Re: 14.070.0 not pulling to 14.074.0 for the 20 meter DSB


Steven Weber
 

Then your out of luck. You can probably pull the oscillator crystal up 4 kHz with a series trimmer, or at least get it in the ball park. That’s about the limit you can go and retain stability.

 

But you’ll be way off center pass of the crystal in the receiver leg and there’s no good way to change that. The receiver will be exceptionally deaf. A L/C tuned circuit could be substituted for the crystal.

 

KD1JV  

 

 

Both crystals say 14.070

 

K2jhu

 

On Mon, Nov 11, 2019 at 1:57 PM Steven Weber <steve.kd1jv@...> wrote:

What frequency is the crystal cut for?

KD1JV

 

 

OK I understand what you are saying. The problem I am having is for the 20 meter D4D kit from crkits.

There are 2 caps, one from pin 7 of the NE602 to ground and one going between pins 6 and 7 and one side of the crystal with the other side of the crystal being grounded. The signal I have is strong but not on 14.074.00

 

John K2JHU...

 

On Mon, Nov 11, 2019 at 1:36 PM Steven Weber <steve.kd1jv@...> wrote:

Capacitive loading lowers the crystal frequency, which are typically the two caps on the SA602/612 pins 6 and 7.  But if you have a 14.070 crystal but really want to be on 14.074, you need to put a capacitor in series with the  crystal to rise it’s frequency. This is best done with a trimmer cap, a 30pfd trimmer cap would likely do the trick.

 

Steve KD1JV

 

Hi all. Hoping someone can advise me what causes the pulling of the 14.070.0 crystal to 14.074.0 In step 3 of the manual it states by adding a wire to the antenna termanual of your transceiver and placing the DSB board near the wire you can zero beat to confirm the frequency. The zero beat approach works fine except my unit in on 14.070.0 the crystal frequency, not the pulled 14.074.0. I don't know what actually pulls the frequency so if anyone can help me with this I truly would appreciate it. Thanks for your time.

 

John K2JHU...

 

 

 

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