Baffin
Active Member
Can anybody recommend a waterproof connector, or method of connecting the cable, for the top of my mast?
Waterproof coax connector
- Thread starter Baffin
- Start date
beneteau_305_553
Well-Known Member
The correct method of joining VHF coax is with 2 male PL259 plugs and a female union. This keeps the correct impedance of the cable. It however is not waterproof. You can make it waterproof by stretching self amalgamating tape over the connectors, but this has to be cut off to disconnect the cable.
You can also use TV coax connectors (again with SA tape) . The impedance will not be quite right but I have used these and have seen no effect
You can also use TV coax connectors (again with SA tape) . The impedance will not be quite right but I have used these and have seen no effect
PBooth
Well-Known Member
Hi, If a joint up the mast can't be avoided, I would do a soldered joint with a heatshrink sleve to waterproof it.
Peter
Peter
fluffc
Well-Known Member
Unless you have the proper test equipment, DO NOT solder-join VHF cable. There will most likely be an impedance mis-match, resulting in a reflection of power back towards the transmitter - potentially damaging it.
The other reason is that with power being reflected back towards the transmitter, then less is transmitted out of the aerial. But as the system is FM, you won't notice any difference until you are nearer the maximum mileage range of the system.
Personally, I have a one-piece wire all the way from the Aerial to the VHF Set.
The other reason is that with power being reflected back towards the transmitter, then less is transmitted out of the aerial. But as the system is FM, you won't notice any difference until you are nearer the maximum mileage range of the system.
Personally, I have a one-piece wire all the way from the Aerial to the VHF Set.
Boatman
Well-Known Member
Get a new piece of coax the right length. A good quality coax will certainly improve the radio. Joints always cause more problems than they solve.
mainmarine
Well-Known Member
The Bulgin Buccaneer pugs and sockets are waterproof and have a coax fitting
G
Guest
Guest
The standard co-ax connectors inside heat-shrink tube ... IF you must ... otherwise best to fit one complete length ... as no doubt you have another joint at bottom of mast ?
I have in past actually twiddled the centre core together ... taped over with insulating tape .... pulled back over top the shield braid making sure it surrounds and beds in with other cables braid connecting .... pulled back over the insulation and then insulating tape to hold it all in place and then heat shrink over top ... lasted years !! Never had any trouble - but it is not advised nor correct procedure !! But when needs must !!
I have in past actually twiddled the centre core together ... taped over with insulating tape .... pulled back over top the shield braid making sure it surrounds and beds in with other cables braid connecting .... pulled back over the insulation and then insulating tape to hold it all in place and then heat shrink over top ... lasted years !! Never had any trouble - but it is not advised nor correct procedure !! But when needs must !!
Baffin
Active Member
Thanks everybody for all that. There's enough there to get me by if I have to go down the route of cutting the cable.
G
Guest
Guest
[ QUOTE ]
Thanks everybody for all that. There's enough there to get me by if I have to go down the route of cutting the cable.
[/ QUOTE ]
there are also torpedo shape co-ax connectors that take the cable in ... join and then close up as an inline. OK they are more designed for TV co-ax use ..... in all fairness - if the cable is joined then the whole assembly taped up well with SA tape ... should be ok till next unstep of mast ?
Thanks everybody for all that. There's enough there to get me by if I have to go down the route of cutting the cable.
[/ QUOTE ]
there are also torpedo shape co-ax connectors that take the cable in ... join and then close up as an inline. OK they are more designed for TV co-ax use ..... in all fairness - if the cable is joined then the whole assembly taped up well with SA tape ... should be ok till next unstep of mast ?
JonBrooks
Well-Known Member
As stated, having no in line joints is by far the best method.
Every joint will induce loss.
Rule of thumb eact joint is 1-2db loss.
3db loss will halve you power.
If you have to join only use the correct type for VHF DO NOT use TV kit.
It will induce more loss, they are not designed to handle transmit power!
It will in time damage your radio.
Also if you have to join use SA tape, makes the best joint water tight I have found over the years.
All the best
Every joint will induce loss.
Rule of thumb eact joint is 1-2db loss.
3db loss will halve you power.
If you have to join only use the correct type for VHF DO NOT use TV kit.
It will induce more loss, they are not designed to handle transmit power!
It will in time damage your radio.
Also if you have to join use SA tape, makes the best joint water tight I have found over the years.
All the best
G
Guest
Guest
[ QUOTE ]
As stated, having no in line joints is by far the best method.
Every joint will induce loss.
Rule of thumb eact joint is 1-2db loss.
3db loss will halve you power.
If you have to join only use the correct type for VHF DO NOT use TV kit.
It will induce more loss, they are not designed to handle transmit power!
It will in time damage your radio.
Also if you have to join use SA tape, makes the best joint water tight I have found over the years.
All the best
[/ QUOTE ]
I do not disagree with your advise to use proper gear and also the joints cause losses ... But I have to say that I have an old Midland 5600 VHF that sits in my office ... it's OLD !! It has a TV joint kit in the co-ax for last umpteen years ... it still works fine ... not one days failure or problem.
My on-board VHF "Seavoice RT550" has a rubbish "marine" deck connector that is supposed to be marine quality .... but is green and needs cleaning often - but it still works .... I reckon in terms of connection the TV connector on the Midland has better contact and continuity than the "marine" rubbish at base of my mast ...
IMHO of course !! /forums/images/graemlins/wink.gif
As stated, having no in line joints is by far the best method.
Every joint will induce loss.
Rule of thumb eact joint is 1-2db loss.
3db loss will halve you power.
If you have to join only use the correct type for VHF DO NOT use TV kit.
It will induce more loss, they are not designed to handle transmit power!
It will in time damage your radio.
Also if you have to join use SA tape, makes the best joint water tight I have found over the years.
All the best
[/ QUOTE ]
I do not disagree with your advise to use proper gear and also the joints cause losses ... But I have to say that I have an old Midland 5600 VHF that sits in my office ... it's OLD !! It has a TV joint kit in the co-ax for last umpteen years ... it still works fine ... not one days failure or problem.
My on-board VHF "Seavoice RT550" has a rubbish "marine" deck connector that is supposed to be marine quality .... but is green and needs cleaning often - but it still works .... I reckon in terms of connection the TV connector on the Midland has better contact and continuity than the "marine" rubbish at base of my mast ...
IMHO of course !! /forums/images/graemlins/wink.gif
john_morris_uk
Well-Known Member
[ QUOTE ]
The correct method of joining VHF coax is with 2 male PL259 plugs and a female union. This keeps the correct impedance of the cable. It however is not waterproof. You can make it waterproof by stretching self amalgamating tape over the connectors, but this has to be cut off to disconnect the cable.
You can also use TV coax connectors (again with SA tape) . The impedance will not be quite right but I have used these and have seen no effect
[/ QUOTE ]Hmm - not sure about your 'correct way'. PL259 are not particularly good connectors.
Might I suggest that a better way would be a male and female inline BNC connector? BNC aren't waterproof either, but self amalgamating tape over the joint followed by u/v resistant spray laquer is what we used 'in the trade'. (And this was for temprary joins!)
If you want waterproof, then 'N' connectors offer some water resistance, but we used to tape them up as well.
For VHF I wouldn't suggest TV connectors at all. They are horrible.
We used to run analysis of the impedence of all the lines that we used. Some of the results were surprising. The commercial lines made by HP were usually very good. In summary, if you want GOOD impedence matching, you have to be very careful about how you put the BNC and N connectors on. The cable trimming etc must be VERY accurate.
I should also point out that for the average yacht VHF, you really aren't going to notice much difference if you soldered the inner and outer of the co-ax togethr in a neat and tidy fashion, made sure that there was no chance of it shorting and taped it all up.
The correct method of joining VHF coax is with 2 male PL259 plugs and a female union. This keeps the correct impedance of the cable. It however is not waterproof. You can make it waterproof by stretching self amalgamating tape over the connectors, but this has to be cut off to disconnect the cable.
You can also use TV coax connectors (again with SA tape) . The impedance will not be quite right but I have used these and have seen no effect
[/ QUOTE ]Hmm - not sure about your 'correct way'. PL259 are not particularly good connectors.
Might I suggest that a better way would be a male and female inline BNC connector? BNC aren't waterproof either, but self amalgamating tape over the joint followed by u/v resistant spray laquer is what we used 'in the trade'. (And this was for temprary joins!)
If you want waterproof, then 'N' connectors offer some water resistance, but we used to tape them up as well.
For VHF I wouldn't suggest TV connectors at all. They are horrible.
We used to run analysis of the impedence of all the lines that we used. Some of the results were surprising. The commercial lines made by HP were usually very good. In summary, if you want GOOD impedence matching, you have to be very careful about how you put the BNC and N connectors on. The cable trimming etc must be VERY accurate.
I should also point out that for the average yacht VHF, you really aren't going to notice much difference if you soldered the inner and outer of the co-ax togethr in a neat and tidy fashion, made sure that there was no chance of it shorting and taped it all up.
john_morris_uk
Well-Known Member
[ QUOTE ]
Unless you have the proper test equipment, DO NOT solder-join VHF cable. There will most likely be an impedance mis-match, resulting in a reflection of power back towards the transmitter - potentially damaging it.
The other reason is that with power being reflected back towards the transmitter, then less is transmitted out of the aerial. But as the system is FM, you won't notice any difference until you are nearer the maximum mileage range of the system.
Personally, I have a one-piece wire all the way from the Aerial to the VHF Set.
[/ QUOTE ]With the greatest of respect, please don't keep alive the myth of 'power being reflected back to the transmitter'. Impedence mismatch is rather more complicated, and the VSWR that arises from the impedence mismatch of a transmission line changing impedence DOES NOT imply that there is reflected power back to the tranmitter.
Its still not a good thing - and the output devices may be damaged. It does nothing for the efficiency of the antenna system either!
I do agree that one piece good quality coax is the way to go. Also the 'capture effect' of FM receivers and their immunity to fading with loss of signal until you get to the 'threshold' of the detector does mean that significant losses in a transmission- reception path can go un-noticed. In other words, you don't notice your system is poor until you are the limits of the system.
By the way, Jon Brooks talks sense as well. Although you could always ask why equipment manufacturers still put crappy SL259 connectors on their radios?
Unless you have the proper test equipment, DO NOT solder-join VHF cable. There will most likely be an impedance mis-match, resulting in a reflection of power back towards the transmitter - potentially damaging it.
The other reason is that with power being reflected back towards the transmitter, then less is transmitted out of the aerial. But as the system is FM, you won't notice any difference until you are nearer the maximum mileage range of the system.
Personally, I have a one-piece wire all the way from the Aerial to the VHF Set.
[/ QUOTE ]With the greatest of respect, please don't keep alive the myth of 'power being reflected back to the transmitter'. Impedence mismatch is rather more complicated, and the VSWR that arises from the impedence mismatch of a transmission line changing impedence DOES NOT imply that there is reflected power back to the tranmitter.
Its still not a good thing - and the output devices may be damaged. It does nothing for the efficiency of the antenna system either!
I do agree that one piece good quality coax is the way to go. Also the 'capture effect' of FM receivers and their immunity to fading with loss of signal until you get to the 'threshold' of the detector does mean that significant losses in a transmission- reception path can go un-noticed. In other words, you don't notice your system is poor until you are the limits of the system.
By the way, Jon Brooks talks sense as well. Although you could always ask why equipment manufacturers still put crappy SL259 connectors on their radios?
G
Guest
Guest
[ QUOTE ]
[ QUOTE ]
The correct method of joining VHF coax is with 2 male PL259 plugs and a female union. This keeps the correct impedance of the cable. It however is not waterproof. You can make it waterproof by stretching self amalgamating tape over the connectors, but this has to be cut off to disconnect the cable.
You can also use TV coax connectors (again with SA tape) . The impedance will not be quite right but I have used these and have seen no effect
[/ QUOTE ]Hmm - not sure about your 'correct way'. PL259 are not particularly good connectors.
Might I suggest that a better way would be a male and female inline BNC connector? BNC aren't waterproof either, but self amalgamating tape over the joint followed by u/v resistant spray laquer is what we used 'in the trade'. (And this was for temprary joins!)
If you want waterproof, then 'N' connectors offer some water resistance, but we used to tape them up as well.
For VHF I wouldn't suggest TV connectors at all. They are horrible.
We used to run analysis of the impedence of all the lines that we used. Some of the results were surprising. The commercial lines made by HP were usually very good. In summary, if you want GOOD impedence matching, you have to be very careful about how you put the BNC and N connectors on. The cable trimming etc must be VERY accurate.
I should also point out that for the average yacht VHF, you really aren't going to notice much difference if you soldered the inner and outer of the co-ax togethr in a neat and tidy fashion, made sure that there was no chance of it shorting and taped it all up.
[/ QUOTE ]
The torpedo connector I have on one set is literally an elongated screw terminal to take central core, then outer braid is trapped in cable grips to provide continuity either side. Once the connector is closed ... it is a tight joint on the full cable at each end. For real watertightness .. you could either SA tape it up or "Pot" the internals in epoxy ...
Yes it is probably totally against Electronics theory / practice etc. but after many years of use ... it's still performing well with good range and pick-up ... no problems with radio ...
On a boat previous ... I used BNC connectors ... had a few left over after putting in an old style co-ax network ...... the VHF cable came through deck to mast base ..... I used them above deck, taped them up after connecting. Had the boat 4 yrs ... each yr it came apart and went back together ok ... VHF worked fine. Last year I took mast down ... connectors fell to pieces when tape taken off .... VHF was still working right up to that point !!! Seems my taping up hadn't been so good that year ...
I agree that there are the proper ways to do these jobs ... but many people end up doing quick available ways .. and they seem to work ... /forums/images/graemlins/wink.gif
[ QUOTE ]
The correct method of joining VHF coax is with 2 male PL259 plugs and a female union. This keeps the correct impedance of the cable. It however is not waterproof. You can make it waterproof by stretching self amalgamating tape over the connectors, but this has to be cut off to disconnect the cable.
You can also use TV coax connectors (again with SA tape) . The impedance will not be quite right but I have used these and have seen no effect
[/ QUOTE ]Hmm - not sure about your 'correct way'. PL259 are not particularly good connectors.
Might I suggest that a better way would be a male and female inline BNC connector? BNC aren't waterproof either, but self amalgamating tape over the joint followed by u/v resistant spray laquer is what we used 'in the trade'. (And this was for temprary joins!)
If you want waterproof, then 'N' connectors offer some water resistance, but we used to tape them up as well.
For VHF I wouldn't suggest TV connectors at all. They are horrible.
We used to run analysis of the impedence of all the lines that we used. Some of the results were surprising. The commercial lines made by HP were usually very good. In summary, if you want GOOD impedence matching, you have to be very careful about how you put the BNC and N connectors on. The cable trimming etc must be VERY accurate.
I should also point out that for the average yacht VHF, you really aren't going to notice much difference if you soldered the inner and outer of the co-ax togethr in a neat and tidy fashion, made sure that there was no chance of it shorting and taped it all up.
[/ QUOTE ]
The torpedo connector I have on one set is literally an elongated screw terminal to take central core, then outer braid is trapped in cable grips to provide continuity either side. Once the connector is closed ... it is a tight joint on the full cable at each end. For real watertightness .. you could either SA tape it up or "Pot" the internals in epoxy ...
Yes it is probably totally against Electronics theory / practice etc. but after many years of use ... it's still performing well with good range and pick-up ... no problems with radio ...
On a boat previous ... I used BNC connectors ... had a few left over after putting in an old style co-ax network ...... the VHF cable came through deck to mast base ..... I used them above deck, taped them up after connecting. Had the boat 4 yrs ... each yr it came apart and went back together ok ... VHF worked fine. Last year I took mast down ... connectors fell to pieces when tape taken off .... VHF was still working right up to that point !!! Seems my taping up hadn't been so good that year ...
I agree that there are the proper ways to do these jobs ... but many people end up doing quick available ways .. and they seem to work ... /forums/images/graemlins/wink.gif
JonBrooks
Well-Known Member
SBC,
I am kinda guessing that you don't TX much on the office set?
The set up you have will be fine for RX.
Also you system is not on a boat at sea...whole different ball game.
Oh and I hope you have the right coast radio station licence /forums/images/graemlins/smile.gif
Oh and why PL259? I have seen the mess most people make of soldering these can you imagine how bad that would be if we all used N types!!!
BNC would not be much better.
PL259 it very much standard on all kinds of radio's. I admit sum HAM sets use N type but most are PL259.
All the best
I am kinda guessing that you don't TX much on the office set?
The set up you have will be fine for RX.
Also you system is not on a boat at sea...whole different ball game.
Oh and I hope you have the right coast radio station licence /forums/images/graemlins/smile.gif
Oh and why PL259? I have seen the mess most people make of soldering these can you imagine how bad that would be if we all used N types!!!
BNC would not be much better.
PL259 it very much standard on all kinds of radio's. I admit sum HAM sets use N type but most are PL259.
All the best
john_morris_uk
Well-Known Member
Jon - /forums/images/graemlins/blush.gif Apologies for the implied slight/dig against manufacturers and PL259's. I hadn't thought through the idea of lots of people's attempts to put N connectors onto co-ax.
I too have seen the mess people make of soldering PL259's....
I too have seen the mess people make of soldering PL259's....
whipper_snapper
Well-Known Member
[ QUOTE ]
PL259 it very much standard on all kinds of radio's. I admit sum HAM sets use N type but most are PL259.
[/ QUOTE ]
In view of your sig, I thought I should ask, don't all current current Yaesu ham rigs use N-type for the 2m/70cm antenna connection and PL259 for the less critical HF connection? With the added bonus that you can't then put the wrong antenna into the wrong socket!
PL259 it very much standard on all kinds of radio's. I admit sum HAM sets use N type but most are PL259.
[/ QUOTE ]
In view of your sig, I thought I should ask, don't all current current Yaesu ham rigs use N-type for the 2m/70cm antenna connection and PL259 for the less critical HF connection? With the added bonus that you can't then put the wrong antenna into the wrong socket!
st599
Well-Known Member
[ QUOTE ]
With the greatest of respect, please don't keep alive the myth of 'power being reflected back to the transmitter'. Impedence mismatch is rather more complicated, and the VSWR that arises from the impedence mismatch of a transmission line changing impedence DOES NOT imply that there is reflected power back to the tranmitter.
[/ QUOTE ]
VSWR is related to the magnitude of the reflection coefficient. With no reflections, VSWR would be 1. If you are saying that an impedance mismatch does not result in a reflected wave, where does the energy not transferred go?
With the greatest of respect, please don't keep alive the myth of 'power being reflected back to the transmitter'. Impedence mismatch is rather more complicated, and the VSWR that arises from the impedence mismatch of a transmission line changing impedence DOES NOT imply that there is reflected power back to the tranmitter.
[/ QUOTE ]
VSWR is related to the magnitude of the reflection coefficient. With no reflections, VSWR would be 1. If you are saying that an impedance mismatch does not result in a reflected wave, where does the energy not transferred go?
JonBrooks
Well-Known Member
Hey John,
No need, none taken!
Whipper,
Have to say I don't know the answer to that but will look into it.
I have little to do with that side of the business, Marine and commercial is my area.
All the best
No need, none taken!
Whipper,
Have to say I don't know the answer to that but will look into it.
I have little to do with that side of the business, Marine and commercial is my area.
All the best
john_morris_uk
Well-Known Member
[ QUOTE ]
[ QUOTE ]
With the greatest of respect, please don't keep alive the myth of 'power being reflected back to the transmitter'. Impedence mismatch is rather more complicated, and the VSWR that arises from the impedence mismatch of a transmission line changing impedence DOES NOT imply that there is reflected power back to the tranmitter.
[/ QUOTE ]
VSWR is related to the magnitude of the reflection coefficient. With no reflections, VSWR would be 1. If you are saying that an impedance mismatch does not result in a reflected wave, where does the energy not transferred go?
[/ QUOTE ]Easy - its not transferred. In simple terms, without mismatch protection, the PA has too much power in without power being tranferred out and it overheats. In practice, nearly every solid state PA will have some sort of VSWR bridge built into the output which will attempt to limit the drive to the stage if there is a mismatch.
The idea of reflected power is WRONG in transmission line theory and comes from a gross simplification of the understanding of VSWR measurement using 'Forward and Reflected' SWR meters. There are reflected waves, but I suggest it is misleading to refer to reflected power. Transmission Line Theory
Sadly even Wikepedia and some other sources promote the myth.
I remember my professor banging on about the common misunderstandings of transmission lines. I also remember my brain hurting from the complex maths involved to show what was going on. Complex in the technical sense - not complicated!
[ QUOTE ]
With the greatest of respect, please don't keep alive the myth of 'power being reflected back to the transmitter'. Impedence mismatch is rather more complicated, and the VSWR that arises from the impedence mismatch of a transmission line changing impedence DOES NOT imply that there is reflected power back to the tranmitter.
[/ QUOTE ]
VSWR is related to the magnitude of the reflection coefficient. With no reflections, VSWR would be 1. If you are saying that an impedance mismatch does not result in a reflected wave, where does the energy not transferred go?
[/ QUOTE ]Easy - its not transferred. In simple terms, without mismatch protection, the PA has too much power in without power being tranferred out and it overheats. In practice, nearly every solid state PA will have some sort of VSWR bridge built into the output which will attempt to limit the drive to the stage if there is a mismatch.
The idea of reflected power is WRONG in transmission line theory and comes from a gross simplification of the understanding of VSWR measurement using 'Forward and Reflected' SWR meters. There are reflected waves, but I suggest it is misleading to refer to reflected power. Transmission Line Theory
Sadly even Wikepedia and some other sources promote the myth.
I remember my professor banging on about the common misunderstandings of transmission lines. I also remember my brain hurting from the complex maths involved to show what was going on. Complex in the technical sense - not complicated!
