Antenna Quandry
Posted at 2:01 PM, Friday, February 2, 2007
You'll only be interested in this entry if you're facing a similar situation.
We've elected to go with a SSB HF/MF radio for longer range comms. Despite high installation costs, the end cost of email or vocal comms is minimal plus it allows us to dial into local marine networks. It's allowed us to sell the Thuraya satphone (only good for Med anyway) and help towards the investment.
We checked out various radios - and plunked for a new ICOM.
ICOM two similar radios - one which is not CE marked, and another that is.
Despite the regs that state you should not install any non CE marked radio on a Brit registered vessel - we chose that ICOM as it was several hundreds cheaper - yet appears to have same functions.
Now we are faced with installation once we've carted it all out from the UK in our baggage.
And its heavy.
Kemers Turkish Technicians say they can wire in radio etc - so all I need do is find the space on the nav station for them to do that bit - plus wire in ATU to lazarette, and bolt on ground plate when the boat is slipped.
The last issues we've addressed are the antenna. The ICOM's have DSC so require a longer (4-8 metre) antenna for radio chatter, plus a shorter (2-3 metre) dedicated antenna for the DSC.
Tried hard to avoid adding these two to our transom as I think they are ugly, and in that postion would be in the way when stern berthing.
We've enough junk hanging off the pushpit rails as it is.
Looked real hard at adding insulators to backstay and create antenna therein. The Hanse 461 backstay is a single wire down from mast to around 4 metres off the deck, where its attached to a metal pulley. Another wire runs from the port transom up through the pully and down to the hydraulic tensioner on the starboard transom - and initially I hoped to use both sides of that wire, using 4 insulators, to create one long and one short antenna required.
Did have some reservations on risking the integrety of the backstay - but initially thought the visuals overcame the safety risks.
Seems not this is not possible - as the two antenna can't be so close to one another. So looked again at one long backstay antenna plus one short whip on transom for DSC. This was possible, but after lotsa research now have got back full circle (mainly due to reported effectiveness and relative costs) to be back with getting the two transom mounted whips!!
Only took three weeks.
If anoyne else wishes for more detail as to why we got there - just ask.
If you want to know pros and cons of whips v backstay both circa £400 - just ask.
If you want to know about whiz bang new US antennas that simply clip onto backstay circa US$400 just ask.
If you want to know why we did not go for an independently hoisted wire for 3p plus one insultator - just ask.
Or if you can't be aaaarst, go get two whips.
Signed off, head of Swagman R&D, and mind hurting antenna bore
JOHN
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