Date   
Re: crystals in BITX

wimmie262000 <jowijowi@...>
 

--- In BITX20@..., "Ashish" <geniusashish85@...> wrote:

can any one tell me whether the body of the crystal should be grounded
or not?
I was thinking about that some time ago and could not find too much
information. The thing is that the crystal C0, usually named "holder
capacitance" plays some role in the dimensioning of the crystal filter
component values (and thus its specs). If a big part of this C0 would
be caused by the housing of the crystal, than it could be shunted away
to ground.
However, I did some crystal measurements using a crystal in test
fixture where the signal passes through the crystal. At the higher
overtones it is clear that C0 has a major influence. Unfortunately
grounding the case did not help much to reduce this influence. So
unless I find some more info I assume the crystal housing has only
minor impact on this holder capacitance.
So from the angle of making a narrower filter I would say that
grounding will probably have a low benefit.

But from a input to output shielding point of view it might be
beneficial. Grounding the crystal case will add some easy shielding.
How much I would not know. Perhaps someone measured it?

All in all I would say yes, ground it when you can. It is simple
enough to do. Just make sure you do not heat the crystal too much.
Solder the far end (opposite the leads). I read that the parameters
might change a bit due to heating. And that is not what you want after
a careful crystal matching process.

Joop - pe1cqp

Re: antenna and baluns

 

I think 16 gauge single strand will be fine but thicker wire should work
better. I have seen a rotary dipole made of aluminium tubing performing
much better than a wire dipole on 20M.

A balun is used to convert an unbalanced feed to a balanced one.
A dipole requires a balanced feed.

I guess that the RG-59 will work OK. The small mismatch will not
result in much loss.

73 Raj

thank you Raj and Arvind...

so shall I go for bare copper wire(single strand)?and what should be
the approximate wire guage?I am having RG-59 cable.I think its 75 ohms
(pls correct me if I m wrong).Shall I use this as feed lines?Will that
work with the BITX tranceiver whose output impedence is 50 ohm?or is
there any need of a balun?

Re: crystals in BITX

wbdmxbaileybobbuttercup
 

--- In BITX20@..., "Ashish" <geniusashish85@...> wrote:

can any one tell me whether the body of the crystal should be
grounded
or not?
its usally a good practice to follow, I always use a ground on all of
mine.

crystals in BITX

Ashish
 

can any one tell me whether the body of the crystal should be grounded
or not?

Re: antenna and baluns

Ashish
 

thank you Raj and Arvind...

so shall I go for bare copper wire(single strand)?and what should be
the approximate wire guage?I am having RG-59 cable.I think its 75 ohms
(pls correct me if I m wrong).Shall I use this as feed lines?Will that
work with the BITX tranceiver whose output impedence is 50 ohm?or is
there any need of a balun?

Re: VXO

wimmie262000 <jowijowi@...>
 

Just did a test with a 27MHz fundamental crystal in a single NPN
oscillator.
Inserting a coil in series with the crystal (T50-2 20wdg ~ 2uH) lowers
the frequency 25.3KHz. Increasing the number of windings made my
reading jumpy. But this could also be caused by the sensitivity of the
counter as I used a series resistor to tap the signal. I did not use a
buffer.

Joop

Re: Hendricks BITX20A manual in Spanish

Arv Evans
 

Jon EA2SN

Very impressive. I really like the color coded color codes! ;-)

This document includes many of the modifications and upgrades which have
been suggested by others on this forum. It is a "must read", even for
those who do not understand Spanish.

Arv K7HKL
_._

iapizloj wrote:

Folks,
I am very happy to announce my little contribution to the spread of
the BITX concept to the Spanish speaking folks. The manual of the
BITX20A is now available in Spanish at the QRPkits website
http://www.qrpkits.com/files/BITX20A_spanish.pdf
<http://www.qrpkits.com/files/BITX20A_spanish.pdf>
I have used lots of colors, graphs and photos, and, in order to save
resources, this manual is prepared to be used directly on screen.
Although the PDF has bookmarks for an easy indexing, I recommend to
use it full-screen (CTRL+L). Some additions have been made to include
identification of the Zener diodes, toroid winding and checking, and
also the adjustment method followed by Leonard KC0WOX on his video.
I am sure this will stirr some building activities.
And now a quick note in Spanish:
Amigos, la traducción completa del manual está disponible en la página
web de Doug antes citada. Espero que disfrutéis de ella tanto como yo
he disfrutado montando el kit y traduciendo el manual. Un cordial saludo.
72,
jon, ea2sn

--
======================================
Web: http://K7HKL.homelinux.net
http://bitx20a.livejournal.com
http://home.earthlink.net/~arvevans/
http://www.geocities.com/k7hkl_arv/
======================================




[Non-text portions of this message have been removed]

Hendricks BITX20A manual in Spanish

Jon EA2SN
 

Folks,
I am very happy to announce my little contribution to the spread of
the BITX concept to the Spanish speaking folks. The manual of the
BITX20A is now available in Spanish at the QRPkits website
http://www.qrpkits.com/files/BITX20A_spanish.pdf
I have used lots of colors, graphs and photos, and, in order to save
resources, this manual is prepared to be used directly on screen.
Although the PDF has bookmarks for an easy indexing, I recommend to
use it full-screen (CTRL+L). Some additions have been made to include
identification of the Zener diodes, toroid winding and checking, and
also the adjustment method followed by Leonard KC0WOX on his video.
I am sure this will stirr some building activities.
And now a quick note in Spanish:
Amigos, la traducción completa del manual está disponible en la página
web de Doug antes citada. Espero que disfrutéis de ella tanto como yo
he disfrutado montando el kit y traduciendo el manual. Un cordial saludo.
72,
jon, ea2sn

[Fwd: Re: Re: VXO]

wimmie262000 <jowijowi@...>
 

--- In BITX20@..., Stanley Grixti <stanley@...> wrote:

very strange ...i only want to pull up just about 1.15khz!

actually i found some other 'old type' they are like hc49 but larger

i tested them in circuit...they all won't move far...only 1 or 2khz
max then dye...i even found one at 4030khz! pity!
What oscillator circuit are you using?
With small capacitances the total impedance increases to a point where
you might need more loop gain to sustain oscillation.

Re: VXO

wimmie262000 <jowijowi@...>
 

--- In BITX20@..., "Ashhar Farhan" <farhan@...> wrote:

70KHz is going to be a stretch even at 24 MHz. To begin with most 24
MHz crystals (that I have in my junk box) are actually 8 MHz
fundamentals oscillating on their third overtone. Overtone crystals
are entirely un-pullable.
Yes, 70K is a lot. I did not realize how much it was. When I looked
again at one of my measured crystals I noticed this is already in the
zone where the crystal spurious exist. A stable oscillator is not
likely there.
Now spurious practically all exist just above the fundamental
frequency (or overtones as well). Not below. So pulling it down is
probably more feasible over a wide range. Phase change is not so steep
there, so likely it will be a bit more drift prone. But then still
better than a VFO.

Are 24.1MHz crystals common? I noticed one of my HAM component
providers carries one. Then 30K down should be relatively easy and
more likely to succeed.

Joop

[Fwd: Re: Re: VXO]

Stanley Grixti
 

very strange ...i only want to pull up just about 1.15khz!

actually i found some other 'old type' they are like hc49 but larger

i tested them in circuit...they all won't move far...only 1 or 2khz max then dye...i even found one at 4030khz! pity!



Mike W wrote:

that's strange.....

On 25 Apr 2008 at 20:00, Stanley Grixti wrote:


but it is marked at 8.100!?!

Mike W wrote:

it just goes to proove what Farhan said about 3rd OT xtals does'nt it.

On 25 Apr 2008 at 19:48, Stanley Grixti wrote:


Hello Juanjo

thanks for your offer, i have found 2 4096mhz xtals in the junk box!
but still it's a long way down

i also found an old 8.100mhz xtal...i though maybe i put the beacon on 18.100.150 which is psk31 frequency also
but guess what!?!? she won't move! o/p is 8.099...will only tune a few hz up and down...no more!! not even 1 khz! :(

i look some more!

73

Stan



Juanjo Pastor wrote:

Hello everybody as this is my first post to the group.

Stan, what about vxoing or supervxoing the 4.096 MHz standard crystals?
If

you can't find them in Malta, send me your address and I will send a couple
of them to you. 26 KHz down is quite a lot with a 4 ish MHz rock but it
could be doable. Another option would be heterodining two crystal
frequencies, like 8 and 12 convinently pulled, I see 8 should be pulled down
and 12 up. Or even better, 12 and 16, I am sure that with the corresponding
pulling you could get the 4.070 mix easily. Anyway I am not into other
digimodes but CW, and I really think it is possible to get a stable
enough

VFO covering from 4 to 4.350 MHz to work all the band. The huff & puff
FLL

is also interesting, and would made a good VFO even better. I will stay
tuned to hear your results. Best wishes to all the BiTXers!

73, 72 de Juanjo, EC5ACA. EA-QRP #104, G-QRP #9742, QRP-L #1662,
FP #899.

Juanjo Pastor
C/San Roque, 4-1�
46460 Silla
SPAIN

e-mail: ec5aca@... <mailto:ec5aca%40gmail.com>
web: http://es.geocities.com/ea5chq <http://es.geocities.com/ea5chq>
web del club: http://www.eaqrp.com <http://www.eaqrp.com>
Tel.: +034 96 120 17 67
Movil: 651 35 35 11
----- Original Message -----
From: "wimmie262000" <jowijowi@... <mailto:jowijowi%40gmail.com>>
To: <BITX20@... <mailto:BITX20%40yahoogroups.com>>
Sent: Friday, April 25, 2008 5:38 PM
Subject: [BITX20] Re: VXO


--- In BITX20@... <mailto:BITX20%40yahoogroups.com>,
"Mike W" <mike@...> wrote:

Duh, why did'nt I see that too Joop:-)
obviously the old grey matter is diminishing.
a very good idea as the 24Mhz CPU xtals are readily available for a
few pence

each. However, is'nt the PSK31 mode sideband depemdent though?, high
side

injection will mean swapping the CIO insertion.
73 Mike G8NXD

Well I see I am wrong in my calculation of the ppm's (quiete a bit
higher), but you got the idea. And I am not sure about the PSK
sensitivity. Could the sideband "orientation" LF not be chosen with
the right BFO frequency?


------------------------------------

Yahoo! Groups Links




Re: VXO

Stanley Grixti
 

Hello Juanjo

thanks for your offer, i have found 2 4096mhz xtals in the junk box!
but still it's a long way down

i also found an old 8.100mhz xtal...i though maybe i put the beacon on 18.100.150 which is psk31 frequency also
but guess what!?!? she won't move! o/p is 8.099...will only tune a few hz up and down...no more!! not even 1 khz! :(

i look some more!

73

Stan



Juanjo Pastor wrote:


Hello everybody as this is my first post to the group.

Stan, what about vxoing or supervxoing the 4.096 MHz standard crystals? If
you can't find them in Malta, send me your address and I will send a couple
of them to you. 26 KHz down is quite a lot with a 4 ish MHz rock but it
could be doable. Another option would be heterodining two crystal
frequencies, like 8 and 12 convinently pulled, I see 8 should be pulled down
and 12 up. Or even better, 12 and 16, I am sure that with the corresponding
pulling you could get the 4.070 mix easily. Anyway I am not into other
digimodes but CW, and I really think it is possible to get a stable enough
VFO covering from 4 to 4.350 MHz to work all the band. The huff & puff FLL
is also interesting, and would made a good VFO even better. I will stay
tuned to hear your results. Best wishes to all the BiTXers!

73, 72 de Juanjo, EC5ACA. EA-QRP #104, G-QRP #9742, QRP-L #1662,
FP #899.

Juanjo Pastor
C/San Roque, 4-1�
46460 Silla
SPAIN

e-mail: ec5aca@... <mailto:ec5aca%40gmail.com>
web: http://es.geocities.com/ea5chq <http://es.geocities.com/ea5chq>
web del club: http://www.eaqrp.com <http://www.eaqrp.com>
Tel.: +034 96 120 17 67
Movil: 651 35 35 11
----- Original Message -----
From: "wimmie262000" <jowijowi@... <mailto:jowijowi%40gmail.com>>
To: <BITX20@... <mailto:BITX20%40yahoogroups.com>>
Sent: Friday, April 25, 2008 5:38 PM
Subject: [BITX20] Re: VXO

--- In BITX20@... <mailto:BITX20%40yahoogroups.com>,
"Mike W" <mike@...> wrote:

Duh, why did'nt I see that too Joop:-)
obviously the old grey matter is diminishing.
a very good idea as the 24Mhz CPU xtals are readily available for a
few pence
each. However, is'nt the PSK31 mode sideband depemdent though?, high
side
injection will mean swapping the CIO insertion.
73 Mike G8NXD
Well I see I am wrong in my calculation of the ppm's (quiete a bit
higher), but you got the idea. And I am not sure about the PSK
sensitivity. Could the sideband "orientation" LF not be chosen with
the right BFO frequency?


------------------------------------

Yahoo! Groups Links


Re: VXO

Juanjo Pastor
 

Hello everybody as this is my first post to the group.

Stan, what about vxoing or supervxoing the 4.096 MHz standard crystals? If
you can't find them in Malta, send me your address and I will send a couple
of them to you. 26 KHz down is quite a lot with a 4 ish MHz rock but it
could be doable. Another option would be heterodining two crystal
frequencies, like 8 and 12 convinently pulled, I see 8 should be pulled down
and 12 up. Or even better, 12 and 16, I am sure that with the corresponding
pulling you could get the 4.070 mix easily. Anyway I am not into other
digimodes but CW, and I really think it is possible to get a stable enough
VFO covering from 4 to 4.350 MHz to work all the band. The huff & puff FLL
is also interesting, and would made a good VFO even better. I will stay
tuned to hear your results. Best wishes to all the BiTXers!

73, 72 de Juanjo, EC5ACA. EA-QRP #104, G-QRP #9742, QRP-L #1662,
FP #899.

Juanjo Pastor
C/San Roque, 4-1�
46460 Silla
SPAIN

e-mail: ec5aca@...
web: http://es.geocities.com/ea5chq
web del club: http://www.eaqrp.com
Tel.: +034 96 120 17 67
Movil: 651 35 35 11

----- Original Message -----
From: "wimmie262000" <jowijowi@...>
To: <BITX20@...>
Sent: Friday, April 25, 2008 5:38 PM
Subject: [BITX20] Re: VXO


--- In BITX20@..., "Mike W" <mike@...> wrote:

Duh, why did'nt I see that too Joop:-)
obviously the old grey matter is diminishing.
a very good idea as the 24Mhz CPU xtals are readily available for a
few pence
each. However, is'nt the PSK31 mode sideband depemdent though?, high
side
injection will mean swapping the CIO insertion.
73 Mike G8NXD
Well I see I am wrong in my calculation of the ppm's (quiete a bit
higher), but you got the idea. And I am not sure about the PSK
sensitivity. Could the sideband "orientation" LF not be chosen with
the right BFO frequency?


------------------------------------

Yahoo! Groups Links


Re: Crystal Filter

Stanley Grixti
 

Hello Farhan

The feedback resistors I have already changed

I shall not be using the mic amp as I will be feeding PSK31

I would be interested in the ideas you have mentioned in the past about direct baseband modulation for PSK31

73

Stan


ashhar_farhan wrote:


there are two things you will need to do with your circuit:

1. change the feedback resistors from 2.2K to 1K
2. instead of using the original BITX mic amp, download the manual
BITX20A from hendricks's site and use that mic amp.

- farhan

Re: VXO

Stanley Grixti
 

Hi Joop

I don't think i have 24.000....i see my junk box later

i think this beacon is going to end up quadruple convertion :P



wimmie262000 wrote:


--- In BITX20@... <mailto:BITX20%40yahoogroups.com>, Stanley Grixti <stanley@...> wrote:
I tried pulling 4mhz cermanic resonators (10 in parallel!!)

got them to 4.070 but wasn't reliable...power starts dropping at 4.065!
Stan, have you considered using a 24MHz crystal for 24.07MHz?
The pulling needed is then reduced to 51ppm instead of 1200 ppm for
the 4=>4.07M.
Sounds feasible to me.

Also the spurious should be less due to "over-mixing".

Joop - pe1cqp

Re: VXO

wimmie262000 <jowijowi@...>
 

--- In BITX20@..., "Mike W" <mike@...> wrote:

Duh, why did'nt I see that too Joop:-)
obviously the old grey matter is diminishing.
a very good idea as the 24Mhz CPU xtals are readily available for a
few pence
each. However, is'nt the PSK31 mode sideband depemdent though?, high
side
injection will mean swapping the CIO insertion.
73 Mike G8NXD
Well I see I am wrong in my calculation of the ppm's (quiete a bit
higher), but you got the idea. And I am not sure about the PSK
sensitivity. Could the sideband "orientation" LF not be chosen with
the right BFO frequency?

Re: VXO

Mike W <mike@...>
 

Duh, why did'nt I see that too Joop:-)
obviously the old grey matter is diminishing.
a very good idea as the 24Mhz CPU xtals are readily available for a few pence
each. However, is'nt the PSK31 mode sideband depemdent though?, high side
injection will mean swapping the CIO insertion.
73 Mike G8NXD

On 25 Apr 2008 at 15:08, wimmie262000 wrote:

--- In BITX20@..., Stanley Grixti <stanley@...> wrote:
I tried pulling 4mhz cermanic resonators (10 in parallel!!)

got them to 4.070 but wasn't reliable...power starts dropping at 4.065!
Stan, have you considered using a 24MHz crystal for 24.07MHz?
The pulling needed is then reduced to 51ppm instead of 1200 ppm for
the 4=>4.07M.
Sounds feasible to me.

Also the spurious should be less due to "over-mixing".

Joop - pe1cqp


Re: VXO

Ashhar Farhan <farhan@...>
 

70KHz is going to be a stretch even at 24 MHz. To begin with most 24
MHz crystals (that I have in my junk box) are actually 8 MHz
fundamentals oscillating on their third overtone. Overtone crystals
are entirely un-pullable.

Even if we assume that we can get a 24 MHz fundamental crystal, we
shouldn't expect more than 24 KHz (0.1%) swing. Using other
configurations of higher pulling actually makes the crystal behave
like a coupling capacitor and that degrades the oscillator to being a
regular VFO.

I would still suggest that you first try a regular VFO. Look at the
one I am using in my signal generator. It is quite stable on 4MHz.
Instead of using a fixed capacitor, using an air spaced polyvaricon
might give you much higher stability. Use a PVC pipe or a 1/4 inch
rolled 35 mm roll as the coil former.

- farhan

On Fri, Apr 25, 2008 at 8:38 PM, wimmie262000 <jowijowi@...> wrote:






--- In BITX20@..., Stanley Grixti <stanley@...> wrote:
> I tried pulling 4mhz cermanic resonators (10 in parallel!!)
>
> got them to 4.070 but wasn't reliable...power starts dropping at 4.065!

Stan, have you considered using a 24MHz crystal for 24.07MHz?
The pulling needed is then reduced to 51ppm instead of 1200 ppm for
the 4=>4.07M.
Sounds feasible to me.

Also the spurious should be less due to "over-mixing".

Joop - pe1cqp

Re: VXO

wimmie262000 <jowijowi@...>
 

--- In BITX20@..., Stanley Grixti <stanley@...> wrote:
I tried pulling 4mhz cermanic resonators (10 in parallel!!)

got them to 4.070 but wasn't reliable...power starts dropping at 4.065!
Stan, have you considered using a 24MHz crystal for 24.07MHz?
The pulling needed is then reduced to 51ppm instead of 1200 ppm for
the 4=>4.07M.
Sounds feasible to me.

Also the spurious should be less due to "over-mixing".

Joop - pe1cqp

Re: Crystal Filter

ashhar_farhan <farhan@...>
 

there are two things you will need to do with your circuit:

1. change the feedback resistors from 2.2K to 1K
2. instead of using the original BITX mic amp, download the manual
BITX20A from hendricks's site and use that mic amp.

- farhan