Thread Rating:
  • 0 Vote(s) - 0 Average
  • 1
  • 2
  • 3
  • 4
  • 5

Frequency counter.
#1

On my Heath Zenith SM 2420 counter there is a "Trigger" knob. When I switch bands on my signal generator, it has to be reajdusted every time to display correct frequency.I do not trust completely my sig. gen., however it is within 100HZ accuracy. As an example, after aligning IF at 260 K.C. I switched to the different band for 1400 K.C. and set the dial on the generator accordingly. The meter displayed 1800.After playing with a "Trigger " knob the screen on the meter indicated 1400. Is that normal? I do not recall such issues in the past. Thanks.
#2

The situation you describe is pretty normal. The waveshape of the output signal changes on each band, so the trigger level may have to be adjusted to compensate for the difference in the waveform symmetry.

The triggering is more critical when the output signal is low. Try to increase the generator output when you have the counter connected to set the freq, then reduce it to the required level for alignment.

The best way to minimize the problem is to add an extra output to the generator, connected before its internal atrtenuator. That way you can continuously monitor the freq while simultaneously generating the attenuated lower lever signal for alignment.




Users browsing this thread: 1 Guest(s)
[-]
Recent Posts
Philco 42-1008 conversion kit
I read about a kit to convert the variable speed changer in the Philco 42-1008 into a single speed unit.  That would rem...alangard — 09:30 PM
HiFi (Chifi) tube amp build - but my own design.
Tim Well...a chassis is metal. Magnetic or not, it does not matter. A transformer has some hum to it. It is natural....morzh — 08:40 PM
Hickok AC51 tube tester
I thought the 83 tube was bad because it looked white but it tests strong. Blue gassy though. I checked the fuse, it was...martinj — 08:37 PM
Shadow Meter Bulb
Ross I am not sure what current limiting effect the incandescent provides. They are two different parts of the sch...morzh — 08:31 PM
12' Philco
Bob Thanks for that photo. I have been looking for it, and I cannot find anythinmg on the web. I forgot it was here...morzh — 08:29 PM
Shadow Meter Bulb
I think after all has been said, I will use the same bulb that is specified for the dial pilot light which is a #55. I ...georgetownjohn — 07:31 PM
12' Philco
There was also this Philco! klondike98 — 07:25 PM
HiFi (Chifi) tube amp build - but my own design.
I expected a challenge and this is just part of it. But, it's also supposed to be fun, entertaining, informative and enj...TV MAN — 07:12 PM
Shadow Meter Bulb
Butting in here with a question. Since the shadow meter is connected directly to the 1st and 2nd I.F.'s wouldn't the met...RossH — 06:43 PM
HiFi (Chifi) tube amp build - but my own design.
Mike, Tim; you are about to enter the twilight zone. Doo doo doo doo, doo doo doo doo This is something alright. I'm go...RodB — 06:26 PM

[-]
Who's Online
There are currently 6146 online users. [Complete List]
» 1 Member(s) | 6145 Guest(s)
Avatar

>