VHF coax connector

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FergusM

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I have removed a badly-sited Driplug VHF connector from behind my deck-stepped mast. I intend to install a deck gland for both the antenna cable and the nav lights, and connect the cables below deck. I bought a V-tronix BNC connector, but was horrified to find that I would have to solder the core of the coax into a thin tube through a very small hole. I have never soldered anything, and it does not appear ot be a good idea to try to learn on such a critically-important connection. I searched on the forum, and found a long thread on VHF connectors which I barely understood, but one poster said that this particular connector wasn't a real BNC connector at all, which has left me even more confused.

Is there any way that I can join the antenna cable from the mast to the cable in the cabin so that I can disconnect it easily when the mast is being taken down? I would prefer something which does not need soldering. I rang the firm based at Kip Marina for a quotation on something else electrical, and found that they are very expensive, so using professionals would have to be a last resort. I have a handheld VHF, and I can get by for the present. I have crimped connectors for the nav lights, so that will not be a problem
 
FergusM,

soldering is really simple, honest !

However try a TV repair shop or similar if one still exists near you; there are in-line connectors where one just pushes in the centre core, no soldering.

Beware there are 2 sizes of co-ax in this context, the connectors are very cheap so I'd grab at least one of each.
 
My VHF antenna is divided as you intend, below a deck gland inside the boat. BNC connectors are quite tricky to get right and not really the right plug for the job. What you need is a PL259 connector. Ideally there would be male and female versions of these but I have never found them. What you can buy is a double female barrel-like connector to join two male PL259s together. Purists will tell you that the plugs should be soldered but mine never have been and my VHF transmits and receives very well indeed. There are versions of the PL259 that have a grub screw connection in the centre pin, although I have not seen one for a while.

PL259s can be had on Ebay for 0.99p, although I dare say these are not of the best quality.
 
Yes, two PL259s and a barrel connector is the way to go. However, be sure your deck gland is the type that can be disassembled to take a PL259 through it - 22mm clearance - so you don't have to refit the PL259 whenever you take the mast down.
 
Many thanks to all of you for the help. You have solved my problem and restored my confidence.

Salty John, the gland I have is the kind that you drill holes in for the wire, and then cut a slit from the hole to the perimeter, so only the cable (5 mm) has to pass through. I take from your last point that I should use a 25 mm hole saw to make a large enough aperture for the plug to pass. I had been thinking of buying one of the Cableports you sell through your website, but had forgotten where I had seen them. I see that it would pass that size of plug, and it is a lot more attractive and looks a much more solid job than the deck gland.

Nigel, I have already bought a tube of the Contralube, so thanks for reminding me to use it here.
 
No, don't cut the sealing material, that needs to fit snugly against the wire. But the outer hole in the gland needs to be big enough to take the plug through. Look at the Index Marine site deck glands and you'll see what I mean.
 
I reckon I'll take the deck gland back, and buy one of the Cableports from your site. I have to check that there is room for it. The factor I have to take into account is that the halyards, reefing lines and so on are taken back to the cockpit on my Hunter Horizon (some nit had fitted the Driplugs bang in the way) and the self-tacking sheet track for the jib passes close to the forward edge of the mast. There ought to be enough clearance immediately aft of the mast. I will check at the weekend.

If I were to use the deck gland, I would take your advice and not slit the seal. As both the cables which pass through it come from the mast, the cables, plugs and seal can stay together attached to the mast for the winter.

Yes, I think the actual hole in the gland would pass the size of plug involved.
 
Just back to the original question on soldering BNC connectors. The trick is to tin the centre conductor then add heat and the slightest bit of silder to the pin side hole.
Yes it takes a bit of practice. OP should practice lots of soldering first. It is a trick to make sure you have enough heat into the joint but not too much. The braid is bent back around the former and trimmed neat with scissors then the comnector is screwed togher. Test to make sure there is no short from strray bits of wire. Also test to ensure the centre pin extends far enough into the lug. You should be just able to catch the pointy end of the pin witha thumb nail. If it is too deep it may not make contact with the socket. Too long will foul up. Both PL 259 and BNC need a lot of water proofing. I think OP has decided to use continuous cable through the deck with a seal around the cable. (Disconnect the cable from the radio then pull the connector through the seal at the deck.) This will be more reliable.
However I remove my mast often and so use a pushpit mounted aerial. olewill
 
FergusM said:
If I were to use the deck gland, I would take your advice and not slit the seal. As both the cables which pass through it come from the mast, the cables, plugs and seal can stay together attached to the mast for the winter.

Yes, I think the actual hole in the gland would pass the size of plug involved.
Click to expand...

It's a matter of seconds to remove the plug from the wire if it is not soldered on. Take the plug off and pull the wire through the gland. All my deck glands are single wire ones of about 6 mm diameter and the path to them is tortuous and narrow. There is no way a plug would pass along it.
 
Salty John said:
Yes, two PL259s and a barrel connector is the way to go. However, be sure your deck gland is the type that can be disassembled to take a PL259 through it - 22mm clearance - so you don't have to refit the PL259 whenever you take the mast down.
Click to expand...

I hate to disagree, Salty John supplies some excellent antenna equipemnt. I don't think much of the PL/SO259s, they are bulky and difficult to use, plus using two and a barrel adaptor increases the number of joints and therefore the losses in the cable run. My own preference is for crimped, in-line, 50ohm BNC connectors - they are compact and have a very positive locking action. Of course, you do need to have the appropriate crimping tool, but ask around and someone will be able to either lend you one or come and fit the bits for you. Ideally all connectors should be below decks, having passed the cable through a gland or swan neck.

Rob.
 
vyv_cox said:
Do they exist? I can find plenty of the double female barrel type, and bulkhead fitting SO-239s, but no in-line ones.
Click to expand...

Males and females are available in just about every configuration one can think of including SO239 inline for various cable types, I have to confess I have never seen them offered retail in UK except at daft prices i.e. around £10 though.
 
Last edited:
rob2 said:
I hate to disagree, Salty John supplies some excellent antenna equipemnt. I don't think much of the PL/SO259s, they are bulky and difficult to use, plus using two and a barrel adaptor increases the number of joints and therefore the losses in the cable run. My own preference is for crimped, in-line, 50ohm BNC connectors - they are compact and have a very positive locking action. Of course, you do need to have the appropriate crimping tool, but ask around and someone will be able to either lend you one or come and fit the bits for you. Ideally all connectors should be below decks, having passed the cable through a gland or swan neck.

Rob.
Click to expand...

Pl259's are terrible connectors.
Their sole claim to usefulness is they are big and chunky and will survive being used by the US military. And they are available cheap.
The 259's you often see in chandlers are rubbish, they do not seal the cable. There are better ones around, but expect to pay a lot more.
On a boat, you want the coax sealed to keep moisture out.
Moisture corrodes the braid and increases loss.
For amateurs, a clamp type BNC is usually a good way forward. Adaptors to the So239 on the radio set are readily available.
The BNC is a more reasonable size to go through a deck gland if needed.
 
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