CMU200 50Watt with B95 Option?

[chick0n]

Hi

I own a cmu200 with option B95 (2nd generator). So I can only use the cmu with 2Watt input.
Option B95 is Sandwiched to the RF-Frontend Board. I opened the Frontend, and there is a 50Watt 17dB attenuator placed. Also there is place for another one.

Maybe it is possible to use the cmu with more than 2W input, when option B95 is disconnected/removed?

Maybe someone with a 50Watt unit could make pictures of his frontend. To compare and see if a 2nd attenuator is placed?

[xmo]

I think port RF1 has that attenuator so it can accept 50 watts whereas RF2 has no attenuator and can only handle 2 watts.

Option CMU-U99/B99 deletes the attenuator and makes the range of RF1 and RF2 be the same.

[chick0n]

I think port RF1 has that attenuator so it can accept 50 watts whereas RF2 has no attenuator and can only handle 2 watts.

Option CMU-U99/B99 deletes the attenuator and makes the range of RF1 and RF2 be the same.

But every CMU200 with B95/96 has a Warning Sticker on Port RF1 and RF2 "Only 2 Watts". Mine too. Why?

Maybe its just the cooling... The 50Watt frontend has a fat heatsink installed, and B95 Option has none.

[xmo]

You are probably right about the heatsink.

I looked in the datasheet again and found that it does say you get reduced power with B95 so that accounts for the sticker.

[Bravo]

You could use an external high power attenuator, & enter the +dB amount on the port 1 settings.

[RBBVNL9]

Dear all,

The maximum power level of the CMU200 is a topic that comes back in this forum every once in a while. Recently, I recorded a video that digs deeper into that topic (see below).

Installing options B95 or B96 brings down the maximum power level of RF1 from +47 dBm (~50W) to +33 dBm (~2W). The technical reason is that the board of these options actually take the physical space where otherwise the heat sinks and fan are for cooling the shunt resistor of the 50W version. With these options, you get some more functionality at the price of less input power. Fine, that is a choice you can make.

More intriguing is option CMU-U99/B99, titled "RF1 level range identical to RF2 option". As far as I can see, this 'option' is always a downgrade. You give up the 50W capability and get nothing in return. (Unless you have an automated setup where you need to switch between input channels that are both exactly –8 to +33 dBm  ?!?). I find it strange to call this an 'option'..

Anyway, here is the video:

https://youtu.be/BtFvhvN3d8A