CM300: how low is low power?

boteman · Post by **boteman** » Fri Jul 25, 2008 11:53 am

How much power does a high band CM300 put out when I have selected low power via the front panel? The shop programmed it for high power, by the way.

I have one here that I am preparing for use as a low duty-cycle control station and you could fry an egg on the heat sink after only 5 minutes of 20-30% transmit time. In fact, it has been sitting here heat-sink-side-up having been idle for well over an hour and it is still quite warm to the touch.

Please forgive, I'm a CM300 virgin. Thanx.

Post by **escomm** » Fri Jul 25, 2008 12:01 pm

Depends on if it is a high power or low power radio. Low power radio is 1-25 watts, adjustable via CPS. High power radio will not accept anything below 25 watts.

It is possible the radio is having power reflected back into it, or there may be some other internal issue. Regardless of the CM300's chintzy heat sink, the symptoms you report are not typical and indicate to me that the radio needs to be looked at on the bench, assuming the power has or hasn't been turned down as you state.

boteman · Post by **boteman** » Fri Jul 25, 2008 1:55 pm

Perhaps I should have had the presence of mind to post the model nummer: AAM50KQF9AA1AN which sounds like a low power to me, but reading how Mother Mo changed the model number schema I'm not sure any more.

Thanks.

Post by **escomm** » Fri Jul 25, 2008 8:05 pm

Nope it's high power, you won't be able to turn it below 25 watts in the CPS.

boteman · Post by **boteman** » Mon Jul 28, 2008 8:10 pm

Crap! What is its max power, then?

Thanks for clearing that up for me, that answers quite a few questions.

Bote

Rayjk110 · Post by **Rayjk110** » Mon Jul 28, 2008 8:27 pm

I believe 25-50 watts (although it will let you bump it to 54)

boteman · Post by **boteman** » Tue Jul 29, 2008 5:50 pm

Wow. Big M is pretty optimistic, looking at this itty bitty heat sink on the thing. What's the recommended duty cycle? 10% ?? YIKES!

Mikey · Post by **Mikey** » Wed Jul 30, 2008 7:20 am

You need to have it checked, i have had several CM200's and 300's come right out of the box with problems with the PA sticking on even when not transmitting. Had one that set in a room for days just in receive and the PA was stuck so the heat sink was so hot you couldn't keep your hand on it. Sent it to the Mother M and it came back all nice and fixed.

Mikey

boteman · Post by **boteman** » Wed Jul 30, 2008 9:11 pm

OK, thanks for the tip.

If it's a Class C amp, should it draw enough current to heat up appreciably with no excitation on its input?

I'm longing for the good old days when Motorola knew how to build real radios.

Post by **motoroladealeruk** » Thu Jul 31, 2008 1:21 am

I don't want to rock the boat but are you sure it's a 25-50watt model???
I had it marked as a 1-25watt...
But i may be wrong!

Mikey · Post by **Mikey** » Thu Jul 31, 2008 6:02 am

Look at the model Number KQF is a 25-45 Watt, KNF is a 1-25 Watt

Mike

CM300: how low is low power?

CM300: how low is low power?

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Re: CM300: how low is low power?

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Re: CM300: how low is low power?

Re: CM300: how low is low power?

Re: CM300: how low is low power?

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