What grade VHF Antenna Coaxial Cable was used in 2000 Hunter 340

[dlochner]

Once again, quality matters. Going cheap on coax and its connectors yields a false economy, especially when you consider the very low cost of an Amphenol PL 259 connector.

Soldering is the way to go. If you have never soldered a coax connector find a Ham and they'll be glad to do it and teach you. Soldering is tricky because if you overheat the center wire it can melt the insulation and short. Getting the braided shield soldered is also a challenge. And when its all done and connected wrap the connection with self-amalgamating tape.

 

[Don S/V ILLusion]

up. Having a switch or coupler (coaxial connector) below the mast should only introduce 0.2 db (plus the 2 extra PL-259).

curious - from where did you get that figure?

 

[marcham]

curious - from where did you get that figure?

https://www.dxengineering.com/parts/dwa-cs-201a

 

[LloydB]

It doesn't make sense to me why you would put a antenna switch in the middle of a perfectly good transmission cable any place between the radio and the antenna. Just a thought

 

[jssailem]

antenna switch in the middle of a perfectly good transmission cable

I installed an AIS Class B transponder. The VHF and AIS frequencies are next to each other on the spectrum. Using a powered switch and an antenna tuned to serve both frequencies, I can use one antenna for both radios. The switch is prioritized to the VHF radio. The AIS signal goes to a dummy circuit in the switch and is transmitted when the VHF radio is not transmitting. I understand that AIS signals are short burst signals on specific time units. If one is missed, it is ignored by the AIS satellite system under the Class B Protocol.

 

[Mark Maulden]

I would not put a switch or connectors at the base of the mast as it’s most likely under the cabin sole (bilge) which is a nasty environment prone to corrosion. Let the next owner solve his/her problem. John mentioned LMR 400 coax. It does have excellent loss figures but it is pretty stiff and should not be bent very hard. I use it for VHF/UHF in my ham shack and had to route accordingly. RG-8 will work just fine for a mast antenna. I put a two meter radio (146 MHZ)on the boat and used the marine antenna through a coax switch between both radios. Done it several times and works well..Just for clarity, it’s best to call antenna wire as coax which is what it really is. Relieves confusion..

 

[Don S/V ILLusion]

https://www.dxengineering.com/parts/dwa-cs-201a

View attachment 228442

”less than 0.2dB” is correct. “Introduces 0.2dB” is not. In actual practice, a good quality switch such as th Daiwa I have introduces no loss. Coax switches are ubiquitous including ham radio stations where every minor loss is important.

 

[sailcapt340]

As a somewhat frustrated update…..
This is what I am faced with. I haven’t found a way to fish a wire through the area I thought I could inside the headliner of the boat. The nest of wires already in there block the access from one side. And approximately halfway in there is a crosspiece, which I feel has an access hole cut into it that passes the wires for the cabin lights through.
As hard and as many times I tried I can’t get a wire through. I used a flat snake, hard thin wire, magnets. I’m open to suggestions here. Any advice to get that antenna cable in there.

But what I thought was the easiest point to get an antenna cable behind the navigation station is worse. It is a solid wall, filled with, my guess is foam insulation. But if I could get the antenna cable at least to the opening there I could tuck it into the corner and run it down behind the wall.


This is my original Ray52 VHF with its flush mount bracket. New VHF radios don’t even come close to matching up to this face plate to make it useful and mount at the pedestal.

This is my original Ray52 VHF and location on the pedestal. Which I’m trying to eliminate by putting the radio inside the boat.

I have made a face plate to mount a new radio back on the pedestal. But that keeps the radio where I don’t want it to be.
And as odd and petty as this may sound, new VHF radios do not have side mounted wired mic cables, as my original VHF.
In the photo you can see a recess area that holds an ice box. With the mic cable coming out the front it will be in the way of the box and I know for certain it will be hit every time someone reaches in to get a bottle. Or when I remove the box itself. And sooner or later that cable will be effected in some way. I know it’s petty and stupid but thats why I wanted the radio inside the boat.

So I’m thinking, Is there a handheld VHF that I can connect to my antenna cable at the pedestal and still use my mast antenna for better range? Is anyone doing this and getting better reception or is that just not necessary?

As I mentioned, I opened to your ideas going forward.
Thank you for the help.

 

[Don S/V ILLusion]

So I’m thinking, Is there a handheld VHF that I can connect to my antenna cable at the pedestal and still use my mast antenna for better range? Is anyone doing this and getting better reception or is that just not necessary?

Routing cables through any boat can be challenging.

Using a handheld with a mast mounted antenna should buy you extended range. It’s a function of ERP vs. cable loss, both easily calculated. The only caution is that handheld antenna connectors are not designed to survive the constant stress from the coax cable movement as you use/move the radio.

You are better served with a fixed mounted VHF which will facilitate power, coax and microphone connection locations which don’t interfere with anything else.

 

[sailcapt340]

[

Routing cables through any boat can be challenging.
Challenging is the kindest words I can use to describe this route.

Using a handheld with a mast mounted antenna should buy you extended range. It’s a function of ERP vs. cable loss, both easily calculated. The only caution is that handheld antenna connectors are not designed to survive the constant stress from the coax cable movement as you use/move the radio.
I really did think this was going to be the case, but had to at least ask. Thank you Don for your expertise, I’ll forget that idea.

It‘s not so much having our hands going into the space below the radio thats the issue. It’s the constant removing of the 4 cup holder tray, that sits on top of the cooler, that will always hit the cable and connector every time. And without that you loose a very convenient shelf.

 

[dlochner]

You may have to cut an access hole near the jam run the cable and then put a cover over the hole. A piece of white plastic would work.

 

[jssailem]

One of the tools used with success is fiberglass rods. They come in various lengths and can help to push wire through confined spaces.

 

[colemj]

”less than 0.2dB” is correct. “Introduces 0.2dB” is not. In actual practice, a good quality switch such as th Daiwa I have introduces no loss. Coax switches are ubiquitous including ham radio stations where every minor loss is important.

This is correct. Also, couplers and connectors do not introduce any measurable losses, and certainly not 0.2dB. Even inappropriate connectors like BNC won't introduce any losses. Sure, losses can be introduced by poor installation, but one needn't plan on that nor avoid them simply because of the possibility.

Someone mentioned that if a splitter is used, then the AIS needs to be mounted next to the VHF. This isn't true. All connections between antenna, splitter, AIS, and VHF are coaxial cable, so all of them can be mounted anywhere and away from each other.

LMR400 is great coaxial, and I use it, but get the LMR400UF version of it. Much more flexible. Don't use it if one plans to home-run the antenna to the VHF and will be pulling it in/out regularly or semi-regularly. The foam core can easily crush doing this. If one is going to use LMR400, then one better be sure they are skilled at installing and sealing connectors and their couplings. The inner conductor on plain LMR400 is aluminum (copper on the UF version), and the outer conductor on both are aluminum foil. Any water will eat this quickly.

Mark

 

[sailcapt340]

I definitely will have to cut an access hole in the headliner, somewhere in the middle of the trough section there is something that turns the snake and I end up out of that trough and going along the headliner in either direction forward or aft. I can hear it in there.
I’ll just have to make up a nice panel to cover up the hole.
I already made a recessed shelf to go into the area the original radio was located. That’s how confident I was that I could route a cable through the headliner of the boat. So I’m committed or crazy.
.

As you all have suggested, I plan on using the LMR400 Ultra Flex cable as well. Once out of the headliner and along the side access panel, the bends will be 90 degrees to get to the navigation station wall. And in the hanging closet behind the wall the open working space is limited at best. And I don’t want to fight a cable in an area that is 4 feet deep.
Thank you all, I‘ll keep you posted.

 

[colemj]

While minimizing coax loss is a good thing, don't overthink it. On our boat, the run from the antenna to the radio is a bit over 100', so the difference between LMR400 and RG213 is 1dB, which is not a lot and probably unnoticeable.

I don't know what the run is on a Hunter 340, but guess it is ~50-60'? If so, the difference in coax loss between LMR400 and RG213 is 0.5dB, which corresponds to a 5% difference in power output between the two. This isn't enough to matter at all. RG213 is more forgiving of bends and future moisture intrusion, so you may wish to consider that instead.

To give a relative perspective, a run of RG213 on your boat will have less loss than our run of LMR400.

Mark

 

[colemj]

Wait, I just reread your original post and notice that you are only replacing the coax from the base of the mast to the radio. This is a very short run, and debating over coax is a bit meaningless for just 15-20'. You might consider RG8X that is half the diameter and much easier to snake through things and make bends.

If the coax up the mast is old or RG58, then that is going to be the bottleneck in your signal. What you do inside the boat won't matter.

Mark

 

[Don S/V ILLusion]

so the difference between LMR400 and RG213 is 1dB, which is not a lot and probably unnoticeable.

actually, that is a 20% signal loss and can be quite noticeable

don't know what the run is on a Hunter 340, but guess it is ~50-60'? If so, the difference in coax loss between LMR400 and RG213 is 0.5dB, which corresponds to a 5% difference in power output between the two. This isn't enough to matter at all.

Mark

Every dB in terms of signal represents a 20% loss. At the margins under weak signal conditions or with high noise level, every little bit can make a big difference.

 

[colemj]

actually, that is a 20% signal loss and can be quite noticeable

While that is theoretically true, it really isn't in a practical sense except on extreme and improbable edge cases. Horizon loss will occur well before the difference between 25W and 20W output power. On the other hand, minimizing this is why I chose LMR400 for a 100' run. However, LMR400 comes with its own caveats that can easily result in a loss greater than the 20% from using a more robust coax type.

Every dB in terms of signal represents a 20% loss. At the margins under weak signal conditions or with high noise level, every little bit can make a big difference.

Agree again. Theoretically and in edge cases. However, the OP's run is likely 15-20', which isn't going to be measurably significant between LMR400, RG213, or even RG8X. For example, the pigtails from our VHF and AIS to the splitter they share are RG58 because it is really easy to run (and the splitter came with these pigtails). The 18" lengths are not adding any practical losses to the system. I've measured it.

And where does one stop on this quest? Our previous boat was cabled by the radio engineer PO with 1/2" Heliax and N-connectors. For sure the lowest possible losses available in VHF frequencies, and half the price of LMR400. In practice, however, there was never a measurable performance difference between it and the 1dB greater loss of the LMR400 I replaced it with (lightning strike). The Heliax was sure a pain to remove, and I would have hated rerunning it again.

In the OP's case, the potential to internally damage LMR400 with several 90* bends and passing through several tight spaces is IMO a higher signal loss risk than a 0.2dB loss in cable type.

The correct way to choose coax is to first determine the physical constraints and environment of the installation, then choose the least lossy coax that best conforms to these limitations. Boats are always a compromise.

Mark

 

[Don S/V ILLusion]

.

The correct way to choose coax is to first determine the physical constraints and environment of the installation, then choose the least lossy coax that best conforms to these limitations. Boats are always a compromise.

Mark

Some things shouldn’t be a compromise; safety being the primary.

It’s largely a moot point for anyone doing coastal sailing. I prefer to focus on what I want and then figure out the best way to accomplish it. I installed ‘direct bury’ 213 coax. Not the easiest to snake through but the short-term effort pays off in optimum performance and safety.

 

[colemj]

Some things shouldn’t be a compromise; safety being the primary.

I installed ‘direct bury’ 213 coax. Not the easiest to snake through but the short-term effort pays off in optimum performance and safety.

These two statements are at odds. If there was no compromise made, then you would have installed Heliax with N connectors. Even LMR400 would have been less of a compromise than 213.

Coastal sailing is probably where the best performance is required. Offshore, we rarely see anything within VHF contact range, and have no land masses or structures that can affect signal path or strength, nor any electromagnetic interference from broadcasting or radar towers and the like.

Mark