"High Power" signal generator needed

[wilhe_jo]

Hi Folks!

I'm in the progress of getting my conducted immunity test setup streamlined (ie. get the conducted and radiated test setup separated).
Up to now, I have a nice Amplifier Research unit which gets moved around... it works, but I'd love to have a fixed setup.

There're several MRF101 amplifier builds around.
I'm confident to build an 150k-80M amplifier (actually, I'll switch between 3 bands for ease of implementation) from the available reference designs.
However, this would only have a power gain of about +20dB...

I guess, having 25W of power would be plenty.
So I'd need 24dBm of drive power (the MRF101 could do 100W@1W drive power).

That's 10dB more than my current generators could do... So I'm out for a new (read: new in my lab, but old and used due to budget constraints) 150k-80Mhz signal gen as well

After looking at various data sheets, I only found the Keysight/Agilent 33250a...
That would give me 1W which would be a very nice match for the MRF101.

I'm sure there are more generators in the 24-30dBm range out there (having some pc-interface)... any recommendations???

BTW: Yes, adding a driver-amplifier came up to my mind, but I did not find a "finished" 150k-80MHz 1W preamp design (with available parts).
So I thought trading time vs money and getting a new signal gen would be fine as well

73


[edit]
Maybe it makes sense to make a list of these higher-power sig-gens...

Gwinstek	AFG-3081	10Vpp @ 50Ω	DC-80MHz
Agilent/Keysight	33250A	10Vpp @ 50Ω	1µHz-80MHz
Rigol	DG5101 (whole DG5000 series)	10Vpp @ 50Ω	depends on model
TTi	TGF4162/TGF4242	10Vpp @ 50Ω <=80MHz	depends on model

[/edit]

[bob91343]

Have you considered an amateur radio linear amplifier?  Some of them can deliver kilowatts.  The frequency might not be adequate so you might need two or three different units.

[wilhe_jo]

Yes, I have... actually I found the MRF101 by looking for some ham-radio stuff.

The 2200m band (just below the 150kHz boundary) is still pretty rarely used.
So there are not too many commercial options. Most do 1.8-30 or 54MHz.

However, you can find several homebrew designs using the relatively new MRF101...
So I think, the amplifier is doable if you can provide enough input power.

Meanwhile I ran through most obvious budget brands (initially, I was searching for used stuff.

73

[bob91343]

For below 100 kHz, consider an audiophile amplifier.

[tautech]

I'm sure there are more generators in the 24-30dBm range out there (having some pc-interface)... any recommendations???

SDG2082X 
SDG6022X ^ both 10V p-p into 50 Ohm uses EasyWaveX SW for remote control
SSG3021X     20 dBm max into 50 Ohm. Has webserver.

[2N3055]

Mini circuits ZHL-32A+ or ZHL-32A-S+ as a driver between AWG  and power amp ??

[wilhe_jo]

I'm sure there are more generators in the 24-30dBm range out there (having some pc-interface)... any recommendations???

SDG2082X 
SDG6022X ^ both 10V p-p into 50 Ohm uses EasyWaveX SW for remote control
SSG3021X     20 dBm max into 50 Ohm. Has webserver.

They don't get you the 10Vpp in the whole .15-80MHz range...

Mini circuits ZHL-32A+ or ZHL-32A-S+ as a driver between AWG  and power amp ??

Hmm, didn't had these on my radar... sounds an interesting option, thanks!


73

[AJ3G]

I think some of the Marconi 202X Series has a high power option. If you look you can have one for reasonable money.

Rich

[wilhe_jo]

Well, I found this in the Marconi 2023/2024 datasheet:

High power
A high power option is available which
provides an RF output up to +25 dBm -
ideal for use as a local oscillator or testing
passive and active components

So that's not bad, but not quite what I'm looking for... In addition, they can't to full power when doing AM:

When AM is
selected, the maximum RF output level decreases
linearly with increasing AM depth to +7 dBm at 99.9%
depth.

I wonder if that's considered in the other data sheets... That's the first one which is that specific on this detail.

73

[AJ3G]

Yes, if you have AM Set, it will not allow you to advance the amplitude beyond a certain number. From what the Marconi User Group says this to give you enough headroom when running AM.

Rich