navtex aerial

[Guest]

Is there any reason why I shouldn't mount a navtex aerial inside? The boat in question is a 38ft grp sailingyacht, aerial is the active antenna supplied with the Nasa Navtex Pro. Mounting the antenna inside would avoid the need for yet another hole in the deck!

 

[tony_brighton]

Many of them are (mine is).

I have a slight question over location in that mine is a bit close to the electrics - I suspect a certain amount of interference is possible when signal strength is low but otherwise works fine.

 

[steve_cronin]

They do tend to miss bits of transmission or more serious the initialising command if the boat drops down below a harbour wall at low water, for example in Trebeurden, when the vital forecast to ensure a safe trip back to the UK might get missed.

We had ours internal for a couple of years but our of frustration, eventually put it on a short mast on the taffrail.

Steve Cronin

 

[ParaHandy]

Steve's right - put it outside. Tested reception of R4 through active antenna inside and outside the boat. Outside, on the taff rail, was far better. Technically (190khz compared with 490/518khz & am rather than usb) may not be right thing or way to do it, but thought it reasonable to do.

Now...the fun starts. Have just stuck aerial wire thro' taff rail and would be deeeelighted to share the tools used...obtained at no small cost in time & effort of advice given by those on this board

 

[Guest]

I tried the Navtex Standard (version before the Pro) aerial inside for the same reasons, but the results were not very successful. However before you drill another hole in your deck, its easy to just try the receiver in your sailing area. The aerial is supplied with a long cable. Temporarily put the aerial up on deck (ducktape works!). When a message starts, walk the aerial into the cabin. Do you get a lot more errors when receiving down below? (garbage text or missing characters). I did.

Hint: set your receiver to ALL MESSAGES to give you plenty of time to observe the performance above and below deck. Make sure to check all the stations you may want to use & not the ones that are out of range. Repeat the test over a few days. I *think* Navtex stations and transmission times are in the Navtex "Instructions for use" leaflet, if not, they are on the web..

FYI: my boat in the balearic islands where there is lots of high terrain in the way and the nearest transmitter is ~150 miles away. Frequency is 518kHz (meduim wave). The boat hull is fibre-glass.

 

[milltech]

If it's a Nasa that you have they do a nice rail mounting bracket for the aerial.
www.allgadgets.co.uk


Boat Junkie

 

[vyv_cox]

My antenna was originally "mounted" (stuck on with carpet tape) to the hull in the aft cabin. It worked but we missed many transmissions. In keeping with Sod's law they were always the ones we really needed. I then moved the antenna to a small mast on the pushpit and reception was transformed. We can receive from almost every European station and once received from Israel.

 

[steve_cronin]

Now this is a bit of kit that I NEVER am without on a boat.

In the electrical trade what we might call a "messenger" they call a "mouse". It is a thin bendy length of spring steel like a tape measure for chasing wires through conduits.

For this purpose I use a length of net curtain wire. You know the white plastic coated helical stuff into the cut ends of which you can screw small hooks. Sometimes I bend these hooks into appropriate shapes with two pairs of pliers; sometimes in REALLY difficult situations I epoxy the cable to the end a few hours before the threading opperation but for most applications taping the cable onto the end few centimetres of the curtain wire is secure enough.

Great stuff: wouldn't be without it. When we had a lifting keeler three boats back I used to to re-thread the keel lifting chain for replacement after it usually parted every 30 months or so.

Steve Cronin

 

[ParaHandy]

If only....I could keep my bit of net curtain wire securely on the boat. It untwists into a mess and unwinds itself from cable ties etc with ease. Thought of putting net curtains up so's I can twitch them in realistic Agatha Christie style whilst peeking out?

 

[steve_cronin]

Ah well you see.....

If you are going to use the "smooth" Agatha Christie style then without a good whipping it will unwind.

I use the rougher no nonsense "Ena Sharples" variety from Northern Co-oPs!

Steve Cronin

 

[ParaHandy]

Re: Ah well you see.....

Oooooh...nothing I like better when you Northern boys talk dirty. A whipping too! Can't wait, can do it chained up wiff real leather thongs pls? Will send address on post card!!!