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frequency counter

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frequency counter

Postby bsachin1279 » Sun Jun 19, 2011 10:02 pm

hi all
i built FLL and frequency counter from site (m-counter project : www.qsl.net/ik3oil)
i experiane problem as same times display show frquency and after same time i show boxes.after again and agfain checking cuircit i could not trace problem. had same one build this unit ,please suggest solution.

thanks sachin
bsachin1279
 
Posts: 3
Joined: Thu Apr 21, 2011 2:31 pm
Location: tarapur

Re: frequency counter

Postby mvs sarma » Sun Jun 19, 2011 11:35 pm

bsachin1279 wrote:hi all
i built FLL and frequency counter from site (m-counter project : www.qsl.net/ik3oil)
i experience problem as same times display show frequency and after same time i show boxes.after again and again checking circuit i could not trace problem. had same one build this unit ,please suggest solution.

thanks sachin

Any circuit can be as stable as the set of components and quality of workmanship while home brewing Please try to check how proper and close are the component tolerances. especially i wonder whether you have used the BB204 devices, or improvised by discrete ones.
Regards
Sarma
mvs sarma
 
Posts: 636
Joined: Wed Oct 11, 2006 4:57 pm
Location: Hyderabad, India

frequency counter

Postby bsachin1279 » Mon Jun 20, 2011 4:13 pm

hello
sharmaji
i use FLL with 20 meter receiver (http://lpistor.chez-alice.fr/rxblucw.htm)
it work well and stabilize vfo.i made same changes as same component r not available .BB909 with mv2109.eliminating MAX293.this receiver work well.
my problem with display doesn't shows frequency after same time .


regards
sachin
bsachin1279
 
Posts: 3
Joined: Thu Apr 21, 2011 2:31 pm
Location: tarapur

Postby mvs sarma » Mon Jun 20, 2011 5:53 pm

Please indicate which make display, did you use. Replace the potentiometer used for contrast, by a single diode 1N4148, cathode facing Gnd and anode connected to pin3.

perhaps the sample level of frequency fed into FLLs too high, please reduce it.
Use always a screened cable to connect the signal to FLL circuit, after attenuation inside the Rx or Tx osc unit.
Ensure that the 12V DC used is pure and not having high Carrier level.
the best is to use a choke in series with +12V line as you know. You may place one 0.1 cap across pin1 and 2 of the LCD display module.

the above precautions should work well
Regards
Sarma
mvs sarma
 
Posts: 636
Joined: Wed Oct 11, 2006 4:57 pm
Location: Hyderabad, India


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