| Author |
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Airhead
| | Posted on Monday, March 25, 2002 - 2:28 pm: | 
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I made a fan kit for a friend to mount on the rear of his base station CB radio. Which way should I mount, to put air in or take the air out?
I wired the pwr to the fans by taking the top of and running wires to the on/off switch so when the radio is turned on the fans come on I just am stumped on the in or out question. BTw I will tell anyone how to make them all you have to do is ask. |
Taz
| | Posted on Monday, March 25, 2002 - 3:30 pm: |
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Good question, most fans blow in |
Tech181
| | Posted on Monday, March 25, 2002 - 6:25 pm: |
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Make them blow towards the radio to direct facter moving, cooler air onto the heat sinks. Just be sure there is adequate space between the fan and the radio to assure good air flow and movement.
Steve
Tech181
Tech181@copperelectronics.com |
Copperfan
| | Posted on Monday, March 25, 2002 - 6:44 pm: |
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i say out so its not pushing the dust into the radio |
Ohiobiker
| | Posted on Monday, March 25, 2002 - 7:26 pm: |
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Well for what its worth: My Yaesu, and all other expencive radios that I have owned have the air drawn across the area to be cooled. This removes the heat and takes it from the equipment, not blowing the heat to other areas of the inside of the radio and/or equipment. Makes no since to me to blow into something, making the heat move about the rest of the components. As in therory of your home: if the fan in the window blows in you are only getting fresh air into the area from one spot, in blowing the air out of your home it then draws air in all the other open windows or openings, making the flow through the entire area of your home...I would assume that it would be a better idea to draw air form something to cool it. Just the way I percieve it.....Have a good day....and hope I have shed some light on this subject...~OHIOBIKER~ |
Bullseye
| | Posted on Monday, March 25, 2002 - 8:42 pm: |
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You will want to mount the fan kit so it draws the hot air AWAY from the radio thereby moving cool air around the heat sink helping it run cooler. |
Taz
| | Posted on Monday, March 25, 2002 - 9:51 pm: |
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Then why does a fan on a car blow on the motor? |
Airhead
| | Posted on Monday, March 25, 2002 - 10:28 pm: |
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OK which way does the fan kit that you can buy blow the air? I will set it that way. |
Dawg
| | Posted on Monday, March 25, 2002 - 10:36 pm: |
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The fan is drawing air through the radiator from the front, cooling the fluid in the radiator, which in turn does the actual cooling of the engine. |
Dx431
| | Posted on Monday, March 25, 2002 - 10:54 pm: |
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Hahaha, Taz, the fan on a car does NOT blow air onto the engine .It is pulling air through the radiator thus cooling the coolent flowing throughout the radiator.
Sorry, I couldn't resist. |
Ironmask
| | Posted on Monday, March 25, 2002 - 11:16 pm: |
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Taz,
It dosen't it just looks that way. In reality it is schrouded closely thus drawing max thru the radiator.
Use the newer cross mounted engines as an example. The fans [usually two small instead of one large] are electrically operated and will run as long as engine temp is above certain limits. With or without the engine running. The opening away from the radiator is small in comparison to the rad. side thus causing greater pulling power. It just needs a place to exhaust the air not aim it.
Iron Mask |
Dx431
| | Posted on Monday, March 25, 2002 - 11:19 pm: |
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Hahahaha.......Dawg, you got your post up before I did....(-: |
Taz
| | Posted on Monday, March 25, 2002 - 11:22 pm: |
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Ok dx like dawg said it still is used for that at some point. |
Airhead
| | Posted on Monday, March 25, 2002 - 11:36 pm: |
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Well which way should I mount the fans in or out/ |
Taz
| | Posted on Monday, March 25, 2002 - 11:42 pm: |
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The purpose of a fan is to blow. |
Ironmask
| | Posted on Monday, March 25, 2002 - 11:46 pm: |
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Airhead,
The consenses of opinion is BLOWING OUT away from the radio.
Besides sucking in all the junk in the air concider that pulling the hot air away is better than blowing cold air into it. This in itself can cause problems with the heat sink.
Iron Mask |
Taz
| | Posted on Tuesday, March 26, 2002 - 1:24 am: |
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what about a computer fan? It blows in! |
Warlock
| | Posted on Tuesday, March 26, 2002 - 5:15 am: |
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Think of it this way. The fan is used to blow like a fan on a stand in your house. A fan used to pull, like an attic fan...pulls the fresh from a window, cools you off, and exhausts into the attic.
The fan should pull from the inside out. The key is your intake hole placement so the air will flow across what you want cooled then out.
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Airhead
| | Posted on Tuesday, March 26, 2002 - 8:02 am: |
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Well that makes sense to me thanks. |
Airhead
| | Posted on Tuesday, March 26, 2002 - 2:52 pm: |
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Say that again PULL the hot air out? Or blow the cool air in? |
Bigbob
| | Posted on Tuesday, March 26, 2002 - 6:26 pm: |
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On my hp xt983 I got a fan blowing in and one blowing out,so there,nyaa. |
Bullseye
| | Posted on Tuesday, March 26, 2002 - 8:41 pm: |
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Pull the hot air out. If you try to blow it in it will just circulate through the rest of the radio and cause other components to heat up. The purpose of the fan is to help cool the whole radio not take hot air from the heatsink and heat up the rest of the radio.You want to "dispose" of the hot air not just push it around through the radio. |
Airhead
| | Posted on Tuesday, March 26, 2002 - 11:19 pm: |
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O Ok got it that is what I did |
RCI2990
| | Posted on Wednesday, March 27, 2002 - 12:25 pm: |
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On my 2990 i have 2 computer fans blowing ON the heatsink. It keeps it pretty cool! |
Taz
| | Posted on Wednesday, March 27, 2002 - 1:32 pm: |
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I think if "ENGINEERS" designed the fans to blow ON the heat sink then the fans should blow in! |
Taz
| | Posted on Wednesday, March 27, 2002 - 1:50 pm: |
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The point of a fan is to keep air circulating, not to keep blowing the same air. as air escapes new air blows in and keeps it "cool" THATS HOW IT WORKS!!!!!!
fans blow in! |
Bullseye
| | Posted on Wednesday, March 27, 2002 - 2:47 pm: |
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Yes Taz you are correct. Fans were designed to blow in BUT in this instance the whole purpose is to circulate fresh air. If you are pulling the hot air away from the radio the laws of physics dictate you will be drawing in fresh ie cool air which in this case is what is trying to be accomplished. So in fact you are right but,you will find as you get older,theory does'nt always hold water with practical application. |
Taz
| | Posted on Wednesday, March 27, 2002 - 6:02 pm: |
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Trust me, by taking the fan and having it blow in you would be taking fresh air and blowing it on the circuits and keeping it cool. Since this radio is not perfectly sealed the air will leak and more will keep coming in. Even 181 says to have it blow on the heat sinks. Make it blow in!
ENGINEERS MAKE THE FAN TO BLOW AIR ON IT NOT TO HAVE AIR TAKEN FROM IT! |
Taz
| | Posted on Wednesday, March 27, 2002 - 6:13 pm: |
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I am done posting on this part. I posted the correct way to mount the fan and I am done arguing. |
Ironmask
| | Posted on Wednesday, March 27, 2002 - 7:41 pm: |
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Bullseye,
You have presented it corectly. I think there is one point that is being overlooked,
That being, you are shocking the heat sink by blowing cool air on it. The best is to draw the heat away from it. Notice the placement of most fans. They are not mounted directly to, or close to the heat sink. usually off to one side. In the case of two fans a greater volume of air is moved but not directly on the heat sink.
Iron Mask |
Triplecguy
| | Posted on Wednesday, March 27, 2002 - 10:01 pm: |
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I gotta add my two cents. I was trained in HVAC in both my job and in school. Air flow is the life blood of all climate control systems. Electronic components such as those we have here in the mountain are all cooled by fans. The fan should pull cooler air across the components and then exhaust to the outside of the component. This air flow could actually be reversed and work quite well BUT only if you made air ducts to route the flow through the component to the outside. If anybody has ever seen how airflow is affected by protruding devices and 90 degree turns when smoke is added to an air flow you understand what I am saying. Convection is a very strong force and you could actually force a hot pocket of air to remain trapped in a certain area no matter how much air your forcing through. It is always best to use a vaccum (created by the fan) to create a void where cooler air is drawn to, rather than try to direct the cooler are to a specific area. But, Taz, you are not completley wrong, there are certain situations where air is forced across something to cool it. However, with electronics it is best to use a fan to pull the cooler air over the surface. A tip to anybody utilizing a fan cooled radio or amplifier-you can make a small filter to cover the air intake of your component by bying a regular furnace filter at Wally World and cut out some of the material and tape it around the intake of the component. This will prevent quite a bit of dust being sucked into your radio.
Dan |
jyd
| | Posted on Wednesday, March 27, 2002 - 7:57 pm: |
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blowing in is best,and i went outside to prove a point my fan on my car pulls air through the radiator and like taz said the air also reaches the motor to.if you put the fan blowing the opisit direction you are not acompleshing anything now if you had 1 blowing in and 1 blowing out then you would be acompleshing somthing.but no need for that,it works good on amps. |
Bullseye
| | Posted on Wednesday, March 27, 2002 - 11:22 pm: |
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TAZ,You need to take a deep breath and count to 10. I have noticed a trend with you the last month or so that if someone posts something not in ageement with you you seem to get mad or you continually state your opinion on the subject repeatedly. There are 2 major problems with this #1 You will not impress others here because most have been around the block with this stuff more than a carousel horse. #2 You are closing yourself off to valuable learning experiences. You seem to be quite intelligent and mature for a 14 yr. old but the thing you are going to have to learn is while you may always believe in your opinion you are not always right, and this can and will cause you problems in the future if you don't learn to control it now. Using only this post for an example nobody said your ideas on the subject were wrong,in fact,I agree with you but in this case the object is to dispell the unwanted or hot air as effiecently as possible. There are times when it is necessary to use a fan to blow on something to cool it but in the case of "high power" electronics you want to draw the air away. I don't want you to take this wrong or in a bad way. It is good to stand by your opinions but you also need to be willing to listen to others. It has'nt been that long ago I was 14 and did the same things but if you remember to listen,not just hear cause there is a difference, as well as talk you will go much farther in life successfully. Sorry so long but I wanted you to think about this. |
Taz
| | Posted on Thursday, March 28, 2002 - 12:44 am: |
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Ok then bullet, taking the air away to cool the radio is fine. You are still pulling the air which is moving it over the electronics components inside which keeps it cool. So weather your pulling hot or pushing cool its basically the same thing. Air is till being moved over it.
1. I am not getting mad. I am as level headed as they get.
2. I dont want you to get mad when I tell you that I dont need anyone to lecture me or tell me "how it goes" because I live with two people who are in the correct positions to tell me that. I understand you feel that you had to make that post and for me.
3. Not everyone thinks the same way. You have your opinions and I have mine. You say tomato I say tamato.
4. May I ask you this question, why do most fans on radios blow in? |
Bullseye
| | Posted on Thursday, March 28, 2002 - 7:20 am: |
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Most electronics that have fans blowing in have a relatively large amount of airspace to use for circulation cb's don't. That is why the fan should exhaust the air. |
Scrapiron63
| | Posted on Thursday, March 28, 2002 - 11:12 am: |
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Taz, what radios are you talking about here:
>>4. May I ask you this question, why do most fans on radios blow in?
All these high dollar Ham radios I have owned have fans pulling the hot air OUT of the radio. Same for this last 1.7 gig computer I bought, it has a fan pulling the heat from the power supply, and another pulling it from the computer. Bullseye make some good points, 14 or any age, you can and will still learn, if you are openminded, i'm 67, still trying to learn. Go back to the top of this discussion and read the post you made about the car fans. A good rule is to put your brain in gear before the mouth. No offense meant, you are a bright lad, but you have not seen/owned or operated every piece of equipment available over the last 30-40 years, none of us have, but I'd bet most that post here way surpass you in owning and trying equipment. Just because you haven't tried or know about something does not automatically make it 'junk' or no good. Think about it. |
Ncrebel
| | Posted on Thursday, March 28, 2002 - 2:04 pm: |
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I've seen on power inverters for example,where the fan blows inside the case to keep the transformer and all the components cool.I think either way would work well but if you have the fan actually sucking the heat out of the unit you need to have a intake point and use the fan for exaust.A radio or and amp usually has no intake
point to use a fan as exaust which is why they use the fan to blow air inside.I think when using a fan to blow directly on something you're always keeping fresh air blowing a a certain component/s
because if you have a fan blowing inside a house what does it do?It will cool one room but it doesn't cool the whole house.Now if you were to get a fan and have it blowing out the window it would suck heat from all over the house out thus keeping the the heat to a certain temp.So I think
it depends on the application.Whether you're trying to keep a few certain parts cool or a whole
unit cool.I actaully sat back and thought it through about this and thats what I came up with.Hope it makes sense. Or hey,I just thought about this one,having the fan blow inside the unit
and having a vent on the other side to blow air in on one side of the unit to the other thus to blow air in and have it pull air out from the other side.That'll work. |
Airhead
| | Posted on Thursday, March 28, 2002 - 7:17 pm: |
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Well i still dont know witch way to turn the fan so HELP I am going to take temp measurments inside the radio both ways to see which way cools the best I will keep the forum posted. |
Ohiobiker
| | Posted on Thursday, March 28, 2002 - 9:04 pm: |
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Hmmmmmmmm....seems we all like to voice our opinions....Here is a question off the subject that I was asked once and had to think about it...the longer you think the harder it is to under stand...Here we go...If you have a deep freezer in your garage...and the inside tempature is set to keep your deer meat at a tempature of -5 degree's...You inadvertently leave your garage door open in the middle of winter and the outdoor tempature is -25 below....then will you deep frezze in turn make heat to keep the inner tempature of the frezzer at -5? Just a thought ....I was ask this as a question at a job interview, I think it was just to see our thinking process...Have fun all... |
Taz
| | Posted on Thursday, March 28, 2002 - 10:40 pm: |
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Put 2 fans on it air head. One blowing in and one taking out? that sounds like a good idea to me.
Can everyone settle on 2 fans? one in one out? |
Hamcber
| | Posted on Thursday, March 28, 2002 - 11:22 pm: |
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I have been quiet, and I intend to stay that way, as soon as I chime in on this one.
When a cabinet has a fan blowing 'in', it pressurizes the cabinet and that in itself lowers the temperature slightly. By allowing a small portion of that air to escape, the positive ventilation is created and warmed air in exhausted.
When a cabinet has a fan blowing 'out' (creating a suction inside the cabinet), it usually has a lot of openings or cutouts in the cabinet to allow air to move very freely through the cabinet and into the fan. You should NEVER create a 'vacuum' by having a fan 'sucking' air from a cabinet that does not have LOTS of openings.
If the cabinet has few openings, you are better to pressurize it. If there are LOTS of openings and they are near the hot electronics, you are better off 'vacuuming' the heat out of the cabinet. Most broadcast gear uses cabinet pressurization since it works better.
See you in another couple of months. |
Freezerman
| | Posted on Thursday, March 28, 2002 - 11:56 pm: |
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Hey Ohio no it can only cool it can not make heat as it has no heating coil. It will however not cool anymore while the temp is so low around it> |
Taz
| | Posted on Friday, March 29, 2002 - 2:17 pm: |
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Ok sounds good. |
