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Motorola Systems Saber III Gets Hot
Posted: Tue Apr 25, 2006 2:32 am
by Alpha87A
Greetings fellow Batlab readers,
I have noticed that my six watt VHF Sys Saber III gets quite hot after prolonged transmissions. I am thinking that it would be a good idea to reduce the RF output to alleviate this concern. What is your opinion?
Also could someone let me know if this unit is designed to tolerate this type of heat buildup? Is there any over heating protection included with this radio?
Thanks
Posted: Tue Apr 25, 2006 11:02 am
by MTS2000des
remeber that any commercial portable isn't designed for "ham" gasbagging. It would be a good idea to set those channels to the low power setting or tune/align the radio to a lower power output. The Saber/Sys Saber PA's are expensive and getting harder to find.
There isn't too much heatsinking on the Saber/Sys Saber, the frame of the radio and that's not much compared to say, a Jedi which has the entire rear chassis to heat sink.
Posted: Thu Apr 27, 2006 4:07 pm
by Grog
That being said, I had an hour long chat the other night, and mine never got warm at all. Quite an improvment over my icom T2H
Posted: Mon May 01, 2006 5:15 pm
by ArmsonOeg
Check your output power. My new Systems Saber III VHF "WHCA" was set at max throughout 7-1/2 watts when i received it
Posted: Mon May 01, 2006 8:36 pm
by Alpha87A
Thanks for your information. I have not checked the actual output on mine yet but I will shortly. I am going to reduce the output to the low power setting of 2 1/2 watts which is more appropriate for my needs.
Jack
Posted: Thu May 11, 2006 5:29 pm
by AEC
Running the Saber at or above rated output power will shorten the life of the P.A and drain the battery faster, not to mention the heat that passes through the case to your hand.
I usually set my 'MAX' to 73, which provides all the TX power I need, while keeping the heat generated lower as well.
Saber frames do NOT provide any valuable heat sinking, the steel frame is only about .050" thick, and that is NOT enough surface area to rely on for heat removal.
Just for grins, I'm going to ship a model I case back home and have slots milled into the case around the P.A location and make them about 2" long and surrounding the radio from front to back in this area to see what heat is radiated out due to convection cooling, I'll have a thermoscan temp meter to take the radio's temperature to see if the slots allow for more rapid cooling(which I think they should logically).
Since I live in a desert, I doubt I'll have moisture problems to worry about, or rain for that matter*laughing*.
Besides, this will only be used as a test fixture and not a daily talker type of use, so a simple blast from the air compressor should get any dust/dirt build up out of the radio before that causes problems of its own.
Hams are too long winded for Sabers, myself included....they were designed for light use in transmit...short conversations and not extended discussions on how the galaxy was formed with the use of cream cheese.
Does anybody set their timeout timers on these radios?
Mine is set to 118 seconds, so I time out before the repeater drops out on me...2 minutes is a long time to talk, and I have been known to carry a conversation well into battery replacement time.
*Remember, if the milky way galaxy was made from chocolate milk, you would never know of its existance!*
Posted: Sat May 13, 2006 2:18 pm
by K8TEK
Hmm, I think you have uncovered the scam of the century. You see, your transmitter is not 100% efficient, meaning that some of the power used to power it is converted into RF, the rest is turned into heat. When you reduce the power, you reduce the amount of RF and also reduce the amount of heat produced.
What you need to do is create a RF board with 100% efficency, meaning 100% of the power that it uses is converted into RF, and that will end your heat issue. That will also make you quite rich because all transmitters create heat as a result of normal operation.
Good luck.
Posted: Tue May 23, 2006 8:20 am
by AEC
I can see it now....150 years into the future.....
All portable radios will be powered with miniature RTG units....
And the minimum power level will be 10 watts.
The common phrase will be: Catch me on subspace.
I really want a WORKING Star Trek communicator badge!
How DO they tune those?
Heat? I thought that was a byproduct of holding the radio in your hand, who ever heard of RF creating heat...must be one of those lunatic Batlabs members inventing things again.....Darn radio geeks!