Amateur Radio HF Antennas

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I have a Gib Sea 106 and i wish to mount an HF antenna somewhere onboard,Problem is i do not wish to adjust the rigging set up IE Backstay antenna,I am considering trying to mount a mobile based milti-band antenna onto the pushpit via an Auto ATU. any suggetions?
 
Shouldn't be any problem as long as you have a good foil earth from the ATU.

Also whips tend not to have as wide a bandwidth as longer aerials as they have a higher Q factor

Iain (GM3YND)
 
I've tried the ATAS tuning antenna (Yaesu) and can't recommend it, not even for 2m where a quarterwave outperforms it.
There is an interesting idea of having a wire threaded inside a rope, which you hoist like a halyard. There is a commercial one available somewhere.
Another one available is a clip-on twin wire setup that clips onto the backstay. No personal experience of this one.
A very large whip with ATU is similar to a car system I once used, and it worked well. Longer the better!
 
I've had good results while anchored using a "bit of wire" hauled up on a halyard. Earth is a 12mm length of copper water pipe dropped over the stern. ATU is an Icom auto ATU bolted to the pushpit.

This of course can't be used while sailing. I was intending to heat up the backstay but then saw the price of backstay insulators.

Would be interested to hear how you get on.
 
The whip on the transom pushpit is probably your best bet. The problem with any wire hoisted up the mast is the proximity of all that conducting rigging and Al mast that ends to soak up the power and shield the signal. Bear in mind also that you may need that radio one day if you lose your mast. olewill
 
Have tried and am still struggling with both options - mobile whip and hoisted wire.

I'm using them for my 80m natter net. I find that the mobile whip gets out OK (swr around 1.5) but the ambient noise level anywhere other than at sea is high enough to give reception problems. in swansea marina, reception was impossible.

the long wire with a tuning coil miid length gives much cleaner reception but is verydifficult to tune because of the proximity of the backstay. this is using an mfj autotuner, which is a more competent bit of kit than those offered by the radio makers. add in the inconvenience of having to hoist when you need and I am thinking of backstay insulators again, though I am still trying to work my way round the long wire problem.

has anyone tried just using a deck stepped mast?
 
I have a whip. When my yacht did the ARC in 2000 her HF radio (Icom M710, ATU + whip) was the best in the 'fleet' according to the previous owner. I find that I get better performance than most yachts but I have not carried out any meaningful trials due to the difficulties of doing so in a marina full of masts.

The Q of a whip will be higher but that is an advantage if the ATU can cope, which the Icom will.

Why not an insulated backstay, by the way?
 
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has anyone tried just using a deck stepped mast?

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Out of interest, I once tried to use the whole rig on a plastic boat with a deck stepped mast. The ATU was an SGC unit. We were underway so the rig was 'moving' a lot. Results were interesting, On 20m, it tuned up beautifully, for a few seconds, then lost it completely, then tuned OK again, then lost it. I assume what was happening was that the frequency of the rig was changing all the time as the rigging shifted and the electrical characteristics of all the shroud/mast conections changed. I did not persist.
 
My apologies for my ignorance of the terminology and the subject. I was just reminded that in the past I have made up "Slim Jim" aerials as VHF emergency jobs, obviously tuned to Ch16! They are simply made from the twin core ribbon used for cheap indoor dipoles and can be slid into a piece of small oval conduit and sealed up both ends with silicone or acrylic mastic. Very effective and no more difficult to stow than a fishing rod.
 
The whip doesn't NEED to be that long. Thought of a fishing rod strung with wire? I could tune a 6ft ss rod on the pulpit as a backup to the backstay (in case of rig failure). Manual ATUs take a bit of time but can be coerced into tuning most things... I was getting consistently good reports from West Med on the 14.303 net. The dynaplate with a big flat copper strap was probably a contributor!
 
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The whip doesn't NEED to be that long.

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No of course not. I was replying to the comment about using J-matched tuned antennas which are not practical for HF on land let alone a boat.

As you say, a whip with an ATU can be almost any length.
 
I gave away screwdriver ant. as i had no need for it, i tried it out on my mates boat, and wished id kept it it performed well espes. on 80 so ill buy another.Good thing about the screw.ant. it is also its own atu...
 
Many thanks for the advice all of you.
Lemain, I dont want to use any of the rigging so i can still use the radio when the mast is down IE French canals ect.
I have been to the local emporium and they have a very nice 2.5M whip that will cover all the HF bands i want so now i need to work out the best way to fit it where it will not get in the way ect. Should i fit an extra Earth lead from the antenna or just an aditional one from the pushpit mounting bolts?
 
Sounds sensible. The wiring details should be included in the ATU handbook. The RF output from the ATU is probably just one large bolt, on a ceramic insulator, onto which you wire a single thick copper cable (i.e. not coax, just insulated copper wire). This is connected onto the base of the whip. You don't need to pick up local earthing.

Don't let anyone touch the wires when you are transmitting - you can get a nasty RF burn that can take many months to heal.
 
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