New Toy!

[Gigahertz]

Just taken delivery of this lovely piece of equipment!

Corsair II 10watt AM Shortwave transmitter. Also came with a crystal.

[teckniqs]

Nice piece of kit there from Dave Martin AKA Barney. Let us know when it's up.

[radio-berlin]

Would love to see a pic of the inside.

[Gigahertz]

Would love to see a pic of the inside.

When I get a chance I'll take some pictures. Circuit diagrams are on the web also!

[teckniqs]

I've got a similar thing here shows around 40-50w on the power meter. I'll take some pictures of that for you too.

[Gigahertz]

corsair.jpg

corsair2.jpg

corsair3.jpg

[MiXiN]

Very nice indeed.

Would love to have a play around with some AM gear, but it's so hard to source anything more than a few mW these days.

Please give us all a shout when you get it set up, as propagation & conditions can make things at these frequencies travel far & wide.

[Albert H]

Why don't you get a soldering iron out and build an AM rig? They're easy! The trickiest part is the aerial. You'll also need to get rid of the heat generated by the inefficiencies involved!

The easy way to do AM is a simple CMOS synthesiser driving a power FET. You modulate the supply to the FET, and away you go!

[Gigahertz]

The Corsette AM transmitter is a simple build to get your feet wet! Its only QRP under a watt!
Here's circuit diagram

Corsette.JPG

Once I get the antenna made I will let you know but pretty snowed under with work and other projects. Might try a NVIS antenna.

[teckniqs]

At least with 6MHz the aerials are a lot shorter than MW.

[Albert H]

Unfortunately, nobody listens to 6 MHz any more. There's only a few more that listen to medium wave, too.

[Gigahertz]

Unfortunately, nobody listens to 6 MHz any more. There's only a few more that listen to medium wave, too.

Ive always listen around 6Mhz and still do!

Its like people say CB and pirate radio is dead! its not dead but just a small portion of people who still do it or listen to it. I honestly thought CB was dead but the activity is quite surprising especially on the SSB section.

a very very small amount of the new generation take a interest in radio.

[Albert H]

Funny you should say that - this evening I got an old portable receiver out and had a scan at a few old pirate frequencies!

[fmdx]

Radio Merlin booms here on Shortwave 6.305 when it's on. Must be close by as it solid don't even fade in or out really.

[Albert H]

Just out of idle curiosity, I had a listen around the old frequencies. There was some activity just under 4MHz, more at 5.9MHz, 9.3MHz, 6.9MHz, 7.3MHz, and 10 MHz. All was AM, except one (mostly speech) station from the 'States on USB. I was really surprised that there was so much going on!
If you want to hear these stations, you need a good receiver - the Tecsun will do - and as much wire in the air as you can get up. Also be careful to disconnect the aerial if there's lightning around. I have a couple of good receivers, and will now keep a watch on the pirate frequencies, and might contribute some programmes myself, I have a 20 Watt carrier, 100 Watt peak FET AM rig for 6.3 (or 6.9) MHz.

I think I'll put some basic AM circuits up here, so you can all have a go!

[bristolpirates]

Google 'Iann's Pirate Chat'. Never works on my laptop, but very good chatroom for SW and MW pirate reports.

[Premier-Carousel]

Can I stick my twopenneth in and say that I too would be very interested in Albert's AM circuits

Stu

[Albert H]

OK folks. I'll put stuff up here later on. Or tomorrow (I'm knackered!)

[james_wilson16]

Albert are you able to build these for anyone else bud? I have been looking for a sw am transmitter for a while.

[Albert H]

Hi James.

Can you solder neatly? Have you got some basic hand tools, a multimeter and a CB SWR bridge? Have you got a shortwave receiver? If you have, you have everything you need except the components. AM gear is actually pretty easy to build - it's not as layout-critical as VHF stuff. I'll put some circuit sketches up here later on, together with some instructions about getting the right results.

If you use three cheap CMOS ICs, a few diodes, and a 4MHz crystal (available for pennies anywhere) you can generate any shortwave or medium wave frequency. You have to do a decimal to binary conversion (it's really easy maths) and connect the right pins on the ICs. The best thing is that you don't need to buy a crystal for your frequency of choice - custom-cut ones are expensive and the nosey hams who run the crystal-cutting companies will want to know why you want that particular frequency....

More to follow!