Hi, Folks!
I've been lurking here for quite awhile now, but would now like to tap the wisdom of the assembled masses (?) for a specific purpose...
I am about to have a RADAR arch installed on my boat (an older Tiara 31 Open Express). Subsequent to that, I want to remove all the old antennas and such which are currently mounted to the sides of the superstructure (such as it is), and relocate them to the arch itself. The two main reasons for this are to keep the side decks as clear as possible for easier access to the foredeck, and to upgrade the antennas themselves. Given the specific application, I've settled on the ubiquitous 8-foot (6dB nominal gain) type as the most appropriate. But alas, that doesn't really narrow things down very much. There are just too many different competing products out there, all poorly differentiated from all the others. Heck, Shakespeare alone has at least a half-dozen different models -- all claiming to be the cat's meow, in at least some way. Then there's Digital Antenna, Glomex, and on and on.
So.... To help sort out the wheat from the chaff, I seek everyone's take on the following question:
In your experience and opinion, what (specific make & model, please) is THE BEST 8-foot (6dB nominal gain) Marine VHF antenna extant?
Cost is only a (distant) secondary issue here, as long as it's not completely outrageous. My primary concerns are performance (including lowest possible SWR), reliability, and long-term durability -- probably more-or-less in that order.
On a semi-related note: From what I've seen, virtually all of these are suplied with varying lengths of either RG-58 or RG-8/X coax permanently attached to the antenna base. Now, I don't really want this tail to wag the dog, BUT... An antenna which uses a NON-integral downlead might be preferable, if all else is also in order. This would allow me to upgrade the downlead to RG-8/U, or RG-213, or perhaps even LMR-400 (if I can tolerate the hassle of running it through the arch tubes), and also keep the run length to only what is really necessary (tho' I could of course also hack the connector off an integral cable then install a new PL-259 at the appropriate length; so that's not a major issue).
Metz or Cellwave.
Metz Manta is what I recommend for a simple VHF antenna. It will outperform your 8 foot glassfiber antenna. Unbreakable, and has a PL259 to connect the cable that you want. I believe the US Coast guard uses them as well.
If you can get it, use Ecoflex VHF cable or Aircell. Expensive but worth it.
Kees posted :
Metz Manta is what I recommend for a simple VHF antenna.
It will outperform your 8 foot glassfiber antenna.
Really?
I have a hard time seeing how that could be. The loading coil will help match impedance and hopefully keep the SWR under control; but still, an under-3-foot whip just isn't going to have the same pattern gain as a full 1/2-wave dipole (such as those generic 8-footers). I'm reasonably conviced that the boat in question is more than stable enough to tolerate the "skinnier" radiation pattern produced by the higher-gain antennas; so why would I want to forego that?
Unbreakable, and has a PL259 to connect the cable that
you want.
This part is nice; but I'm still concerned about the performance potential. I think it's notable (and significant) that Metz doesn't even mention "Gain" on their product page.
I believe the US Coast guard uses them as well.
Could be. And if I were on a smallish RIB/inflatable that routinely gets subjected to rough treatment in severe conditions, the small rugged whip would be an undeniable attraction. But that's not my situation.
If you can get it, use Ecoflex VHF cable or Aircell.
Expensive but worth it.
The Ecoflex "10 Plus" stuff looks very interesting, save for it's relative inflexibility (check those specs for "Bend Radius" at http://www.ecoflex-usa.com/index.php?id=23 ). If I wind up with a suitable antenna, I'll definitely look into that further. Thank you.
But the Aircell stuff is WAY too lossy to even consider -- or at least to put any effort into chasing after. Per http://www.nevadaradio.co.uk/cables-leads-plugs/antenna-cable/ssb-electronic-aircell-7 , its attenuation factor is about 7.6dB per 100 Meters @ 144 MHz. That works out to about 2.3dB per 100 feet, also @ 144 MHz. By comparison, a good RG-8/U (such as Belden 9913) can do better (per http://hamradio.arc.nasa.gov/coaxcableloss.html , it's spec'd as 1.8dB/100-ft., even at 200 MHz). RG-213 and LMR400 are better still.
Thanks for your thoughts, but I think I'm still looking for my "World's Best VHF Antenna".
Seems unlikely for your boat your going to benefit from a very thick cable. The cable length is short and the height of your antenna above sea level is fairly minimal. Beware when you pick a cable some types require expensive special tools and/or hours of practice to make a superb connection.
I think you should focus on which antenna & wire combo will(1) allow a single length of cable pre-made to the exact length you need or the cost and skill necessary to put your own end on the cable is not prohibitive (2) the antenna end of the cable can be detached from the antenna for future storage or antenna replacement (3) the antenna end of the cable is small enough it can be snaked thru your boat.
Some things to keep in mind:
1. Kee's advice above resonates with me. Weigh it strongly in your decision.
2. Plan now for an AIS antenna as you install anything in your Arch. Note that with AIS a short antenna is just fine, 3db makes sense also, works better in heavy seas. I have a lot more use of my VHF, now that AIS is broadcasting my vessel name.
3. A product like the Garmin VHF-300 or Ray 240 has a transiever that can be positioned much closer to the antenna (instead of at the helm), radically reducing the antenna cable length. Maybe you want to consider using this VHF, make your antenna choice based on using whatever wire comes with it, cut to the right length, and bend on the connector yourself (Shakespeare has a connector for 58 or 8X cable that is very simple to install on a cable end with tools you probably already have)
Dan Corcoran (b393capt) posted :
Seems unlikely for your boat your going to benefit from
a very thick cable. The cable length is short and the
height of your antenna above sea level is fairly minimal.
Physics (and cable specs) says that it will benefit. But granted, given that the cable run is rather short (at least as compared to a large cruising sailboat with a masthead antenna), that benefit will be relatively small. Still, better to have and not need, than need and not have.
Beware when you pick a cable some types require expensive
special tools and/or hours of practice to make a superb
connection.
I don't intend to get too carried away here. But I have enough experience in various other RF applications to know that reducing cable losses is the closest thing you can get to "free lunch" in terms of antenna system performance. Anything else you do to improve performance in one area (such as increasing directional gain, for example) invariably imposes a trade-off in some other aspect (such as coverage pattern).
I think you should focus on which antenna & wire combo will
(1) allow a single length of cable pre-made to the exact
length you need or the cost and skill necessary to put your
own end on the cable is not prohibitive
I have the skills (decades of electronics experience, albeit mostly in a different context, including building my own cables for various purposes). The tools are another matter, if a particular cable/connector combo requires an oddball crimp tool that I don't happen to have. In that case, I'd have to factor in the cost of the tool to the cost of that particular antenna/cable combination. But as I said before, cost is really not a major concern, as long as it's not outrageously high. And besides... I like overkill (I used Quad-Shield RG-11/U for my TV antennas, for example).
(2) the antenna end of the cable can be detached from the
antenna for future storage or antenna replacement
This is indeed an attractive feature; but one which seems surprisingly rare.
(3) the antenna end of the cable is small enough it can be
snaked thru your boat.
And/or, an easily field-installable connector. At that point, all I have to worry about fishing through arch tubes and such is the cable itself.
Some things to keep in mind:
1. Kee's advice above resonates with me. Weigh it strongly
in your decision.
Noted.
2. Plan now for an AIS antenna as you install anything in
your Arch. Note that with AIS a short antenna is just fine,
3dB makes sense also, works better in heavy seas. I have a
lot more use of my VHF, now that AIS is broadcasting my
vessel name.
Yep. I ordered the arch with two extra gear-mounting plates, in part for this very reason. Actually, I sat down and made a list of everything I might conceivably want to mount to the arch over the next several years -- which definitely includes AIS, tho' it probably won't happen right away -- and decided that the stock four auxiliary mounting plates (each of which can generally fit two smallish devices, such as antennas or similar) just weren't enough.
3. A product like the Garmin VHF-300 or Ray 240 has a
transiever that can be positioned much closer to the antenna
(instead of at the helm), radically reducing the antenna
cable length.
While that's a nice theory, it probably won't work out all that well in this particular boat. Unless the whole transceiver box were mounted to the arch itself (which I don't see happening, for presumably obvious reasons), it could only get perhaps 4-6 feet closer vis-a-vis it's location at the helm station. And even at that, it would have to be stuffed up under the gunwale, which is far from ideal in other ways. If I go to a two-piece radio on this boat, the "black box" will no doubt be mounted below, in one of the hidden cubby-holes behind/under the dinette.
Speaking of the radio itself... The boat currently has two VHF radios, one at the helm and one below. The former is a relatively recent/decent Standard-Horizon with Class D DSC. The latter is an older (or at least, lower-end) S-H, with only bare-bones features (no DSC, very limited scan modes & programming, etc.). They both work "acceptably", and I currently have bigger fish to fry; so for now, I'll leave things as they are. But if things go according to the current plan, in a year or so (emphasis on the "or so"), I'll replace the helm radio with something as close to SOTA as possible, then move the old helm radio below to replace the cheapie. Not sure what that "SOTA VHF" will be, yet. Ergonomically and overall design-wise, I like the Simrad RS86; but it falls a bit short on features, particularly as it relates to AIS & DSC -- and it's REALLY pricey.
Maybe you want to consider using this VHF, make your
antenna choice based on using whatever wire comes with
it, cut to the right length, and bend on the connector
yourself (Shakespeare has a connector for 58 or 8X cable
that is very simple to install on a cable end with tools
you probably already have)
At this point, I think I have enough known choices that I can safely eliminate from consideration any antenna that comes with pre-attached (i.e., non-removable) RG-58. Hence, RG-8/X is the practical minimum acceptable cable; and if (due to availability or similar) I have to stick with that, it's probably "good enough". But that still doesn't get me to the elusive "THE BEST" 8-ft. VHF antenna.
All I can say is that 100% of the fishboats in the Pacific NW use Morad antennas. Their marketing is terrible, but look at www.morad.com for the specs. You can buy them directly or from fisheriessupply. I have two of their vhf antennas and one ais antenna on my boat. Peform well and you get 6DB without 8 feet of unsightly fiberglass.
Antennae break. It may take a bit more to break a very expensive one, but more 'break' is always available. My antenna decisions are based on pain of replacement.
I also think that there is only one place on a boat for a soldered connection, and I don't want to be doing that while dangling from a jungle gym in a quartering sea.