Stealth Microwave SM2325-47 Amplifier

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tonyaxn
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Joined: Tue Jun 09, 2015 4:13 pm

Re: Stealth Microwave SM2325-47 Amplifier

Post by tonyaxn » Sat Mar 02, 2019 8:40 am

Hello Mike...

That's very helpful... now off to technical stores (the garage) to source the appropriate parts !

Thanks
Tony.

G1BVI
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Joined: Wed Aug 02, 2017 7:32 am

Re: Stealth Microwave SM2325-47 Amplifier

Post by G1BVI » Tue Mar 12, 2019 9:16 pm

For anyone who has a Stealth Microwave 2527 25W Amp, this has an output power of 20Watts at 2.4GHz

73

Nick

radiogareth
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Re: Stealth Microwave SM2325-47 Amplifier

Post by radiogareth » Thu May 09, 2019 7:59 pm

Finally got round to supplying 12 volts to my Stealth 2327-s471lrf 'purple heatsink' 2.4 GHz amplifier (labelled 60 watts). It has a hunger for amps at 12 volts, soaking up 15.5 amps and understandably getting warm. The On/Off pin seems to have no effect, either connecting it to GND (via 5K6 resistor) or to 12 volts (via R). Does this amp need something different to switch the bias on/off? Can't find any data for it, unlike its 9cm cousin.
Hooked up to a HP server PSU rated for 82 amps on 240V and which gives 12.3 on load.
Soaking up 180+ watts, so I guess 60 watts out (I haven't fed it with anything yet) would seem OK.
Or is it a bin-job'?
I can switch the PSU remotely via a low voltage control line, but it would seem logical to use the amp as designed (well sort-of!).
Guidance welcome....
Gareth G4XAT

G8GKQ
Site Admin
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Re: Stealth Microwave SM2325-47 Amplifier

Post by G8GKQ » Thu May 09, 2019 8:18 pm

Gareth

Can you post a photo of the connections on the end of your Stealth? There are 2 small feedthroughs on the one that I have seen. They both needed a 5K6 to +5 to make the amp work. Current consumption seems about right. It won't need much drive (less than a milliwatt) so start with a big attenuator on the input.

Dave, G8GKQ

g0mjw
Posts: 935
Joined: Sat Sep 20, 2014 9:15 am

Re: Stealth Microwave SM2325-47 Amplifier

Post by g0mjw » Thu May 09, 2019 8:48 pm

radiogareth wrote:
Thu May 09, 2019 7:59 pm
Finally got round to supplying 12 volts to my Stealth 2327-s471lrf 'purple heatsink' 2.4 GHz amplifier (labelled 60 watts). It has a hunger for amps at 12 volts, soaking up 15.5 amps and understandably getting warm. The On/Off pin seems to have no effect, either connecting it to GND (via 5K6 resistor) or to 12 volts (via R). Does this amp need something different to switch the bias on/off? Can't find any data for it, unlike its 9cm cousin.
Hooked up to a HP server PSU rated for 82 amps on 240V and which gives 12.3 on load.
Soaking up 180+ watts, so I guess 60 watts out (I haven't fed it with anything yet) would seem OK.
Or is it a bin-job'?
I can switch the PSU remotely via a low voltage control line, but it would seem logical to use the amp as designed (well sort-of!).
Guidance welcome....
Gareth G4XAT
The output is 50W, that's what the 47 refers to 47dBm. 18A at 12V, not 13.8! Very low drive, sometimes the first device is non-working from over drive. There is loads of data on the web, including a data sheet, don't know why you have not found it. For DATV with long overs, I have just been applying power. There are forward and reverse detectors and a low level output options, you may have these. You will need fans to cool it. Expect 15-20W of DATV -30dB shoulders.

Mike

Close enough https://html.alldatasheet.com/html-pdf/ ... 25-47.html

Mike

radiogareth
Posts: 338
Joined: Wed Jan 06, 2016 9:46 am

Re: Stealth Microwave SM2325-47 Amplifier

Post by radiogareth » Fri May 10, 2019 6:34 am

Thanks Mike. I'll cautiously give it some RF and see what comes out then.
Your description matches my unit although the RF sample SMA has been blocked off with something. Still got Fwd and Ref if I need to measure things.
Gareth

G1BVI
Posts: 155
Joined: Wed Aug 02, 2017 7:32 am

Re: Stealth Microwave SM2325-47 Amplifier

Post by G1BVI » Fri May 10, 2019 12:36 pm

With 12V ONLY applied to the Amp you shouldd get something under 0.5 Amps drawn NOT the full current.
On my amp I have a pin marked TTL On /Off and as I recall one pin marked CTRL.
I linked these two together and my PTT line enables a relay that applied +5V to these pins. (They are TTL )
At this point your Amp will be switched ON and current will be drawn.
My 2527 gave full output (25W ) @2.5 GHZ

The same input (-9dbm) gave 20 W @2.4GHz

Hope that is of some help

Regards

Nick

g0mjw
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Joined: Sat Sep 20, 2014 9:15 am

Re: Stealth Microwave SM2325-47 Amplifier

Post by g0mjw » Fri May 10, 2019 1:05 pm

There are several different options available. As a base you get RF and and RF out and power. Even the purple heatsink is an option.

As it happens mine has heatsink, sample output, forward and reverse power and a level indicator options fitted. The TTL on/off and high speed switching options are not fitted but I know about them as they are fitted on some of my other SM amplifiers.

A lot of people have no idea what these amplifiers are, not how useful they might be. I have bought a complete rack for £5 with 2 amplifiers and power supplies in the past. To be fair, the front panel had a dent in it. It is quite easy to identify them. SM - Stealth Microwave. 2527 2.5 - 2.7 GHz, - 47 47 dBm = 50W. The SM3436-44 model is very common and useful on 9cm. The SM2325-47 is good for 13cms. The SM0825-36 is a useful 4W broadband amplifier covering 800-2500MHz.

Mike

radiogareth
Posts: 338
Joined: Wed Jan 06, 2016 9:46 am

Re: Stealth Microwave SM2325-47 Amplifier

Post by radiogareth » Sat May 11, 2019 2:16 pm

Picture of the beast. I'll sort out 5 volts and try it.
Gareth
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radiogareth
Posts: 338
Joined: Wed Jan 06, 2016 9:46 am

Re: Stealth Microwave SM2325-47 Amplifier

Post by radiogareth » Sat May 11, 2019 7:38 pm

OK, So I've been testing....I took the lid off and noticed that the +12 volt feedthrough was shoved in and bypassing what I assume if the main power switch, a beefy P-type FET. FET seem to have survived - no reason not to really, as tab is Drain so all it was doing was bypassing the gate control.
Closer inspection of the PCB shows the rev track missing a bit ?? and what looks like a non-original extra resistor has been added. The extra resistor is 18K but the gate end of the track metres 2K to ground, which would switch the device on. The 'extra' resistor can be seen bottom right of the FET picture, joining onto the cut 'FWD' track.
Checked sensible voltages at the gates of the two finals - 1.6 volts.
The wire I'm feeding it with isn't quite up to the job and I'm getting 10.5 at the amp, drawing 15.5 amps. (1 volt drop over its length)
Fed it a bit of RF and its amplifying, but even with Lime drive on 96 (-9dBm on mine) I was only getting +20 dBm out, so 0.1 watts.
Other than looking at the in and out of each driver stage, anything else I should be considering? Nothing obviously had the smoke let out of it.
TIA
Gareth
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