Interested in how more experienced folks than myself have solved the mast to antenna isolation issue
-
You can now help support WorldwideDX when you shop on Amazon at no additional cost to you! Simply follow this Shop on Amazon link first and a portion of any purchase is sent to WorldwideDX to help with site costs.
Antenna mast isolation
- Thread starter Christopher17
- Start date
thanks, should be pretty easy to figure out, not sure what blue water pipe is but I suppose any nonconductive water pipe that will fit over the mast will do the job
...sooooo what is isolating the mast going to do?
Be kinda hard to do something like that on a tower where the mast has to fit inside the rotor...plus where the mast go's threw the top section of tower, there wouldn't be room for any plastic pipe stuff...
Be kinda hard to do something like that on a tower where the mast has to fit inside the rotor...plus where the mast go's threw the top section of tower, there wouldn't be room for any plastic pipe stuff...
The mast becomes part of the antenna when connected , I don't have a good way of explaining this but the mast is taking away from the the antennas resonance, or robbing usefull power , one example was imagine the antenna is a barrel and your filling it with water,( rf power) the mast and coax are a hole in the bottom the water leaks out the holes, plug the hole and less rf power is lost, I'm not sure I explained that right, or how to isolate when a rotor is involved
blue colored water pipe simply means it is used for potable (drinking) water purposes.
you should consider moving your choke coil to 1/4 wl down from the connector.
you should consider moving your choke coil to 1/4 wl down from the connector.
I will try that just for experimental purpose, been putting it there on my home brew 1/4 wave antennas, I don't have a common mode issue, it's quiet as a mouse like it is, if it's a resonance thing I would say worth trying, but doesn't really make sense to me otherwise
It's about return loss to the antenna,..... the more the better.
Without going into detail, basically the antenna can not radiate any more power than the value of the return loss.
Isolate antenna from mast pipe. I hear and read so many different opinions on this most contradicting the other. I'm not certain it makes any significant difference?
Location of choke coil from base of antenna. I hear and read so many different opinions on this most contradicting the other. I'm not certain it makes any significant difference?
Who decides? I'm confused.
My A-99...not isolated from the mast and choke coil possibly too close to base of antenna? Too much trouble to take it down just to experiment.
One of my two horizontal dipole antennas...both configured the same. Mounted on fiberglass pipes and baluns at feed points. Should be just fine.
Location of choke coil from base of antenna. I hear and read so many different opinions on this most contradicting the other. I'm not certain it makes any significant difference?
Who decides? I'm confused.
My A-99...not isolated from the mast and choke coil possibly too close to base of antenna? Too much trouble to take it down just to experiment.
One of my two horizontal dipole antennas...both configured the same. Mounted on fiberglass pipes and baluns at feed points. Should be just fine.
I have run a lot of antennas over the last 40+ years and never had a problem with any of them. Basically what you are saying is that the antenna manufacturers and the antenna design engineers do not know what they are talking about when they design an antenna meant to mount directly to a metal mast. No offence but I know who I will put my money behind.