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Old 21st Aug 2009, 5:34 pm   #41
Jaded
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Default Re: Keeping radios working following analogue switch off.

I concede: and am looking forward to conversion, (Dab to AM!).
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Old 24th Aug 2009, 6:20 pm   #42
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Default Re: Keeping radios working following analogue switch off.

the simple way round this is to use a larger arial to recive forigan stations
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Old 30th Aug 2009, 11:44 pm   #43
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Default Re: Keeping radios working following analogue switch off.

I don`t think anybody has commented on the design for a transmitter in the recent Summer issue of The Radiophile which uses a 6SL7 driving a 6V6 with 328 volts on it and totally broadband tuning!!
I have written a letter to him which he has promised to publish in the next issue together with any reply from the author.
THIS IS THE SORT OF THING WHICH WE MUST TRY AND STAMP ON NOW. Amateurs know that you can work the world on a 6V6 PA.
Pat G3IKR
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Old 31st Aug 2009, 12:14 am   #44
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Default Re: Keeping radios working following analogue switch off.

I thought somebody had commented, but I can't find the post. Maybe it's in another thread.

Driving a 6V6 efficiently, and feeding the RF into a decent aerial, certainly will make a good transmitter. The Radiophile circuit does neither of these, as it's designed to give the 6V6 an easy life, tolerant of RF drive failing, and especially as it's feeding only a few feet of wire, it's a fair bet that it won't get out very far. I'd be a bit worried about harmonics being radiated though, as there's no aerial tuning or filtering.

We do want to enjoy our old MW radios, and it makes sense not to rock the boat by generating anything which could attract official attention!
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Old 31st Aug 2009, 10:09 am   #45
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Default Re: Keeping radios working following analogue switch off.

As mentioned earlier in the thread, the moderators neither approve of, nor allow discussion of, this sort of transmitter. Even given the restricted operating conditions, it is highly likely to exceed the guidlines as to what is acceptable here. The publishers of Radiophile must take their own decisions.

No further discussion of this transmitter here please.

Paul
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Old 21st Nov 2009, 2:28 pm   #46
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Red face Re: Keeping radios working following analogue switch off.

I'm already tranmitting R2 on med wave so my radios have my choice on that band. I use a sky box as the signal source and this means I can change the content to just about anything. I assume this sky thing will continue after the swich-off. Regards to all Jonathan
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Old 21st Nov 2009, 8:29 pm   #47
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Default Re: Keeping radios working following analogue switch off.

Did n't see this topic running earliar this year. I have built the amazing AMT3000 and just using a short aerial running up to the curtain rail and a mains earth it gives great results around the house and not very far outside it. Because of the strength of the local signals I had to choose a channel very carefully and ended up on 819khz. Great during the day but severly limited at night by strong interference from continental stations. The audio quality of this is brilliant and just wish that the same people would design a good FM mini transmitter as some of the FM senders I have experianced have been nothing short of a joke, suffering either low range or poor audio quality.
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Old 21st Nov 2009, 10:21 pm   #48
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Default Re: Keeping radios working following analogue switch off.

Is there a source for the AMT3000 in the UK? My "surprise" Christmas present this year is going to be one of these low power AM transmitters. At the moment I am not sure whether to go for the Spitfire or the AMT3000, I hope Father Christmas does his research well!
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Old 21st Nov 2009, 10:30 pm   #49
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Default Re: Keeping radios working following analogue switch off.

Just googled it but cannot UK dealer.

David
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Old 21st Nov 2009, 10:31 pm   #50
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Default Re: Keeping radios working following analogue switch off.

Spitfire is available UK delivery on EBAY
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Old 21st Nov 2009, 11:22 pm   #51
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Default Re: Keeping radios working following analogue switch off.

Democratic voice!!?
People who are opposed to this change can register their opposition by signing an online petition to Downing Street at
http://petitions.number10.gov.uk/AM-FM-Radio/
may save the need for a "Gizmo"

Last edited by vmp4gmpt4; 21st Nov 2009 at 11:31 pm. Reason: http link update
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Old 22nd Nov 2009, 1:22 pm   #52
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Default Re: Keeping radios working following analogue switch off.

Thanks David, I will look into the Spitfire. Has anyone had any experience of this unit?

Thanks,
Paul.
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Old 7th Feb 2010, 9:05 pm   #53
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Default Re: Keeping radios working following analogue switch off.

wouldn't turning off the countries analog radio services(and for that matter analog TV) be illegal without the majority of the population voting for it to happen? there was no vote
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Old 7th Feb 2010, 9:17 pm   #54
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Default Re: Keeping radios working following analogue switch off.

Sounds as if this is going OT.Having said that and this is were i might get a rocket! This goverment has done what a lot would consider and be correct,illegal.So they will do what ever they like.

David
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Old 7th Feb 2010, 9:38 pm   #55
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Default Re: Keeping radios working following analogue switch off.

Oh, not another political tirade! The govenrment of the day is elected by the people of this country. Whether their decisions are legal or illegal is a matter for the courts.

I for one do not welcome these discussions on this forum.

Dave

Last edited by Framer Dave; 7th Feb 2010 at 9:40 pm. Reason: typo
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Old 7th Feb 2010, 10:05 pm   #56
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Default Re: Keeping radios working following analogue switch off.

I can't really see a problem with keeping our radios working.

MW gives plenty of options from Europe in the evening . LW can be received most of the day and SW usually has something from somewhere any time, It might need an aerial but in the 30s and 40s when a lot of our interesting sets were introduced this was normal. The main trouble would be interference from whatever replaces the current transmissions.

Even this might have a solution. I have been amazed how crystal radio enthusiasts in the USA receive large numbers of stations, even when they have a few very powerful local stations close by.
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Old 7th Feb 2010, 11:22 pm   #57
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Default Re: Keeping radios working following analogue switch off.

To avoid interference, why not build a modulator in a screened case, somewhat along the lines of a signal generator (or maybe even adapted from one). This could be connected to the radio via a coaxial cable. The signal could be attenuated to the bare minimum required for adequate reception. With care, I would have thought that this set-up could be made to emit very little RF power.

We have to remember however that there is no permissible level at which this would actually become legal, so perhaps to satisfy the most fastidious attitude to the law one had better retreat to feeding audio into the set - via the gram input where one exists. N.B. if doing this, be sure that the set does not have a "live" chassis" - otherwise either the mains supply or the audio will have to be coupled via a safe isolating transformer.
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Old 8th Feb 2010, 10:31 am   #58
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Default Re: Keeping radios working following analogue switch off.

Quote:
Originally Posted by Paul LS View Post
Thanks David, I will look into the Spitfire. Has anyone had any experience of this unit?

Thanks,
Paul.
Yes - lots of people on the forum it seems.

Oh, and of course, Ofcom, but what they do about it remains to be seen.
(Not a lot, I suspect).

These medium waveband micro-transmitters are not licensable anywhere in Europe as there is no frequency allocation. (The supplier doesn't claim that they're licensable in the UK - only that they conform to FCC requirments in America, which has no relevance anywhere else in the world).

Maybe there ought to be an allocation, and I've lobbied Ofcom about that, as this is an issue which is bound to gather momentum, and I think legalisation, subject to approved standards, is a better solution to enforcement. But as things stand, to use any such equiment - be it commercially made or homewbrew, contravenes WT Act, and hence, is a criminal offence.

Ofcom tend to be reactive rather than proactive, only responding to complaints of interference, and their prime concern is of course, non-interference to other spectrum users - notably the emergency services and air traffic control.

That just isn't going to arise with micro-power MW devices such as the Spitfire, (which, even at a cursory glance, is a well designed and constructed and satisfies the FCC). I can't therefore imagine Ofcom mounting dawn raids on Spitfires - they've all on dealing with pirate broadcast stations in all major cities, not least, London.

Any low power transmitting devices used in the UK or rest af the EU must conform to CE and operate on approved frequency allocations. There are lots of examples of such devices - wireless central heating room thermostats, baby alarms, intruder alarms, intercoms, remote garage door openers, car key fobs and so on. What all of these devices have in common, is that they conform to all legal requirements.

It's unlikey that Ofcom will ever receive a complaint about devices such as the Spitfire - after all, the worst that could happen is that a neighbour happens to tune into a spot on MW and hear music from a Spitfire. So what - they'll probably just think it's a MW station.

A pragmatist might therefore take the view "don't ask - don't tell - keep on not minding".

Many have said "so what - they aren't legal, but I don't care - what chance is there of being detected - I only use it in my house". That may be so, but remember that they are sold in the US as community broadcast transmitters - albeit with an efficient aerial.

The interest which has been shown on the forum for quite a while now, shows that there is a clear need for a legal device, part from which it seems that some members of the forum are openly discussing the construction and use of MW tranmitters.

You're not even allowed to use home-brew tranmitters on authorised amatuer bands for which you've passed an amateur radio exam and hold a licence if you only hold the entry level Foundation licence - you can only use commercial equipment or approved kits.

I've mentioned this issue several times on here, and I don't want to be labelled as a copper's nark for Ofcom or a self-righteous "Billy no-mates" out to spoil other people's enjoyment, but It surely isn't within forum rules to be debating, encouraging or condoning the use of equipment which amounts to a criminal offence.

It's the sort of activity that - if engaged in at all, is best done by consenting adults in private!

David,
G4EBT
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Old 8th Feb 2010, 12:01 pm   #59
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Default Re: Keeping radios working following analogue switch off.

This forum neither encourages or discourages the use of illegal microtransmitters. We allow them to be discussed, with the proviso that they must be very low powered and unlikely to cause interference to third parties.

It is an individual decision to use or not use a microtransmitter. Most forum members will be well aware of the legal position (and any that didn't know certainly do now.)

Please don't continue to revisit old arguments about legality or illegality.

Paul
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Old 8th Feb 2010, 12:47 pm   #60
kalee99
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Smile Re: Keeping radios working following analogue switch off.

Hi all,
Been retransmitting onto Medium wave here for years using a kit I bought many years ago (now unavailable). I am very pleased with the results which do not extend outside my property. Just seen this new valved kit for sale iTx - Tube AM Broadcast Transmitter Kit”. Looks very nice and is fully tunable across the MW with the power regulated by limiting the HT. I think I may give this one a go as it’s rather appealing to use valves to send a signal to valve sets?
Anyone tried this kit already?
Paul
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