Redmond
Well-Known Member
I noticed that some boats have a ladder arrangement to separate the feed cable from the back stay until it reaches the isolated section. Does this improve the efficiency?
SSB Antenna
- Thread starter Redmond
- Start date
Benbow
Well-Known Member
Yes. It is very important, otherwise you have capacitive coupling and all your RF energy is soaked-up.
chasroberts
Well-Known Member
What's the minimum distance you should stand it off then, please?
Chas
Chas
Benbow
Well-Known Member
a couple of inches should do it. I have seen nice stand-offs made from many things, ranging from toilet outlet pipe to the plastic spacers from a bee hive!
KellysEye
Well-Known Member
Don't think it needs a couple of inches, ours runs up a piece of water hose and it works fine.
Benbow
Well-Known Member
You mean outside the pipe I take it? So that it is standing off by the fulll thickness of the pipe ? That would probably be ok.
Ships_Cat
Well-Known Member
Don't think it needs a couple of inches, ours runs up a piece of water hose and it works fine.
Should be stood off at least several inches (4 or so is preferable). It is not a simple arcing problem one has to prevent, the spacing is to minimise capacitive coupling (as has been said). However, on a plastic boat which does not have the backstay chain plate(s) grounded then if closely coupled all that will happen is that the section below the lower insulator will also radiate which is not much of an issue (except it may present a rf burn hazard). If the chain plate(s) are grounded (or the boat is metal) then one should ensure that standoffs are used.
I would making the comment that "working fine" is a relative term when it comes to ssb as it almost always works - however, it will work even "finer" with a proper installation.
John
Should be stood off at least several inches (4 or so is preferable). It is not a simple arcing problem one has to prevent, the spacing is to minimise capacitive coupling (as has been said). However, on a plastic boat which does not have the backstay chain plate(s) grounded then if closely coupled all that will happen is that the section below the lower insulator will also radiate which is not much of an issue (except it may present a rf burn hazard). If the chain plate(s) are grounded (or the boat is metal) then one should ensure that standoffs are used.
I would making the comment that "working fine" is a relative term when it comes to ssb as it almost always works - however, it will work even "finer" with a proper installation.
John
Benbow
Well-Known Member
[ QUOTE ]
I would making the comment that "working fine" is a relative term when it comes to ssb as it almost always works - however, it will work even "finer" with a proper installation.
[/ QUOTE ]
I echo all of those comments, but especially the one above. It is virtually impossible for a single HF station to have any real idea of how 'good' their setup is. All we can do is implement a system which is theoretically as good as it can be. Under some circumstances this will make no difference whatsoever, other days it will make the difference between making contact or not.
So for instance, ' I just tape my antenna feed to the backstay, and it works just fine ' is often heard. As Mr Cat says, just how bad that is depends on the boat and will vary from day to day with the weather. But it is a 'bad thing'.
I would making the comment that "working fine" is a relative term when it comes to ssb as it almost always works - however, it will work even "finer" with a proper installation.
[/ QUOTE ]
I echo all of those comments, but especially the one above. It is virtually impossible for a single HF station to have any real idea of how 'good' their setup is. All we can do is implement a system which is theoretically as good as it can be. Under some circumstances this will make no difference whatsoever, other days it will make the difference between making contact or not.
So for instance, ' I just tape my antenna feed to the backstay, and it works just fine ' is often heard. As Mr Cat says, just how bad that is depends on the boat and will vary from day to day with the weather. But it is a 'bad thing'.
KellysEye
Well-Known Member
>(or the boat is metal) then one should ensure that standoffs are used. I would making the comment that "working fine" is a relative term
We are a metal boat and we run the cable inside a water hose. How do I know it works fine...people have often commented on the strength of our signal. I think that the most important part of an SSB installation is the ground, get that right and most other things are tinkering (not that I'm against tinkering).
We are a metal boat and we run the cable inside a water hose. How do I know it works fine...people have often commented on the strength of our signal. I think that the most important part of an SSB installation is the ground, get that right and most other things are tinkering (not that I'm against tinkering).
Ships_Cat
Well-Known Member
I suggest that you have alot to learn about radio my friend. Your mistake is a basic one not made by many with metal boats.
John
John
