Page 1 of 1
CDM-1550 ls Power Level Control
Posted: Fri Apr 18, 2014 12:57 pm
by RoryB
Got big trouble... bought a CDM-1550LS on EBAY, 40 watt R range. I am going to use it in a pt-pt link between repeater sites; the path is LOS and not that far so I thought I could run the radio down to around 7 to 10 watts in low power. I am not having much luck... I have Tuner32 and changing the softpots for low power does not seem to have the effect I thought it would. I seem to be stuck between 20 and 25 watts. Any advice???
Thanks Guys!
Rory, K6CKS
Re: CDM-1550 ls Power Level Control
Posted: Fri Apr 18, 2014 4:36 pm
by Will
Are you selecting LOW in the programming?
Some radios like the Maxtrac and Radius will not go below 2/3 power before becoming spurious and drawing excess DC power.
Re: CDM-1550 ls Power Level Control
Posted: Fri Apr 18, 2014 4:52 pm
by RoryB
Yes I set the power level to "low" for the conventional channel. 2/3 of rated power output would be about 12 watts which would be acceptable for a low powef l.can't get the radio to budge off of 20.
Re: CDM-1550 ls Power Level Control
Posted: Fri Apr 18, 2014 5:18 pm
by escomm
You will make spurs if you go that low
How about 20 watts and an attenuator
Or run it at 20 watts without an attenuator
Or get a low power model
Re: CDM-1550 ls Power Level Control
Posted: Sat Apr 19, 2014 2:48 pm
by Will
escomm wrote:You will make spurs if you go that low <snip>
"You will make spurs if you go that low" on the radio's transmit power. The transmitter "will make spurs".
The transmitter will go spurious or unstable below two thirds rated transmitter power output. The transmitter final power amp transistor IS running in Class C. Trying to reduce transmitter power below the Class C operation will cause the spurious and or unstable operation, and the transistor will draw excessive DC current overheating it.
Re: CDM-1550 ls Power Level Control
Posted: Sat Apr 19, 2014 11:06 pm
by escomm
25 * .66 = 16.5
Have a nice day Will
Re: CDM-1550 ls Power Level Control
Posted: Sun Apr 20, 2014 12:33 pm
by Will
escomm wrote:25 * .66 = 16.5
Have a nice day Will
Tks, I am having a very good day..
The OP's radio IS 40 watts, you missed that?
Re: CDM-1550 ls Power Level Control
Posted: Sun Apr 20, 2014 4:19 pm
by escomm
25-40 watt radio
40 * .66 = 26.4
Just sayin'