Using polystyrene caps and with the VFO not having any buffer stage the
device fed by a 9v PP battery drifts not more than 20 Herz in 30 minutes.

Frank GM0CSZ / KN6WH

What kind of battery is a 9v PP battery? And, it would likely be helpful to
know what the Inductor is that the negative temperature coefficient of the
poly cap is compensating for. Is that drift specification for the first 30
minutes after turn on or after the oscillator has been on for a couple of
days?

W4ZCB

Using polystyrene caps and with the VFO not having any buffer stage the
device fed by a 9v PP battery drifts not more than 20 Herz in 30 minutes.
----------

What kind of battery is a 9v PP battery? And, it would likely be helpful to
know what the Inductor is that the negative temperature coefficient of the
poly cap is compensating for. Is that drift specification for the first 30
minutes after turn on or after the oscillator has been on for a couple of
days?
-----------
A 9v PP battery is a standard battery pack , alkaline /NiCad / NiMH as
used in all sorts of consumer electronics incl battery operated smoke
alarm devices. Dimensions :45x25x17 mm. Available all over the world.
The battery is 'velcro-ed' to empty space on the board
I did not use dedicated neg temp coeff components ,but used 4 recycled
polystyrene caps from the junk box.

FET is 2N3819 but any other HF FET would do.
The tuning cap is a air variable cap (old style trimmer ,silver plated
plates and ceramic body) with added reduction gear/scale in front panel.
Adjustable inductor with core is from Toko .It is mounted on its side,
soldered to PCB material plane.
There is a compact foil trimmer for fine adjustment

Since double sided PCB board was used , I drilled many holes in the
material and soldered through hole pieces of wire ,such that the 2
copper planes are connected at many places.

The 20 Hz stability is reached after applying power to the circuit for
approx 20 minutes in a room with a stable temp.

The power supply connection to the circuit is via an insulated pin which
sits on a tiny board island (having used a special PCB foil cutter which
removes a tiny ring of copper material) .
Although I also could have used an upright 10 MegaOhms (1/4 W) resistor
serving as pin and 'insulator'.

The unit is built onto an 2mm thick piece of aluminium bent as an L

Summarising : A typical little project using predominently junk box
components, with success resulting from using RF friendly components
and shortest possible connections between frequency determining elements.

I don't have a web site to post to ,but can take a pic and send it to
those interested, by email

You can contact me by e-mail by removing abcxyz from my NG address


Frank GM0CSZ / KN6WH

now almost fully migrated to Linux (using Mandriva 2007.1 distro)

"Highland Ham" wrote in message
...
Using polystyrene caps and with the VFO not having any buffer stage the
device fed by a 9v PP battery drifts not more than 20 Herz in 30
minutes.
----------

What kind of battery is a 9v PP battery? And, it would likely be helpful
to know what the Inductor is that the negative temperature coefficient of
the poly cap is compensating for. Is that drift specification for the
first 30 minutes after turn on or after the oscillator has been on for a
couple of days?
-----------
A 9v PP battery is a standard battery pack , alkaline /NiCad / NiMH as
used in all sorts of consumer electronics incl battery operated smoke
alarm devices. Dimensions :45x25x17 mm. Available all over the world.
The battery is 'velcro-ed' to empty space on the board
I did not use dedicated neg temp coeff components ,but used 4 recycled
polystyrene caps from the junk box.

And I assume that the PP means Peak to Peak. I'll acknowledge that a battery
has a peak Voltage, in this case, something close to 9 Volts. I doubt it
could be rated as Peak to Peak which would imply at least a couple of the
things wired back to back and providing around 18 Volts. (Peak to Peak
speaking of course, not Push Pull, cancelling even harmonics, or even
Push-Push, cancelling odd ones.)

The polys have a generally acknowledged negative temperature coefficient and
as such must be correcting for something. The inductor is an air wound
solenoid, wound on a toroid or perhaps a (for the frequency range spec'd)
quite long piece of coaxial cable?

If you observed 20 Hz of drift over a half hour, after a 20 minute warm up,
I would be inclined to ask as to the ambient temperature variation during
that 30 minute exercise.

W4ZCB
NOT linuxed, have enough trouble with Bill Gates's products.

Harold E. Johnson wrote:

And I assume that the PP means Peak to Peak. I'll acknowledge that a battery
has a peak Voltage, in this case, something close to 9 Volts. I doubt it
could be rated as Peak to Peak which would imply at least a couple of the
things wired back to back and providing around 18 Volts. (Peak to Peak
speaking of course, not Push Pull, cancelling even harmonics, or even
Push-Push, cancelling odd ones.)
========
PP is just an identification for this size of battery like AA and AAA
for 1.2/1.5 V cylindrical batteries

The polys have a generally acknowledged negative temperature coefficient and
as such must be correcting for something. The inductor is an air wound
solenoid, wound on a toroid or perhaps a (for the frequency range spec'd)
quite long piece of coaxial cable?
=======
The Toko inductor with adjustable core is a canned component frequently
used by homebrewers and still available . It comes in 3 model for
various frequency ranges. In Europe (and that includes Britain ) it is
particularly popular by the QRP community.

If you observed 20 Hz of drift over a half hour, after a 20 minute warm up,
I would be inclined to ask as to the ambient temperature variation during
that 30 minute exercise.
==========
As stated in my previous message ,the above referred freq. drift was
observed at a stable room temperature. In fact it was in an underground
civil defense bunker where a radio club is hosted by the local
Emergency Planning people( a sort of regional FEMA)


NOT linuxed, have enough trouble with Bill Gates's products.
============================
Having problems with Bill Gates' bloatware is the best possible reason
to move to Linux ,which is free and can be freely and frequently updated
at umpteen repositories world wide.
It takes some effort ,since everything in Linux can be configured by the
users . But that keeps the 'grey matter' in the head active .
Also Linux doesn't need the latest and fastest machine .
I run my system on a motherboard with a 1GHz Athlon processor and 1024MB
of RAM ,from AD 2001.
My advice : GOFOR Linux and enjoy !


Frank GM0CSZ / KN6WH

Highland Ham wrote:


Also Linux doesn't need the latest and fastest machine .
I run my system on a motherboard with a 1GHz Athlon processor and 1024MB
of RAM ,from AD 2001.

To me that is a supercomputer class machine; linux kernel development
unfortunately is a moving target and your arrows had better be made of
recent generation silicon. For those of us who need to target old x86
(386, 486, PI, PII and PIII) and cpus in the embedded space, (ARM7, etc.)
I recommend researching the large number of alternative OSs available
including *BSD, OpenSolaris, various RTOSes like UCOS-II, FreeRTOS, eCOS,
opensource MS-DOS workalikes and others with much smaller footprints, for
amateur radio related work unless your intended user applications are
linux specific. If you are doing DSP or realtime development, I
urge you to consider an RTOS over any *ix.

The linux machines (x86, ARM7 and others) in my domain are all at 2.4.x
kernels due to the increasing requirements of newer kernel versions; in
fact I maintain some 0.9x and 1.x linux systems for special requirements
for their relative simplicity.

Regards,

Michael

The linux machines (x86, ARM7 and others) in my domain are all at 2.4.x
kernels due to the increasing requirements of newer kernel versions; in
fact I maintain some 0.9x and 1.x linux systems for special requirements
for their relative simplicity.
====================================
This thread has moved off-topic ....my fault , I included the word Linux
in an earlier message .

To most users Linux is just one of many operating systems being an Open
Source replacement for Windows . Nothing more ,nothing less.

It is the result of a rare phenomenon ;'international cooperation' among
hundreds if not thousands of volunteering (usually professional)
enthousiasts across the globe, who through the Internet formed Linux
communities which continue to flourish. This has resulted in an ever
improving operating system now available in a variety of distributions
constituting ultimate freedom, no longer the sole domain of 'geeks' but
of ordinary computer users.
I am glad having embraced Linux.

Frank GM0CSZ / KN6WH

PS : My last words on this topic in this NG

I can't seem to find polystyrene caps in DigiKey. Poly everything but
styrene.

NPO and COG seem to be synonymous and are defined at +/- 30 PPM/deg C.
I find nothing called zero TC and the vast majority say nothing at all
about TC.

js

--
PHOTO OF THE WEEK: http://schmidling.com/pow.htm
Astronomy, Beer, Cheese, Fiber,Gems, Sausage,Silver http://schmidling.com

"Highland Ham" wrote in message
...
=======
The Toko inductor with adjustable core is a canned component frequently
used by homebrewers and still available . It comes in 3 model for various
frequency ranges. In Europe (and that includes Britain ) it is
particularly popular by the QRP community.

Frank GM0CSZ / KN6WH

I'd avoid using any "canned" Toko style inductors with adjustable cores.
The most stable coil designs don't use adjustable cores, which are
an invitation to thermal instabilities. Especially ferrites or the types
with cups.

Pete k1zjh

"Highland Ham" wrote in message
...
[...]
PP is just an identification for this size of battery like AA and AAA
for 1.2/1.5 V cylindrical batteries

It's PP3
^



--
Posted via a free Usenet account from http://www.teranews.com

"Harold E. Johnson" ) writes:
"Highland Ham" wrote in message
...
Using polystyrene caps and with the VFO not having any buffer stage the
device fed by a 9v PP battery drifts not more than 20 Herz in 30
minutes.
----------

What kind of battery is a 9v PP battery? And, it would likely be helpful
to know what the Inductor is that the negative temperature coefficient of
the poly cap is compensating for. Is that drift specification for the
first 30 minutes after turn on or after the oscillator has been on for a
couple of days?
-----------
A 9v PP battery is a standard battery pack , alkaline /NiCad / NiMH as
used in all sorts of consumer electronics incl battery operated smoke
alarm devices. Dimensions :45x25x17 mm. Available all over the world.
The battery is 'velcro-ed' to empty space on the board

And I assume that the PP means Peak to Peak.

No, it's the designator for the type of battery. Just like there used
to be "A Cells" and "B Cells". It's the common 9v battery, as he
explained. They are simply refered to as "PP" in Europe, just as
they have A4 paper over there rather than the 8.5 by 11 inch paper
that's common in North America.

Get out the ruler, and you'll find that his dimensions match the
battery in your smoke detector.

Michael VE2BVW