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Discussion Starter · #1 ·
Could anyone make a good rec on these two items for an Olson 30 (~35' mast) for offshore use? I've been reading tons, and am more confused than ever. I took a good look at what's up there now this weekend while replacing everything else, and noticed some nicks in the cable that went into the braided core of the coax cable, so I removed it and want something better. The antenna is quite old, but just a simple stainless whip about 3' long. I'd like something appropriate (not 8' long, obviously), but I'm not sure if I really need to pony up the bucks for Ancor's RG-213 cable and a $200 Shakespeare antenna if I don't really need it.

Any help would definitely be appreciated!

Ray
 

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Learning the HARD way...
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What, exactly, do you mean by "offshore use?"

Well, you KNOW that the water tight integrity of your co-ax is shot, so you really should be replacing that. I would look at LMR400(or equivalent) from this place; Low Loss 400 Cables | ShowMeCables.com

Frankly, spending $50 on a new GAM antenna would be cheap insurance.
 

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Discussion Starter · #3 · (Edited)
Offshore use = coastal stuff (mainly), but also to Bermuda. That cable is already gone- I dropped it yesterday, so it will be replaced with something better.

Is that lowloss cable tinned? I couldn't find any info on that from the web page.

I probably should qualify this question with something I'm learning about VHF antennas- my boat is silly light (4200 lbs) and is very tender- so having something big and long doesn't make sense. I'm sure some of these things are also quite heavy...
 

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I just replaced my 35 year old cable with RG-213 and used connections PL 259 as described in this article Easy VHF Connections Photo Gallery by Compass Marine How To at pbase.com We have a simple 3 ft Metz antenna which seems to work ok on top of our 50' mast. It is my limited understanding that VHF is only line of sight and with my 34' boat I can probably only get 16 miles or so of distance due to the horizon line but I am pulling that from my limited knowledge so you should verify that for sure...
 

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Id second a metz antenna for vhf marine use. Coasties and law enforcement use them and I also feel they are built good. Cable I dont have any brand I would know or can recommend.
 

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I buy coax from The RF Connection Home Page . On your boat the difference between RG-8X ($20) and RG-213 or LMR400 ($35) isn't significant. Get good silver teflon connectors, NOT the Shakespeare crimp on. MaineSail has some solder-crimp parts he thinks well of; I haven't tried them yet. I use solder-solder parts and self-amalgamating tape.

A 1/4 wave (~18") or end-loaded 5/8 wave (~40") antenna is fine. You don't need a fiberglass radome. There are lots of good antennas. The things to consider are the seal of the coil at the bottom and the quality of the connector on the bottom. In the best of worlds you'd mount the antenna so it is isolated from the mast - sometimes that isn't practical.
 

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I replaced the antenna and coax on my 27' boat with a Metz antenna and LMR-400-DB coax (the "waterproof" version of LMR-400, something that might come in handy on a boat). I also moved the antenna from the masthead to the stern rail. This obviously puts the antenna quite a bit lower, but it makes it much easier to inspect and repair (if need be); I also haven't noticed much of a difference in range. I also used high-quality soldered connectors, and sealed the connector-coax joint with heat-shrink tubing and rescue tape.
 

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If it were me, on a 35' mast, I'd use LMR240 and crimp-on connectors like Mainesail recommends. The LMR240 is high quality, low loss cable that is only 1/4 inch thick. It's easy to route through tight spaces. The loss is about the same as RG213. Per 100', at VHF freq's, the loss is around 3dB, RG213 is about 2.8dB, & LMR400 is 1.5dB. Considering that you will most likely have significantly less than 100', the difference in loss between any of these cables is negligible. Comparing to LMR400, your signal attenuation would be just 1.5dB difference between the two. In real-world operating, you would not be able to distinguish that small of a loss in signal strength.

People will get on here and talk about about what percentage of signal -3dB loss is, but it doesn't equate to the same percentage of actual range. I'm just saying that if you had the cables and compared side by side, you wouldn't be able to distinguish which one was the higher loss cable, neither would a distant station copying your signal.

LMR400 is only about $0.30 per foot more and is a little more durable because of the size. RG213 is OK, but more expensive than LMR400. All are fine for a VHF installation, and if you can get one for a good price, go with that.

I'm an RF engineer and have been in wireless communications since the mid eighties. We have been using crimp-on connectors for just as many years. I recall a debate over what was better, solder or crimp, back then, but really thought it had been put to bed already. Soldered connectors are no more reliable than crimp-on in any VHF installation. In fact, the only time they are superior, is in certain UHF/microwave installations that are more susceptible to passive inter-mod because of dissimilar metals between the connector and cable. They still use non-soldered connections most of the time anyway. Considering that you will likely be using PL259 (UHF) connectors, which are possibly the most difficult to solder the braid properly, I'd recommend you pick up a crimping tool after you decide which cable to go with. You can find a cheap one on eBay for about $30. Seal the connectors. It doesn't matter what type you use, they will all eventually let moisture in if exposed. I put 3 concentric layers of adhesive lined heatshrink at the base of the connector to strengthen the joint. This makes the cable/connector extremely durable. Then wrap in appropriate weatherseal tape. Self-amalgamating, butyl, silicone, etc. You can acquire a small amount from wherever you purchase the cable & connectors. Just make sure you install it the way the manufacturer recommends. For example, butyl is not meant to be exposed, but wrapped in a rubber tape similar to regular electrical tape. This will ensure you will not have to go up the mast anytime soon. If you need to splice the cable through the deck, just need to extend with a thinner cable, or have two shorter pieces, etc, don't be concerned about excessive losses by adding connectors inline. A couple of connectors, if properly installed, will have such a small impact on overall performance, that you would need test gear to detect it. Soldered PL259 connectors are installed poorly so often that the performance is degraded. Good luck with the installation.
 

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Discussion Starter · #10 ·
Thanks, El Rubio- I've purchased rg-213 and a few connectors from Defender already- bought the Shakespeare quick connect variety from them before knowing that they don't fit rg213 (which I asked the salesman to verify beforehand), discovered the mistake and ordered the solder connectors (the only other connectors in the right size) so now I have 4 connectors that I will return to them. Do you happen to have a recommendation for an online store for connectors and tool (besides ebay, if possible)? I've already called around Charleston, and nobody has them in stock...

Ray
 

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Discussion Starter · #11 ·
Hey, never mind- found the RF connection page (thank you, SV Auspicious!) and they had everything in stock and very affordable ($37 for the tool, and $2 for each connector). Thanks again, you guys- very helpful!

Ray
 

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Connectors - Amazon.com: Coax Connector UHF PL-259 PL259 Male Crimp for RG-8 RG-213 2-Pack - by W5SWL ®: [email protected]@[email protected]@http://ecx.images-amazon.com/images/I/[email protected]@[email protected]@31hAtsS-4jL

Crimp tool -

These are common tools that can be located at most electronic supply stores. I chose Amazon because the crimper is cheap, but sufficient for your application and ease of ordering. Solder the center pin and crimp the outer ferrule. Below is a link for some butyl sealant. If you have some of the butyl that Mainesail sells, you can use that just as well. Wrap the exposed connector at the base of your antenna with electrical tape, cover that in the butyl, finally wrap again in electrical tape.

Coax seal -
 
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