On Sat, 03 Sep 2005 15:06:22 +0300, nn wrote:

"Eamon Skelton" wrote in message
news
What happens if you adjust L7?

73, Ed. EI9GQ.

I haven't touched it. But as far as I understand its there to avoid
oscillation
to disturb regulation process insuide L09. So it should have nothing to do
with the crystal "pushing". (Let me know if I am totally wrong...

Pasi, oh2pt

It looks like a fairly low inductance which resonates with
the 12pf, 68pf and other capacitances in the oscillator to form
a 116MHz tuned circuit. Try adjusting it to see if it will
pull the oscillator to the correct frequency. If you turn
it too far, it will reduce the L.O. output or stop it
from running. If you are not happy with the result, you
can always put it back where it was.

If all else fails, you could try putting a variable capacitor
or inductor in series with the crystal.

73, Ed. EI9GQ




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"Eamon Skelton" wrote in message
news
a 116MHz tuned circuit. Try adjusting it to see if it will
pull the oscillator to the correct frequency. If you turn
it too far, it will reduce the L.O. output or stop it
from running. If you are not happy with the result, you
can always put it back where it was.

If all else fails, you could try putting a variable capacitor
or inductor in series with the crystal.

73, Ed. EI9GQ

Ed,

What is the best way to know the value before i touch it?
Should I measure the voltage after this coil - or how?
And most probably there is RF-voltmeter needed?

Pasi

Count the number of turns as you adjust. If it has little or no effect
on frequency, return the slug to its original position by turning in the
opposite direction for the same number of turns you counted while
adjusting it.

Scott
N0EDV

Pasi wrote:
"Eamon Skelton" wrote in message
news
a 116MHz tuned circuit. Try adjusting it to see if it will
pull the oscillator to the correct frequency. If you turn
it too far, it will reduce the L.O. output or stop it
from running. If you are not happy with the result, you
can always put it back where it was.

If all else fails, you could try putting a variable capacitor
or inductor in series with the crystal.

73, Ed. EI9GQ


Ed,

What is the best way to know the value before i touch it?
Should I measure the voltage after this coil - or how?
And most probably there is RF-voltmeter needed?

Pasi

On Sun, 04 Sep 2005 14:09:14 +0300, Pasi wrote:


What is the best way to know the value before i touch it? Should I measure
the voltage after this coil - or how? And most probably there is
RF-voltmeter needed?

Pasi

It would be very difficult if not impossible to find the
exact inductance of L7 while it is in circuit.

Just count the number of degrees of rotation you make
to the tuning slug. You could mark the slug and former
with white paint or tipex before you start. If you don't have a
VHF frequency counter, you could use a 2M beacon as a frequency reference.
Most of the 2M beacons audible from here are correct to within +/- 200Hz.
GB3MCB is usually within 100Hz.

Even a very good crystal oscillator is unlikely to
be stable to less than 1 ppm, so there is little
point in trying to get an error of less than 100Hz.

73, Ed. EI9GQ.


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Hi everyone,

Transverter is now on correct frequency. LO was tunable through
this L7. And it is still oscillating after the pull

I was very pessimistic that this L7 would affect on freq. Thank you
for your advice. Btw, I have to say that this German piece of electronic
has really good quolity inside the box.

73 Pasi, oh2pt

"Eamon Skelton" wrote in message
news
On Sun, 04 Sep 2005 14:09:14 +0300, Pasi wrote:


What is the best way to know the value before i touch it? Should I
measure
the voltage after this coil - or how? And most probably there is
RF-voltmeter needed?

Pasi

It would be very difficult if not impossible to find the
exact inductance of L7 while it is in circuit.

Just count the number of degrees of rotation you make
to the tuning slug. You could mark the slug and former
with white paint or tipex before you start. If you don't have a
VHF frequency counter, you could use a 2M beacon as a frequency reference.
Most of the 2M beacons audible from here are correct to within +/- 200Hz.
GB3MCB is usually within 100Hz.

Even a very good crystal oscillator is unlikely to
be stable to less than 1 ppm, so there is little
point in trying to get an error of less than 100Hz.

73, Ed. EI9GQ.


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linux-2.6.13
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