Re: Clock Kit.


geoff M0ORE
 

Hans,

is it "safe" to connect an input such as a 1PPS signal to an input of an AT chip without the AT chip being powered. I know some chips are fussy about having an input voltage higher than the supply voltage.

I used AND gates with the 1PPS signal on one input and the supply to the ProgRock or VFO on the other input so the 1PPS is blocked until the ProgRock / VFO is powered up.

On 24/07/2020 19:25, Hans Summers wrote:
Hi just connect all my QRP Labs kits in parallel to the QLG1 outputs. No drivers. No splitters. Just everything in parallel. 

73 Hans G0UPL
http://qrp-labs.com

On Fri, Jul 24, 2020 at 9:17 PM Arv Evans <arvid.evans@...> wrote:
In olden days we could just use a 74HC buffer chip to act as a multi-device driver.

_._

On Fri, Jul 24, 2020 at 11:23 AM Dave <VE3GSO@...> wrote:
Sounds to me like we need a GPS ancillary driver which would take a single GPS receiver and make available several, suggest four, identical outputs to drive a QRPLabs clock, U3S, QCX+, and VFO.  OK, maybe six outputs just in case!
Probably would not be a huge seller, but one would find a home in this shack.

Dave


On Jul 24, 2020, at 12:54, KEN G4APB via groups.io <lfoofui.nbz42=ntlworld.com@groups.io> wrote:



Hi Bill,
do you not suffer interference from the clock/gps combination placed like that?

Unfortunately, I get severe ‘pulsing’ broadband interference from the gps data bursts from mine. I started with a plastic case and have spent considerable time and effort screening, series choke and resistor filtering, ferrite blocking and miles of copper tape, short screened leads and earthing in an attempt to reduce this. I can still hear it on nearby rigs from LF to 2m. The only real ‘cure’ is to place it on the opposite side of my room away from all my rigs.

I have three gps modules feeding U3S kits and they all have similar issues, but providing I only want to transmit say WSPR, and not receive much, it works.

73 Ken G4APB

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