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Old 11-06-2015, 10:27   #46
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Re: Recommended coax for triatic stay HAM antenna

Autumnbreeze,

1) First off, I've been self-employed for > 30 years....so I DO understand variable budgets!!


2) Next...you've been busy!! Hooray!!
Seriously, I was a bit tired when I wrote the above....so glad you took no offense!!


3) As for further recommendations....and trying some other things / set-ups...
--- Although using alum foil for testing seems to be something that folks recommend, it just seems odd to be....as you're unlikely to get any decent RF connection with it....
And, of course, it CANNOT be used for any permanent installation....the alum will fall apart quickly, even if you could some how get a connection with it...
Use COPPER!!!

--- Do not worry about an RF ground attachment to the radio itself, as this usually causes RFI troubles!!

--- ONLY connect your RF antenna ground / counterpoise to the remote tuner's ground lug...

--- If you have an underwater bronze thru-hull (or external grounding plate) near-by (within 6' - 8' or so), run a copper strap from the tuner ground lug to that, and you're good-to-go, as far as a RF ground / counterpoise goes!!

--- If you cannot connect to the sea-water for your ground/counterpoise, then using lifelines, pullpits, toe-rails, etc. is an excellent (and very inexpensive) counterpoise....and will work better than a KISS (whether home-brewed or store-bought)....

--- If you cannot use lifelines, toe-rails, pullpits, etc. for some reason, then a home-brewed KISS, or other radial set-up is good...

{fyi, using any exact "lengths" of the wires that you use to make up a radial(s) for use on-board our boats is all but completely unnecessary!!! As, we cannot effectively run radials symmetrically away from the feedpoint, nor keep them away from each other and other metallic objects/wiring/etc., both of which is necessary in order to maintain any resonance....And, further...if we place the radial wire CLOSE to each other (such as in a KISS, or home-brewed-KISS), we will find VERY few resonances at all!!!
So, cutting any wires to any specific lengths here is a waste of time/effort, etc. and an exercise in frustration....(btw, this has been well-known and proven by math/science for longer than I've been alive....as well as demonstrated by me in the tests I did a couple years ago....see the posts here...
Re: KISS-SSB Counterpoise

But, if you do wish to make an attempt at making things close to resonance on some popular freqs, then use ~16', ~18.5', ~28', ~32', and if you have the room, 37'....these correspond to approx. 1/4-wave when close to ground, near 14.3mhz, 12.3mhz, 8,2mhz, 7.2mhz, and 6.2mhz....if you desire to calculate lengths for other freqs, an approximation is 230/freq = length in feet....

Understand that you will not get these to present much in the way of hi-Q resonances, and their exact resonances WILL vary depending on where/how they are run in your boat!! So, making them to any specific length is a bit of a waste...

Oh, and BTW.....in general many shorter radials is MUCH better than fewer longer ones, no matter what frequency or placement!!!
So, cutting a few scrap pieces of wire, connecting them to the tuner ground lug, and tossing 'em in the bilge, WILL work about as good as spending the time calculating/cutting, etc....
Them's the facts!!! }



4) The trouble with using "on-air" testing, is that it take 3 VERY important things to even come close to making any absolute conclusions....
a) instantaneous switching between antennas / grounds / etc...as minute-to-minute propagation variations can be of much greater change than what you see between the different systems you're trying to evaluate....(some times these propagation variations/fades can be as much as 20db or more in just minutes....so using instantaneous switching is VERY important....and certainly trying to compare what worked one day versus another day, just isn't viable...)
b) knowledge / experience in radiowave propagation...
c) knowledge / experience in antenna systems and ground systems....

But, if you evaluate over a LONG period of time, say over a year or two, and use many hundreds of test results, you can get some useful data from on-air testing....
And, this is why you will hear many of us "old" hams / long-time RF guys, make comments on what antennas work for certain purposes, etc....it's 'cause many of us have both the math/science background AND decades of practical experience...



5) As for the "costs" involved....
Quote:
Originally Posted by autumnbreeze27 View Post
I enjoy the HAM, I just hate having to rig/de-rig my antenna... so I called the rigger out... and he's like "Oh yeah, $400-$500 and we're good." and then the quote came back at $800... and now it's up to $1500... and I still have other rigging work to do.
--- You CAN make your own "triadic antenna", pretty cheaply!!
Use a piece of SS lifeline wire....and you can use some double-braided polyester line (Sta-Set), or Spectra, Dynemma, etc. to secure it to both the mizzen and main mastheads!!!
NO "rigging insulators" needed at all!!!
As this is NOT a piece of structural rigging!!!
(this is why I was advocating trying a "temp" antenna up there...)

--- You CAN then run a wire (SS lifeline wire) up from the gunwhale to the mizzen masthead, also secured by double-braid poly (Sta-Set), or Spectra, or Dynemma, etc....
And, here again NO rigging insulators are needed!!!
As, again, this is NOT a piece of structural rigging!!!


And, guess what....
You've just built a variation of Bill's "alt backstay antenna", and are using Scott's design of feeding from the deck...and having an antenna to mizzen masthead and then to the main masthead (via the triadic)....
And, you do NOT need to hire a rigger, nor buy any rigging insulators!!!



{heck, you could do this with some scrap copper wire....but wouldn't last long (maybe a few months of sailing?)....but scrap copper wire is what works best for testing/experimenting....}


Now, understand that this will not be quite as good as insulating the mizzen shroud (and spreader) and feeding that and triadic, directly.....as you are adding another wire to the mix of SS rigging, masts, etc....but this is WAY LESS EXPENSIVE than the multiple rigging insulators you'd require otherwise, not to mention saving on rigging labor!!!


You can even, try this without the triadic....and see...


This is why I was advocating trying a "temp" antenna....as all that takes is some scrap wire and a few minutes stringing up on a halyard!!!





6) I understand your concern....BUT...
Quote:
Originally Posted by autumnbreeze27 View Post
Lighting up the whole rig to see if it would work as an antenna isn't really appealling to me... the thought of pumping 100w of power into the grounding of all the boat electronics...
But, this is not a real problem...
Most of this energy will be radiated into the air, NOT dissipated into your electronics....nor shunted to ground...

Understand that this is usually NOT a very effective wide-band transmit antenna, but it can work....and it is CHEAP (free!)....

Yes, it can cause RFI to other systems on-board, and can be frustrating to figure out some solutions to these....but it can be a usable antenna, and can be experimented with for free...
Again, not my primary recommendation, but it is a usable approach in some circumstances...




I do hope this helps...

Fair winds..

John
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Old 11-06-2015, 10:32   #47
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Re: Recommended coax for triatic stay HAM antenna

Sorry, also left out from my last post, I'm very thankful and appreciative of everyone taking the time to respond to my questions and lend their wisdom/experience and advice.
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Old 11-06-2015, 11:38   #48
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Re: Recommended coax for triatic stay HAM antenna

Quote:
Originally Posted by El Pinguino View Post
Top left, first page, under 'operation', above a picture of a radio....

Dunno, never owned one, just going by what I am reading on the PDF. Caveat Emptor Etc

I do know that 130s and 140s work on all frequencies, as do my other tuners....

While one anecdote does not a theory make, I can confirm that the AH-4 tuner does in fact tune to marine SSB bands in addition to amateur bands. I've tested it hooked up to a modified IC-706MkIIG.

Beausoleil is a ketch also, but it has split, independent stays for the main and mizzen. The rear stays for the main attach to the same chainplates as mizzen's upper shrouds. Each rear stay, port and starboard, has a 48' insulated section, tied by GTO-15 to the AH-4 tuner for the 706, and an older AT-120 for our M700 marine SSB. The effective antenna lengths are about 60' or so. We used the 706 mainly for Winmail, but it's opened up to the marine frequencies for the inevitable day our M700 dies ;-)
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Old 11-06-2015, 13:08   #49
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Re: Recommended coax for triatic stay HAM antenna

autumnbreeze,
I really wish I could just go and add to/edit my earlier post...but, oh well...


Have a look at these poorly drawn sketches, using your photos....you'll see I've drawn 4 different antenna designs / ideas....using this basic approach:
Quote:
Originally Posted by ka4wja View Post
5) As for the "costs" involved....--- You CAN make your own "triadic antenna", pretty cheaply!!
Use a piece of SS lifeline wire....and you can use some double-braided polyester line (Sta-Set), or Spectra, Dynemma, etc. to secure it to both the mizzen and main mastheads!!!
NO "rigging insulators" needed at all!!!
As this is NOT a piece of structural rigging!!!
(this is why I was advocating trying a "temp" antenna up there...)

--- You CAN then run a wire (SS lifeline wire) up from the gunwhale to the mizzen masthead, also secured by double-braid poly (Sta-Set), or Spectra, or Dynemma, etc....
And, here again NO rigging insulators are needed!!!
As, again, this is NOT a piece of structural rigging!!!


And, guess what....
You've just built a variation of Bill's "alt backstay antenna", and are using Scott's design of feeding from the deck...and having an antenna to mizzen masthead and then to the main masthead (via the triadic)....
And, you do NOT need to hire a rigger, nor buy any rigging insulators!!!



{heck, you could do this with some scrap copper wire....but wouldn't last long (maybe a few months of sailing?)....but scrap copper wire is what works best for testing/experimenting....}


Now, understand that this will not be quite as good as insulating the mizzen shroud (and spreader) and feeding that and triadic, directly.....as you are adding another wire to the mix of SS rigging, masts, etc....but this is WAY LESS EXPENSIVE than the multiple rigging insulators you'd require otherwise, not to mention saving on rigging labor!!!


You can even, try this without the triadic....and see...


This is why I was advocating trying a "temp" antenna....as all that takes is some scrap wire and a few minutes stringing up on a halyard!!!

The blue box is the AH-4, the black lines are the SS lifeline wire, the orange lines are double-braid poly (Sta-Set, etc.)....you can use ONE continuous piece of SS lifeline wire, crimp a loop at the ends (and near the middle, if using the triadic), crimp a short piece of GTO-15 wire at the lower end to feed from AH-4 tuner...

Depending on your mast heights (mizzen and main), and your exact positioning of this antenna....and of course, how it is run / avoiding other rigging by a foot or so, etc....you can rig an antenna such as this in lengths from ~ 30' to as much as 55' - 60'....
I think 40' - 45' overall (including the GTO-15 wire) is good....longer (55' - 60') is better for optimizing for lower freqs (3.5 - 6mhz), but usually unnecessary and can adversely effect the low angles on the higher freqs (> 14 - 16mhz)....

Have a look:










I think you see why I originally stated you could use some scrap wire to "test" all this with....it is much easier than working with SS wire-rope, etc...
If you cannot fit rigging insulators into your budget, and/or you cannot use Scott's approach, or Capt John's (Beausoleil) approach, one of the ones I drew above and described earlier, will work well...and these are just variations of Bill's "alternative backstay antenna" design...



I hope this helps....if not, I'm not sure what else to do ...


Fair winds...

John
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Old 27-06-2015, 13:02   #50
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Re: Recommended coax for triatic stay HAM antenna

Quote:
Originally Posted by ka4wja View Post
autumnbreeze,
I really wish I could just go and add to/edit my earlier post...but, oh well...


Have a look at these poorly drawn sketches, using your photos....you'll see I've drawn 4 different antenna designs / ideas....using this basic approach:


The blue box is the AH-4, the black lines are the SS lifeline wire, the orange lines are double-braid poly (Sta-Set, etc.)....you can use ONE continuous piece of SS lifeline wire, crimp a loop at the ends (and near the middle, if using the triadic), crimp a short piece of GTO-15 wire at the lower end to feed from AH-4 tuner...

Depending on your mast heights (mizzen and main), and your exact positioning of this antenna....and of course, how it is run / avoiding other rigging by a foot or so, etc....you can rig an antenna such as this in lengths from ~ 30' to as much as 55' - 60'....
I think 40' - 45' overall (including the GTO-15 wire) is good....longer (55' - 60') is better for optimizing for lower freqs (3.5 - 6mhz), but usually unnecessary and can adversely effect the low angles on the higher freqs (> 14 - 16mhz)....

Have a look:










I think you see why I originally stated you could use some scrap wire to "test" all this with....it is much easier than working with SS wire-rope, etc...
If you cannot fit rigging insulators into your budget, and/or you cannot use Scott's approach, or Capt John's (Beausoleil) approach, one of the ones I drew above and described earlier, will work well...and these are just variations of Bill's "alternative backstay antenna" design...



I hope this helps....if not, I'm not sure what else to do ...


Fair winds...

John
Hello John,

Good work with the ideas and sketches there, but I would like to offer another suggestion that I haven't seen mentioned. After skimming through this entire thread I did not see any mention of making the triatic stay into a "sloper" antenna. If I missed that please forgive me as I will briefly cover it here. I've used slopers for years on my sailboats. One of my sailboats did a 7 year circumnavigation and that sloper antenna put out the best signal in the fleet. In fact the people I sold the boat to that did the circumnavigation stayed in contact with me by ham radio during the first part of their cruise from Los Angeles, down to Mexico and then on through the South Pacific cruise. With the sloper on their boat (a Rawson 30), and the sloper I installed on my Morgan 41 Classic, we were able to have very solid boat to boat ham communications from my slip in Ventura Harbor, CA all the way down past Tahiti. The Rawson's signal using that sloper was almost a loud as the land based net control station in Papeete and was consistently the loudest signal from any boat down there into the Southern California area---pretty amazing considering that the Rawson had the short rig 34 foot mast.

The sloper not only puts out a great signal there are also other annoying sailboat problems it solves. Here's how and why.

The installation of the sloper begins by insulating the triatic stay using a radio insulator with a marine eye at the top of the triatic stay and regular rigging insulator on the lower end of the triatic stay about a foot or so away from the mizzen masthead. Then you connect your coax feedline (in my case double braid RG-213X) at the very TOP forward end of the triatic stay at the radio insulator (with a marine eye on one end). When connecting the triatic stay to the coax at the masthead insulator, you also connect the ground (braid) of the coax to a stainless strap that goes up (or around) the masthead and connects to the headstays and upper mainstays. This accomplishes a beautiful thing. Using this method means that you don't need a ground counterpoise in the sailboat at all. No KISS, no foil, no bonding foil or any of that is needed at all. Why? Because the entire grounded rig sits beneath the sloper triatic and thus is the counterpoise (or grounded side) of an inverted "V" antenna. NOW get this! Unlike a bottom connected antenna running up to the masthead, your metal mast and all it's associated wire rigging and fittings are no longer in the way of your antenna! Now all these grounded parts are an active part of the antenna as they become part of the counterpoise itself! (it's way more technical than this but for all practical purposes you can think of it as such). If you Google "inverted V ham antenna" what you will see in the drawings looks like nothing more than an Upside down wire V antenna which very much resembles our sailboat rigging with the mast holding up the apex of the upside-down V...Yep, just like our sailboat rigging. One side of the V is hot (in our case the backstay or triatic stay), the other side gets grounded to the mast, headstays, and all the rigging. What we actually end up with our sailboat version of this antenna is more of an unbalanced inverted V, with more on the grounded leg of the antenna, but, for practical purposes it functions VERY well in this configuration.

Both of my slopers where on sloops so I used the backstay as the insulated hot side of the antenna and my headstays as the other grounded side of the antenna, however, the principle is exactly the same with the triatic stay.


Now for a little bit of technical stuff, but I'll keep it simple. The second beauty of this system is that the "current loop" of an inverted V antenna (thats the part of the antenna that actually radiates your radio signal off the wire and out into space) is at the masthead, NOT down in the lazarette where it typically tries to function in a bottom connected backstay antenna and automatic tuner type system. This is the single most reason why bottom connected backstay antennas cannot compete with a top connected sloper antenna for long range communications. Not to mention that it saves you all the work of laying foil in the boat, running copper straps and such all over the place attempting to find the ever elusive ground counterpoise inside the boat. In essence your counterpoise has just been moved outside the boat to your mast and rigging.
.
The fact that the current loop is located at the masthead is the real reason the sloper works so well. Here's another way to envision this; pretend your head is the current loop of your antenna. Sticking your head out of the lazarette, how far can you see to the radio horizon? Now, lets go up the mast to where the sloper's current loop is. How far you can see to the radio horizon from the bosun's chair at the masthead? It's a huge difference as there is a much lower angle of radiation to the horizon with the sloper antenna's connection at the masthead and THAT is what gives you such great "skip" (distance) as your signal bounces of the ionosphere around the world. (the lower the angle of radio radiated signal the fewer bounces off the ionosphere are required to reach great distances as each bounce takes a little off your signal's strength on the receiving end). With a current loop in the lazarette I can imagine that it could take dozens of "bounces" off the ionosphere before it caught up with the sloper's first bounce---in theory anyway.

If anyone is interested in the the "how to" of this sailboat antenna let me know as there are a few other tricks that must be done---like the coax length is very critical but there is a simple "length" formula that solves this. I may be able to dig up old photos of the strapping system that I used at the masthead to connect the coax and backstay at the top. It would be identical to the triatic version and the strapping method makes it possible using PL-259 coax connectors to make the connection to the stainless bonding strap so the braid of the coax is not exposed to the marine environment. Then you seal up the coax connector with coax-seal and rig-wrap and you're all done. That connection lasted the 7 year circumnavigation---no problem.

Oh, one more thought; if the folks that like the idea of an automatic tuner at the mizzen masthead would care to hear it I have a very interesting story about that setup compared to the sloper I installed on my previously owned Rawson 30. It will save you a lot of money...

Cheers! Fair winds and happy hamin'

Martin
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Old 27-06-2015, 14:50   #51
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Re: Recommended coax for triatic stay HAM antenna

Martin,
Thank you for posting all of this....
FYI, I've not only studied antenna design and engineering (and radiowave propagation) for > 40 years now, but I also teach these subjects...

You spent quite some time explaining everything for everyone, and I just don't have the time right now (spent quiet some time myself typing in another thread this afternoon!) to go thru everything point-by-point....but in brief...

--- Please understand that there is no "hot" or "ground" side in RF, when connect an antenna....there is as much radiation from what you reference as the "counterpoise" (the mast, forestay, other rigging, etc.) as there is from the insulated triadic...
(actually since the antenna is fed in an unbalanced way, the amount of antenna current flowing in each part would vary quite a bit, depending on frequency, etc...)


--- Secondly, yes "inverted-v" antennas of all shapes / sizes and configurations do work....and the ones that are at least 1/2-wave above ground (or even better above sea water) work very well...

Depending on the angle of radiation referenced, we will typically we'll see from 4db to 8db more gain from a horizontal antenna as a vertical antenna....and it is only on the really long paths, multi-multi-hop-paths, where a vertical over sea water will equal or surpass a horizontal antenna's advantage...
(please see some of my other posts, where I made detailed comparisons)...
These are two different posts of mine here, where I give detailed comparisons...
HF shore station

HF shore station




--- And, yes....getting the high-current point higher up is good....but this all really depends on the exact antenna design....its not about getting this high-current point higher up to make your signal have a lower angle of radiation....
The angle of radiation is not controlled by where the high-current point is..




--- Also, if I could be a bit blunt here...
I'd like to once again try to dispel a myth that your antenna (or its radiation pattern / angles) have anything at all to do with how your signal bounces off the ionosphere (reflected and refracted)....
It does NOT!!
The ionosphere sets the angle that your signal travels from "point a" to "point b", NOT your antenna!!

I know, I know.....this goes against all the common ham-operator talk, against all the adds, against all the discussions, etc....but that doesn't change the facts!

The pure 100%, scientific fact is that the whatever angle the ionosphere can reflect and refract at, at that particular moment, at that particular frequency, for that particular communications path, IS the angle that your signal travels and is how the communications take place....
The antennas used have absolutely nothing to do with what angle your signal travels at!!!

How much signal your antenna produces at whatever angle the ionosphere is reflecting at, at that time, freqs, path, etc. can have a bif effect on how strong / reliable your signal is, but it is the ionosphere that controls the angles that the signals propagate at...

BTW, there are times when the ionosphere can reflect/refract signals at multiple angles along the same communications path, thereby creating two distinctly different sets of communications paths, to/from the same locations, at the same time, on the same band!!
This is sometimes/many times, the case when the bands are "opening" or "closing" for some paths....typically within an hour or two of the opening or closing....and this happens quite often, along a popular path of the US to Europe on 20m.....there are times during the day (usually early morning or evenings) where 20m is open from the US to Europe on a lower-angle, two-hop path...and on a somewhat higher-angle, three-hop path, at the same time!!!
Just saying, the ionosphere is a weird animal....and I've been studying it for 40+ years now....and I still try to learn something new as often as I can...



--- FYI, in most of the radio engineering universe and ham universe, the antenna you describe as a "sloper" is called a "half-sloper", in that "half" of the antenna is the sloper and the other "half" is the metallic support, etc...
In your case, with your antenna design, I'd say it is a cross between an inverted-v and a "half-sloper"....(in my opinion, of course....as we can all use different names, and no worries!)


--- And, more on-topic....the antenna you describe is also VERY close to what was advised to try here quiet a while ago...and that was to load up the whole rig, or at least the mizzen rig, and see how it all works...
Or, even to load up one insulated wire AND the rest of the rig as a counterpoise (which is pretty much what you describe here, just that you describe specifically using the triadic as the insulated antenna wire...)


Again, thank you for contributing all of your info/experiences....I only hope the original poster here doesn't get over-whelmed by everything!!


Fair winds...

John

P.S. Just a brief comment for all....
Do NOT forget that in all the fuss made over the antenna, ground system, counterpoise, etc....we should NOT forget that it is the OPERATOR that will make as much difference as all of the antenna system!!
Just saying, that if some sailors/cruisers would spend even half the time they do discussing antennas/grounds, etc. on actually learning about radiowave propagation and actual operating techniques/procedures, they'd find their antenna choices to be MUCH MUCH easier!!!
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Old 27-06-2015, 17:21   #52
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Re: Recommended coax for triatic stay HAM antenna

Quote:
Originally Posted by ka4wja View Post
Martin,
Thank you for posting all of this....
FYI, I've not only studied antenna design and engineering (and radiowave propagation) for > 40 years now, but I also teach these subjects...

You spent quite some time explaining everything for everyone, and I just don't have the time right now (spent quiet some time myself typing in another thread this afternoon!) to go thru everything point-by-point....but in brief...

--- Please understand that there is no "hot" or "ground" side in RF, when connect an antenna....there is as much radiation from what you reference as the "counterpoise" (the mast, forestay, other rigging, etc.) as there is from the insulated triadic...
(actually since the antenna is fed in an unbalanced way, the amount of antenna current flowing in each part would vary quite a bit, depending on frequency, etc...)


--- Secondly, yes "inverted-v" antennas of all shapes / sizes and configurations do work....and the ones that are at least 1/2-wave above ground (or even better above sea water) work very well...

Depending on the angle of radiation referenced, we will typically we'll see from 4db to 8db more gain from a horizontal antenna as a vertical antenna....and it is only on the really long paths, multi-multi-hop-paths, where a vertical over sea water will equal or surpass a horizontal antenna's advantage...
(please see some of my other posts, where I made detailed comparisons)...
These are two different posts of mine here, where I give detailed comparisons...
HF shore station

HF shore station




--- And, yes....getting the high-current point higher up is good....but this all really depends on the exact antenna design....its not about getting this high-current point higher up to make your signal have a lower angle of radiation....
The angle of radiation is not controlled by where the high-current point is..




--- Also, if I could be a bit blunt here...
I'd like to once again try to dispel a myth that your antenna (or its radiation pattern / angles) have anything at all to do with how your signal bounces off the ionosphere (reflected and refracted)....
It does NOT!!
The ionosphere sets the angle that your signal travels from "point a" to "point b", NOT your antenna!!

I know, I know.....this goes against all the common ham-operator talk, against all the adds, against all the discussions, etc....but that doesn't change the facts!

The pure 100%, scientific fact is that the whatever angle the ionosphere can reflect and refract at, at that particular moment, at that particular frequency, for that particular communications path, IS the angle that your signal travels and is how the communications take place....
The antennas used have absolutely nothing to do with what angle your signal travels at!!!

How much signal your antenna produces at whatever angle the ionosphere is reflecting at, at that time, freqs, path, etc. can have a bif effect on how strong / reliable your signal is, but it is the ionosphere that controls the angles that the signals propagate at...

BTW, there are times when the ionosphere can reflect/refract signals at multiple angles along the same communications path, thereby creating two distinctly different sets of communications paths, to/from the same locations, at the same time, on the same band!!
This is sometimes/many times, the case when the bands are "opening" or "closing" for some paths....typically within an hour or two of the opening or closing....and this happens quite often, along a popular path of the US to Europe on 20m.....there are times during the day (usually early morning or evenings) where 20m is open from the US to Europe on a lower-angle, two-hop path...and on a somewhat higher-angle, three-hop path, at the same time!!!
Just saying, the ionosphere is a weird animal....and I've been studying it for 40+ years now....and I still try to learn something new as often as I can...



--- FYI, in most of the radio engineering universe and ham universe, the antenna you describe as a "sloper" is called a "half-sloper", in that "half" of the antenna is the sloper and the other "half" is the metallic support, etc...
In your case, with your antenna design, I'd say it is a cross between an inverted-v and a "half-sloper"....(in my opinion, of course....as we can all use different names, and no worries!)


--- And, more on-topic....the antenna you describe is also VERY close to what was advised to try here quiet a while ago...and that was to load up the whole rig, or at least the mizzen rig, and see how it all works...
Or, even to load up one insulated wire AND the rest of the rig as a counterpoise (which is pretty much what you describe here, just that you describe specifically using the triadic as the insulated antenna wire...)


Again, thank you for contributing all of your info/experiences....I only hope the original poster here doesn't get over-whelmed by everything!!


Fair winds...

John

P.S. Just a brief comment for all....
Do NOT forget that in all the fuss made over the antenna, ground system, counterpoise, etc....we should NOT forget that it is the OPERATOR that will make as much difference as all of the antenna system!!
Just saying, that if some sailors/cruisers would spend even half the time they do discussing antennas/grounds, etc. on actually learning about radiowave propagation and actual operating techniques/procedures, they'd find their antenna choices to be MUCH MUCH easier!!!


John, John, John

Please... When you say >>"Again, thank you for contributing all of your info/experiences....I only hope the original poster here doesn't get over-whelmed by everything!! << Well, I did not mean to overwhelm anyone as I tried to keep it in very lay-person speak. However, I know that got you going, so you now are dragging out the text books and that just helps to overwhelm folks. I was trying to AVOID all the tech talk and just talk in lay terms about what just may work way better, and MUCH cheaper than some of the antenna systems being discussed.

My entire point here can be summed up very easily and succinctly; a properly installed half-sloper (yes it's a half-sloper, but can we keep it simple? Then the questions start; wouldn't a FULL sloper be better? ha!), again, a half-sloper will outperform a bottom fed backstay with a lazarette mounted antenna tuner in ever single case I have compared it to in my real life experiences. I'm talking over 40 years in my experience. How long have you experimented with a "half-sloper" on a sailboat? I'd like to know the hours you've put in tuning, testing, and using one...please let us know.

I have brought up the sloper antenna many times on sailing forums and I was trying to avoid another situation where all the techies come out of the woodwork expounding upon all the wonderful knowledge they have gathered over the years and guess what that does? It chases away the lay person that could actually benefit from this subject. It is my opinion that tech talk should not be the main focus here. It is my true belief that what works compared to what doesn't work or doesn't work as well should be the main focus. Many people are unaware of the alternatives this kind of antenna affords. I am simply trying to put it in as simple terms as I can so as not to chase people away from this antenna. I have personally shared the performance of the sloper on my boat with many people over the years and they are amazed at how well it works. One was a poor chap three docks over on an end-tie that had just invested over $4,000 in an Icom ham rig setup with a mizzen mounted tuner (120? 130? can't remember) right up at the top of the mizzen mast with a vertical antenna mounted above that. The equipment was pricey and the installation? Well, in Marina del Rey, CA let's just say there are no deals to be had installations. I heard him calling his buddy down in Acapulco, Mexico on another boat. He called and called. I could hear his buddy calling him just fine but they could not hear each other. (I remember I logged it as S7 with some qrn). So I butted in and told him his buddy was calling him. Then I called his buddy and we had a good solid S7 conversation. The next thing is this guy from the other dock is pounding on the side of my boat to come aboard. He didn't believe me that I was actually talking to his friend. I handed him the mic and he was stunned... His buddy was perfectly readable and they had a very nice solid conversation. Now, his boat was an Island 41 ketch on an end tie and was nice and out on the open as his antenna was in the clear. Me? Not so lucky. My little Rawson 30 was in the middle of the dock full of much taller masts, and mine had the shortest mast at only 34 feet tall over all. I felt bad for the guy, but that's the way it worked out. Did he care about current loops? The name of the antenna? Ionospheric studies? Nope...he just wants something that works! And he saw and experienced just that.

So... regarding "hot versus" ground. Current loop higher? Ionosphere skip? Balanced unbalance? It's a HALF sloper? Geez... Here we go again. Should I have gotten into the technical side of all this stuff so I could let everyone know how much I know, how much you know, and start this tech debate? Been there and done that. I'm not into it. Why? Because folks would get overwhelmed and get bored to tears and very likely skip over or dismiss what could be the best antenna they could have had. So, I think not. I'm trying to stay away from that and just keep this as simple as possible and keep it about what works really REALLY well. Of course the subjects you want to correct me on are true. Of course there is no "hot versus ground" in an unbalanced antenna system. Of course the ionosphere is in a constant state of flux, of course antennas higher up work better. But is a backstay higher up than a top fed sloper? Not to the layman it isn't. So I had to mention the current loop so as to take into account the effective radiating part of the antenna. I'm trying to make the lay person aware...without getting too scientific...that's all. I think it's OK for the lay-person to think of some things in very basic terms so to keep things VERY simple. As to your thinking an unbalanced half-sloper is very similar to the attempting to load up the entire mast and rigging? I'd take serious issue with that, but I'm not going to here. I long ago said I wouldn't get involved in expounding the virtues of what I know my real world experience has taught me. Why? Because here we are again, trying to open our textbooks and show all about what we know. Now, it is quite possible and in fact highly likely that you are WAY more educated on this antenna subject than I am, but, I doubt very much you have logged more hours with (half) slopers as I have actually spent using this antenna on a sailboat AND COMPARING it to other antenna types in real world tests. In fact, my first sloper was installed on my Rawson 30 in the mid 1970's and I've used them ever since. I do know they work better than any sailboat antenna I've compared them to, to date---period. That's a pretty strong statement to make. But when you've had dozens and dozens of real world 'in the anchorage', 'at the dock', and out sailing on the air comparisons, I would like to say that all the technical mumbo jumbo aside, these antennas are absolutely fantastic in their performance in the real world and nothing comes close to them on small sailboats. Additionally, when set up properly it has been my experience that they also solve some of the headaches aboard the boat that other type antennas actually create. For example such things as having to lay foil or screen in the hull, or stray RF running around the boat, which is nonexistent when a few simple installation techniques are followed. Is this a perfect antenna? No. You know there are no perfect antennas. For those seriously interested in the (half) sloper, there are some slight performance issues, but I consider the trade offs insignificant. Here are a couple; the sloper is somewhat directional off the back of the boat and it does appear to achieve a few db gain. But I cannot say truly how much gain. We would have to model that in antenna modeling software or put a real scale model on the antenna range. Also, in real world polar curves I have run offshore there are also two severe sharp nulls at about 35 to 45 degrees off each side of the bow. However, in boat to shore on-the-air testing I was not able to hold the boat on a course consistent enough hold a null on the land based signal, and I tried, so in my case I consider these sharp nulls to be insignificant and I usually never bother mentioning them.

So John, thanks for preaching to the choir ;-) but I'm not getting into that side of it at all anymore. I've spent way to much time arguing text book when it's real world use that really matters.

If there are any people interested in the details of installation and some of the pitfalls I have run into and solved, then I'd be happy to discuss it with anyone by sending me a PM.

Thanks, and whatever the decision, I hope it works out the best for the OP and everyone is happy with their results.

Cheers and fair winds....

Martin
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Old 27-06-2015, 18:00   #53
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Re: Recommended coax for triatic stay HAM antenna

Martin,
I was sincere when I wrote "thank you for posting all of this"!
But perhaps my thanks wasn't clear?
So, please forgive me....I seem to have unintentionally caused you to take offense...
So, please accept my apologies!
Seriously, I meant no offense and did not wish to overwhelm anyone, either!


BTW, no textbooks here....I'm 200 miles from my desk!
Everything above is from actual real-world, personal, first-hand experience over the past 40+ years....(as well as from my studying/teaching)

Now, I do NOT try impress/influence anyone with any of that....'cause it ends up in a pissing contest, which I have no interest in!
But, you DID ask....so there you go...
My first real antenna was a 40m dipole, I built in 1972....and then a series of windoms, long-wires, loops, etc....as well as verticals, and home-brewed yagi and quads....and then into the 80's with helix's, horns, turnstyles, dishes, loop-yagi's, etc....I've built antennas for freqs from 1.8mhz thru 1296mhz amateur/maritime, as well as 137, 1691, 3700, 6425, etc. mhz....

Not to mention working 160m contests, VHF/UHF contests, designing/building and operating my own moonbounce station in the 1980's...etc. in addition to all the "normal" HF and VHF operating...mostly SSB and CW....some data (built my own RTTY encoder/decoder in 1982, and have used AX.25 packet as well as PACTOR, etc.) etc.. etc....

And, as for direct, real-world, personal, first-hand experience with HF radios/antennas on-board sailing/cruising boats, mine started in 1973....that's when I did my first SSB install (actually was assisted by the official installer/tech, 'cause I didn't have a 1st Class Phone license that was needed at that time), and have done dozens and dozens since then, and used HF comms on-board sailing/cruising boats (including my own) for 40 years now, from Florida, Bahamas, Caribbean, N. Atl., the Med, etc...
On-board, I've used slopers, loaded entire rigs, triadic wires, fishing pole antennas, a wire strung up a flag-halyard, etc. etc.....as well as the common backstays, whips, etc. etc.

But, Martin NONE of that has any bearing at all on the discussion at hand....
So, I'm not sure why you asked...but there you go....

And, none of that does, in anyway, reduce the validity of your experiences and knowledge....(which is why I said thank you for posting all of what you did...all I was trying to do point out the fallacy of the antenna setting the angle the signals propagate at, etc...sorry I wasn't clear



So, again....
Please understand that I am grateful that you took the time to post all that you did....and I think it WILL be helpful to others....
If that is not good enough for you, I don't what else to say...
except:

Fair winds...

John

P.S. That's all for tonight, I'm going to watch a movie with my 94 yr old Mom, who (along with my late father) was a long-time ocean sailor/cruiser....so I cannot disappoint her!
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Old 28-06-2015, 21:44   #54
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Re: Recommended coax for triatic stay HAM antenna

The rigger came out and isolated the starboard mizzen shroud (32'7") and the triatic (24'8"). The end configuration is IC-7200 connected to the AH4 tuner (used the entire length of the included cables to run it from the nav table to behind a cabinet. From there it's GTO-15 going through the deck, up along the shroud (I made up some stand-offs) and then connects above the isolator about 6' off the deck.

Do I still need one of these Isolators? I get a lot of noise in the marina and I'm anxious to try it away from the dock.
T-4

Do I need a lightning arrestor? Or is disconnecting it from the radio just as good?
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Old 28-06-2015, 22:11   #55
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Re: Recommended coax for triatic stay HAM antenna

Quote:
If there are any people interested in the details of installation and some of the pitfalls I have run into and solved, then I'd be happy to discuss it with anyone by sending me a PM.
G'Day Martin,

I had read one of your earlier posts on the sloper, and when I had our mast out a couple of years ago put some coax up it and connected as described. Length of the cax was per your recommendations, fed through a MFJ manual tuner, and the backstay is about 65 feet long between insulators.

I've only used it on 40 so far, and find that it loads up beautifully, very low SWR at the tuner, and that it picks up far less noise than my normal setup, which is loading the entire rig (less the insulated backstay) via a shroud. So far, so good... but my signal reports on the daily Comedy cruising net (7.087 at 2140 Z right now) have consistently been several S units lower than with the old set up. Distances have ranged from local to ~1000 miles.

This has been disappointing to me to say the least. The only thing that comes to mind as an explanation is that I used RG-58 coax (no room for another fat cable), thinking that losses at these frequencies should not be extreme; perhaps that was an error.

Wonder if you have any comments?

73 de Jim N9GFT/VK4GFT
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Old 29-06-2015, 08:13   #56
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Re: Recommended coax for triatic stay HAM antenna

autumnbreeze,
Sounds like you've got things well in hand!!

As for the "need" for a line isolator....well, no there's not an absolute need for one...
Their purpose is to remove any stray RF on your coax (i.e common-mode RF current), thereby reducing/eliminating primarily transmit RFI / RF feedback, etc....(as well as sometimes reducing receive RFI, but not to a great extent)...
{note that sometimes your transmit signal can cause other electronics on-board to go a bit "nuts"....and getting all of your transmit signal to your antenna, or shunted to ground, is a good way to reduce/eliminate these issues.....but be aware, sometimes on some boats, they still have some issues...."ya pays ya' money, and ya takes ya chances!"...}
You can think of a coaxial cable "line isolator" as > a dozen ferrites on your coax....it does nothing if there is no problems / no stray RF flowing on the coax (outside of the coax).....
So, if you have no RFI, no RF feedback, etc. then the answer is NO....no, you don't need a line isolator....but, even then it might help in some instances on some bands/freqs...
On a budget, no worries....if you've got no transmit RFI troubles, then there is no need for a line isolator...
Quote:
Originally Posted by autumnbreeze27 View Post
Do I still need one of these Isolators? I get a lot of noise in the marina and I'm anxious to try it away from the dock.
T-4

Do I need a lightning arrestor? Or is disconnecting it from the radio just as good?
Lightning protection is a REALLY BIG (and REALLY CONTROVERSIAL) subject....which I can discuss with you some other time...

But, for now...
No lightning arrestor "needed".....
Many hams (me included) simply disconnect the coax (and power) from their radios when not operating....and this does work every well...
On-board my boat though, I just pull the DC power plug out of the back of the rig, when I'm off the boat....but when I'm on-board, I do nothing at all...(pain in the ass to disconnect the GTO-15 all the time... )


I hope this helps...

John
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Old 29-06-2015, 08:32   #57
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Re: Recommended coax for triatic stay HAM antenna

Jim,
I'm on my way out, and you addressed this to Martin....so, I won't ramble...

The loss of RG-58 at 7.2mhz is about 1db/100' when matched (SWR 1:1)...
But, with an SWR of 5:1, it is about 2.3db/100'
and, at 10:1 it is about 3.6db/100'
and, at 20:1 it is 5.5db/100'

Not knowing what your SWR was on that line it's impossible to be certain, but I suspect it was 10:1 or so....and with the loss being only about 3.6 db/100', it's doubtful the line loss was the proximate cause of the difference in performance...
More likely, different antenna patterns (different angles of radiation) and different distances, and different propagation...
Comparing antennas in the real world usually requires one of two things:
a) An almost instantaneous way of switching between antennas (within a few seconds is best), to eliminate propagation variations from the results...
b) A long-term test, over a period of months, etc. over multiple paths, etc. to give a full picture of the averaged results over time...


Jim, specific to your application, 40m "local to ~ 1000 miles"....
From "local" to about 400 miles, you'd want an antenna with more "high angle" radiation for the Near Vertical Incidence Skywave signals....which your 65' backstay (whether fed from top or bottom) is not...
I am surprised by your comment that the antenna has a low swr at the tuner??? As a 65' wire is about a 1/2-wave on 40m, and fed at the end would present an impedance of 1000's of ohms (with the large SS wire rigging, about 1500 - 2000 ohms) and an swr of 10:1 - 20:1....even with the other part of the rig connected to the coax shield, this should've shown as a high un-matched swr....(and of course the coax loss would show a lower swr at the transmitter end, but I'm surprised that it was "very low"...)

If you give more info, maybe I can help later...
Gotta' go..
I hope this helps...

John
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Old 29-06-2015, 12:34   #58
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Re: Recommended coax for triatic stay HAM antenna

Jim,
No ramblings this afternoon....and I will try not to overwhelm anyone, either...
A few quick things just as FYI's...


--- Some surprising stats for long-range skywave comms on HF...
For typical one-hop or two hop paths, from 3000 - 4000 miles long (such as US east coast to Europe), the range of angles of signals on 40m is quite small...
With 55% of the time signals arrive at angles of 10* or below (and a full 10%, at 1*....yes one degree!)
And, 35% of the time from 11* to 18*.....and the remaining 10% of the time from 18* to 26*...
This is averaged over more than a decade, throughout the whole 11-yr solar cycle.....so, while stats can be mind numbing, these are pretty cut 'n dried...


--- Contrast those low angles with typical daytime regional coverage, using Near Vertical Incidence Skywave (NVIS) on 40m....
Where signals from "close-in" (125-150 miles) arrive at angles of about 75*....
From 200 - 250 miles, ~ 65* - 68*...
From 300 - 400 miles, ~ 55* - 60*...
From 400 - 450/500 miles, ~ 45* - 50*...


--- Over land, typical "ground wave" range on 40m is about 40 -50 miles....BUT...
But, over sea water it can 2 - 3 times this....
SO...
So, having a vertical antenna (backstay, whip, or sloper, etc.), CAN be of great benefit to using the lower HF bands for "close-in" / "local" comms, out to 100- 150 miles or so, via "groundwave"....
(in actuality, the sea water and a vertical antenna combine to make a truly excellent groundwave comm system for the lower HF bands...
The US Navy did many studies of this, I remember reading one done in the 70's, where they were using 1-kw and 5-kw transmitters (at 2mhz - 6mhz) and HF groundwave over sea water for tactical comms, out 200 miles (and depending on time-of-day/noise, out 300 miles)...
But, with our 100- 150 watt radios and typical RFI on-board, we aren't in the same situation as the US Navy...



Now, if you look at the above info, you may begin to see why the "middle-range" communications (from 250 - 500 miles) have been the most challenging for many cruisers...
And, while the 8mhz marine band works similarly to 40m (a bit longer), if you look "up" to using a higher freq, although there can be a skip zone, 12mhz marine works well and typically has a narrow skip zone....(but with no voice ham radio comms between 7.3mhz and 14mhz, it does place some cruising hams in a tight spot....needing better high-angle antenna for the 100 - 500 ranges during daytime on 40m, and still have a good low-angle antenna on both 40m and 20m, etc. when long-range comms are desired...)



Okay, that's enough rambling....
I hope I didn't overwhelm...

Fair winds..

John
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Old 29-06-2015, 13:11   #59
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Re: Recommended coax for triatic stay HAM antenna

For anyone buying any coax make sure you are getting a good quality cable, I suggest Times Microwave as the vendor of choice. No affiliation other than being a happy customer, I use over a thousand ft. of coax, various sizes, a year.

Get a cable that meets the MIL-C-17 standards, in this case an TCOM-240-LS is what you would want. The TCOM cable is a high flex cable that will live a nice long life up a mast. The TCOM is available in 200 to 600 series sizes. Just make sure you get a connector that works well with flex core coax, preferably gold plated. With flex core, up a mast, use a crimped connector, not a soldered one. The core with work harden at the soldered joint and fail.

There is a lot of cheap import crap out there that is marked Times Microwave that is counterfeit so its best to buy from a reputable dealer. The cheap stuff won't take a connector well, might be over or under sized, all sorts of problems. The trouble isn't worth the minor cost savings.
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