Looks good and quite useful. If you ever re-spin the board, I would recommend including a place for range limiting resistors on the ends of the EFC adjustment pot. That way they can be low TCR resistors and the TCR effects of the pot can be minimized and the EFC adjustment can be made less twitchy. But, at the expense of possibly needing to tweak the range resistors as the oscillator ages.

Hi There’s a lot of debate out there about that. When used as a variable resistor (two terminal device) there is no doubt that a sereis resistor can help. When used as a voltage divider (three terminal device) the claim by the pot manufacturing OCXO companies is that you are better with no added resistors. The material in the pot is all same / same and the TC as a divider is quite low. Yes, there are other opinions out there ….. Bob > On Dec 23, 2017, at 6:57 PM, Mark Sims <holrum@hotmail.com> wrote: > > Looks good and quite useful. > > If you ever re-spin the board, I would recommend including a place for range limiting resistors on the ends of the EFC adjustment pot. That way they can be low TCR resistors and the TCR effects of the pot can be minimized and the EFC adjustment can be made less twitchy. But, at the expense of possibly needing to tweak the range resistors as the oscillator ages. > _______________________________________________ > time-nuts mailing list -- time-nuts@febo.com > To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there.

 On 24 December 2017 at 13:18 Bob kb8tq <kb8tq@n1k.org> wrote:

 Hi

 There’s a lot of debate out there about that.

 When used as a variable resistor (two terminal device) there is no doubt that a
 sereis resistor can help. When used as a voltage divider (three terminal device)
 the claim by the pot manufacturing OCXO companies is that you are better with
 no added resistors. The material in the pot is all same / same and the TC as a
 divider is quite low. Yes, there are other opinions out there …..

 Bob

     On Dec 23, 2017, at 6:57 PM, Mark Sims <holrum@hotmail.com> wrote:

     Looks good and quite useful.

     If you ever re-spin the board, I would recommend including a place for range limiting resistors on the ends of the EFC adjustment pot. That way they can be low TCR resistors and the TCR effects of the pot can be minimized and the EFC adjustment can be made less twitchy. But, at the expense of possibly needing to tweak the range resistors as the oscillator ages.

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An optional ressistor in series with gate output would be nice for reducing aberrations seen at a high impedance load at the end of a piece of 50 ohm coax. Bruce > > On 24 December 2017 at 13:18 Bob kb8tq <kb8tq@n1k.org> wrote: > > Hi > > There’s a lot of debate out there about that. > > When used as a variable resistor (two terminal device) there is no doubt that a > sereis resistor can help. When used as a voltage divider (three terminal device) > the claim by the pot manufacturing OCXO companies is that you are better with > no added resistors. The material in the pot is all same / same and the TC as a > divider is quite low. Yes, there are other opinions out there ….. > > Bob > > > > > > On Dec 23, 2017, at 6:57 PM, Mark Sims <holrum@hotmail.com> wrote: > > > > Looks good and quite useful. > > > > If you ever re-spin the board, I would recommend including a place for range limiting resistors on the ends of the EFC adjustment pot. That way they can be low TCR resistors and the TCR effects of the pot can be minimized and the EFC adjustment can be made less twitchy. But, at the expense of possibly needing to tweak the range resistors as the oscillator ages. > > > > _______________________________________________ > > time-nuts mailing list -- time-nuts@febo.com > > To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > > and follow the instructions there. > > > > > > _______________________________________________ > time-nuts mailing list -- time-nuts@febo.com > To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. >