[OZAPRS] Frequency drift of VK6UZ-4

[Ray Wells]

I think we all know which station should be the primary net reference.

Thanks, Fritz.

Ray vk2tv


On 03/07/11 00:22, Fritz Berrer wrote:
> Hi All,
>
> Today I have checked and retuned some of the oscillators of my FT-ONE,
> APRS gate RX. As to be expected with a unlocked crystal controlled TRX
> they were off frequency to varying degrees.
>
> The 20.000MHz PLL Reference oscillator is now set to 20.000 000 3 MHz.
>
> The 48.615MHz PLL Reference Oscillator can't be set any higher than
> 48.614825, probably aging of the crystal - the TRX is old enough for it.
>
> The 54.280MHz PLL Local Oscillator is now set to 54.280 001. The three
> parameters are now set within original Yaesu specifications.
>
> Any further VCO checks and alignments I can't do as I don't have the
> Service PCB extender kit.
>
> A carrier at 10,1476 MHZ of -73 dBm was then injected to verify
> reception and signal level of the RX set to 10,1476 MHz USB. The APRS
> gate is set for RX only!
>
> The test equipment used is a HP8920A RF Communications Test Set and a
> HP5335A 12 digit counter, both with their external 10MHz Reference inputs
>
> fed from a HP Z3801A Time and Frequency Receiver.
>
> I will monitor the setup the next couple of days, especially the
> frequency offsets generated by the DSP TNC.
>
> My personal view of a great gate setup would be a DSP TNC, especially
> for RX, and a RX or TRX capable of being driven by a GPS derived 10MHz
> reference clock.
>
> Humble apologies to those who are aggrieved by my gates previously
> reported frequency offsets. Hopefully, today's activities corrected that
> situation
>
> and the problem is fixed now, if not the gate will be off air permanently.
>
> 73s and good DX
>
> Fritz Berrer,
>
> VK6UZ
>
>
>
>
>
>
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