SSB / Ham Antenna

[AnchorageGuy]

We are installing an Icom 802 on board our trawler Beach House. I have installed dozens of these radios so installation is not an issue. But with the trawler, we plan to install a whip antenna. My question is for those of you with actual practical experience. Is there a significant difference between a 16 foot or a 23 foot antenna for SSB/Ham use? Our cruising will be US Coastal and Inland waters and the Bahamas. We will be communicating with local nets and friends throughout the US. Weather fax and Pactor connections are also a consideration. We don't need to connect to Europe or the south Pacific. Looking for some real world advise. Thanks, Chuck

[lorenzo b]

The recomended lengh for an Icom 802 is 23'. From listening to two ham keeks who worked on mine, I do believe the length does matter. If you check with your local ham radio club, you will find people who know about various antennae.

[btrayfors]

Yep, size really does matter! Lots of studies have shown that shorter vertical antennas are not as efficient at transmitting...expecially in the lower frequency bands..as are longer ones.

If there's no good reason not to, I'd go with the standard 23' whip antenna.

BTW, attention to grounding IS important. One of the trawler's on the Waterway Net -- in fact the trawler belonging to this year's Club Commodore -- is in the Bahamas. He did some work on his ground yesterday, and his signal improved A LOT over what it has been for the past several months (as heard this morning by me in the DC area, and by stations in Marathon, FL, Charleston SC, and Tampa, FL).

Bill

[ActiveCaptain]

There will be a huge difference between different sized antennas for SSB. It's not so much the size difference, although that helps. It's the ratio of the wavelength period to the antenna. 23' is a sweet spot for the SSB frequencies used.

There are two other things that are equally important though:

1. Make sure you have an antenna tuner. Skipping that part when using an omnidirectional antenna will kill performance. The matching Icom 802 antenna tuner is the AT-140:
http://www.westmarine.com/1/1/6921-1...-ssb-m802.html

2. Work on ground plane for the boat - make sure you have a definite plan for that. A better ground plane will provide better distance communications than beefing up the antenna. When our boat was built, they laid copper mesh inside the hull for ground plane. As a result, I have no trouble logging DX communications to Russia and India - I do it all the time as long as the boat is in open water.

It's especially easy now to get a General class ham license. Having that opens a much wider range of frequencies and capabilities.

...Jeff aka W1ACA

[AnchorageGuy]

Originally Posted by btrayfors

Yep, size really does matter! Lots of studies have shown that shorter vertical antennas are not as efficient at transmitting...expecially in the lower frequency bands..as are longer ones.

If there's no good reason not to, I'd go with the standard 23' whip antenna.

BTW, attention to grounding IS important. One of the trawler's on the Waterway Net -- in fact the trawler belonging to this year's Club Commodore -- is in the Bahamas. He did some work on his ground yesterday, and his signal improved A LOT over what it has been for the past several months (as heard this morning by me in the DC area, and by stations in Marathon, FL, Charleston SC, and Tampa, FL).

Bill

Thanks Bill and all. We plan to install the Kiss system since we have received so many good reports on it. There is no real reason to limit the antennae length except the it will probably be installed in the side of the flybridge and 23 feet is pretty high in the air. The plan is to use the Morad antenna, which is aluminum and probably stronger than the Shakespeare for instance. As I said earlier, I have install dozens of the Icoms over the years so at this point the devil is in the details. Chuck

[ka4wja]

Chuck,
I'd like to elaborate a bit on Bill's excellent (and accurate) comment that "size does matter".....
And, using the info you provided, we can easily see what would be the better recommended antenna length (the longer the better)....

Originally Posted by Waterwayguy

Our cruising will be US Coastal and Inland waters and the Bahamas. We will be communicating with local nets and friends throughout the US. Weather fax and Pactor connections are also a consideration. We don't need to connect to Europe or the south Pacific. Looking for some real world advise.

1) For your application here, you're likely to be using 4, 6, and 8mhz maritime frerqs for voice comms / nets, etc. possibly some 12mhz and 3.8, 7, and 14mhz ham radio comms as well......and 4, 6, 8, 9, and possibly 12mhz for WeFax from the USCG via NMG and/or NMF.....and near 2.6, 5 to 6, 7 to 8, 10, and 13/14 mhz for sailmail and winlink....

So, making your HF antenna system to operate optimally on these lower frequencies is what I'd recommend......


2) Use of a vertical antenna, whip or backstay, which is too short (in terms of the wavelength of the frequencies used), reduces antenna system efficiencies significantly.....
(hence Bill's advice that size matters)
But, using a vertical antenna that is too long (vs. wavelegth), effects the low radiation angle, which allows strong signals at great distances of 4000 to 10,000 miles.....

So, when needing to communicate over a wide range of the HF spectrum and over a wide range of distances, using an end-fed vertical antenna requires either some compromises or some thought into where/when/what freqs you'll be using the most.....

BUT, the good news in your case / your application, you're not likely to ever have an antenna too long.....unless you erect a 60'+ tuna tower

And, in actuality I'd recommend the biggest, talllest vertical you can install......and I assume that will be the 23' whip, but if you could fit/afford the BIG 35 footers, go for it!!!

Also, remember that the antenna begins at the AT-140 (or SG-230) tuner, which I assume will be placed immediately under (or next to) the base of the whip......


{ FYI, for MF/HF comms up to a few hundred miles (typically 25miles to 400 - 500 miles, using 2mhz to about 6 or 7mhz, and most times to 8mhz), especially during daylight hours, a full-sized horizontally polarized antenna (such as a dipole or full-wave loop) can't be beat for the Near Vertical Incidence Skywave (NVIS) propagation, BUT is wholely inpractical on-board any vessel smaller than "mega-yacht" size.....

So, using a vertical polarized antenna means we can have a decent "ground wave" / "direct wave" signal, which is useable from about 10-15 miles (on the higher HF freqs, above 15mhz) out to 30 - 50 miles (on 2-6mhz)......but this does nothing for what the "meat" of your typical usage will be, which is from 100 to 500 miles, on 2/3/4 mhz thru 7/8mhz...and from 400 - 2000 miles 0n 7/8 thru 12/14 mhz....so, making the antenna system work optimally on these frequencies is the best approach, hence the advice given here is: bigger is better... 17' whips will work okay, 23' is better, and 35' is better still.........

Keeping the entire length below ~ 40' - 45" is typically accepted for most cruisers, as this still allows for very good low angle of radiation on 14mhz, without significantly reducing antenna system efficiencies on the lower freqs below 7mhz......but those desiring to optimize for the lower freqs (especially 1.8 and 3.6mhz) may use longer length antennas (such as my ~ 63' backstay antenna) to great advantage, without significantly effecting their higher freq operations.... }

Originally Posted by Waterwayguy

There is no real reason to limit the antennae length except the it will probably be installed in the side of the flybridge and 23 feet is pretty high in the air.

3) As long as it is properly mounted and supported, install the biggest vertical you can fit / afford....
(the BIG 35 footer is a nice antenna....but is VERY expensive...)

Originally Posted by Waterwayguy

The plan is to use the Morad antenna, which is aluminum and probably stronger than the Shakespeare for instance. As I said earlier, I have install dozens of the Icoms over the years so at this point the devil is in the details. Chuck

4) I'm not too familar with Morad's HF antenna offerings.....but please be sure to use some Penatrox-A on all the alum-to-alum joints/connections, as well as on all alum-stainless, alum-copper, alum-bronze, etc....this will allow many years of trouble free operation.....(I've been using it for 30+ years on shore and on-board, and is especially nice for copper-copper connections and copper-stainless connections that may be subjected to lots of sea water, such as RF grounding straps, keel bolts, etc. in bilges, etc... )
If you fail to use proper joint/connection compounds (such as Penatrox-A), you're asking for trouble using an alum HF antenna on board....

(I couln't get Morad's site to work, but I suspect they have some recommedation for using compounds such as Penatrox???)



I do hope this helps....

John

[AnchorageGuy]

John, Fantastic information. I think the 35 foot would not be practical but the 23 will work fine. I am totally unfamiliar with the Penetrox, but will certainly follow your recommendations. I can't get the Morad site up either but found it here, Alphatron USA - Morad Antennas VHF UHF Single Band Cellular CB . Based on yours and Bill's recommendation we will install the 23'. Your suggestions on frequencies are just about right on. It does help and thanks. Chuck

[ka4wja]

Chuck,
You're welcome....

1) Looking at the site you referenced I see that Morad is using anodized alum (and white powder coating) and nickel-plated brass connectors (??), which go a long way to reducing oxidation issues with connections....but I'd still recommend Penetrox-A for all alum-to-alum connections and all alum-stainless / alum-copper / alum-brass connections.....(and even all bare copper-copper connections)

Penetrox-A is a conductive grease (and anti-sieze) , designed to improve electrical contact/connection and eliminate oxidation, etc...specifically important with alum-alum connections and alum-other metal connections....
(sort of like Tef-Gel, but instead of isolating the metals, it allows low-resistance electical connections without oxidation, nor galvanic corrosion...)



2) As I wrote earlier, I've been using Penetrox on antennas, etc. for about 30 years.....and purchase it thru AES (or DX Engineering), but you can also usually find it at electrical supply houses......
(one small bottle will last you a lifetime on-board....)

Penetrox A Aluminum Copper Anti Seize Seez

AES Price list

http://www.aesham.com/photos2/PENPENETROXA.jpg



I hope this helps...
Good luck and fair winds...

John

[AnchorageGuy]

Thanks John, Appreciated. I have just order some and will order the antenna later in the week. Chuck

[sea_goin_dude]

FYI you might want to take a look at the OUTBACKER antennas. Check at AES and HRO, ham radio outlet. might solve your problem. Good efficient antenna although I think it is overpriced but may be what you need.

Jerry / W1NRA....ham call

[jurgen99]

If you calculate the radiation efficiency of a 16ft versus a 23 ft whip, the 23 foot whip almost has double the radiation efficiency of the 16 ft whip. The calculations I quickly did were for 5 ohms of ground loss on 2.182mhz. The 16ft antenna has a 4% radiation efficiency, the 23ft antenna 10% radiation efficiency. In simple terms if you apply 100 watts to the 16 ft antenna you will radiate 4 watts. If you apply 100 watts to the 23ft antenna you will radiate 10 watts. You also have to factor into the equation the antenna tuner losses. This might reduce the efficiency by another % or 2 or even 3. As you go higher in frequency as others have indicated, the efficiency will become better. Above 6mhz a 23 foot whip will work as well as a backstay if you have a decent ground system. A 23 ft antenna even when used with an antenna tuner will have reasonable efficiency at 4 mhz and above. You will radiate about 25 watts on 4mhz which on 4mhz is a reasonable amount of power considering the short distances and high signal strength you typically encounter. A 23ft whip would be my choice. I would not suggest using any antenna small than this. 73 Jurgen

Originally Posted by Waterwayguy

We are installing an Icom 802 on board our trawler Beach House. I have installed dozens of these radios so installation is not an issue. But with the trawler, we plan to install a whip antenna. My question is for those of you with actual practical experience. Is there a significant difference between a 16 foot or a 23 foot antenna for SSB/Ham use? Our cruising will be US Coastal and Inland waters and the Bahamas. We will be communicating with local nets and friends throughout the US. Weather fax and Pactor connections are also a consideration. We don't need to connect to Europe or the south Pacific. Looking for some real world advise. Thanks, Chuck

[jurgen99]

The Outbacker would be like using a dummy load as antenna compared to the above 23 foot whip. The efficiency on the lower marine frequencies will be less than 1% 73...Jurgen

Originally Posted by sea_goin_dude

FYI you might want to take a look at the OUTBACKER antennas. Check at AES and HRO, ham radio outlet. might solve your problem. Good efficient antenna although I think it is overpriced but may be what you need.

Jerry / W1NRA....ham call

[Steve Pope]

I have been following the whip antenna thread with interest as I have a SEA 111 SSB that I am planning to install and had thought that having a separate whip antenna would be sensible given that if had a mast failure I would still have the whip. I recently read about rope antennas and also thought one of them could possibly give some redundancy as well.
Cheers,
Steve.

[Steve Pope]

Sorry, that should be an SEA 222 SSB.
Cheers,
steve.

[sea_goin_dude]

Originally Posted by jurgen99

The Outbacker would be like using a dummy load as antenna compared to the above 23 foot whip. The efficiency on the lower marine frequencies will be less than 1% 73...Jurgen

That dummy load Outbacker did talk from Death Valley to Alabama/Georgia. Never hurts to have another whip type antenna just in case you lose everything else to a dismasting or storm damage.