Centering the antenna on the groundplane will provide the most truly omni-directional pattern.
If the antenna is off-set more to one side of the ground plane, there will be a semi-directional lobe formed putting more signal on the broad side of the chicken wire and a weaker signal on the short side.
Somewhere in the threads is a detailed instruction for bonding metal such as the chicken wire, maybe the right search term will bring it up.
Wow.. I have tried all kinds of things to bond the copper wire to the chicken wire.. nothing is working.. I didn't find the info on how by searching.. ideas?
This was posted in another thread but since the question was also asked here it is duplicated:
Soldering using a torch and electronic grade solder flux is tricky because the high temperature of the torch oxidizes the copper and the solder won't stick. It can be done but don't get things too hot. Try a 40 watt iron.
Else,
Acid core solder should work but will corrode.
Try forming a pigtail of the chicken wire and use a wire nut to fasten it to the copper wire. Fill the wire nut with silicone dielectric grease to keep out moisture. You can get the grease at an auto parts store (sometimes free for the asking).
Neil
Yeah - I realized after I was on my way in to work that it was a serious nono to double post. Mea Culpa.
Thank you! I ended up with pigtail+wire nuts.
The issue now is that with it tuned, im getting about a block and a half now.. I am sure it is not the fault of the transmitter - it was doing great on the roof, except for the hum, which is why I moved it to the ground - I was tired of running up and down a ladder onto a 40 year old roof that may not handle much more of that 🙂
I did notice the number were crazy with power and no audio; maybe because im standing on the chicken wire?
I dunno - still trying for the perfect sound 😀
I wonder if my issue could be due to the change I made in the wire to antenna and ground?
Inside the box, I was using a very heavy gauge insulated wire to both ground and antenna. What was happening is a loud hum sound, so I swapped those out for some really thin rg58 (I think) - anyway its tiny shielded wire to antenna and ground (two seperate cables, by the way)
I will try with the thicker wire on the tx today and see where it gets me.
[UPDATE: Tried the new wiring] - its just weird. I was getting some solid sound a long way off prior to moving the transmitter and antenna to the ground level. I tested continuity from ground on the tx to the chicken wire - some loss, but the electrical is there.. i tested from antenna screw in point to the actual antenna.. electrically it is fine.. I am getting about 200' and the dignal just POOF dies.. no fade, just dead. It's really odd.
The load impedance on the roof will differ from that on the ground so the transmitter will have to be retuned from scratch. Did you find that you had to change the loading coil tap? It is almost certain that this will be needed.
As a master of making silly mistakes I suggest you check that the receiver is tuned to the transmitter frequency and not an adjacent frequency. (I did that once.)
If you did retune, did anything look different with how it tuned? It could be that you have tuned to the proper test point readings but are not at resonance. I never tuned this model tx. but have seen this happen on another model where it appears resonant but isn't.
I run a ground mounted transmitter over radials which pushes 85 mW into the antenna system and the range on a car radio is close to 1 mile and I would expect comparable performance from your installation. Keep trying.
Neil
Back to the roof today. We shall see how it goes. A person with my level of understanding in this thing really should be doing this the easiest way possible.. 🙂
Hi mlr. Yesterday I re-read this entire thread and jotted down the numbers showing the size-area of your chicken-wire-on-the-ground, 10-feet X 20-feet....
That's not much for AM, but I realize you have a "postage-stamp-size lot."
In PhilB's "Ultimate Antenna" post he advises that radials be at least 30'x30'
And I believe that somewhere Rich suggested that 1/4-wave radials were needed to get the best result.
I ended up with 20x20 - BUT; it did no good.
I just put the transmitter on the roof again, and now its me fighting static. no idea whats going on now.. I moved it to 1710 (yeah yeah..) just to have a pristine channel to test on, then move back to 1650 once I "figured it out" - nasty static from driveway to the end of the signal, and a total drop off at 1.5miles. I even put it up another 5 feet, givinf me about 25' up in the air.
Next step: remove the audio chain, plugin my iPhone to the RCA inputs, and see what happens...
Since you know it worked very well the first time it was elevated, something must be different this time, but you just aren't noticing it YET.
Maybe whatever is "changed" is the same reason it didn't work well on the ground.
That static on the driveway is new is it? It wasn't there before?
I just spent four days tracing old house-wiring to get a map of how Boris Karloff hooked it all up... what a total mixup.
Figuring out electronic puzzles takes great brain power.
Part 15 today and tomorrow.