Emergency antenna connection

aitchem

aitchem

Well-Known Member
Joined
11 Nov 2003
Messages
340
Location
Aberdeen, UK
Visit site
Hello
I am fitting a navicom rt650.
The mast antenna will be a new metz.
This will leave me with the old antenna going spare. Ideal as a
Emergency antenna.
My question is can the two antenna be permanently connected
Or should they both run to the radio and be swapped as required??

Thx
Howard
 
aitchem said:
Hello
I am fitting a navicom rt650.
The mast antenna will be a new metz.
This will leave me with the old antenna going spare. Ideal as a
Emergency antenna.
My question is can the two antenna be permanently connected
Or should they both run to the radio and be swapped as required??

Thx
Howard
Click to expand...

I have no idea if you can connect two antennae at once but I would think if you did and one failed it could well prevent the other from working.
 
I wouldn't connect them permanently. You could use an A/B switch, but it would be one more insertion loss for little benefit.
If you have a problem with one antenna you disconnect it at the radio and connect the other antenna, this means there are no common parts of the two antenna systems so you wouldn't be moving the fault from one antenna to the other.
 
aitchem said:
Hello
I am fitting a navicom rt650.
The mast antenna will be a new metz.
This will leave me with the old antenna going spare. Ideal as a
Emergency antenna.
My question is can the two antenna be permanently connected
Or should they both run to the radio and be swapped as required??

Thx
Howard
Click to expand...

Where will the emergency antenna be located? Not at the top of the mast with the Metz?
 
Emergency VHF aerial.

If in extremis, and no spare TX/RX aerial, after say a dismasting, untuck the centre conductor from any remaining useable wire for close to 59 1/4 inches (from memory) to form a dipole.(i.e. strip away the outer braid but retain it taped onto the sheathed cable portion)
I believe this is better than nothing.

If I'm wrong I'll be informed quite quickly!
 
paulclan said:
If in extremis, and no spare TX/RX aerial, after say a dismasting, untuck the centre conductor from any remaining useable wire for close to 59 1/4 inches (from memory) to form a dipole.(i.e. strip away the outer braid but retain it taped onto the sheathed cable portion)
I believe this is better than nothing.

If I'm wrong I'll be informed quite quickly!
Click to expand...

I think I know what you mean and if I understand your explanation correctly, it will work - but doesn't answer the OP's question.

The answer is NO. Please don't try and connect both at the same time. If you want to use the emergency antenna (that you are leaving on the pushpit) then unscrew the PL259 on the back of the VHF and plug the emergency (spare) antenna in instead.

Although it would be possible to use a coax switch, and they are available quite cheaply its an unnecessary expense and another point of failure for damp to get into things. It will also add some loss to the antenna system.
 
Last edited:
I have a pushpit mounted AIS antenna. I have a extra piece of coax with plugs connected & if the stick comes down, I can connect the AIS antenna to the VHF.

If I didn't have the AIS receiver, I'd have the same antenna arrangement. Coax switches are fine but it's just another bit of kit to go wrong. If you decide to use a switch, you must use a coax switch. Don't use a normal toggle switch. You can get a coax switch from Maplin.
 
paulclan said:
If in extremis, and no spare TX/RX aerial, after say a dismasting, untuck the centre conductor from any remaining useable wire for close to 59 1/4 inches (from memory) to form a dipole.(i.e. strip away the outer braid but retain it taped onto the sheathed cable portion)
I believe this is better than nothing.

If I'm wrong I'll be informed quite quickly!
Click to expand...

I use almost exactly the same system - except that I strip back 19 1/2 inches to make a vertical dipole.
 
You must log in or register to reply here.

Share this page

Top