Thanks Don - it's amazing how moving a decimal point over one spot can cause problems. 

I've recalculated it again using 1000 in a milli instead of 100 and the answers ended up bring pretty close to yours.  Time to start putting stuff together.

Thanks again..

73

Clinton

Hi,

I'm just after confirmation that what I'm about to do sounds right to the more experienced here (please!)..

I've currently have a TinyTrak3 connected to a Maxon 1 watt radio for playing with APRS.  It all seems to work fine, except the range is a bit average.

As a learning experience, I figured instead of just getting a more powerful radio, I'd build a low power VHF amp from a kit to see how it works.  I've ordered an 8 watt 2m amp from Minikits.  After reading through the instructions (twice ), I noticed in the specs that the PA module has a maximum P_in of 40mW.  So, I figured I'd need to put in an attenuator to reduce the 1W from the radio down to <40mW for the amp.

If I've done all my calculations right, I'm looking for ~6dB of attenuation, which I can get by making a Pi attenuator using 150 ohm resistors for Shunt In/Shunt Out, and a 38 ohm resistor for the series, which will give me a P_in of somewhere near 30mW.

Does that sound right to anyone else?  Anything else I should look for/other recommendations?

Cheers

Clinton

After I got my license, my XYL (We're both 30 ish) noticed that there was a new radio in the 4x4 (IC-2200), and the other radio (IC-400Pro [UHF CB]) had moved to a different spot.  I was impressed enough that she noticed that small change.  She asked what the new radio was for, and she listened attentively for the 3 minute spiel.

Her question at the end of it all?  "So, if something goes really wrong and you get hurt, can I use either of the radios to call someone for help without having a callsign?"

So, she understands my interest in it all, and she can see the practical side of it, but has no interest in it herself.  Each to their own.  I'm not overly interested in her "Wine Tour" weekends either, but I can see the practical side of it!