KR22A: Short range?

[dave w]

I open it up and tweaked the adjustment in the middle of the buttons and got it to work OK. It took a lot of small adjustments and tries.

Brian H (or anyone that might know) do you know what adjustment rustbucket is making? Maybe TX freq?

[Brian H]

I don't know. So I looked at the schematics from the FCC web site.

C6 6pf variable capacitor. In the RF oscillator/output transistor stage. Yes oscillator is also the output stage.

Gee at Motorola we didn't like outputs to oscillate all by themselves. 

Now did he tune it closer to 310MHz or to the frequency of the receiver. That could be off itself. 

[Eddie_T]

I reworked an old garage door opener for a friend using a receiver, a universal module and the KR22A. It worked fine for a couple of months then he had to exit the car almost go inside the garage to get it to work. I swapped him an HR12A which works much better. The HR12A didn't serve me well as the dimmer overshoots badly (a moot point when we all are stuck with Al Gore twisty bulbs).

I opened the KR22A to replace the 3 volt battery and found that it instead had gone two-up on batteries by using wafer thin batteries. I couldn't close the case using two of the originals so I am going to add a four AA or AAA external battery pack since I only use it from my easy chair. The wafer thin batteries may help the range by doubling the voltage but cuts battery life significantly with the wafer thin approach. IMO a serious design flaw.

[Brian H]

The KR22A with two cells.
Use a thinner CR2016 cell.
The older ones used a CR2032.