Which VHF should I choose^

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Chas C
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Which VHF should I choose^

Post by Chas C » Wed Aug 03, 2011 7:28 pm

Today I have a standard horizon HX270E, had it for probably 4-5 years or so, its reception is a bit flaky and CG keep telling me my signal is very poor or unreadable even when set to 5W.

What do others recommend as good radios - I'm looking to spend up to £250
features I'm looking for are: 6W+, good battery life, sized to fit in BA pocket.
features that would be nice to have are: GPS

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PhilAyr
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Re: Which VHF should I choose

Post by PhilAyr » Wed Aug 03, 2011 8:17 pm

Chas C wrote:its reception is a bit flaky and CG keep telling me my signal is very poor or unreadable even when set to 5W.
Assuming that the re-chargeable battery is still in serviceable condition, it could be that you are in a bad signal area. Have you tried it out in an area of known good signal strength ? I really don't think that a new 6w radio is going to make much of a difference to the quality of transmitted signal, and incorporating a gps to the radio is merely going to add a further drain on battery life. I would check out the battery, or upgrade to the HX280E (5w). B.t.w. useing standard alkaline batteries reduces the power of the transmitted signal.

Phil

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Chas C
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Re: Which VHF should I choose

Post by Chas C » Wed Aug 03, 2011 8:35 pm

Thanks for the advice but I know its the radio - its been fully charged and when used alongside another newer 5W radio its been noticeably not as good, poorer reception and transmission where the CG didn't complain about the other radios performance but always told me mine was poor. I never use alkaline batterys.

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PhilAyr
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Re: Which VHF should I choose

Post by PhilAyr » Wed Aug 03, 2011 8:59 pm

Chas C wrote:Thanks for the advice but I know its the radio - its been fully charged and when used alongside another newer 5W radio its been noticeably not as good, poorer reception and transmission where the CG didn't complain about the other radios performance but always told me mine was poor. I never use alkaline batterys.
Interesting ! As a last resort you could try swapping the aerial for a known good one. Other than that it does sound like it is time to buy a new one. Watch out for the corroding contact problem on some of the icom models.

Good luck

Phil

Sprucey
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Re: Which VHF should I choose

Post by Sprucey » Wed Aug 03, 2011 9:10 pm

Try a new aerial first. they often recieve well but dont transmit with older damaged abused aerial.
Sprucey

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Chas C
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Re: Which VHF should I choose

Post by Chas C » Wed Aug 03, 2011 9:23 pm

Thanks - I have already replaced the antenna but it made no difference (should have mentioned).

I was hoping for recommendations on good performing radios - will keep the old one I have for person to person comms - but would like something more reliable for talking to CG.

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Yakdiver
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Re: Which VHF should I choose

Post by Yakdiver » Wed Aug 03, 2011 9:33 pm

What every you get keep it in an aquapak they last a lot longer, yes I know they say there waterproof.
My £50 el-cheapo Midland is still going strong after many many sea trips.
Name Richard
Point 65n Sea Cruiser
Ocean Prowler

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MikeB
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Re: Which VHF should I choose

Post by MikeB » Wed Aug 03, 2011 9:35 pm

Chas C wrote: I was hoping for recommendations on good performing radios - will keep the old one I have for person to person comms - but would like something more reliable for talking to CG.
There are numerous recent threads on VHF - I still recommend the Icom M71. And before you keep it in an Aquapac, check the numerous threads on that subject! Mike.

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andyE
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Re: Which VHF should I choose

Post by andyE » Wed Aug 03, 2011 9:43 pm

Icom M71 has been my choice. 6 w and a 2000ma battery. I have a new high gain antenna and now has better reception , I lost the original one. It will last a good 3 days and on duel watch and scan.

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Taran Tyla
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Re: Which VHF should I choose

Post by Taran Tyla » Thu Aug 04, 2011 3:57 pm

I use a Plastimo SX200, it was only a hundred notes, its intuitive to use, waterproof & the battery last ages. Theres an image on my blog http://www.seakayaking-adventures.com/p/equipment.html

simonmc
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Re: Which VHF should I choose

Post by simonmc » Sat Aug 06, 2011 1:19 pm

I use a Standard Horizons HX851. Couldn't find any reason for not getting a DSC handheld, a no-brainer if you can afford it. No problems so far - don't use it that much - it just sits there ready for use.

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MikeB
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Re: Which VHF should I choose

Post by MikeB » Sat Aug 06, 2011 1:31 pm

simonmc wrote:I use a Standard Horizons HX851. Couldn't find any reason for not getting a DSC handheld, a no-brainer if you can afford it. No problems so far - don't use it that much - it just sits there ready for use.
Battery life is a concern - see here. I tend to the view that something I might rely upon as a lifesaver (the magic "red button" on a DSC radio), really needs to be as close to 100% reliable as possible. If that's not a factor, then indeed, why not have a radio with DSC.

Mike.

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catweasel
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Re: Which VHF should I choose

Post by catweasel » Sat Aug 06, 2011 3:39 pm

I use SH HX851E and have no battery life problems (9-10 hours) GMDSS is more reliable than a voice transmission alone IMHO.
Safe paddling, Andy.

stewh
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Re: Which VHF should I choose

Post by stewh » Thu Aug 11, 2011 10:44 am

Chas, Don’t let an extra watt of power influence your decision, as an increase from 5W to 6W will not make the slightest bit of difference to your received signal strength at the other end of the contact. You have to double the output power before any increase in received signal is discerned.
Signal strength reporting uses S-units on a scale of 0 to 9; S0 being no signal received, and S9 meaning a very strong signal. To move one S-unit higher requires a 4X increase in power at the transmitter.

http://en.wikipedia.org/wiki/S_meter

If you want to get a better signal out from any radio, the best, and usually most cost effective way, is to use a higher gain antenna; and as a bonus this will also improve your receive capabilities.

Regards, Stewart

Dave28
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Re: Which VHF should I choose

Post by Dave28 » Thu Aug 11, 2011 11:08 am

Stewart, Does the "higher gain antenna" (I am now totally out of my depth) do anything to overcome the basic problem of transmitting from very close to the water?

Or to put it another way - I've got a bog standard HX280E; how would I diagnose whether it would benefit from a higher gain antenna, and if it would, where would I go look for one

stewh
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Re: Which VHF should I choose

Post by stewh » Thu Aug 11, 2011 11:47 am

Dave, In a kayak you will always be close to the water, but a higher gain antenna is usually longer than the standard "Rubber Duck" type antenna supplied with a hand-held radio, so the top of the antenna is a teeny bit higher. An HT (hand-held radio) is essentially a close-range communication radio, but the CG have repeater stations situated at strategic locations around the coast, and often they are high up a hill, which improves the area of coverage. There isn't 100% coverage of the coast however, and there are many radio black-spots, especially the North West coast of Scotland.

There have been several threads on this very subject on the forum. I'm at work at the moment, so don't have time to do a search, but I'll try to find further info for you later.

Regards, Stewart

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Chas C
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Re: Which VHF should I choose

Post by Chas C » Thu Aug 11, 2011 11:55 am

Hey Stewart - thanks for the great info.

What would be helpful is some info on how to obtain high gain antenna's (when your not at work ;-)) - perhaps my old horizon would be better with one. Sadly I've only been able to find normal ones.

Snots
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Re: Which VHF should I choose

Post by Snots » Thu Aug 11, 2011 1:29 pm

I bought one of these:
http://www.entel.co.uk/products/marine/lcd_vhf.htm
seems pretty good - battery life is excellent, and it's submersibme
bought mine for £110 inc vat
I'll buy a DSC/GPS version sometime (with PLB features) when the market improves, but the SH HX851E needs some competition IMHO... Hopefully some more will come onto the market soon...

Ken_T
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Re: Which VHF should I choose

Post by Ken_T » Thu Aug 11, 2011 1:33 pm

Hi,
The radiation pattern around a monopole antenna is like a disc with a wedge shaped cross section. A high gain anttena flattens the wedge to put more power into the part closer to horizontal (antenna vertical), this means with a high gain antenna it will be more important to keep the antenna close to vertical. The only thing you can do about the height of the antenna is to raise it up, the design cannot overcome this problem. Hope this is clear & helps.
Ken

stewh
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Re: Which VHF should I choose

Post by stewh » Thu Aug 11, 2011 4:55 pm

Ken, In fact the radiation pattern of a vertical monopole antenna with an adequate ground plane in free space is more like a doughnut. Unfortunately an HT does not have a good ground plane, the body of the HT and partly the person using it form a ground plane of -sorts, but a poor one at that. Also the antenna is not high enough to be considered to be in free space, so all theoretical radiation patterns go out the window. What has been proven over time is that a higher gain antenna will out-perform a lower gain one. It is relatively easy for the user to keep the antenna vertical, unlike a fixed position antenna on a boat which is subject to pitch & roll, unless the antenna is gimbled (sp) somehow.
A half wave dipole, either centre-fed, or off-centre-fed with the feeder running through the bottom half of the antenna to the feed point (think Shakespeare marine VHF antennas), overcomes the poor ground plane effect exhibited by a 1/4 wave vertical monopole.
Changing from the usually supplied helically-wound rubber Duck antenna to a full-size 1/4 wave antenna has a dramatic effect on the transmit/receive signal strength. Taking a further step up to a 1/2 wave dipole or a 5/8 wave monopole has even more effect. When it comes to antennas, big is definitely beautiful.
If you have never done this before, attach one end of a 1/4 wavelength of insulated copper wire to any ground point on your HT, and let it hang vertically. Watch the signal strength increase dramatically. What you will have done is provide a better ground plane or counterpoise for the antenna to work against.

Regards, Stewart

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Re: Which VHF should I choose

Post by Ken_T » Wed Aug 17, 2011 8:14 am

Hi Stewart,
If you plot gain against direction for a 1/4 wave monopole on a perfect ground plane you get a squashed doughnut, I was trying to describe where the signal would go to or be recieved from ( I tried to keep it simple, but I failed to achieve this). The main point was that a high gain antenna may not be more efficient than a low gain one, but concentrates the signal into a smaller range of directions rather than increasing total radiated power. I accept that the imperfect ground plane (& other non ideal factors) severly change the radiation pattern & the efficiency. The other point I was trying to make is that the antenna should be kept close to vertical during use rather than holding the radio like a mobile 'phone with the antenna at about 45 degrees (as I hae often obeserved users doing). Sorry for any lack of clarity.
Ken

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Jim
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Re: Which VHF should I choose

Post by Jim » Wed Aug 17, 2011 1:52 pm

Ken_T wrote:Hi Stewart,
The other point I was trying to make is that the antenna should be kept close to vertical during use rather than holding the radio like a mobile 'phone with the antenna at about 45 degrees (as I hae often obeserved users doing). Sorry for any lack of clarity.
Ken
Annoyingly the lash tab I now use for mine is at 45 deg on my BA so reception is a bit patchy. For transmitting I currently hold the thing up to my face so it's pretty much vertical in 2-way use, but something to think about if I go back to the speaker mic. I used to have the radio more or less vertical clipped to the corner of my front pocket but got fed up of the occasional antenna in the armpit moments so moved it - I think the same trip the speaker mic wasn't working. Obviously I haven't made time to investigate that little issue yet....

I'll probably sew a dedicated VHF loop on the BA somewhere it will hold the thing in as near vertical position as possible.
@ PhilAyr (and anyone amused by the other thread) - I'll need to get a SL&BC-COC1 for that :-)

Dave28
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Re: Which VHF should I choose

Post by Dave28 » Wed Aug 17, 2011 5:10 pm

I have a horizon HX280E submersible - I was out paddling today with a friend who has the Horizon 751 floatable and it was noticable how much more signal she was getting than me - not so much from the big CG/Port Control Masts but from other waterborne users.
The 751 will definitely be top of my wish list if ever I can justify replacing my 280.

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MikeB
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Re: Which VHF should I choose

Post by MikeB » Wed Aug 17, 2011 5:17 pm

Might the squelch settings be different? This would affect the reception of weaker signals.

Dave28
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Re: Which VHF should I choose

Post by Dave28 » Thu Aug 18, 2011 11:28 am

How could one tell? On both radios there are discrete squelch settings rather than a spectrum. They were both on one bar, but only the designers would know whether that was the same or different. It may be that the only difference inside the radios is that they've tweeked the sensitivity (and hence the squelch) on the 751. Either way the 751 was audibly performing better than the 350.

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almvsalutay
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Re: Which VHF should I choose^

Post by almvsalutay » Wed Aug 24, 2011 3:09 pm

Hi
Good news on my dealings with Icom UK, my current and untrustworthy M33 which has had multi able returns to the factory is currently being replaced with the newer M35 model, hopefully just in time for me to use at the IOW Sea Kayak Symposium this Bank Holiday weekend.
Lets hope the M35 is more reliable???
Well done ICOM UK for customer service :D

Al
Check out "Paddle Malta" on facebook

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Chas C
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Re: Which VHF should I choose^

Post by Chas C » Sat Sep 03, 2011 4:56 pm

Thanks everyone for your advice - in the end I've gone for an Icom IC-M71, nice small size and long battery life. Will keep the old Horizon for inter-group comms.

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