[R-390] Operating Hours / MTBF

[Bob Camp]

Hi

The list has been a bit quiet recently....

Obviously this could be an intro to dig up just about any of the 
dreaded old threads.

Here's my question - How much do you operate your R-390 and how long 
does it operate between maintenance "events"?

If I go back and look at the MTBF numbers that are tossed around on 
tube era radios you see numbers in the 50 to 150 hour range.

These numbers have always seemed a bit low to me. There is an awful lot 
of data on a variety of radios though that support those kind of 
numbers. The justification for most of the solid state radios was in 
part the reduction in maintenance from eliminating the tubes. The 
radios involved were from a range of applications. I suspect that an 
airborne radio was a bit lower reliability than a fixed base R-390.

Good old Mil-hbk-217 gives some factors for different enviroments. Even 
if we assume that the "inflation" factors for ground benign versus 
airborne apply it's hard to see how you get past about 1000 hours. Last 
time I checked that's about a month of 24/7 operation.

Since this is all based on averages you really can't figure them from 
the statistics of one radio. You need a fairly large group of radios to 
figure out what's going on.

Just to start the database off here's some more or less accurate data. 
I run a set of four radios and would *guess* that they are somewhere 
above the 200 hour mark.

I'm not sure what constitutes a maintenance event according to the 
military. I suspect it was a combination of routine alignments as well 
as fixing stuff that was broken. For our purposes I'll define an event 
as something that requires you to get into the radio. As long as you 
don't have to dig into the radio to teak something or to fix it then 
it's not an event.

So any body want to contribute to the data base?

	Enjoy!

		Bob Camp
		KB8TQ