High Gain VHF Whips

[Out-Station]

G'day all, I'm looking for a high gain, say 6db or close to VF whip in a 1.8m or close to length. I have found the shakespear and scalar optiions but the shortest i can find in a quality high gain unit is 2.4M which i was thinking might be a bit long for mounting on a hard top.

Is there any such thing as a 1.8m or so high gain vhf whip?

Scott

[scottar]

From memory all the higher gain/ high performance options came in 2.4 metre format or bigger. Not that the extra 0.6 of a metre will make a huge difference but a standard antenna at a great height (top of a yacht mast) pretty much outperformed a trailer boat with a high gain anyway - point being that it's line of sight. If you are going for high gain for maximum performance - go the 2.4. Also be wary of going too high in the gain. Even on bigger boats I have had reported issues with 9dB gain antennas - the compressed radiation pattern giving broken transmission in rough conditions.

Just to add - if you really want an antenna in a 1.8 metre package, check to see if scalar or someone like commex communications can do a custom build.

[Out-Station]

Thanks Scottar, sounds like i am searching for something that doesn't exist without spending silly money, i'll just go with a regular type one. I've alway's preffered the type that doesn't have a co ax connection in its base where the screw the whip on, for me it would seem that a heard wired version is better because of less loss through joins, the old style ones are getting harder to find though in favour of a screw on whip type setup.
Scott

[Spaniard_King]

Have a look at the Shakespear Galaxy 5225XT probly the best antenna on the market and well worth the $$

I stock them. PM me if you want a price

[chocolatemoose]

2nd vote for the ZCG range

[Out-Station]

Thanks for tha advice men, so what wold be the performance difference between the below, the scalar 2.1, tallks about being 2DB whilst the gm is 3db half wave, whats all this mean? I figure thati only get to build a boat every 20 years so i may as well get it right!!

https://www.gme.net.au/catalogue/ant...ps/aw366v.aspx

https://zcg.com.au/d/ZM21-VHF/

[scottar]

The gain is a comparison to a Isotropic Radiator (theoretical radiation pattern that has equal signal in all directions) that is created by the way the antenna compresses the radiation pattern. Things like half wave, quarter wave etc refer to the antennas length/construction which basically sets how they create their respective gains.

https://www.air-stream.org/technical...ted-power-eirp

If you think of the radiation pattern as a donut of a certain volume - the more you squash the donut, the further it will move out from the centre. This is essentially the effect of increasing an antennas gain - more out with less up and down.

[Out-Station]

Scottar, thanks, which ones more good??

[scottar]

The ZCG would be better quality. The GME is the most available antenna in the country so if you managed to break one when away on a trip would be the easiest to source a replacement whip.

[Dignity]

The ZCG would be better quality. The GME is the most available antenna in the country so if you managed to break one when away on a trip would be the easiest to source a replacement whip.

So would both brands fit the same base. I've noticed that my range has deteriorated and I believe it maybe the aerial at fault so may need replacement. Also is there an easy way to test the aerial.

[Any_Weather]

Gday guys, just on Sams reduced range issue. Last year at 1770 I could easily contact the boat that was part of our trip at close range. In this I mean up to 10km however reaching round hill or hearing the rocky met weather forecasts were not happening. I thought straight away it must have been the aerial as it was an icom unit and base and aerial that was less than 3 years old. I don’t really use the vhf unless I am up there with other boats. I replaced the aerial when I came home and never really used it again until same deal this year.
Still we didn’t hear anything on 81 or 82 when we were solo and then when the second boat turned up we used channel 10. Once again in close range it was fine but 10km apart we got nothing. They could hear the Gladstone pilots in helicopters and all that we use to be able to hear. Clearly the issue is not fixed. I came home with the intent of going back to a gme radio, new lead and base and new aerial to hopefully fix the problem.
I bought a base/lead and aerial to start and as soon as I touched the lead at the aerial to sort out how to pull a new one through, it fell apart in my hand. The connection was all corroded off at the base.
I installed a new base/lead and used the old aerial and now can contact noosa coast guard from inside the upmost one passage so I suspect the range is going to be better offshore.

Cheers
Lee


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[Dignity]

Lee, I suspect that could be my problem as I used to easily get Mooloolaba Coast Guard 20km away now it is done to less than 10km. Looking at my aerial it is a Navman but until I can do some work on it I won't be sure if it is the same problem. At some stage there was a crack near the base of the aerial due to it hitting a tree on way to the ramp which I repaired using heavy dual wall heatshrink and everything worked well for several years and I don't recall whether mine was a whip that screws onto the base or older style where it was connected direct through which I think it was. When I recover enough I thought I would cut away the heatshrink and check, but once again there must be a way to check the aerial, I dimly remember an ohm meter will just show a short circuit.

(Does it also mean you now have a spare aerial I can buy off you, just need to buy a new base.)

[Any_Weather]

I returned the aerial and upgrade it to a reel which were on sale at that boating fishing place


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[Dignity]

I returned the aerial and upgrade it to a reel which were on sale at that boating fishing place


Sent from my iPhone using Ausfish forums

No worries Lee. I've moved my thread to Electronics http://www.ausfish.com.au/vforum/sho...84#post1646384 as I've managed to hijack out-stations thread (my apologies)

[scottar]

Lee, I suspect that could be my problem as I used to easily get Mooloolaba Coast Guard 20km away now it is done to less than 10km. Looking at my aerial it is a Navman but until I can do some work on it I won't be sure if it is the same problem. At some stage there was a crack near the base of the aerial due to it hitting a tree on way to the ramp which I repaired using heavy dual wall heatshrink and everything worked well for several years and I don't recall whether mine was a whip that screws onto the base or older style where it was connected direct through which I think it was. When I recover enough I thought I would cut away the heatshrink and check, but once again there must be a way to check the aerial, I dimly remember an ohm meter will just show a short circuit.

(Does it also mean you now have a spare aerial I can buy off you, just need to buy a new base.)

Navman antennas were a Pacific unit rebranded. I think from memory (10 plus years on that stuff so not an ironclad guarantee) there is a connector built into the base. Not all bases are the same either.