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Si5351A synthesizer comparison
Charles Brown
Si5351A synthesizer
I have both an Si5351A with TCXO
one with the 27.000 MHZ crystal, both are
mounted in the same type QRP-LABS case, both have the
same highly regulated power supply. A ham person wants to
know what is the frequency stability comparison of
Number 1 versus number 2?
The purpose of both is a VFO for a 28 MHZ beacon.
28206.50
Ken N4SO/B Elecraft K2
6 Watts, QRP Labs Si5351A VFO
Kenwood TS-520 from ~ 1974 production year
####
I have both an Si5351A with TCXO
one with the 27.000 MHZ crystal, both are
mounted in the same type QRP-LABS case, both have the
same highly regulated power supply. A ham person wants to
know what is the frequency stability comparison of
Number 1 versus number 2?
The purpose of both is a VFO for a 28 MHZ beacon.
28206.50
Ken N4SO/B Elecraft K2
6 Watts, QRP Labs Si5351A VFO
Kenwood TS-520 from ~ 1974 production year
####
Alan G4ZFQ
On 20/03/2023 02:25, Charles Brown wrote:
If you are talking QRP Labs TCXO then it will be superior to a simple crystal.
I'd use a TCXO but whether that matters really depends on the requirements of this beacon. CW? WSPR?
73 Alan G4ZFQ
I have both an Si5351A with TCXOCharles
one with the 27.000 MHZ crystal,
If you are talking QRP Labs TCXO then it will be superior to a simple crystal.
I'd use a TCXO but whether that matters really depends on the requirements of this beacon. CW? WSPR?
73 Alan G4ZFQ
Hans Summers
Hi Ken
The TCXO is a 0.25ppm device. In my tests the variation was within this over my measured temperature range 5 to 65C.
A crystal will be, very roughly, 100x worse.
However in both cases there will be variations from device to device, some better than others, etc. Neither have a straightforward straight line frequency vs temperature curve either. So the question also depends on what the ambient temperature is. A crystal will look very good (perfect in fact) at the inflection point of its frequency to temperature curve. At that specific temperature the curve gradient is zero. Nearby for small temperature variations the frequency shift will also be much less than elsewhere on the curve.
As Alan says, there is also the question of what stability you need. If it's a 10m WSPR beacon it will probably need the TCXO unless you make some effort in thermal care of the crystal vs its surroundings. If it's a 10m CW beacon it likely won't matter much.
So there are a lot of variables but generally to answer the specific question on relative frequency, I would say about, ball park, a factor of 100 between a plain crystal and the TCXO version.
On Mon, Mar 20, 2023 at 5:26 AM Charles Brown <udntneedtoknow14@...> wrote:
Si5351A synthesizer
I have both an Si5351A with TCXO
one with the 27.000 MHZ crystal, both are
mounted in the same type QRP-LABS case, both have the
same highly regulated power supply. A ham person wants to
know what is the frequency stability comparison of
Number 1 versus number 2?
The purpose of both is a VFO for a 28 MHZ beacon.
28206.50
Ken N4SO/B Elecraft K2
6 Watts, QRP Labs Si5351A VFO
Kenwood TS-520 from ~ 1974 production year
####
Charles Brown
Alan and Hans,
Thank you for the answer.
I am not running Weak Signal Propagation Reporter.
10 meter CW beacon where frequency variation is normal on the band.
room temperature variation and voltage variation is about zero (http://www.qrpkits.com/wallwarttamer.html)
load variation unknown
frequency variation is none.
28206.50
Ken N4SO/B Elecraft K2
6 Watts, QRP Labs Si5351A VFO
QRP Labs TCXO (Kenwood TS-520SE only)
Kenwood TS-520 27.000 MHZ Crystal
####
Thank you for the answer.
I am not running Weak Signal Propagation Reporter.
10 meter CW beacon where frequency variation is normal on the band.
room temperature variation and voltage variation is about zero (http://www.qrpkits.com/wallwarttamer.html)
load variation unknown
frequency variation is none.
28206.50
Ken N4SO/B Elecraft K2
6 Watts, QRP Labs Si5351A VFO
QRP Labs TCXO (Kenwood TS-520SE only)
Kenwood TS-520 27.000 MHZ Crystal
####