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Heatsink upgrade for 800mW* 1.3GHz Transmitter READYMADERC US Ver

Posted by skimmer, 04 July 2012 · 298 views

readymaderc 800mw heatsink upgrade transmitter rmrc
Hi guys,

I'm sure your all know the 1.3Ghz transmitters from RMRC I bought the following one and like it
800mW* 1300MHz Transmitter - NEW CUSTOM READYMADERC US VERSION

I was doing some work to replace the loose wire harness that connects my battery and video camera with an old USB cable so I could have the power audio and video in a single 4 conductor shielded cable. I noticed on the transmitter that the loose wires disappear into the side of the box.Attached Image

so I opened it up and this is was I saw :)
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Yep its a regular 300mw transmitter box with the output beefed up to 800mw at 14V (well 600mw at 12V which is probaby what most of us will use if you are using a 3cell lipo.)

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Anyway You'll notice the whole unit weighs 74 grams and the box weighs 53 grams!!! Plus all those shims are not the best way to conduct heat from the smaller transmitter box to the outside case. We can do better than that!!

So why not take an CPU heatsink from my old old, OLD desktop computer which I've been looking for a reason to decommission and chop it up to fit on the actual transmitter box? When that little silver box uses 800mw it gets hot to the touch.
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UPDATE:
I've been looking for a heatsink that might fit the dimensions for you guys. I found one!!! So after digging and digging I found one the exact size you need 50mmx25mmx10mm. Turns out this is a heatsink designed for the LM2596 power modules (what ever that is@#$!!) and will handle 2-3 watts!! NICE!
Here is a link to one here: just do a search for LM2596 Heatsink... about $2US.
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Anyway I Used my good old desk top band saw (with new blade :) ) and my sanding station, here is what I came up with, again heatsink dimensions are 50mmx25mmx10mm tall. You'll notice I made the base about .125" thick, thats plenty thick to distribute the heat though the fins.
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Now the fun part, We need a thermally conductive epoxy to glue the two parts together. I happen to have some Cotronics Duralco 128 Ceramic Filled Epoxy which is crazy expensive. But man it is good!! you can call up Cotronics, number is on the bottle in the photo, you only need 5 grams of mixed epoxy. I think they sell 1 ounce packages. You can get the same effect with some JB weld. I've seen overclocker guys use a  dab of thermal grease at the center of a heat sink and then use a tiny about of JBweld around the perimeter to bond the headsink to the part and seal in the thermal grease.
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So here is the heatsink glued onto the transmitter. Once I got the heatsink in place and the glue was setting I plugged in an antenna and power and let the transmitter heat up the glue to help cure it.
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Here is the final weight not bad!! 42grams. I just took roughly and once of weight out of this thing and you can easly hold it in your hand with the power on, plus once its in my quad it will get even more cooling.
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Here is the final install in the back of my HT-FPV the 1/2" height worked out really well. Anyway I hope this helps!
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Very sweet mod, definately going to keep this in mind on future mods. For those of us without a spare desktop to break apart, do you happen to know of any suppliers that would have such a heatsink in the correct dimensions?
Sorry I looked real hard when I was doing the mod, however I just came across a super cheap heat sink from newegg, do some bandsawing, filing, and sanding and you should be all set.

MASSCOOL 5C12B3 50mm Ball CPU Cooler this one is only $5.00 its already got one of the dimension 50MM, just need to cut it in half and file,saw the base flat and away you go!
Nice mod, hope more people do this, the weight saving is really a lot.

do you happen to know of any suppliers that would have such a heatsink in the correct dimensions?

Both Farnell and Digikey stock all kinds of heatsinks . .. not exactly cheap but the selection is there.
Ebay is not a bad place for these kinds of things either. Look for "northbridge heatsink"
ok I found one the exact size you need!! turns out it is a heatsink for a LM2596 power module! plus it will do 2-3watts so you could do the upgrade for a 1000mw transmitter too if you wanted to...
Here is a link to one here: just do a search for LM2596 Heatsink... about $2US.
Thats a great find, thanks for updating us with it.

June 2013

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