"Beating the heat for older radios."
Add a cooling fan!
It is true that I am just a newly licensed ham, but I have been doing work on my elder father's ham shack equipment that was left to me after he pasted away. I have been under his license for many years and I worked with communications while serving in the military. I work from a practical but experimental approach.
In this case I found that
several of my older Kenwood 7800 /7950 two-meter radios did not like
the heat and lack of airflow in my shack. When the inside temperature of
one of the radios hit 120 degrees Fahrenheit on transmit, the led
screen on the radio started to flash and generally act
I went further with the
project. I wanted a way to turn the fan on and off. I then found
a small little hole in the back of the radio case on the flat spot
next to the fins that appeared to have nothing much next to it, so I
CAREFULLY drilled it out just a little bit to a more usable
size in which to mount the switch.
Then I inserted a micro flip switch similar
to the picture above and it looked like it should have been made that
Now I am not going to recommend that everybody go
ripping out the speakers of all their radios, especially since many newer
radios already had internal fans hooked to the transmit side of their
boards these days. Also many radios may not be as troubled by the
heat build up in the case as the older radios, however for my money I
think this fix is hard to beat in the heat we have been having of late.
Onward to the next radio, it will get a thermistor controller to turn it
on automatically, so what do you think?
Not so bad for guy who has not even had his ticket for a month.
Parts used 1 ea Canadian Radio Shack 273-248A fan.
Switch (on/off) of your choosing that will fit your particular
location in your radio.
It is advisable to insure that if you do want to install an internal cooling fan that you do not use a fan rated at other than 12-15 volts DC. Many "CPU' fans may be rated at much less voltage than your radio's supply voltage which will usually burn them out quickly.
So be wise and check
the "specs" on the fan you intend to use! Remember, if you plan to use the
DC power that supplies your radio, use the same voltage fan.
Another location option for the fan is the back of the radio attached to the cooling fins provided for most radios. These fins act as a heat sink and the additional air movement across them will certainly help to dissipate more heat. The "forced air" from the fan should move between the fins if possible. Use your own ham ingenuity in the mounting process and location and provide a way to shield fingers from the fan blades for safety if they are external!
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