Hi,
First time user. Sr. Citizen now, very, and weak on ant. theory.
Looks like an excellent Group; really glad I found you folks.
I do receiving only. Icom R8600.
Due to property limitations, the best I can do is a simple 60 foot end fed ant. outside.
Works, but not great.
I do some listening, also, pretty low down, around 500 KHz. But pretty much anywhere up to 30 MHz, or so.
Question:
If I add another 60 foot length by "doubling back," this new length close to the existing length,
what would be a minimum separation that I should have between the existing length and this new length
to minimize the possibility of any signal cancellation, etc. ?
Would 6 inches to a foot be enough ?
Or, is this a really poor geometry, and not even worth trying ?
One more, please: Any of these indoor active antennas like the MFJ units worth a try ?
They have that vertical extension post for an ant.
Or, being indoors, it is going to pick up all the house RFI, and probably not
even worth a try ? If worth a look, suggested units under, $ 50 ?
Thanks, really appreciate the help,
Bob
Receiving Ant. Question, Please
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Andrew (grayhat)
- Posts: 137
- Joined: Sat Jun 11, 2022 2:59 pm
Re: Receiving Ant. Question, Please
Good for you! Wandering the bands, lower frequencies, very interesting stuff.
I have been a listener for more than 50 years. I found that I just needed to get / make a simple switch and run a few different wires around whatever space I had. I would certainly try more wire in the air at those frequencies. You might even add an inductor, a bunch of copper wire windings around a piece of wood or PVC, in line. In your situation I'd add a bunch of turns of copper wire on a 12 inch piece of PVC, put it somewhere where I can support it, even near the feedpoint. I would also strive to make it as close to an open loop as possible. Zigzag it all over the place, just get a bit more wire out there. I would also run a counterpoise of some sort, a long piece of wire (short is fine, longer is better) right near or even underneath the ground. More wire is better at that low a frequency, zigzag, close spaced, ground wire running underground, whatever is easy to lay out. Then I might want to feed it at a few different places (just another wire attached to the main antenna wire), running back to a switch, so that I can see what works best at any given time. You need no "feedline" like coax or twin lead, really, just wire in and out of your operating position. DC ground (to you cold water pipes) may be helpful, too. Try attaching a wire to your house electrical ground and see if it helps at the given frequency. Probably the most important thing for me would be to get more wire up, some long length of wire attached to the ground terminal and run along the ground, or underground, even right underneath your actual antenna wire. A simple antenna tuner would be my second thought, made for the range of frequencies you are on..... a simple L network ( a big coil and a wide range variable capacitor, lots of internet instructions for this, be sure to find the ones focused on lower frequencies, or BCB, broadcast band ). Let us know how you do, I am very interested.
I have been a listener for more than 50 years. I found that I just needed to get / make a simple switch and run a few different wires around whatever space I had. I would certainly try more wire in the air at those frequencies. You might even add an inductor, a bunch of copper wire windings around a piece of wood or PVC, in line. In your situation I'd add a bunch of turns of copper wire on a 12 inch piece of PVC, put it somewhere where I can support it, even near the feedpoint. I would also strive to make it as close to an open loop as possible. Zigzag it all over the place, just get a bit more wire out there. I would also run a counterpoise of some sort, a long piece of wire (short is fine, longer is better) right near or even underneath the ground. More wire is better at that low a frequency, zigzag, close spaced, ground wire running underground, whatever is easy to lay out. Then I might want to feed it at a few different places (just another wire attached to the main antenna wire), running back to a switch, so that I can see what works best at any given time. You need no "feedline" like coax or twin lead, really, just wire in and out of your operating position. DC ground (to you cold water pipes) may be helpful, too. Try attaching a wire to your house electrical ground and see if it helps at the given frequency. Probably the most important thing for me would be to get more wire up, some long length of wire attached to the ground terminal and run along the ground, or underground, even right underneath your actual antenna wire. A simple antenna tuner would be my second thought, made for the range of frequencies you are on..... a simple L network ( a big coil and a wide range variable capacitor, lots of internet instructions for this, be sure to find the ones focused on lower frequencies, or BCB, broadcast band ). Let us know how you do, I am very interested.
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Andrew (grayhat)
- Posts: 137
- Joined: Sat Jun 11, 2022 2:59 pm
Re: Receiving Ant. Question, Please
Hi all,
Thanks for leads, and thoughts.
Sure is a lot to know, for me.
Have always been very weal in ant. theory.
Stay in touch,
Bob
Thanks for leads, and thoughts.
Sure is a lot to know, for me.
Have always been very weal in ant. theory.
Stay in touch,
Bob
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Andrew (grayhat)
- Posts: 137
- Joined: Sat Jun 11, 2022 2:59 pm
Re: Receiving Ant. Question, Please
Here I am ... or better said here we (the forum community) are, feel free to post questions and discuss doubts
A last note, as Thomas knows (yeah, I think I "tortured him"
) I'm a huge fan of the LoG antennahttp://www.kk5jy.net/LoG/
and for a number of good reasons, not only it's cheap and easy to build/install, but in own experience it's the only antenna which does REALLY drop the QRM (and to some extent the QRN too) and it drops it dramatically, then if you want to see (ok, hear) the difference, here's an example
https://www.youtube.com/watch?v=wMb8i5QajW0
that being said (written)... up to you
As a note, a "humble" random wire antenna for TX (and RX) coupled with a LoG for RX (only) are a pretty darn good combo