Best way to connect SSB ground plane sections

"But 198kHz Westerglen is on poor ground, and is well audible to the north beyond Iceland."

I am not familiar with the transmitter, but many professionally installed vertical antenna installations have miles (and I mean literally miles) of copper wire buried in a radial pattern from the foot of the mast.
 
john_morris_uk said:
Maybe your guard rails happened to be a low impedence at 14 MHz by co-incidence?
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They were continuous ie a 10m by 4.5m rectangle.

On a slightly different subject, any way of stopping the connection from the atu to the earth point (ie the keel) radiating? On my last installation I used old fashioned copper cored spark plug wire to connect from atu to aerial and top earth, and I could get my voice coming out of the Yanmar engine overheating alarm thingy on transmit. There was so much RF around at times ( hence the efforts to try all sorts of alternative earths) that you wondered what you were doing to yourself.
 
jason -and the arguenauts said:
They were continuous ie a 10m by 4.5m rectangle.

On a slightly different subject, any way of stopping the connection from the atu to the earth point (ie the keel) radiating? On my last installation I used old fashioned copper cored spark plug wire to connect from atu to aerial and top earth, and I could get my voice coming out of the Yanmar engine overheating alarm thingy on transmit. There was so much RF around at times ( hence the efforts to try all sorts of alternative earths) that you wondered what you were doing to yourself.
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It could be many things. It might not even be the ground lead radiating, after all the engine electronics could be picking up the RF from the radiating element itself. Can you give more precise details of the installation? Where is the ATU? How long is the backstay and how is the ATU connected to the backstay and how long is the ground connection to the ATU from the keel/sintered plates?
 
RF interference

Years back I was involved in radio maintenance on local Fokker F28 jets. HF radio was vital in the outback. The HF transmitter was about 200w PEP but used at that time in AM double sideband mode. The Transmitter would come out very clearly over the passenger address system. A complicated aluminium cover was made to go over the antenna lead in to shield the lead in but not add too much capacitance. This seemed to stop the radiation inside the plane.
Now you don't have an aluminium boat (I am guessing) so radiation from the antenna lead in is not such a problem as it gets out through the fibreglass but as you have found it can get into electronics.
My best suggestion is to use shielded wire for the engine instruments /alarms or fit a shield over the cable bunch. The shield braid from RG8U coax will go over a bunch of 6mm diameter but more than that will require a wrap around. Foil could be used or run it in copper pipe. The shield must be earthed well to negative power at least at one end.
Yes radiation can be from the antenna lead in or the ground cable. An alternative path for the gound line might help. The engine cables should be separated as far as possible from the ground and antenna cables.
good luck olewill
 
Interesting thought. It must have confused the helmsman having a commentary from the engine alarm.

You have to get down to the basics of how an aerial works.

The idea is to create an electrical and magnetic field, with a specific relationship between the two.

To do this requires an interaction between two elements. In a dipole it is the two legs of the dipole. It is this relationship that determines the radiation pattern of the aerial.

With a vertical aerial the fields are generated between the vertical element and the ground plane ie the Earth.

Where a length of wire connects the source (ATU) to the Earth then that will become effectively part of the aerial and the fields generated will be affected by it.

So you will not be able to eradicate the field that causes the effect - all you can do is modify the system so that the fields do not start to induce energy into the engine alarm or shield the alarm (and the bits of wire connected to it) from the field.

Worth remembering that an earth wire with RF currents flowing through it isn't always at earth (0) volts. I used to have my radio gear in a 1st floor bedroom with a substantial earth lead going out of the window. It was fine on every band except 15M. If I went on xmit on 15 everything around the equipment became live with RF.

The earth lead was a quarter wavelength on 21 mhz

Funny stuff RF
 
john_morris_uk said:
It could be many things. It might not even be the ground lead radiating, after all the engine electronics could be picking up the RF from the radiating element itself. Can you give more precise details of the installation? Where is the ATU? How long is the backstay and how is the ATU connected to the backstay and how long is the ground connection to the ATU from the keel/sintered plates?
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Sorry - misunderstanding. On my new boat I have not yet installed the SSB so I was wondering if there was any way to shield the earth lead from the ATU since that obviously radiates and since using shielded wire withan earthed shield wont work.

Just trying to get a practical idea of how best to tackle the installation this time round.
 
That would help Beadl;e but on the last installation it came through the VHF speaker (set turned off) and cause a pals instrument lights to flicker 2 pontoons away in Swansea marina:eek:. There was simply too much RF around in the boat.
 
Hmmm

Sounds fun

How much power are you using?

The obvious assumption must be that if all the RF is floating around the boat there can't be much left to go up the aerial.

Do you have a SWR meter in the set up?

What sort of ATU are you using?

How is the "earth" set up?

Have you any form of suppresion in the power leads?

How is the power connected to the transmitter?

Sounds like ther may be some form of earth loop

Have you any de-coupling capacitors in the power circuit?

Have you tried any ferrite beads on the power feed to the TX?

As well as illuminating neighbouring boats could you actually work anyone?
 
No matter what you do , it will be very dificult on a small yacht, to eliminate rf at hf. because of the rigging mast and safety rails so close together , even with a ballanced system with twin feeder, youll still light your leds up as you modulate. thats why i only use verticals now off the sterntuned to the part of the band that i normaly use. on 80 , 40, 20 etc i get good results , i dont want wires up backstays or insulated backstays either ,as really dont find it at all nessasary,and earthing on a small boat like mine 37 ft. didnt really make much differance as so close to water anyway... if conditions arnt good i dont bother on that band ...best of luck anyway...............by the way swr is no more than 1.5-1 on any band i use , and that is through a bird swr power meter...100 watts and no atu regards....
 
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