Detachable antennae: PMR446 vs. Wifi

Licence free two-way radio services that now includes both FM and digital channels. Discuss models, modifications and other similar worldwide standards such as FRS and GMRS.
friendly1uk
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Re: Detachable antennae: PMR446 vs. Wifi

Post by friendly1uk » 30 Jul 2011, 12:41

wind in the antenna wrote:
wind in the antenna wrote:
Converted radio equipment
PMR446 users are reminded that their radios are only licence-exempt if they are built and
operated within the conditions of the exemption regulations. If modifications are made to the
equipment, such as adding an antenna connector, the overall maximum ERP or other technical
parameters must not exceed the permitted levels set out in the Interface Requirement.
Why are you repeating yourself?
This appears to be a guideance note. So the fact it appears a socket can be fitted as long as radiated power stays within spec won't really stand in a court.

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Re: Detachable antennae: PMR446 vs. Wifi

Post by wind in the antenna » 30 Jul 2011, 13:22

I might well be repeating this and other very clear statements from the official regulator, but so to, do we frequently read the unresearched and incorrect opinion from those with a victim complex that a radio needs to have to feature a fixed antenna in order to meet the conditions required to operate under the licence exempt PMR446 service.

I suggest you take the time to read the specifications and conditions yourself and then take a more informed view.

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Re: Detachable antennae: PMR446 vs. Wifi

Post by Mikel » 30 Jul 2011, 15:08

quote]Why are you repeating yourself?
This appears to be a guideance note. So the fact it appears a socket can be fitted as long as radiated power stays within spec won't really stand in a court.[/quote]


I think you will find that a court of law would look upon a guidance note produced by the regulating body as illustrating best practice on how to comply with the law.

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Re: Detachable antennae: PMR446 vs. Wifi

Post by No Rest » 31 Jul 2011, 09:29

The record for long distance contact via WiFi is 237 Miles :o

http://www.engadget.com/2007/06/19/vene ... 237-miles/

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Re: Detachable antennae: PMR446 vs. Wifi

Post by troffasky » 01 Aug 2011, 12:49

wind in the antenna wrote:I might well be repeating this and other very clear statements from the official regulator,
If you'd added a little comment the first time you'd pasted that in, it might have been a little more obvious what you were getting at, and therefore not require posting twice in the same topic [a threaded discussion would have helped here too, but nm].

Anyway, having read IR2009 and the apparently reference number-less "Analogue and Digital PMR446 Information Sheet", there's nothing about antennae socket not being permitted, yet detachable antennae not being permitted is oft-cited [Wikipedia for one].

So, going back to the original question, why did I think detachable antennae aren't permitted? Because I've never seen anything marketed as a complaint PMR446 radio that featured a detachable antenna. If they exist, then they're in the minority. So then, if they're permitted, why so few? I'm going to assume at this point it's because a) they're targeted at idiot consumers, and a removable antenna increases support costs [another thing to go wrong] b) they're low-margin, and a socketed antenna increases the bill of materials.

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Re: Detachable antennae: PMR446 vs. Wifi

Post by bigbloke » 01 Aug 2011, 13:33

My recollection, is that when DPMR446 was legalised in the UK, the
rules changed very covertly, and that "slightly" higher gain removable antennas were permissible on the digital service (i.e. 1/4 wave verticals) , and:

Since the only digital446 radio to gain type acceptance was an icom (which if memory serves had, or was later modified (?) to support a removable antenna ?)

Given that the aforementioned Icom could also operate on analogue 446 (?)
It was <implicitly> a type approved analogue 446 radio with detachable antenna.

Therefore again <implicitly> a removable antenna was no longer an obstacle to type approval.

Certainly in the VERY early days of 446 (when those of us here used to subscribe to Dean's site and before) The original Alinco 446 had an SMA socket underneath
the antenna which was super-glued on to obtain type approval. Now they have that appalling rotating lolly stick on the back! :(

I have a sense of deja vu, recalling a thread on here many moons ago
where Ian (SIBC) and another chap (whose 'nick' I have forgotten - sorry!) were giving their first hand DPMR446 experience the "thumbs up" and all this detachable antenna stuff was clarified in some detail ?? I remember a comment about receiving DPMR 446 traffic from a cellar or underground room some 2 miles away ? (or similar) where analogue couldn't get ? (was it Ducat ??)

Doubtless someone with more "forum time" than I can dig it up ? 8)

Regards

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Re: Detachable antennae: PMR446 vs. Wifi

Post by wind in the antenna » 01 Aug 2011, 15:13

There were some rumblings from the regulator in the early days about the requirement for an integral antenna, but since then, we moved away from the situation where PMR or more correctly PBR radios required type approval.

You can, perfectly legally, buy and install a suitably programmed Motorola such as this ...

Image

into you car with any antenna, say a 6.3dBd colinear as long as the erp is less than 500mW.

The reason that we can do this is that the GM1280 was released onto the market since April 8th 2000 and meets the minimum interface requirements, as well as having the ability to work within the parameters required in addition for licence exempt PMR446 use.


The reason that dedicated PMR446 radios do not have removable antennas are I believe threefold.
  • Cost
  • Sales may be restricted in other parts of the European Union
  • There would be no advantage to the user as it could only legally be replaced with an antenna of the same or less gain without reducing the RF drive power


I do apologise for posting the original quote twice it was a simple mistake. I had meant to add a link to the reference source but if I'm labouring this point, it's only because it germane to the topic of this thread.

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Re: Detachable antennae: PMR446 vs. Wifi

Post by G0TVJ » 02 Aug 2011, 09:00

bigbloke wrote:
I have a sense of deja vu, recalling a thread on here many moons ago
where Ian (SIBC) and another chap (whose 'nick' I have forgotten - sorry!) were giving their first hand DPMR446 experience the "thumbs up" and all this detachable antenna stuff was clarified in some detail ?? I remember a comment about receiving DPMR 446 traffic from a cellar or underground room some 2 miles away ? (or similar) where analogue couldn't get ? (was it Ducat ??)
There was certainly a long thread like that on 446user involving, inter alia, Ducat, SIBC and me, all of whom have, or had, the Icom radios and I'm pretty sure that was where the tales of DPMR in the basement came from (I think that was indeed Ducat). I also think there was a similar thread on here at some time but I have miserably failed to find it again :(

Definitely no removable antennas on mine though. Maybe that's changed?

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Re: Detachable antennae: PMR446 vs. Wifi

Post by sec1223 » 02 Aug 2011, 09:15

best homebrew antenna iv used for wifi was a2.4ghz bi-quad...

it worked pefect over ahalf mile range (not that far but it was better than the rest i used)

pretty easy to build too !
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Re: Detachable antennae: PMR446 vs. Wifi

Post by G0TVJ » 02 Aug 2011, 11:33

@ bigbloke

The only thread I can find on here about the Icom 4029 is this one: http://www.transmission1.co.uk/forum/vi ... 029#p40136

I wonder if we're just remembering the old one on 446user and mistakenly thinking it was on here?

Neil

Edit: Found it now, I think: http://www.transmission1.co.uk/forum/vi ... it=4029sdr
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Re: Detachable antennae: PMR446 vs. Wifi

Post by friendly1uk » 02 Aug 2011, 16:10

bigbloke wrote:My recollection, is that when DPMR446 was legalised in the UK, the
rules changed very covertly, and that "slightly" higher gain removable antennas were permissible on the digital service (i.e. 1/4 wave verticals) , and:

Since the only digital446 radio to gain type acceptance was an icom (which if memory serves had, or was later modified (?) to support a removable antenna ?)

Given that the aforementioned Icom could also operate on analogue 446 (?)
It was <implicitly> a type approved analogue 446 radio with detachable antenna.

Therefore again <implicitly> a removable antenna was no longer an obstacle to type approval.

Certainly in the VERY early days of 446 (when those of us here used to subscribe to Dean's site and before) The original Alinco 446 had an SMA socket underneath
the antenna which was super-glued on to obtain type approval. Now they have that appalling rotating lolly stick on the back! :(

I have a sense of deja vu, recalling a thread on here many moons ago
where Ian (SIBC) and another chap (whose 'nick' I have forgotten - sorry!) were giving their first hand DPMR446 experience the "thumbs up" and all this detachable antenna stuff was clarified in some detail ?? I remember a comment about receiving DPMR 446 traffic from a cellar or underground room some 2 miles away ? (or similar) where analogue couldn't get ? (was it Ducat ??)

Doubtless someone with more "forum time" than I can dig it up ? 8)

Regards

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Re: Detachable antennae: PMR446 vs. Wifi

Post by ducat » 29 Apr 2018, 22:04

It was indeed I!.

The transmission in question was from my mates cellar, where i was sat with an Icom 4029 to my wife a mile away across a river valley in our kitchen.

As clear as a very clear thing.

Still got the radios, and both currently on charge for a trip to the Norfolk broads in May! (mobile signal can still be a bit sketchy on the broads!)

Sorry to drag up an old post, but I still love these radios.
Last edited by ducat on 29 Apr 2018, 22:22, edited 1 time in total.
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Re: Detachable antennae: PMR446 vs. Wifi

Post by ducat » 29 Apr 2018, 22:18

Just out of interest, does anybody still use these, or is it only me?

Been away from the forum for a long time!
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Re: Detachable antennae: PMR446 vs. Wifi

Post by paulears » 30 Apr 2018, 08:03

The entire point of short range, licence free radios is to provide simple comms over short ranges. If you want longer ranges, then you buy a different product and licence it. All the people who seem to have a weird need to use PMR446 (in the UK) over longer ranges, would be far better off doing it somewhere else where higher powers and longer ranges work, and don't suffer from the longer range also making interference from the other users worse. Wifi on the other hand using narrower beams and gain for point to point comms isn't making things worse, but actually for many, cutting down interference. I don't see any link between the two services.

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