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Discussion Starter · #1 ·
i apologize if this might sound like a daft question. im after a fixed vhf radio and im unsure on what to get or what make and model. what do i need to look for spec wize. are there any differance on sound quality? what distance offshore i can use it etc.

price wize the cobra fixed vhf look good value, i have a handheld cobra which i will be using as a spare and its decent for the £40 i paid for it.

cheers in advance
 

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Hi Hugh,ive a Standard horizon gx 1500e and its a good unit.Not the cheapest but IMO a great value unit and very simple to use,couple that with a decent antenna and it wiill serve you well.See what sort of price they are going for at the SBS,i got mine from the London show for a good price .

Ian
 

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Discussion Starter · #3 ·
thanks ian, i was thinking i might get a good deal on one at the show aswell. il google the one you have.

cheers m8
 

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Hi, personally I not a big fan of the Cobra stuff...
Id choose between Icom or Standard Horizon. Both will be available with good deals at Southampton, Im sure. SH do a GX1100 at about £90 too..Both makes have 3 year warranty.
All fixed VHfs should be rated at 25w of RF output power and with a good antenna you should get at least 25 mile range, further at sea where the transmission should be able to travel 'line of sight'.
Please also remember that you need a ships radio licence for the boat, free if applied for online at OFCOMs site. This will give you a callsign and MMSI number for your vessel.
You also need to have an operators licence. A Short Range Certificate, (SRC), is perfectly adequate and is usually a 1 day course. The RYA website will tell you your nearest provider.
Regards Tony
 

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well we have a icom m421 the m411 big brother, and both are good sets, but the proof is getting the right areil and tuning it in correctly to get the most out of the 25w, also it pays once a year to get the ariel a swr reading to make sure the ariel is workinmg properly as they dont like sea water inside them much.
 

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but the proof is getting the right areil and tuning it in correctly to get the most out of the 25w
So you go and buy a Glomex, Pacific, Banten and pretty well any other marine vhf antenna. How do you tune it ??
Other than keeping the coax on a short a run as possible or using a better grade coax !!

Alan
 

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Hugh

OK there are dear and cheap VHF's.

Go for one with as simple a functionality as is possible and make sure it has a clear, easily readable screen.

Anyone can use the VHF to call fred up on the boat next door, but if you need it in anger you are going to be in a bit of a panic with your heart racing and adrenalin pumping.
If there is anything complicated about the unit it will make the emergency much harder to deal with.
Easy functions and a clear screen.

I would go for Icom, Standard Horizon or possibly Northstar.
 

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Discussion Starter · #10 ·
cheers guys, thanks tom, hopefully il find a good deal at the boat show but they are resonably priced anyway.

any ideas on an antena to go for? ive heard of glomax, do they all fit the same same units?
 

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Hi hugh,the general opinion for antennas is the longer the better for range especially on a small boat sitting lower in the water.It should come with a length of coax attached for you to cut to your desired length,some will come with a connector which you then fit after cutting to go into the vhf unit.I got a deal on a 2.4 mtr glass glomex with a glomex stainless ratchet mount for about £65.

Ian
 

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Discussion Starter · #12 ·
Hi hugh,the general opinion for antennas is the longer the better for range especially on a small boat sitting lower in the water.It will come with a length of coax attached for you to cut to your desired length,some will come with a connector which you then fit after cutting to go into the vhf unit.I got a deal on a 2.4 mtr glass glomex with a glomex stainless ratchet mount for about £65.

Ian
thanks ian
 

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yes the glomex ones are good but make sure its a j pole which dont need a ground plane. and try and get a swr meter to get the length of the cable right, because if the swr reading is to high modern sets will cut the power down so not to strees the set to much. as 25w will soon end up 5w lol. the idea is as the singal wave crosses the cable this is were the socket is needed thats what the swr bridge reads most times you just need to cut about a inch of at a time untill its right.
 

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yes the glomex ones are good but make sure its a j pole which dont need a ground plane. and try and get a swr meter to get the length of the cable right, because if the swr reading is to high modern sets will cut the power down so not to strees thset to much. as 25w will soon end up 5w lol. the idea is as the singal wave crosses the cable this is were the socket is needed thats what the swr bridge reads most times you just need to cut about a inch of at a time untill its right.
So I have my glomex 2.4m antenna and a swr meter .How do I cut the cable so it reaches my vhf set and dosn`t cut the power down?
This is a new one to me!!!
Where`s Tony Fry when you want him !!:icecream:

Alan
 

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well according to my dad whois a radio ham, fit areil, then take 5 turns about 4 inches across and tie rap together near the set this acts s a choke and helps stops interverance, then leave about 8-9 inch tail, then bare the coax and take a reading, if the reading is high then cut a inch of and try again , keep cutting a inch at a time until reading is nearly zero this is when to fit the conector, depending on your meter you may have to fit conector every time, it takes time but will give you the best result,
 

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What your dad is saying is correct for some types of antenna.
On most if not all ( never seen any) marine vhf antenna the coax is not part of the "tuning".
Marine antennas are pre cut to a specific length to have the lowest VSWR (Voltage Standing Wave Ratio) over the 156-163 MHz frequencies, normally reaching less than 1.2:1 at 160MHz.
Just keep cable runs as short as possible and if you have to run the coax a long way(not likley on a small boat) then use RG-8X coax.
Make sure the PL259 connector is fitted correctly and it should all work fine.:thumbs:

Might also be of interest to some.. http://www.youtube.com/watch?v=SdEglNHyHB4&feature=related
Also
http://www.worldseafishing.com/forums/showthread.php?t=223678

Alan
 

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Why keep the run as short as possible ? What do you do with the excess cable ?
Basically its to reduce signal loss in the the cable (resistance).
Thats why on a long run you would use a larger better quality coax like RG-8X. The same principle as voltage drop in electrical wiring.
Just cut off the cable you don`t need.

Pretty much all Joe Blogs needs to know about marine Vhf without geting to technical is here.. http://www.boat-project.com/tutorials/vhfant.htm

Alan
 

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But you said "Marine antennas are pre cut to a specific length to have the lowest VSWR"

So, wouldn't cutting the cable or changing it for RG-8X introduce the possibility of a high VSWR ?
It just the antenna which is pre-cut to a specific length,not the cable.
Changing the cable to RG-8X shouldn`t present any problems providing you join the Coax correctly.

Alan
 

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When I was into CB many moons ago (30 odd years) we "tuned" the aerial to adjust the SWR reading by either reducing or increasing it"s length to get an SWR reading of 1-1. Don"t remember ever altering the length of the coax.
Earlier this year I bought a SWR meter as I had a problem with my VHF.
I now have 2 different sets on 2 different antenna"s & the meter shows that they have both been factory "tuned" to 1-1 already.

headlight
 

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But most (if not all) marine antenna's don't have a separate cable/antenna, they are one and the same.
True, it`s not an ideal world.
If you want to change to RG-8X the you will have to join the coax.
Ideally this would be done as close to the antenna as possble.
Iv`e done it in the past using a deck connector and also a PL258 barrel connector.
The Shakespeare PL-258-CP-G looks the job but iv`e never used one.
http://www.shakespeare-marine.com/connectorshow.asp?menupick=PL-258-CP-G
Any connector has the possibiity of reducing the gain buy a small amount but in normal operation it would proberly never be noticed

Prehaps Tony Fry knows of a better method of joining coax, i`m sure he would have used plenty of RG-8X !!

Alan
 
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