Antenna Question - 4' or 8'

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PowellBride

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We are looking at a new Antenna, the Shakespeare Quick Connect. Wondering if anyone has use the 4' antenna at Powell or do we Really need the 8'

Any thoughts?
 

Gem Morris

Well-Known Member
I don’t know a lot about antenna so maybe what i’ll say is not really helpful?

First of all make absolutely sure it is compatible with your existing radio - call the manufacturer if necessary. Then based on your own experience with your existing antenna in years past are you able to communicate like you want?

I only have a handheld on my run about but on the houseboat I can often hear the National Park Service broadcasting but can’t hear the other side of the conversation with the boaters out on the lake.

If 8 foot will help you receive both sides of conversations that would be nice, but maybe it only helps your broadcasting not receiving?
 

PowellBride

Well-Known Member
Good Thoughts - We are getting a new radio & antenna ...... to go with the new boat :). We had a 14 year old radio & 10 year old 8' antenna on the old boat. Not convinced that the 8' antenna gains all that much at Powell as the rock walls seem to block the range of most antennas. The new quick connect allows us to store the antenna when not in use, which is really nice - supposed has the same range and the static antenna's. Obviously stowing a 4' would be easier ....
 

potter water

Well-Known Member
Antenna height is everything in marine communications. Even the two feet that the 8 foot antenna gains you over a 4 foot can make a lot of difference in range. The 4 foot antenna radiates at two feet above the base. The 8 foot radiates at 4 feet above the base. The radiation pattern from the antenna is shaped like a doughnut with the doughnut center sitting at the mid point of the antenna. The 8 foot also gives you a significant gain in effective radiated power over the 4 foot as it flattens the doughnut like squishing it flat between your hands, pushing more "doughnut out the sides in the form of more radiated power. So, go for the 8 foot for the price difference. Yes, it takes up some space when down, but is well worth it in marginal communication conditions which are the rule, not the exception on Powell. Also, remember that the marine frequencies are line of sight, they don't bend over the curve of the earth or go around corners. But, they can and do bounce of canyon walls in strange ways that allow some unusual communications. Also, NPS has a repeater on Navajo Mountain that if you can see NM, you can talk to NPS. Go tall, or go home. That is the motto of us amateur radio operators.
 

Endurance

Well-Known Member
VHF-Antennas-2.jpg

It's best to match the antenna to its intended use. Different antennae have different coverage patterns. You will see that expressed in dB gain. I am attaching a picture to help illustrate this. Shorter antennae have lower dB gain. You can think of them as a "shotgun" pattern. Longer antennae have higher dB gain. You can think of them as a "rifle" pattern. What works best depends on what you're putting them on.

If you have a handheld radio that is as likely to be horizontal as it is vertical, you want a good wide pattern. You get that with a short (low dB gain) antenna.

If you have a smaller boat that leans from side to side as you turn it, or if the bow goes up and down depending on if you're on plane or not, you would do better with a mid range (moderate dB) antenna. A four footer would be a good bet here.

If you're on a houseboat that is pretty stable from side to side and wouldn't plane to save your life, you would do well with an antenna that has a "rifle" pattern. An 8-foot or longer (higher dB gain) antenna is a good bet here.

So, like so many questions, the answer is, "It depends."
 

bubba

Well-Known Member
Radios are best viewed as a completc system instead of just one component, they work best when each component is balanced to the next.


Not long ago the 2-way was your only link for on lake communications to friends and NPS. Today with cellular coverages increasing the radios are no longer your only option but are a crucial life saving tool especially when needing a lot of help quick, looking for a lost dog, boat accident, or even a call in the blind for an epipen or a cup of sugar, not to mention listening durind a wind period.


There are other threads on this but as a review your radio system includes antenna height, antenna, cables and radio. For best range try to mount your antenna as high as possible, or use the longest antenna possible on a low boat. Read up on the reviews for help picking an antenna, for me I would look at the Shakespeare’s Galaxy xp 5225. Use the shortest cable possible between the radio and the antenna and make sure this cable is shielded and that the connector has been properly attached. For a radio there is no reason to be beyond a Standard Horizon GX 1700. Make sure your power wires are not undersized.


The 8 foot galaxy will not be happy in choppy water on a small boat. The quick connectors you mention are a visual enhancement first, which is great if looks are important to you, but it is still a splice. Consider reaching out to a marine radio store in Seattle or Florida, the will know which antenna will have the longest throw, understanding Powell will be shorter.
 

Squirrel

Well-Known Member
Bubba said; Use the shortest cable possible between the radio and the antenna and make sure this cable is shielded and that the connector has been properly attached.
I thought that the cable had to be in increments of a certain length for resistance or some other reason. I am replacing my antenna to a 4' unit and will shorten the cable from supplied length to about 5' What are the proxcimity requirements for the antenns location to the operator? Sq
 
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potter water

Well-Known Member
If you aren't experienced at installing connectors properly, you will create more risk of radio problems getting rid of the 1 foot than leaving well enough alone.

Don't overthink the antenna cable issue. Just make it as long as it needs to be and be happy, don't worry. The key thing is that it is line of sight and under such circumstances whether your radio is feeding 15 watts or 25 watts to the antenna, you won't notice change in range. A good radio is, of course, important, and the tallest and highest practical antenna and mount will swamp out any value of fussing with a 4 foot cable or a 6 foot cable. If you are cruising off shore on your way to the Bahamas, then a lot of issues come into play, but you are still limited to not getting over the visible horizon with marine band radios. That is why off-shore cruisers use single side band commercial or ham band radios. They communicate on lower frequencies around the world on the same 25 watts as the marine band radio that is frequency limited to visible horizon. The best radio and shortest cable are worth little compared to a high and tall antenna in the Marine Bands.
 

Pegasus

Well-Known Member
Great advice from all, and I'll throw in a real life unscientific example of the height differences vs. performance from a test of my own that I conducted in 2015 around Padre Bay (including in canyons).

My dinghy has a 4' antenna; the top of the antenna is about 5 ft above the water line.
My ski boat has an 8' Galaxy antenna; the top of the antenna is about 12' above the water line.
My cruiser has a 23' Galaxy antenna (8' antenna on top of a long extension, but sold as a 23' antenna); the top of the antenna is about 28' above the water line.

All have new quality ICOM VHF radios and proper cables and are fixed mount units.

The dinghy radio is good for communicating both directions for about a 3-5 mile radius; the ski boat about a 10-12 mile radius. And the cruiser about a 20-23 mile radius. I should note that I can "hear" radio traffic on all of the VHF's from quite a long distance, but my experience is transmitting is severely impacted by antenna height (more than receiving is impacted) as others have noted.

p.s. - I have a new ICOM 6 watt handheld - it seems to be good for communicating up to 3-5 miles also and definitely works best line of sight (i.e. not in the canyons). I do not consider the handheld adequate for emergency communications on Lake Powell - only helping anchor/dock/etc.

p.s.s. - I was able to hold a two-way conversation from my cruiser slip at APM to a friend on a houseboat anchored in Gunsight Canyon late last October. That's about 12 miles direct as the crow flies I think and is far from line of sight with APM being down in the canyon, etc. I was actually surprised that the VHF worked in this specific circumstance.
 
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Lance Cue

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I am trying to find a replacement for an old broken 6'5 shakespear antenna on my 240. I cant fit an 8' and finding a good quality 6' seems difficult. Came across this digital 4' that claims 4.5db. Seems maybe middle of the road between an 8' 6db and other 4' 3db might be good for my situation. Maybe i would put it on a 2' extention. Any thoughts? Anyone have one of these antennas?https://www.hodgesmarine.com/DIGITAL-VHF-4FT-528-VW-WHITE-4-5DB-p/dig528-vw.htm?CartID=2
 

Pegasus

Well-Known Member
I am trying to find a replacement for an old broken 6'5 shakespear antenna on my 240. I cant fit an 8' and finding a good quality 6' seems difficult. Came across this digital 4' that claims 4.5db. Seems maybe middle of the road between an 8' 6db and other 4' 3db might be good for my situation. Maybe i would put it on a 2' extention. Any thoughts? Anyone have one of these antennas?https://www.hodgesmarine.com/DIGITAL-VHF-4FT-528-VW-WHITE-4-5DB-p/dig528-vw.htm?CartID=2
I have two antennas of this brand - have had them for over 10 years and they are of very good quality. Mine are both 8' antenna's with extensions. Digital brand is more expensive than Shakespeare generally. The reviews of the 528 that you are looking at are very good.

As I'm sure you are aware, height above the water is one of the major determinators of how far the signal goes, and 2 ft or 4 ft higher does make a huge difference as in miles further transmission as I wrote about above in this thread (other determinators being dB rating and connection/cable/radio).
 
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