Best Money No Object VHF antenna?

[matthewriches]

I've been having some issues with the vhf. it's an icon m-505 so a decent bit of kit. approx 1m banten antenna with <3m coax. swr is good.

yet i struggle to get 5 miles. receiving is rubbish also. i don't hear barely any coastguard.

2 companies i've spoken to said if swr is good then it will be the antenna.


Any ideas please?

 

[[2068]]

I'd start by checking the cabling and connectors before changing the antenna.
A 1m aerial should give good reception across 5 miles or so.

 

[TrailerSailer]

I replaced my antenna with a Metz from Salty John. At the same time I also replaced the coax. I can now pick up the Channel Islands coastguard in Weymouth if that is an appropriate test of good reception.

 

[Alpha22]

+1 for Metz. As high as you can get it. Away from another metal and antennas. For the cost of a decent bit of cable and new plugs...... do it anyway.

 

[grumpy_o_g]

Agree with all above. Metz have a good rep but a decent antenna is useless unless the location and cabling (especially any connections) are also top notch. I would normally expect an SWR check to show up antenna problems as well, though not always - are you saying you've had SWR meter on it - if so what were the results? Another question - has it always had this range since you've had the boat or has something changed?

If you have had a SWR check then you can be fairly comfortable you won't blow anything up by transmitting into no load. If you know someone with a suitable handheld or easily dismounted fixed VHF then swap out your ICOM and see if they are noticeably better. I'd be surprised if they were but it eliminates the set itself as the problem unless it's something really weird.

My first step would be as per FlowerPower and check all the cabling and connectors - cabling first. Make sure the cables are not degraded kinked or cut in anyway, and that there aren't any tight bends. For the connectors disconnect them one by one first, checking that are on securely and tightly as you do so, then check very carefully for any signs of water getting in or other degradation, not forgetting to check the actual connection surfaces. If that all looks good then dismantle the connectors and remake them.

After that recheck the set and then look at the antenna location.

 

[oldgit]

Speak to Icom about the radio.Some early ones had a problem with a ceramic filter.
It makes the set deaf.
All marine aerials are 10 pence bit of copper wire in a glassfibre tube,the cost comes in the quality of the tube and the fitting that holds it to the boat.
Bit of wire sellotaped to a broomstick would give similar results.. It may not last as long.
Ps.We had chap come into our workshop brandishing a PL259 connector enclosed in very fancy packet......Can I have another one just like this he said ?
Yes we said,that will be £1.50.
He left the empty packet that had contained his PL259 on our bench.
Glanced at it later, chap had paid £ 8.95 for it at a local chandler.
PPs Vtronix.

 

[Tintin]

"<3m" of cable suggests to me that the aerial is not mounted high.

Height dramatically affects range.

How high off the waterline is the tip of the aerial?

 

[Alpha22]

All marine aerials are 10 pence bit of copper wire in a glassfibre tube,the cost comes in the quality of the tube and the fitting that holds it to the boat.
Bit of wire sellotaped to a broomstick would give similar results..

That's a bit of an over generalisation...... Whilst many are simply a vertical conductor, many are not and have a base loading coil (Such as the Metz) and accuracy, quality of materials ect come in to play more.

 

[oldgit]

That's a bit of an over generalisation...... Whilst many are simply a vertical conductor, many are not and have a base loading coil (Such as the Metz) and accuracy, quality of materials ect come in to play more.

The coil is merely there to shorten the physical length of the aerial its electrical length is exactly the same ie 1/4 wave 5/8 wave etc .Provided the feeder is matched to radiator it will work well.
Forget all the advertising tosh.
Marconi designed a excellent aerial a few years ago a better design has yet to be invented.

 

[DavidMcMullan]

+1 recommendation for Metz.

 

[matthewriches]

"<3m" of cable suggests to me that the aerial is not mounted high.

Height dramatically affects range.

How high off the waterline is the tip of the aerial?

The radio is already high up. Tip is prob about 5-6m on a motorboat that is.