to try other antenna concepts like magnetic loop antennas.
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Neil E. Hodges
in reply to DD8SF • •Thanks. I'll go with screw connectors. :3
Are you talking about something like this? Looks pretty straightforward, so I'll see what I can do with it. 👍
Neil E. Hodges
in reply to Neil E. Hodges • •Neil E. Hodges
in reply to Neil E. Hodges • •Well, I got a local minimum at 50.3 MHz, but the SWR is horrid. :(
I started by shortening the antenna by folding it as shown in the photo, but it was very slowly moving the local SWR minimum up. Once I started actually cutting the down-turned ends, it started moving said local minimum up more quickly to this point. Not sure what the safest thing to do here is now to get it to a "normal" (straight dipole), though. :/
#AmateurRadio #HamRadio
Neil E. Hodges
in reply to Neil E. Hodges • •Neil E. Hodges
in reply to Neil E. Hodges • •Neil E. Hodges
in reply to Neil E. Hodges • •