I was just noticing the blue coax close up to the camera.

Yes, not sure what that was.
That used to belong to a local RSL station that went down some time ago. I had 2 of them, one basically scrap and that one.

No worries.

Phoenix. There's a blast from the past. Those guys were old school necks.

That's right, I believe that a company called Radica took them over and still continued to build them. They also built a matching 50 watt linear as well.
I will admit, its a cracking bit of kit, audio compression pre emphasis and stereo too. I have fitted RDS to it as well. If I get a moment I'll upload a picture of the innards.

This is it.

I bought an SBS LP2 with an SBS PA250 about 15 years ago from a guy who runs a long (still) running House station. That was a nice piece of not so little kit and would have originally cost quite a lot of money, until the person I bought it from "found" it somewhere in Hampshire next to a large lattice aerial tower and sold me it.

....Unfortunately I lost it when a person who I'd asked to look after it's house got raided for growing skunk. Oops.

Err about the pa.....

SOTS 87 7 wrote:This is it.

I actually remember putting a bid on an identical setup to this on ebay, got well outbid.
They went for near on £400. I was quite shocked.

This just turned up on my doorstep, it's 150W





What you you think?

okay what i think:
Old direct on freq pll
amp using old type transistors and ripped out of a other old rig
And a LPF is missing on the output
And i think this box will hum like hell (100MHZ osc)
Also the maxium power of the output transistor is 100W
Sorry but this is what i think about it
Hope you not payd a lot for it

The Driver and output transistors comming from the ebay UHF amplifier
http://www.ebay.com/itm/PA-PCB-With-Mot ... 20d634a8ea

RF-Head wrote:
okay what i think:
Old direct on freq pll
amp using old type transistors and ripped out of a other old rig
And a LPF is missing on the output
And i think this box will hum like hell (100MHZ osc)
Also the maxium power of the output transistor is 100W
Sorry but this is what i think about it
Hope you not payd a lot for it

Yes, the parts are old! The builder is retired and had some spare parts lying around so I asked him to make a tx from them. The output transistor is only capable of 100W? Maybe I need to call my rig builder to see if this is only 100W!

Max 100Watt
http://www.hgsemi.com/UploadFiles/2011612135538180.pdf

RF-Head wrote:Max 100Watt
http://www.hgsemi.com/UploadFiles/2011612135538180.pdf

Thank you for this information - much appreciated.

I'd get hold of a filter for it and see how you get on - perhaps he hasn't installed one because there wasn't room in the box he's used. You need to make sure the output is clean and there are no in band sprogs. I'm not familiar with that exciter so can't comment on that part. What I can say is the I'm not impressed with the overall layout, it's untidy and you need to make sure it doesn't take off when you fire it up. If it does, I'd say you need to fix the layout within the box rather than mess with tuning etc.

The good news is, that (despite the 30yo transistors) there's nothing wrong with the topology of the amp. If he's tuned the PA strip, then it looks like it has been designed for band II. Those are inefficient devices however and without a fan, there's no way that thin heatsink would be anywhere near adequate with that PA running at 100W output (doubt you'll get that) at the final. So make sure the fan's in good nick.

Not sure how you guys can see the numbers on the transistors but if the final is a 2N6166 be careful, they are not rugged at all and will blow quite easily into a poor antenna.

As others have said you may find this hums a bit (or maybe not, just have to try it) and also I would add a low pass filter.

The driver is a greek design from a guy calling himself Aspisys. I haven't had one on the bench ever but saw the circuit diagram which looked okay to my eyes.

When you fire this up, firstly make sure the antenna is 100% good and secondly periodically check how hot the heatsink is getting; if you can't hold your hand on it for more than a few seconds it's too hot.

Save the pic to your computer then you can enlarge the image.

The amp looks like it's been laying around in someones junk box since the 80's, it may have been built recently with old parts, i wouldn't like to bet on it.

I'd bench test the transmitter first to see if it's actually works before connecting to an aerial, as others have said add a lpf on the output, make sure the aerial is tuned or the output transistor will more than likely fry if theres a mismatch.

How do you know the guy you got it off, his he a member on here?

I'd be having a quite word in his ear about a refund if i'd paid for a new 150 watt transmitter, unless you got a really good deal.

quiet not quite

I bought a big box of those PA's exactly the same as on eBay. I paid £10 for 20 of them!