On Mon, 25 Aug 2003 17:25:14 +0100, "Leon Heller"
wrote:


Putting two of the same freq. crystals in parallel increases the tuning
range considerably.

Anyone tried putting two ceramic resonators in parallel?

--

"I believe history will be kind to me, since I intend
to write it." - Winston Churchill

On Mon, 25 Aug 2003 17:25:14 +0100, "Leon Heller"
wrote:


Putting two of the same freq. crystals in parallel increases the tuning
range considerably.

Anyone tried putting two ceramic resonators in parallel?

--

"I believe history will be kind to me, since I intend
to write it." - Winston Churchill

This is my first visit to this newsgroup...I am a new MI3.

I would like to put together a very simple QRP CW transceiver. The schematic
I am using includes a 3.560MHz crystal oscillator.

Maplin's, Farnell etc. sell 3.579545MHz or 3.686400MHZ crystal oscillators
respectively and I am wodering will these do the job or should I be looking
for a 3.560MHz crstal? The circuit does have a 65pF trimmer capacitor for
tuning but I want to sure about the crystal before I order.

Thanks for your help.

Chris

Chris wrote:
This is my first visit to this newsgroup...I am a new MI3.

I would like to put together a very simple QRP CW transceiver. The schematic
I am using includes a 3.560MHz crystal oscillator.

Maplin's, Farnell etc. sell 3.579545MHz or 3.686400MHZ crystal oscillators
respectively and I am wodering will these do the job or should I be looking
for a 3.560MHz crstal? The circuit does have a 65pF trimmer capacitor for
tuning but I want to sure about the crystal before I order.

(without seeing the schematic I can't know for sure but...)

I doubt the trimmer capacitor will be able to "warp" the frequency from
3.579545 to 3.560. I would be *certain* you won't be able to warp it
from 3.6864 to 3.560. I would expect more like maybe at most 5KHz
(3.579545=3.574).

I wouldn't think that would be a big problem though, with regard to
3.579. You'll just be operating on 3.579 instead of 3.560. (you do
need to double-check and make sure your license allows operation on the
higher frequency but I'd be VERY surprised if it doesn't.)

3.686400 will work from a technical standpoint too. However, I think
that frequency is in the phone band in Europe so it might not be a
suitable choice for a CW transceiver.
--
Doug Smith W9WI
Pleasant View (Nashville), TN EM66
http://www.w9wi.com

Chris wrote:
This is my first visit to this newsgroup...I am a new MI3.

I would like to put together a very simple QRP CW transceiver. The schematic
I am using includes a 3.560MHz crystal oscillator.

Maplin's, Farnell etc. sell 3.579545MHz or 3.686400MHZ crystal oscillators
respectively and I am wodering will these do the job or should I be looking
for a 3.560MHz crstal? The circuit does have a 65pF trimmer capacitor for
tuning but I want to sure about the crystal before I order.

(without seeing the schematic I can't know for sure but...)

I doubt the trimmer capacitor will be able to "warp" the frequency from
3.579545 to 3.560. I would be *certain* you won't be able to warp it
from 3.6864 to 3.560. I would expect more like maybe at most 5KHz
(3.579545=3.574).

I wouldn't think that would be a big problem though, with regard to
3.579. You'll just be operating on 3.579 instead of 3.560. (you do
need to double-check and make sure your license allows operation on the
higher frequency but I'd be VERY surprised if it doesn't.)

3.686400 will work from a technical standpoint too. However, I think
that frequency is in the phone band in Europe so it might not be a
suitable choice for a CW transceiver.
--
Doug Smith W9WI
Pleasant View (Nashville), TN EM66
http://www.w9wi.com

Alternatively you could consider getting a 3.58 MHz ceramic resonator. It is
pullable from about 3.50 to 3.60 MHz and might even cost less.

--
Sverre Holm, LA3ZA
---------------------------------
www.qsl.net/la3za

Alternatively you could consider getting a 3.58 MHz ceramic resonator. It is
pullable from about 3.50 to 3.60 MHz and might even cost less.

--
Sverre Holm, LA3ZA
---------------------------------
www.qsl.net/la3za

"Chris" wrote in message
...
This is my first visit to this newsgroup...I am a new MI3.

I would like to put together a very simple QRP CW transceiver. The
schematic
I am using includes a 3.560MHz crystal oscillator.

Maplin's, Farnell etc. sell 3.579545MHz or 3.686400MHZ crystal oscillators
respectively and I am wodering will these do the job or should I be
looking
for a 3.560MHz crstal? The circuit does have a 65pF trimmer capacitor for
tuning but I want to sure about the crystal before I order.

Putting two of the same freq. crystals in parallel increases the tuning
range considerably.

Leon
--
Leon Heller, G1HSM

http://www.geocities.com/leon_heller

"Chris" wrote in message
...
This is my first visit to this newsgroup...I am a new MI3.

I would like to put together a very simple QRP CW transceiver. The
schematic
I am using includes a 3.560MHz crystal oscillator.

Maplin's, Farnell etc. sell 3.579545MHz or 3.686400MHZ crystal oscillators
respectively and I am wodering will these do the job or should I be
looking
for a 3.560MHz crstal? The circuit does have a 65pF trimmer capacitor for
tuning but I want to sure about the crystal before I order.

Putting two of the same freq. crystals in parallel increases the tuning
range considerably.

Leon
--
Leon Heller, G1HSM

http://www.geocities.com/leon_heller

You could use a ceramic resonator but you might need a different circuit.

Either of the crystals you mention will work. However as mentioned by
another poster 3.6864 isn't in the CW part of the band. Personally to avoid
dissappointment I'd advise against 3.579 too: there isn't much activity
there. 3.560 is the standard QRP calling frequency and there's plenty of
activity there. You can get 3.560 crystals, try
http://www.jabdog.com/crystals.htm amongst others.

Alternatively you can get use a 3.579 crystal and modify it down to 3.560.
See this page on my web site for details
http://www.hanssummers.com/radio/penning/index.htm.

Hans G0UPL





"Chris" wrote in message
...
This is my first visit to this newsgroup...I am a new MI3.

I would like to put together a very simple QRP CW transceiver. The
schematic
I am using includes a 3.560MHz crystal oscillator.

Maplin's, Farnell etc. sell 3.579545MHz or 3.686400MHZ crystal oscillators
respectively and I am wodering will these do the job or should I be
looking
for a 3.560MHz crstal? The circuit does have a 65pF trimmer capacitor for
tuning but I want to sure about the crystal before I order.

Thanks for your help.

Chris