So, I've seen loads of horn exciters/10 ghz transmitters but never a link receiver box, probably due to the fact that sat cans are usually installed into the FM transmitter box by the builders,. My builder is not using a sat can in my TX, so i'm gonna have a go at making one myself. I thought i'd show off my handywork hopefully in return for some pointers from you tech-savvy lot. Here is what i've managed to source so far:

The aluminium box and flex


Power supply


Pre-wired sat can


RCA socket


I'm just waiting for some new HSS drill bits to arrive then I can get going with building it.

One question - Will I need to earth the RCA socket?

Yes.

Just out of interest can't you add the satcan into transmitter enclosure once you have received it?

Is there no room left in the enclosure ??? be interested in seeing inside your rig builders box with a lid off if there ain't room

Also instead of adding another power supply just for the satcan why not take a feed from the rig? Your making a lead for audio so why not run a 12v back too???

Or I'm I missing something

Gigahertz wrote:Just out of interest can't you add the satcan into transmitter enclosure once you have received it?

Is there no room left in the enclosure ??? be interested in seeing inside your rig builders box with a lid off if there ain't room

Also instead of adding another power supply just for the satcan why not take a feed from the rig? Your making a lead for audio so why not run a 12v back too???

Or I'm I missing something

Don't worry you're not missing anything. I'm just trying to get to grips with building electronics stuff and radio gear and this is a little intro project for myself. I've got another satcan that is ready and wired up that could go inside my rig when I get it, so I might just do what you suggest if it's possible.

shuffy wrote:Yes.

Thanks shuffy

You're welcome. Sorry if that sounded flippant but... that's the answer! Good to have some more stations up here.

triplestack wrote:

Gigahertz wrote:Just out of interest can't you add the satcan into transmitter enclosure once you have received it?

Is there no room left in the enclosure ??? be interested in seeing inside your rig builders box with a lid off if there ain't room

Also instead of adding another power supply just for the satcan why not take a feed from the rig? Your making a lead for audio so why not run a 12v back too???

Or I'm I missing something

Don't worry you're not missing anything. I'm just trying to get to grips with building electronics stuff and radio gear and this is a little intro project for myself. I've got another satcan that is ready and wired up that could go inside my rig when I get it, so I might just do what you suggest if it's possible.

Cool no problem good luck with your station !

Put a audio amp in there and do tests from sites !

Gigz

Gigahertz wrote:

triplestack wrote:

Gigahertz wrote:Just out of interest can't you add the satcan into transmitter enclosure once you have received it?

Is there no room left in the enclosure ??? be interested in seeing inside your rig builders box with a lid off if there ain't room

Also instead of adding another power supply just for the satcan why not take a feed from the rig? Your making a lead for audio so why not run a 12v back too???

Or I'm I missing something

Don't worry you're not missing anything. I'm just trying to get to grips with building electronics stuff and radio gear and this is a little intro project for myself. I've got another satcan that is ready and wired up that could go inside my rig when I get it, so I might just do what you suggest if it's possible.

Cool no problem good luck with your station !

Put a audio amp in there and do tests from sites !

Gigz

That's a great idea actually! Good thinking batman!

Basic box is finished & tested - works nicely. I've got an audio amp module on the way (from China) that i'm gonna try and squeeze into the box as well, but that's gonna be a little further down the road. Please ignore the shocking soldering skills. Have a butchers:









What do you lot reckon? Am I in the crew now?!

Maybe you should put one metal plate between switching psu and satcan. Psu can radiate some noise into audio path...

pjeva wrote:Maybe you should put one metal plate between switching psu and satcan. Psu can radiate some noise into audio path...

I did notice a little noise in the audio from this when connected to an amp and speakers. The psu has a metal lid, which I still have here (see below picture), will this suffice or will I need something more substantial?

If it is not enough, add full bracket between psu and satcan. It can be made from thin metal with just small holes to pass cables through. Also add 1n, 10n and 100n capacitors from supply + to ground as close as possible to satcan supply input

Put some cable ties around the mains cable to stop it being pulled out by accident. You can also just tie a knot in it, which does the same thing.

Also, you can try removing the red wire from the phono socket to the mains earth, it should work anyway with the metal box and coax already connected to the satcan.

pjeva wrote:If it is not enough, add full bracket between psu and satcan. It can be made from thin metal with just small holes to pass cables through. Also add 1n, 10n and 100n capacitors from supply + to ground as close as possible to satcan supply input

Thanks for the advice pjeva, the satcan has some caps around the + input, you can't see them in the other photos. Will I still need to put some in? It works really well as it is to be honest - have a look:

Analyser wrote:Put some cable ties around the mains cable to stop it being pulled out by accident. You can also just tie a knot in it, which does the same thing.

Also, you can try removing the red wire from the phono socket to the mains earth, it should work anyway with the metal box and coax already connected to the satcan.

Done & done!



I tested it again today, it works perfectly. Dead chuffed.

What is the code on that voltage regulator? (soldered on side of satcan) is it 7812?

s2000 wrote:What is the code on that voltage regulator? (soldered on side of satcan) is it 7812?

It does indeed s2000

You need a 15v psu then... a 7812 voltage regulator needs roughly 3v more on the input side to be able to regulate 12v properly on the output. It might be the reason you are hearing some noise through the speakers...

You've done a nice job but I would try and steer clear of switch mode power supplies for audio circuits (especially cheap chinese ones), they can have a lot of electronic noise which if not surpressed can be problematic... (maybe another reason you are hearing noise through the speakers).

Why not try and build a 15v linear supply? they are relatively easy to make and you will learn a lot more about electronics..

On second thoughts you could just build a simple unregulated dc power supply as you already have a 12v regulator on the satcan..

s2000 wrote:You need a 15v psu then... a 7812 voltage regulator needs roughly 3v more on the input side to be able to regulate 12v properly on the output. It might be the reason you are hearing some noise through the speakers...

You've done a nice job but I would try and steer clear of switch mode power supplies for audio circuits (especially cheap chinese ones), they can have a lot of electronic noise which if not surpressed can be problematic... (maybe another reason you are hearing noise through the speakers).

Why not try and build a 15v linear supply? they are relatively easy to make and you will learn a lot more about electronics..

s2000 wrote:On second thoughts you could just build a simple unregulated dc power supply as you already have a 12v regulator on the satcan..

Brilliant information thanks s2000, I like this kind of response it's very constructive. When I tested it today I couldn't hear any noise at all really, I think the problems before was the distance I was testing the link over, it was only about 7 foot. I stuck the LNB in my garden and horn was about 30 foot away and the audio was nice and crisp. Even had a decent bottom end! Inside the psu there is a pot which allows a small increase in voltage to around 14v so i've whacked that up and put the metal cover on.

I'm just having a look into unregulated dc power supply circuits as we speak

It may well be that you broke a hum loop, when you removed the redundant ground connection (as per Analyser's suggestion). Generally, you want to be as close to a "star point earth" model as possible. Doubling up causes multiple paths to mains earth, which leaves different grounds at slightly different potentials, where the potential difference (voltage) is AC hum.
As "S2000" said, the 12V regulator will not do anything worthwhile with only 12V input. It can't provide any regulation, and effects may be unpredictable. I think it will just give a small additional voltage drop, and not much else. Also bear in mind that switching supplies can also radiate the switching frequency, and it can also be present on the output rails. A regulator would normally help to suppress this. It can't do that if it's not regulating, but the 10uF caps should help (although if the supply itself is well filtered, it may not be an issue anyway). I wonder if your PSU has an output voltage adjustment.....