Navtex aerial

[clyst]

Hi guys , sorry for a stupid question but I'm having trouble receiving with my elderly ICS Navtex which I think is related to the aerial. I have continuity across the sheathed wire and the screening of the coax lead ...... Is this normal ? TIA
Terry

 

[BobnLesley]

No idea regarding the continuity, but have you recently relocated the antenna?
On our Albin Vega we had the antenna inside the saloon (received better there than the cockpit-????) but it needed to be in a specific spot, when we tried moving it <6" one way and <12" the other) it wrecked the reception; I don't know enough to explain why, but if you've moved yours, that may be the problem.

 

[greeny]

In the absence of antennae experts at the moment, , I seem to remember that some navtex antennae are "active" and are powered and have circuitry in them. This could explain the continuity. A passive antennae should not have continuity. - I'm sure someone with more knowledge will be along soon though to confirm this or otherwise.

 

[clyst]

No idea regarding the continuity, but have you recently relocated the antenna?
On our Albin Vega we had the antenna inside the saloon (received better there than the cockpit-????) but it needed to be in a specific spot, when we tried moving it <6" one way and <12" the other) it wrecked the reception; I don't know enough to explain why, but if you've moved yours, that may be the problem.

Thank for your input but no not moved it .

 

[vas]

I vaguely remember that my LOCATA (sp?) had a switch re active passive antenna, is there a chance you have such an thing and has been toggled the "other" way?
when you say problem receiving, I guess you receive nothing, right?

 

[clyst]

In the absence of antennae experts at the moment, , I seem to remember that some navtex antennae are "active" and are powered and have circuitry in them. This could explain the continuity. A passive antennae should not have continuity. - I'm sure someone with more knowledge will be along soon though to confirm this or otherwise.

Iv drawn the guts Of the antennae out of its casing ......... Doesn't seem to be any circuitry to it just the sheathed wire and screen attached to the windings .

 

[clyst]

I vaguely remember that my LOCATA (sp?) had a switch re active passive antenna, is there a chance you have such an thing and has been toggled the "other" way?
when you say problem receiving, I guess you receive nothing, right?

Yep not receiving at all although it fires up ok and runs through its checks . It doesn't have a screen .... It's a paper printout type . There is only an on off switch for the isolation of machine .

 

[greeny]

Ok so next check is to disconnect coax from antenna and from Navtex instrument and check coax alone for short circuit. Then check antennae for short ct.
Interesting page from Frank that explains everything if you're interested in finding out more and link below that does show that the Navtex antennae is pwered and active in some cases, Maybe not yours though. One thing to be aware of is that navtex reception is often very poor in harbours and marinas surrounded by masts etc, and if inland up a river say. We used to find that reception improved no end once clear of land. Before we left the marina we often had problems receiving anything.

NAVTEX problems in more detail - Franks-Weather - The Weather Window
Navtex aerial

 

[greeny]

Just remembered and ours was the same printout type as yours i think. When you do the diagnostic check and get the printout, doesn't it tell you on that whether the antenna is ok or not? I can't remember for sure but think it does.

 

[Bilgediver]

Hi guys , sorry for a stupid question but I'm having trouble receiving with my elderly ICS Navtex which I think is related to the aerial. I have continuity across the sheathed wire and the screening of the coax lead ...... Is this normal ? TIA
Terry

I would suggest you go straight to the horses mouth and ask the right questions. ICS have taken this equipment back in house and I have always found them good to deal with and helpful.

I believe you have more than just an active antenna on the taffrail so yes continuity is definitely a possibility and hope you didn' t zapp something. Speak to ICS because they my confirm a work around or offer to fix. Make sure you know which model when calling them.

ICS Electronics Ltd

+44 (0) 1903 731101

 

[Deleted member 36384]

If the antenna roughly looks like a sharks fin it is likely goosed as they do fail, usually death by water ingress, even small amounts over a long period. I have went through two of the shark fin styles before updating to a new antenna.

 

[clyst]

I would suggest you go straight to the horses mouth and ask the right questions. ICS have taken this equipment back in house and I have always found them good to deal with and helpful.

I believe you have more than just an active antenna on the taffrail so yes continuity is definitely a possibility and hope you didn' t zapp something. Speak to ICS because they my confirm a work around or offer to fix. Make sure you know which model when calling them.

ICS Electronics Ltd

+44 (0) 1903 731101

Thank you .....will do .

 

[vas]

Yep not receiving at all although it fires up ok and runs through its checks . It doesn't have a screen .... It's a paper printout type . There is only an on off switch for the isolation of machine .

mine is also a printout only, but does have 2 switches (hidden) and a jumper or something to chose antenna type (iirc-haven't bothered checking it now since it does work fine)

 

[Bilgediver]

mine is also a printout only, but does have 2 switches (hidden) and a jumper or something to chose antenna type (iirc-haven't bothered checking it now since it does work fine)

That was why I suggested the OP called ICS . I am pretty sure it might be possible to run it off a long wire however that might not be so if the receiver is in the exterior unit.