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Old 19th November 2012, 07:05 PM   #71
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Quote:
Originally Posted by Cassiel View Post
I'm beginning to like this idea. So you could trigger airport mayhem with only a small transmitter? Wow, terrorism has never been cheaper.
Even worse: one student got a rescue team in his apartment because his broken TV transmitted some signal on SOS frequency.

http://www.mavromatic.com/2004/10/fl...ts-sos-signal/
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Old 19th November 2012, 07:29 PM   #72
sco1t is offline sco1t  United Kingdom
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amazing story
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Old 19th November 2012, 08:00 PM   #73
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Originally Posted by sco1t View Post
Oh I see I need to look up Class D, and it's ok the radio has a line input on the back anyway . I was just trying to learn about transmitters. but thanks
Fine.

Then let me teach you something about transmitters?

1) do *not* build one without knowing the rules and regulations in your country
2) be 100% certain that what you build meets those requirements
3) start with something that is *known* to work, and known to meet the legal requirements
4) follow the advice of those who you have asked for advice and have been where you are and know what they are talking about

Ok?

I am worried that if you are having trouble figuring out and reading where the amateur bands are, and the difference between MW and SW, that your knowledge base isn't really up to doing your project.

Keep in mind that *it could be*.
I built myself from scratch a CW and screen modulated novice transmitter from the ARRL handbook when I was 12-13 years old, and got myself a novice license (here in the USA), and the transmitter worked. I did not know very much about what I was doing, but I took the advice of another ham who was kind to me and gave me lots of advice - but he didn't do the work for me either.

So, if you want to *learn* about transmitters, get a copy of the RSGB and/or ARRL handbooks (older ones too) and read. It will tell you a ton about transmitters, all in one place. You can get a copy of the "west coast" handbook, by Bill Orr W6SAI (iirc) after that... (if ur money is limited, use the library's copy for a while)

Then too, go to Pete Millet's site and download any of the dozens of classic text books, including the "bible" aka the Radiotron Designer's Handbook by F. Langford Smith. (you can buy a copy of that too, on Amazon, it's back in print apparently).

That should keep you busy for a few days, and give you almost all the answers to the questions you've been asking so far, and most of the ones you may ask for some time to come.

I'd suggest doing some reading there, and *then* asking for explanations if you need any.

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Old 19th November 2012, 08:29 PM   #74
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Also go to the library and borrow the RSGB Handbook.
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Old 19th November 2012, 08:32 PM   #75
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Quote:
Originally Posted by Don Hills View Post
Also go to the library and borrow the RSGB Handbook.
URL please?

?????? ?????? ????? Ipad - YouTube
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Old 20th November 2012, 12:21 AM   #76
freax is offline freax  Australia
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Quote:
Originally Posted by Cassiel View Post
I'm beginning to like this idea. So you could trigger airport mayhem with only a small transmitter? Wow, terrorism has never been cheaper.
And this gentlemen is where I wash my hands of this thread.

Its been nice knowing you guys. *hint* *hint*

Btw just a heads-up for all you youngsters who thinks its cool or raaad to kill people, the authorities can/are probably watching this thread with great interest and anything you say or do can and will be used against you in a court of /US/ law and you could be charged with Terrorist activities before you even commit a crime.

Just so you know. It ain't the 90's anymore. or even the 00's, its 10's now. And I don't paticularly feel like going to Federal prison or Guantanamo.
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Old 20th November 2012, 01:02 AM   #77
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Hi bear, thanks for the advice I will get some books and don't worry Freax i'm not a bad person I don't even know what raaad means lol.... Would it make people happier if I just got an old CB radio to play with? no licence needed from 2006 for less then 5 watt
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Old 20th November 2012, 01:12 AM   #78
freax is offline freax  Australia
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You can't transmit music on CB and get away with it, they (the government) will know and will now come down on you for copyright theft in addition to illegal broadcasting, 5 watts (13 watts on SSB) can burn you (Lookup RF burns, have a sick bag handy) if you don't have an antenna or dummy load setup (a dummy load would be ideal).

http://www.transmission1.co.uk/forum...php?f=2&t=1835
http://www.eham.net/ehamforum/smf/in...?topic=72822.0

To top that off the output transistors in a CB radio aren't heatsinked/rated for constant use, so you would have to use it for 30 seconds then stop transmission for 30 seconds.

And the microphone input of a CB radio can't be easily adapted for line input without checking for RF coming back down the microphone input into your computer/cd source and burning something out inside there.

In Laymens terms, I wouldn't bother, and CB radio's can still produce RFI/Harmonics on the lower VHF band, so you've just replaced one problem (taking out ATC) for another. (Taking out Police/Ambulance/6m/10m HAM radio service).

Build a kit.

Last edited by freax; 20th November 2012 at 01:22 AM.
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Old 20th November 2012, 01:20 AM   #79
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I was meaning a cb to talk to people not music my friend has one and gosh can't even use real radios to talk to people now? can I still use my phone? . I understand what you mean though. In my dad's CB book it says filters must be fitted to the antenna to block outgoing VHF/UHF interference.
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Old 20th November 2012, 01:25 AM   #80
sco1t is offline sco1t  United Kingdom
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oh infect it don't matter I'll never do anything with transmitters again
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