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Re: Frequency Stability

 

Hello Vernon

The idea of the 150MHz is that it keeps the Si5351A "busy" while not transmitting, which keeps it warm; then when it starts transmitting, it is already warm and there is not much temperature change. Sometimes 150MHz is too high and causes a drift in the other direction, and needs to be reduced for that reason. It takes some experiment to get it right. But I always found best results on a multi-band Ultimate3S by having 10m first, then 15, 20m, 30m etc going down in frequency.?

73 Hans G0UPL

On Thu, Nov 9, 2017 at 6:22 PM, Vernon Matheson <vmath@...> wrote:
Thanks Hans...would I reduce the 150.000.000 maximum frequency by 28.200.000??
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On 11/09/17 10:54 AM, "Hans Summers" <hans.summers@...> wrote:
Hi Vernon

I suggest putting the sequence of the bands the other way around: start with the highest frequency and then step down.?

Park Mode 2 is useful in the gaps between transmissions but makes very little difference if the gap is only 8 seconds. So use Park Mode 2 for the long wait at the end of calibration and before the Mode 0] configuration starts. Have it sequence through starting at the highest frequencies then stepping lower.?

73 Hans G0UPL

On Thu, Nov 9, 2017 at 5:35 PM, Vernon Matheson <vmath@...> wrote:
?Hi all,
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I have been trying to reduce the drift on my wspr tx when running 5-6 bands. I seem to be able to get one band with zero drift and the next band in sequence has some drift. See the data for 20m versus 30m below
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I have attached a small heat sink on the 27mhz xtal as suggested but am wondering about park mode. U3S is also in a qrp labs case.
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If I set to mode 2 and say 149.000.000 as suggested it doesn't change much.
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Would I be better to use park mode #1 and then 149.000.000 for a frequency.
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Vernon
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Timestamp Call MHz SNR Drift Grid Pwr Reporter RGrid km az
?2017-11-09 14:24? ?VA1VM? ?14.097148? ?-22? ?-3? ?FN85ij? ?0.2? ?G4ZFQ? ?IO90ir? ?4509? ?59?
?2017-11-09 14:24? ?VA1VM? ?14.097165? ?-24? ?-2? ?FN85ij? ?0.2? ?F4GUK/SDR? ?JN18et? ?4828? ?61?
?2017-11-09 14:24? ?VA1VM? ?14.097153? ?-20? ?-3? ?FN85ij? ?0.2? ?K9AN? ?EN50wc? ?2102? ?263?
?2017-11-09 14:24? ?VA1VM? ?14.097157? ?-2? ?-3? ?FN85ij? ?0.2? ?W9HAM? ?EN64? ?1865? ?275?
?2017-11-09 14:24? ?VA1VM? ?14.097156? ?-22? ?-3? ?FN85ij? ?0.2? ?G0DLV? ?IO70ru? ?4286? ?60?
?2017-11-09 14:24? ?VA1VM? ?14.097150? ?-22? ?-3? ?FN85ij? ?0.2? ?G0LUJ? ?IO83ls? ?4305? ?55?
?2017-11-09 14:24? ?VA1VM? ?14.097157? ?-21? ?-3? ?FN85ij? ?0.2? ?KA4PKB? ?EN41kf? ?2287? ?268?
?2017-11-09 14:22? ?VA1VM? ?10.140154? ?-26? ?0? ?FN85ij? ?0.2? ?SWLKCL? ?FN03ip? ?1281? ?267?
?2017-11-09 14:22? ?VA1VM? ?10.140156? ?-9? ?0? ?FN85ij? ?0.2? ?SWLNXZ? ?FN13co? ?1165? ?265?
?2017-11-09 14:22? ?VA1VM? ?10.140153? ?-22? ?0? ?FN85ij? ?0.2? ?K9AN? ?EN50wc? ?2102? ?263?
?2017-11-09 14:22? ?VA1VM? ?10.140152? ?-18? ?0? ?FN85ij? ?0.2? ?VE3YX? ?FN16fd? ?1107? ?279?
?2017-11-09 14:22? ?VA1VM? ?10.140160? ?-22? ?0? ?FN85ij? ?0.2? ?VE3BSB? ?FN14uv? ?1020? ?272?
?2017-11-09 14:22? ?VA1VM? ?10.140153? ?-20? ?0? ?FN85ij? ?0.2? ?K4COD? ?EM73sc? ?2266? ?240?
?2017-11-09 14:22? ?VA1VM? ?10.140154? ?-18? ?0? ?FN85ij? ?0.2? ?K1BZ/3? ?FM19ne? ?1311? ?243?
?2017-11-09 14:22? ?VA1VM? ?10.140150? ?-21? ?0? ?FN85ij? ?0.2? ?N4CDN? ?FM18iu? ?1362? ?243?
?2017-11-09 14:20? ?VA1VM? ?7.040163? ?-27? ?0? ?FN85ij? ?0.2? ?N4TVC? ?FM18is? ?1367? ?242?


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