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Cool That Rig!

Daniel Bartlett (vk4tdb) on September 24, 2000
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Have you ever felt the back of your radio after hours of operation (or especially after a long transmit session)? It can be extremely hot, and may cause damage to itself.

My Standard C5608D 2m / 70cm dual-bander suffered from this problem to an extreme degree. After only one hour of receive operation, the heatsink recorded a temperature of 47�c, when the air temperature was only 28�c!

I fixed this problem by increasing the ventilation space from 2cm to 8cm, and installing an 8cm square fan above it, which operates as soon as the rig is powered. I took the fan out of a broken computer power supply, which I purchased for A$1 from a hamfest in May 2000.

By the way, you can buy these fans new for A$30 at most electronics stores, but why pay that much, when you can get one for almost nothing?

After testing (on a 26�c day), I found that the fan can cool the heatsink from 45�c to 21�c (a reduction of 24�c) within four minutes. My radio felt cold to the touch, which was excellent outcome, I thought.

My rig no longer suffers from heat stress (loss of characters from LCD display), and is now working to it's optimum potential. This idea is an old one, but after experiencing these fantastic results, I thought it necessary to share it with you.

Actually, the second feature of the fan is to keep `me' cool on a hot day, but that's another story! :-)


Member Comments: Add A Comment
Hot !! Reply
Anonymous post on September 25, 2000 Mail this to a friend!
My shack used to be in our attic room which would get up to about 35 C in the summer. After a couple of hours on my FT847, it would drop back the output. It was because it was getting too hot & the set was limiting power output to try to allow additional cooling. I also used PSU fans to cool the Rig & power supply which also got very hot. To cool myself, I 12V Car Radiator fan was used. Run at 12V it was like a turbine ( loud & too powerful ). I was using a working computer PSU to power all of them & so I took the 5V output for this fan & it worked a dream. I still use the smaller ones for the PSU & RIG even though I have moved my shack. There's enough to worry about in a contest, without your set malfunctioning because of the heat.

73 Rob
 
RE: Hot !! Reply
by N2MG on September 25, 2000 Mail this to a friend!
If I recall correctly from my DOD days, the US military reliability findings for semiconductors claim that for every 7degC increase in temperature, the life of a semiconductor is cut in half. I suspect that data was gathered over lots of examples (you know the military). So 24degC is a LOT of lifetime.
 
RE: Hot !! Reply
by AD8K on September 26, 2000 Mail this to a friend!
Make sure the fans draw the air out of the rigs and have plenty of places for the air to get into the rigs. The fans if pressuring the rig will charge the dust particles and cause the dust to cling to the internal components of the rig. Very bad. Vic AD8K
 
Cool That Rig! Reply
by WB7CYO on October 23, 2000 Mail this to a friend!
I use a heatsink set on top of my TM241 Kenwood to help keep excess heat off the front of the case.
I find that the LCD background lights last longer. The TM241 is on 24 hours/7 days a week on
packet. I placed the heatsink on top, near the front of the rig.
73, Lee
 
RE: Cool That Rig! Reply
by G4iFB on November 18, 2000 Mail this to a friend!
Cooling a linear and your rig is even more important in a CONTEST, of course.

One of my pals has a water cooling system on 23 & 13cms - for field day, the tubes circulate water into a plain bucket. Works wonderfully with the added bonus of no fan noise - in fact, the first time I saw it, the microwave tent was totally silent. I thought he was off the air with a fault, whereas in fact he was running 400W on a voice keyer! I think the linear runs tubes with external anode fins, like the 2C39 I guess, but I don't know the details for sure.

If you can sort out the plumbing, water cooling is MUCH more efficient than air because the thermal capacity of water ('specific heat' I think is the correct term - boy, that takes me back a long way to school physics!) is so much greater, even without added antifreeze. The old mainframe computers used (use) water cooled CPUs, requiring smaller water chillers than the equivalent air conditioner units I believe.

GL! Gary G4iFB
 
Cool That Rig! Reply
by g3pjv on November 29, 2000 Mail this to a friend!
my rig is the icom ic720a and after about 1 hour of transmiting and receiving at 100w the heat sink is two hot to touch, and i get reports of bad modulation. I am taking part in the ARRL 10 meter contest and am inventing an other colling fan to stick on the back of my rig to hopefully keep it cool for the contest.
Paul
G3PJV
 
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