Linear lab amp DC-30MHz?

[John Devereux]

Gonna take a HELL of a big pi-network to go down to "DC". ;-)

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[Ancient_Hacker]

Gonna take a HELL of a big pi-network to go down to "DC". ;-)

Not that bad, if you dip it in liquid Helium. IIRC there's such a
thing as a superconducting DC transformer. But I usually like my Pi
warmed up.

 

[Ancient_Hacker]

Years ago I stumbled onto what looked like a forced-air furnace at a
junkyard. Well, it did have a big fan, but the heating elements were
48 4CX250B toobs, all in a distributed-amplifier topology. The thing
was too heavy to drag home. And what would the wife say?

 

[Rich Grise, but drunk]

Years ago I stumbled onto what looked like a forced-air furnace at a
junkyard. Well, it did have a big fan, but the heating elements were
48 4CX250B toobs, all in a distributed-amplifier topology. The thing
was too heavy to drag home. And what would the wife say?

Where's this junkyard at? How deep could they be? ;-)

Cheers!
Rich
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[Joseph2k]

Hello Richard,



If you don't want to build it yourself check out companies like these:

http://www.wavecontrol.com/index2004.php?p=pantalla&pant=RF Amplifiers %20DC%20-%201GHz&idm=385

They claim that the 50WD1000 does 50W from DC to a GHz. It is probably
really expensive, the size of a book cabinet and you may need a crane to
get it into the building.

Regards, Joerg

I would consider some of the Apex devices, they have have high bandwidth
power amplifiers. Some of them are pretty impressive.

 

[Oliver Betz]

What are the most cost effective options for buying or building a
linear amp for general lab work that will do DC up into the early tens
of Mhz?

http://www.ophirrf.com/ sells DC powered modules (e.g. 5303055), but
they are still around 3500USD. And you don't get DC.

Oliver

 

[Joerg]

Hello Oliver,

http://www.ophirrf.com/ sells DC powered modules (e.g. 5303055), but
they are still around 3500USD. And you don't get DC.

If you ever need something this big consider buying a used ENI amp. They
are very wideband and I have used them in susceptibility tests. That way
we also found some glitches that they thought were 'digital', so
sometimes clients wanted to own one afterwards and usually we could find
a used one.

However, one has to know this RF power stuff. Otherwise somebody in a
uniform might knock on the door some day.

Regards, Joerg

 

[Oliver Betz]

[20W wideband amp]

If you ever need something this big consider buying a used ENI amp. They

I'm already considering this, but it seems that people don't sell many
of them.

[...]

However, one has to know this RF power stuff. Otherwise somebody in a
uniform might knock on the door some day.

at lower frequencies (the OP wrote "early tens of Mhz", that's also my
range), the risk is low.

Oliver

 

[Joerg]

Hello Oliver,

I'm already considering this, but it seems that people don't sell many
of them.

Yes, it's tough. Keep your eyes peeled for when an EMI lab shuts down
somewhere in Europe. Most likely they have some. For me buying equipment
from businesses that closed has yielded the best deals for lab gear.

at lower frequencies (the OP wrote "early tens of Mhz", that's also my
range), the risk is low.

That depends on where your location is. Maritime and air traffic still
uses shortwave a lot across the oceans. They don't like it when somebody
messes with their communications.

One common trick to avoid trouble is to try to do most measurements or
at least the initial ones on an ISM frequency. 13.56MHz is one of my
favorites.

Regards, Joerg