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Bruker BFX-5 RF amplifier

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TheMerovingian

Fri Oct 09 2009, 03:12PM

Registered Member #14 Joined: Thu Feb 02 2006, 01:04PM
Location: Prato/italy
Posts: 383

I came accross a working RF (5W) amplifier and some meters of VHQ coaxial cables, part of an NMR instrument that my institute is dismantling and basically throwing away. I took it and i'm figuring out how to test it. The idea is to connect a signal generator at 1MHz (50 ohm) and on the output a 50ohm dummy load to test the waveforms. It has one output and several inputs: HP/AM AC (IN) , LP AM (IN), LP AC (IN) and RCP3 (IN) plus one power regulation knob.

Has it any value on the market of amplifiers? I don't want to set up a pirate radio (5W means jail) and i'm not really in the RF world. What fancy experiments i can do with it?

What the inputs mean?

Proud Mary

Fri Oct 09 2009, 05:41PM

Registered Member #543 Joined: Tue Feb 20 2007, 04:26PM
Location: UK
Posts: 4992

high power amplitude modulation
low power amplitude modulation
low power AC (unmodulated carrier)

RCP usually designates a difference signal in this sort of context (It can also mean right circular polarization)

TheMerovingian

Fri Oct 09 2009, 06:34PM

Registered Member #14 Joined: Thu Feb 02 2006, 01:04PM
Location: Prato/italy
Posts: 383

Being designed for NMR experiments i suppose it is ultra low THD and ultralow noise (because NMR experiments are very very sensitive).

I will test it and then i will decide what to do (it is sitting in my office room near other salvaged parts like a signal generator and an oscilloscope)

Sulaiman

Fri Oct 09 2009, 08:00PM

Registered Member #162 Joined: Mon Feb 13 2006, 10:25AM
Location: United Kingdom
Posts: 3140

I know that amateur radio is thriving in Italy, I'd expect it to sell easily on eBay.
A good hf amplifier is (to me) a good bit of kit to keep around - I'm sure you'll find some interesting things to do with it-
- micro-sstc
- small plasma speaker
- diathermy on small objects
- 11 MHz 'citizen's band' There's quite a DX community.
(DX = distance, not local exchanges of abuse)
- Kirlian photography

there must be more , others may have better ideas.

TheMerovingian

Fri Oct 09 2009, 10:27PM

Registered Member #14 Joined: Thu Feb 02 2006, 01:04PM
Location: Prato/italy
Posts: 383

Interesting, maybe it will remain in my possession for now, the problem is that i have not enough space for this equipment, (it would be good to have a room dedicated to electronics

) so it is sitting in my office. I would like to sell it to buy a decent 60 ot 100Mhz Digital scope but i can save it for the rainy weekends

The kilian corona-ish photoes are very very beautiful. The micro sstc too, it can be useful to learn impedance matchings, tunings etc.

I have seen on ebay such amplifiers and they have very high cost, with the lower power ones costing around 1000$-2000$ (and the 100+W models around 7000-20000$). It is a very rugged old-fashion class A amplifier with power meter. A photo of it:

Sulaiman

Sat Oct 10 2009, 06:14AM

Registered Member #162 Joined: Mon Feb 13 2006, 10:25AM
Location: United Kingdom
Posts: 3140

I didn't realise they are so expensive - in which case I'd sell it !

If you do sell it be sure to mention the bandwidth - 300 MHz
(I'm not sure, check online) which is VHF/UHF and sell the co-ax with it.

It's not too difficult to make a simple 5W hf (<30 MHz) amplifier
... one or two IRF510 and some small components.

TheMerovingian

Sat Oct 10 2009, 09:05AM

Registered Member #14 Joined: Thu Feb 02 2006, 01:04PM
Location: Prato/italy
Posts: 383

Judging from the size and fusing it is a class A amplifier, dunno the bandwitch, cannot find the specs on the net and cannot figure out how to measure it without a 1GHz scope

. It comes from an old bruker 200MHz spectrometer so i think that it is something in this range, probably a bit higher because it is some kind of accessory so it must fit with various experiment conditions. Cannot use it for CB. because in italy it is forbidden to use amplifiers even if you don't go above the power limit. In italian CB langage you are using a "scarpone" (boot or booster), if not you are "liscio" (plain or regular).
THe sstc would be fun, but probably no streamers to be seen a such low power.

Proud Mary

Sat Oct 10 2009, 10:02AM

Registered Member #543 Joined: Tue Feb 20 2007, 04:26PM
Location: UK
Posts: 4992

You could put the output into a dummy load so very little RF energy is radiated.

Steve Conner

Sat Oct 10 2009, 11:16AM

Registered Member #30 Joined: Fri Feb 03 2006, 10:52AM
Location: Glasgow, Scotland
Posts: 6706

TheMerovingian wrote ...

Cannot use it for CB. because in italy it is forbidden to use amplifiers even if you don't go above the power limit. In italian CB langage you are using a "scarpone" (boot or booster), if not you are "liscio" (plain or regular).

That's the funniest thing I've read all week! Italian radio operators are famous for running way over the legal limit with crappy signal quality. I've seen a website where an Italian ham describes a 10 kilowatt amp that he built and used, and Zetagi brand linear amps are famous the world over for their illegal power levels and crappy signal quality.

As others have mentioned, this is a precision Class-A RF amp for NMR measurements, and pretty much useless for boosting radio transmissions. Why not sell it and buy 20 Zetagis

Proud Mary

Sat Oct 10 2009, 11:27AM

Registered Member #543 Joined: Tue Feb 20 2007, 04:26PM
Location: UK
Posts: 4992

What about making your own NMR rig with it? I've seen very simple circuits designed for the home constructor.

Or you could use it as a linear for SSB

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