开云体育

Hi Manuel

I have sent the file to Farhan too for his server but I'm not sure if he can
expose it as a download from a web URL or an FTP site as you did. I
downloaded from you extremely fast. I will send you also a copy of the 29
seconds. Thanks again for alerting us to this!

73 Hans G0UPL

My Internet conection is fairly asymetrical(3MB download/100Kbps
upload), i can't put the video in my "domestic server" the download
would be very slow. Although, i can try. Hans, send me the file to
msraya(ARROBA)ono.com and I post it in the server.

That piece of news appear for the first time in eham.net. There are a
mirror of the video here: . This site is
more fast to download.

73s
Manuel

Thanks for the video Manuel.

The total size of the video is 77Mbytes and it lasts 7m 25s. For those with
a slower connection, I have extracted the 29 seconds section which shows
Farhan building his BITX20, and a short interview. This file size is
5.1MBytes. I can email it to whoever wants to see it - ideally it would be
nice if someone (Manuel?) could host it on their website or FTP space... I
tried to put it in the group files section but it was too large. I can't
host it on my own website for the same reason (my filesize limit is 1MByte).


If 5.1MBytes is still too much for you, I have uploaded a frame from the
interview to the group home page: .

72/3 Hans G0UPL

Hello!

I have received the message that the international news channel CNN
will offer the next day 8 of May at 20 h UTC in their section Global
Challenges, a program on the paper of the ham radio in the Tsunami of
the past 26 of December and on the VU2RBI operator Bharathi Prasad,
centered in the use of the HF and Echolink.

One could discharge the video, although it occupy 75 Mb,
ftp://espectro.sra.ufsc.br/pub/CNN_Tsunami_HamRadio.mpg
if you have a quick connection or wait for to see it through satellite
syntonizing the international CNN. I have dircharge the video and see
also a shortly interview to Farhan!!

I want to thank Rahul VU3WJM for the good work in their PCBs. I am
working in a PLL for my BITX15, MC145170 based and PIC control, but i
am working slowly...

Sorry for my english ;-)
Greetings
72s
Manuel
EB7HPM/EC7ALV

Hi everyone, The link works if you take off the final full stop.

Sam I have 'cut and pasted' from...

as I would probably have made typographical errors :-)
ISTR finding some of these articles in PDF form on the web.
hth Mike W, G8NXD
....
excerpt from

"Ladder Crystal Filter Design", by J. A. Hardcastle, November 1980, QST, Page
20. This article was a little scary with all the formulas and such, and he
only explored one filter using 8.454MHz crystals. His outlines and formulas
weren't that difficult to follow, but the article didn't exactly make you want
to rush to build one.

The second one is "A Unified Approach to the Design of Crystal Ladder
Filters", by Wes Hayward, May 1982, QST, Page 21. This was the first article
that hinted at the fact that regular computer crystals or color burst crystals
could be used in a very effective homebrew crystal filter. Be aware that Fig.
3 in the article doesn't include the values for the toroids. The feedback for
that appeared in the July 1987 issue of QST, Page 41. Circuits needed to
evaluate crystals were given, however, he included the statement "None of the
filter circuits in this paper is suitable for exact duplication."

The classic article of all time, that in my opinion, bust open the doors to
easy and inexpensive homebrew receivers, was the article "Designing and
Building Simple Crystal Filters," by Wes Hayward, QST, July 1987, P 24. This
article showed how using the same capacitance for each capacitor in a crystal
ladder filter gave very good results, very inexpensively, and easily adjusted
bandwidth. The article inspired me to build several filters with crystals on
hand, and they all worked great! In the past, the crystal filter was always a
difficult item because of the expense and critical matching requirements, and
now it was the easiest thing to build for the homebrew receiver.

I never used any of the evaluation circuits that were recommended for matching
the crystals, yet I was always able to build a filter that worked very well in
the receivers I built. His very simple formula for adjusting the bandwidth by
changing the value of the capacitors worked with every filter.

Doug DeMaw wrote an article in the January 1990 issue of QST, page 21, "A
Tester for Crystal F, Q and R", that improved on the circuits that were in Wes
Hayward's "Unified Crystal...." article, and gave all the instructions for
picking and matching the crystals that would work best with Hayward's
"Designing and Building Simple Crystal Filters".

excerpt from

Hi Sam,

The link doesn't work although I checked it before. Now I uploaded
the file in the filebox.
73
Ruud.

--- In BITX20@..., pe2bs@t... wrote:

Hi Sam,

In his article "A Simple SSB Tranceiver" Farhan discribed how to

select the

crystals for the IF filter and how to calculate the C's. You can

find the

article on: .

73's

Ruud

-- Oorspronkelijk bericht --
To: BITX20@...
From: Sam Caldwell <samc@x...>
Date: Tue, 03 May 2005 22:08:35 +1200
Subject: [BITX20] 10Mc/s Crystal Filter
Reply-To: BITX20@...


Some time ago there was reference to a method of selecting the best
four crystals for the IF filter. Naturally, I tucked it away
somewhere in my computer for safekeeping, and now for the life of

me I

can't lay my hands on it.

Can anyone point me towards the original ( or similar ) material ?

Regards, Sam C., ZL1SAM




Yahoo! Groups Links

_____________________________________________________________________

Je eigen persoonlijk e-mailadres bij Tiscali? Registreer nu
een domeinnaam bij Tiscali. Ga naar

Hi Sam and friends,

In the Farhan's home page, you can find a very good article about Ladder filters, I have been used with success...

Have a great day!!!!

Celso - PY2XT

GG66rf

Some time ago there was reference to a method of selecting the best
four crystals for the IF filter.????? Naturally, I tucked it away
somewhere in my computer for safekeeping, and now for the life of me I
can't lay my hands on it.

Can anyone point me towards the original ( or similar ) material ?

Regards, Sam C., ZL1SAM

Hi Sam,

In his article "A Simple SSB Tranceiver" Farhan discribed how to select the
crystals for the IF filter and how to calculate the C's. You can find the
article on: .

73's

Ruud

-- Oorspronkelijk bericht --
To: BITX20@...
From: Sam Caldwell <samc@...>
Date: Tue, 03 May 2005 22:08:35 +1200
Subject: [BITX20] 10Mc/s Crystal Filter
Reply-To: BITX20@...


Some time ago there was reference to a method of selecting the best
four crystals for the IF filter. Naturally, I tucked it away
somewhere in my computer for safekeeping, and now for the life of me I
can't lay my hands on it.

Can anyone point me towards the original ( or similar ) material ?

Regards, Sam C., ZL1SAM




Yahoo! Groups Links

_____________________________________________________________________

Je eigen persoonlijk e-mailadres bij Tiscali? Registreer nu
een domeinnaam bij Tiscali. Ga naar

Some time ago there was reference to a method of selecting the best
four crystals for the IF filter. Naturally, I tucked it away
somewhere in my computer for safekeeping, and now for the life of me I
can't lay my hands on it.

Can anyone point me towards the original ( or similar ) material ?

Regards, Sam C., ZL1SAM

Hi bitxers
Just added a picture of the BITX17 with shielded VFO --> Photos -->
PA2RF

73
Ron

Hi David,
the fact that the receiver works well shows to me that the mixer works?
If you have both signals on the mixer, the 14 MHz should come out. The
only thing you can do is checking of the diodes polarity and the
correct connections of the transformers but I think you did this
already.
My experience is that the mixed signal is so low in output compared to
the 'unwanted' signals that I think your 14 MHz signal is present but
you do not notice it. In the 'modifications' directory, I described an
aditional (standard) coil that helped some. You can try that and try
to have a peaked coil on 14 MHz to get the wanted signal.
Keep us informed,
Chris.

When transmitting only the 4 Mhz (VFO) signal is on base of Q13 .
The VFO level is about 1Vpp. The 10 Mhz modulated audio is about
600mVpp at the base of Q12.
I can see my 10 Mhz signal at the mixer but no 14 Mhz exits the

mixer.

any ideas?
The receiver works well.

When transmitting only the 4 Mhz (VFO) signal is on base of Q13 .
The VFO level is about 1Vpp. The 10 Mhz modulated audio is about
600mVpp at the base of Q12.
I can see my 10 Mhz signal at the mixer but no 14 Mhz exits the mixer.
any ideas?
The receiver works well.

The fact that there was no need to change the microphone circuit may
be means that also spoken word can be transmitted? With SSB, I made
many QSO's. My antenne is a sloping dipole, I found out that the
received noise and QRM is much less if I receive on the 10 mtr. dipole
that is on the roof. It improves the S/N ratio (resulting in beter
readebility) a lot.
Chris.

Just made my first PSK31 qso on 18.102 MHz with the homebrewed

BITX17

I made an RTTY qso (rst 559 with Greece). No change of the mic
input

Hello Rahul and friends

I built 6 different frequency (3, 3.58, 4.192, 7.151, 14.318 and
18.432MHz) VXOs all are very stable...I will update my homepage with
a description of each one... when I start with these experiments I
made a description you may see at;



Sorry about the bad English, I learn it by my self...

73 From Brasil

PY2OHH Miguel





-- In BITX20@..., Rahul Srivastava <vu3wjm@y...> wrote:

Dear Miguel,

Hi!

This all is very interesting. I feel some correction is in order

for 80mts range mentioned. But what I am more interested is the 18mhz
tuning you mention, it makes making a 20mtr radio with 4mhz IF and
18mhz LO a snap. 400khz range gives more than adequate 20mtrs
coverage.

Worth trying.

Greetings and 73

Rahul VU3WJM



Miguel Angelo Bartie <py2ohh@y...> wrote:

Hello

I build 3 VXOs called "hipervxos" for 40m, 20, and 10m to use with

BITX,

They use a classic Colpits oscilattor with 3 parallel xtals and a
series inductor (special) and a series variable capacitor
For 40m I use 3 x 3020 kHz xtals and the actual range is 2068 to

3010kHz

For 20m I use a commercial 3 x 4194 kHz xtals covering 4190 to 3990

kHz

For 10m I use a commercial 3 x 18432 kHz xtals covering 18400 to
18000kHz.
The BITX 40m is running good, the 20m still in test (but is ok

too),

and the 10m version I built only the VXO.
The exciter and the PA are the same I change the vfo, the band pass
filter and the low pass filter.
I will make some pictures and I will post here.

73 from PY2OHH Miguel








---------------------------------
Yahoo! Groups Links

To visit your group on the web, go to:


To unsubscribe from this group, send an email to:
BITX20-unsubscribe@...

Your use of Yahoo! Groups is subject to the Yahoo! Terms of

Service.

__________________________________________________
Do You Yahoo!?
Tired of spam? Yahoo! Mail has the best spam protection around

Hello Ron

I will post the pictures and make a description of the coil ... I use
a fixed coil... one or two in series.
The main problem is the coil... when you try to change with other who
has the same indutance value it does not work... the coil must have
only one layer, with a thin wire 0.15mm diameter or less... I use one
or more adjustable ferrite cores ...
I have also built a Huff-Puff 2 ICs VFOs who works fine ... it is a
great deal ... look the pictures at the photos area in the HuffPuff
Group.

73 from Brasil
PY2OHH Miguel


--- In BITX20@..., Ron Brink <pa2rf@y...> wrote:

Ola Miguel,
I like to see some picts of your super VXO's Miguel. Great coverage

with only 3 xtals. Is the output stable over the whole range? Do you
use one or more (switchable) coils in series with the xtals to cover
the range?

I have shielded my BIT17 VFO (soldered some unetched PCB's around

it) and now the VFO with Huff&Puff is also stable when I force it out-
of-tune e.g. by placing the desk-lamp just above the vfo. Added one
picture in the photobox.

73
Ron
PA2RF

Miguel Angelo Bartie <py2ohh@y...> wrote:

Hello

I build 3 VXOs called "hipervxos" for 40m, 20, and 10m to use with

BITX,

They use a classic Colpits oscilattor with 3 parallel xtals and a
series inductor (special) and a series variable capacitor
For 40m I use 3 x 3020 kHz xtals and the actual range is 2068 to

3010kHz

For 20m I use a commercial 3 x 4194 kHz xtals covering 4190 to 3990

kHz

For 10m I use a commercial 3 x 18432 kHz xtals covering 18400 to
18000kHz.
The BITX 40m is running good, the 20m still in test (but is ok

too),

and the 10m version I built only the VXO.
The exciter and the PA are the same I change the vfo, the band pass
filter and the low pass filter.
I will make some pictures and I will post here.

73 from PY2OHH Miguel








---------------------------------
Yahoo! Groups Links

To visit your group on the web, go to:


To unsubscribe from this group, send an email to:
BITX20-unsubscribe@...

Your use of Yahoo! Groups is subject to the Yahoo! Terms of

Service.

---------------------------------
Do you Yahoo!?
Make Yahoo! your home page

Dear BITX-radiofriends,

Just made my first PSK31 qso on 18.102 MHz with the homebrewed BITX17
with Arthur UX1HW in Ukraine. Only 5 Watts RF out from an IRF510 and
an end fed half wavelength wire antenne from my attic window into the
garden under a 30 degrees angle. I copied him 599 and he gave me 599
as well. Distance between our radiostations: 2100km.
Conclusion; the bitx is a fine rig to make digimode qso's. Earlier I
made an RTTY qso (rst 559 with Greece). No change of the mic input
circuitry required. Only requirement; make your VFO stable, short
time drift <10 Hz. I used the Huff&Puff circuit. A VXCO will also do
fine.

Bye bye & enjoy homebrewing
Ron
PA2RF

==========First part of psk31 qso===========

UX1HW UX1HW de PA2RF PA2RF PSE K

e tt

PA2RF de UX1HW
GE dear my friend
Thanks for your CALL
ur RST 599 599 599
my NAME : Arthur Arthur Arthur
my QTH : Kremenchuk Kremenchuk
Loc : KN69QC
HW?
BTU
PA2RF de UX1HW kkk

Hi Folks,
I was browsing other newsgroups this morning, enjoying my new broadband
connection when I came across a post referring to



They have just about everything that I have been looking for in the way of
hard to find components and cases etc. And I thought that I would share it
with the constructing masses :-) in the hope that you find that much sought
after part too.

Many Thanks to Giancarlo Moda for the link.

HTH, Mike W, G8NXD

ps. I have no connection with the company
--

Hi!

Have posted a file with few mods that I have incorporated. It is
possible your version may not require them.

I needed slightly higher IF gain mainly because of poor quality
devices and low recovered audio.

I still need to do a spectogram and confirm the passband. Some
impedence matching maybe also required.

Sorry for poor quality PDF, looking for better schematic software.

73

Rahul VU3WJM

Hello,

This email message is a notification to let you know that
a file has been uploaded to the Files area of the BITX20
group.

File : /BITX 20 V1,2&3 /BITXmod.pdf
Uploaded by : vu3wjm <vu3wjm@...>
Description : BITX mods and shunt IF amp arrangement

You can access this file at the URL:


To learn more about file sharing for your group, please visit:


Regards,

vu3wjm <vu3wjm@...>