You're probably OK checking out the actual maker of the fan and ordering one of that model number from an alternative source like Grainger.
It being part of a transmitter, which lives a hermit existence, the one issue that presents itself with other motor-driven devices probably does not apply. Years ago I maintained a flock of cartridge machines with direct-drive motors. Could buy them direct from the manufacturer really cheap. Problem was that the motors bought that way soon became noisy. The company that made the motors was UMC Electronics. Same company that manufactured the cart machines (Beaucart). Their own cart machine operation was getting SELECTED motors off the assembly line...equipped with instrument grade bearings rather than the ordinary ones. Same motors were sold for many purposes and there was no way, outside the factory (then in West Haven, CT) to tell the good ones from the ordinary ones!
To their credit, the good ones were sold by the Beaucart parts department at the same price as you'd pay for the ordinary ones ordered through the regular UMC supply houses.
Was a good company with a good product that never gained the traction of many of the name brands....
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When you're done impeaching the prez, keep on going; recall every member of congress and lock 'em up! Let's try NO govt. for a while.</P>