Re: 14.070.0 not pulling to 14.074.0 for the 20 meter DSB
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my mistake. C2 is the 150 and C3 the 27. John K2JHU...
On Tue, Nov 12, 2019 at 7:30 AM John via Groups.Io <johnk2jhu= [email protected]> wrote: Thank you for getting back to me. My C2 in marked 27J and C3 is marked 150 which we assumed is the 15 as different manufactures have different markings on there parts. Also the way i determined the oscillating frequency was to place a short wire into the antenna input of my FT-817 and placing the D4D board near the radio which resulted in a strong signal at 14.070 and nothing at 14.074.
On Tue, Nov 12, 2019 at 6:51 AM Adam Rong < rongxh@...> wrote: John,
Make sure the oscillator capacitors used with 14.070 crystal are 15p and 27p. If not, you are referring to the wrong part list.
Make sure the way to measure the frequency is correct. Your probe will introduce capacitance and it will impact oscillating frequency. ? Adam this did not help. The documentation and schematic say for the 20 meter version of the kit the 14.070 crystal is pulled to the ft8 frequency of 14.074. My unit does not pull the 14.070 crystal frequency to 14.074. There for not working for ft8. What could cause this problem.
John K2JHU... On Mon, Nov 11, 2019 at 7:05 PM Adam Rong < rongxh@...> wrote: John,
See this thread.
14.070 crystal is okay for filter with relatively big insertion loss. ? Well I don't understand. They sell lots these kits. Not sure how many are for 20 meters as the 20 meter kits are the only ones that pull the crystal frequency. I think I will contact the owner of crkits and see what he has to say. Thank you very much for your time.
John K2JHU... 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 ? ? ? ? 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 ? 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.
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