Clock Calibration

[shortride]

This isn't a big deal but I am curious if there is an adjustment that will calibrate the clock on my R75 receiver? I can set the clock with the exact time with the time tick and 24 hours later it will be about 2 seconds fast. If the clock continues to gain 2 seconds every 24 hours, that could really make the clock inaccurate. As I said it's not a big deal, only a curious. Is this typical of these receivers?

 

[nanZor]

Yes - mine does about the same, so not to worry. I rely on other clocks if I need long-term accuracy.

 

[shortride]

Yes - mine does about the same, so not to worry. I rely on other clocks if I need long-term accuracy.

I just wrongfully assumed that the clock in a higher end receiver would be more accurate.

 

[majoco]

Depends where the clock gets it's basic timebase from. Perhaps it's from one of the receiver oscillators, or maybe just a clock chip and a 32,768Hz crystal - if it was from a receiver oscillator (which I doubt, as it would have to be powered up even when turned off) I would expect much better than 2secs in 24hours.

I have a homebrewed digital clock set to UTC which counts down from the 240v 50Hz mains - never been wrong except when we have a power cut!

 

[dkf435]

Looked at service manual and does not look like any trimmers on X111 and X112, both crystals for the main CPU, unless you had a good freq counter I do not think you could get it any better then it is.

David Kb7uns

 

[nanZor]

Of course the Icom engineers would be laughing at us wondering why we aren't using the R75 to tune WWV(H), CHU, JJY time signals etc.

 

[Jimru]

I asked the same question some years ago when I first got my R-75. It really does seem like a bit of a let down, with the price paid for the receiver.

 

[zz0468]

I just wrongfully assumed that the clock in a higher end receiver would be more accurate.

The R75 is a mid-range receiver. High end receivers generally make provision for an external time base reference and everything is derived from that.

If you have the service manual and can located the oscillator that the clock is referenced to, you might be able to tweak it closer, but it will still drift some.

 

[ratboy]

I've never had a clock in a receiver that really was very accurate. Closest was in my NRD-525 when it was new, but now it's as inaccurate as the little AAA battery LCD clocks you buy for a couple of bucks are. My watch listens to WWV and even though I have set it, over and over again, to be dead on, it resets itself so it's 4 minutes ahead. Exactly four minutes.

 

[Jimru]

The clock in my Radio Shack DX-398 is off by a couple of minutes a month, as well. The unit can be set to record at a preset time, so one must adjust accordingly, if that's a feature that matters to ya!