Date   
Re: Low cost frequency counter & Huff Puff stabiliser kit

Jim Tonne <tonne@...>
 

I think that, in general, when giving an address after the first "/" the case (upper or lower) is case-sensitive. So "Huffpuff" didn't work but "huffpuff" did.

Nice work, by the way, Hans! Good stuff.

- JimT WB6BLD

Kits versus homebrewed BITX units

Arv Evans
 

Hi

Building a BITX20 from a kit (PCB and parts) is possibly a quicker and more repeatable approach to obtaining one of these transceivers. However, maybe now is an appropriate time to re-state the original objective of Farhan's BITX20 effort. This intent was to provide a schematic and direction that supported assembling a working SSB transceiver from locally available components that could be salvaged from surplus electronics items and from local surplus markets. That ideal and his approach is still very valid and is probably a logical way to build your BITX20 if you want to do it at minimum cost and/or make modifications to the circuit.

There is a lot of interest now in the BITX20A kit from QRPKITS.COM, but the original method of homebrewing your BITX20 is still viable. What this kit does provide is involvement of another group of QRP Builders who prefer kits instead of, or in addition to, homebrewing from individual components using Manhattan or Ugly-method construction. Without earlier work by Farhan and many others the BITX20A kit would probably never have become reality. What this new kit does contribute to the earlier method is that we were able to fine tune the design to eliminate some spurious signals, slightly increase power output, and to make the design available to this different group of builders.

The BITX20A kit has attracted a lot of interest, but there are also other kits available from India, the UK, and a bare PCB from Far Circuits <http://www.farcircuits.net/tcvrs1.htm>. There are probably more that I am not yet aware of. The option of building your own version of Farhan's original BITX20, or the BITX20A using your own PCB or non-PCB methods is still available as well.

What I have tried to say in this rather long posting is that "we do not want to loose site of the original BITX20 intent of anybody being able to afford and build a simple QRP SSB transceiver". By your sharing information, results, and suggestions via this forum, we should be able to continue interest, design evolution, and at the same time keep supporting the idea that anybody should be able to build his own quality SSB transceiver. And above all, maintain the rather unique international nature of this effort.

Arv - K7HKL
_._

Re: Kits versus homebrewed BITX units

ki6ds@...
 

Well said Arv, and I totally agree. That is why we posted all of the
schematics, etc. about the BitX20A on this website. There is nothing at
all that would keep anyone from using the BitX20A schematic and building
the circuit using either Manhattan or Ugly style. As Arv said, there are
a lot of guys out there who cannot source the parts/ and or prefere to
build with a pcb. Our goal was to fill that void, and improve the design
while we were at it. It was and is a wonderful design to start with and I
am amazed at how Farhan was able to build the first rig using the parts
that he did. True ingenuity!! Over 1/2 of the orders so far are from
foreign countries, which really surprised me. 72, Doug

Re: Low cost frequency counter & Huff Puff stabiliser kit

Arv Evans
 

Hans

Good project that should stimulate lots of interest.
I am impatiently waiting for one to install in my latest BITX20.

Arv
_._

Hans Summers wrote:



Hi all

Seems a good time to mention that I am working on a frequency counter
and Huff Puff stabiliser kit for the BITX20. There are two reasons for
this:

1. To seek your comments and feedback on this idea. Anyone interested?

2. So that if you think you would like to add it to your BITX20, you
bear this in mind when designing your BITX20 front panel - I.e. Leave
space for the frequency display. The LCD module size is 108 x 20mm
(4.25 x 0.79 inches). Screen size is 89 x 10mm (3.5 x 0.4 inches).

Brief details of what I am working on:

- Kit to be ultra-low cost

- Single chip design using ATtiny2313 microcontroller from Atmel
(20-pin DIP chip), which will be supplied ready programmed

- Small PCB

- LCD Readout of frequency with 10Hz resolution

- No buttons, no switches: for simplicity and to keep cost absolutely
minimal

- the AVR will have minimal external components! 32.768kHz watch
crystal for low cost, and a trimmer to adjust it so the frequency
counter can be calibrated

- the single AVR microcontroller will do frequency counting and Huff
Puff stabilisation simultaneously

- I plan that the device will measure BOTH the VFO AND the 11MHz BFO
and will add the two frequencies together to produce the displayed
received frequency. This way, once you have calibrated your frequency
counter, if you adjust the BFO the received frequency is still
correct. Also, if anyone uses a slightly different IF dependent on
local crystal availability, then the unit will still work Ok and does
not need the IF offset to be programmed in.

- Three signal connections required to the BITX20: VFO output, VFO
fine tune (For Huff Puff stabilisation) and BFO output

Info on Huff Puff, for people who don't know what I'm talking about,
is here: http://www.hanssummers.com/radio/Huffpuff
<http://www.hanssummers.com/radio/Huffpuff> . Basically the BITX20 VFO
will be locked to within a fraction of a Hz of various discrete
frequencies separated by some amount such as 20 or 30Hz. You tune as
normal, and when you stop tuning the stabiliser quickly moves the VFO
to the nearest lock point and it sticks there permanently until you
next move the tuning knob.

Comments welcome

73 Hans G0UPL
http://www.hanssummers.com <http://www.hanssummers.com>

Re: Kits versus homebrewed BITX units

Greg W:-) <onegammyleg@...>
 

Hi Arv

Thanks for that group email., I am of the same opinion.

I am not in the same financial situation as our many radio friends in
other countries.
But in the same spirit behind the original bitx20 I will not be buying
a kit , rather I willl be building mine from mostly junk box parts.

I have set a price limit of 10Euro's for the whole project., half of
which will go to toroidal cores.
It is bound to create some lateral thinking to accomplish that I'me sure.

While anyone can get anything if they have lots of money , it takes a
lot more will power , brain power and lots of late nights thinking to
get something with only peanuts to spend.

My hat is off to our RF comrades in less well off countries
(particularly in India) that are contributing well to the ham radio hobby.

Greetings to all ..

gregW:-) OH2FFY

=====================================================================

--- In BITX20@..., Arv Evans <arvid.evans@...> wrote:
SNIP
What I have tried to say in this rather long posting is that "we do not
want to loose site of the original BITX20 intent of anybody being able
to afford and build a simple QRP SSB transceiver".
SNIP

Arv - K7HKL

Re: Low cost frequency counter & Huff Puff stabiliser kit

Steven Weber <kd1jv@...>
 

- Single chip design using ATtiny2313 microcontroller from Atmel (20-pin
DIP chip), which will be supplied ready programmed
- the AVR will have minimal external components! 32.768kHz watch
Hans, Are you aware the AVR parts can only count external events to
slightly less than 1/2 the CPU clock frequency? I use a tiny2313 in a small
counter with a four digit LED display and run the clock at 10 MHz, so it
can count directly signals up to about 4.5 Mhz. An external /10 counter
(74HC4017) reduces the frequency of the signal to be measured so it can
count up to 45 MHz. I use a 100 ms time base for a resolution of 100 Hz, as
a 1 second time base is too slow for digital dial applications. BTW, the
counter is built with SMT parts on a 2.0" x 1.1" board and includes the LED
display. Board depth is 0.4".

I also made a Huff and Puff stabilizer using the Tiny45, since it needed at
least 2 internal counters and the tiny45 was the only 8 pin chip with two
counters available. This one uses a 16.26 MHz clock, so it will directly
work with VFO's up to about 8 MHz. It uses a frequency counter based
approch, where it compares the latest frequency count with the last count
to see if the VFO frequency has shifted. If the delta is more than 500 Hz,
is assumes the frequency has be manually changed and resets the
correctional voltage to center, then waits 2 seconds after the frequency
has settled down to start stablizing again. Stabilization is done by
producing short pulses into a 47 ufd cap through a 4.7K resistor.
72,
Steve, KD1JV
"Melt Solder"
White Mountains of New Hampshire
http://kd1jv.qrpradio.com

Re: Low cost frequency counter & Huff Puff stabiliser kit

hans.g0upl@...
 

Hi Steve,

- Single chip design using ATtiny2313 microcontroller from Atmel
(20-pin
DIP chip), which will be supplied ready programmed
- the AVR will have minimal external components! 32.768kHz watch
Hans, Are you aware the AVR parts can only count external events to
slightly less than 1/2 the CPU clock frequency?
Yes... the ATtiny2313 datasheet recommends a factor of 0.4. However, I
have a trick which lets the ATtiny2313 count frequency all the way up
to its maximum clock frequency of 20MHz. But I've got to prove it
works, first.

If all goes according to plan, the tiny2313 will be able to count both
the 11MHz BFO and the 3MHz VFO, by itself without any external
division, then add them together and send the result to the LCD. Which
is great, because the less components go into the circuit, the easier
it is to make and the cheaper the kit can be!

73 Hans G0UPL
http://www.hanssummers.com

Re: Low cost frequency counter & Huff Puff stabiliser kit

kd1jv <kd1jv@...>
 

Yes... the ATtiny2313 datasheet recommends a factor of 0.4. However, I
have a trick which lets the ATtiny2313 count frequency all the way up
to its maximum clock frequency of 20MHz. But I've got to prove it
works, first.
Hans,

That will be a good trick if it works - and I'd sure like to know how
you do it :-)

Okay, I think I know what your going to do. Had to think about it for a
few minutes, hi. The 11 MHz signal could be used as the CPU clock and
counted by one counter, while the 3 MHz signal was counted by the other
counter. The 32578 Hz crystal would be a seperate, external oscillator
and is slow enough it could be counted by pin change interupts to form
the time base without needing its own divider. But, the 11 MHz signal
is coming from the BFO which is stable so only has to be counted once.
Therefore, only a single counter might be need to count the BFO
frequency (aka internal CPU clock) and then switched to counting the
VFO. Now the time base could have its own event counter, making the
program a tad simpler.

This is something of a special case solution, but it should work. If I
didn't have so many other things to do at the moment, I'd try it out
and see if it does.

Oh, and here's another idea to make it even lower cost. You really
don't care exactly what frequency your at, so long as you know *about*
where you are. A row of six LEDs, set up as a bank of two and a bank of
four can indicate 100 kHz and 10 kHz digits in BCD format. I suppose
you could add 1 kHz digits too, but then you'd have to start
multiplexing due to lack of ports. LEDs cost a lot less than a LCD, are
easier to get and take up far less front panel space.

73, Steve KD1JV

Re: Low cost frequency counter & Huff Puff stabiliser kit

Bay Mete
 

Hi Hans.
This is a very good idea, I will be waiting for it too.
73 de Mete TA3EP


2007/9/13, Hans Summers <hans.g0upl@...>:



Hi all

Seems a good time to mention that I am working on a frequency counter and
Huff Puff stabiliser kit for the BITX20. There are two reasons for this:

1. To seek your comments and feedback on this idea. Anyone interested?

2. So that if you think you would like to add it to your BITX20, you bear
this in mind when designing your BITX20 front panel - I.e. Leave space for
the frequency display. The LCD module size is 108 x 20mm (4.25 x 0.79inches). Screen size is 89 x 10mm (
3.5 x 0.4 inches).

Brief details of what I am working on:

- Kit to be ultra-low cost

- Single chip design using ATtiny2313 microcontroller from Atmel (20-pin
DIP chip), which will be supplied ready programmed

- Small PCB

- LCD Readout of frequency with 10Hz resolution

- No buttons, no switches: for simplicity and to keep cost absolutely
minimal

- the AVR will have minimal external components! 32.768kHz watch crystal
for low cost, and a trimmer to adjust it so the frequency counter can be
calibrated

- the single AVR microcontroller will do frequency counting and Huff Puff
stabilisation simultaneously

- I plan that the device will measure BOTH the VFO AND the 11MHz BFO and
will add the two frequencies together to produce the displayed received
frequency. This way, once you have calibrated your frequency counter, if you
adjust the BFO the received frequency is still correct. Also, if anyone uses
a slightly different IF dependent on local crystal availability, then the
unit will still work Ok and does not need the IF offset to be programmed in.


- Three signal connections required to the BITX20: VFO output, VFO fine
tune (For Huff Puff stabilisation) and BFO output

Info on Huff Puff, for people who don't know what I'm talking about, is
here: http://www.hanssummers.com/radio/Huffpuff . Basically the BITX20 VFO
will be locked to within a fraction of a Hz of various discrete frequencies
separated by some amount such as 20 or 30Hz. You tune as normal, and when
you stop tuning the stabiliser quickly moves the VFO to the nearest lock
point and it sticks there permanently until you next move the tuning knob.

Comments welcome

73 Hans G0UPL
http://www.hanssummers.com

Re: Kits versus homebrewed BITX units

bright235spark <davisjo@...>
 

I for one am pleased there is a kit for the BITX 20. I studied
electronics at night school for 2 years and the biggest barrier to
finishing projects was the sourcing of components.

For even recent circuits, some parts become obsolete. I have a shelf
full of incomplete projects, I also have a shack full of kits that
work and have given me pleasure in building and using.

The bitx can be built either way and there are clever people out there
who will make it better and in the spirit of home brew.

In the meantime, thanks Doug for the chance of a kit, my order soon,

Regards to all

John

F5VLM G-QRP 12122

--- In BITX20@..., ki6ds@... wrote:

Well said Arv, and I totally agree. That is why we posted all of the
schematics, etc. about the BitX20A on this website. There is nothing at
all that would keep anyone from using the BitX20A schematic and building
the circuit using either Manhattan or Ugly style. As Arv said,
there are
a lot of guys out there who cannot source the parts/ and or prefere to
build with a pcb. Our goal was to fill that void, and improve the
design
while we were at it. It was and is a wonderful design to start with
and I
am amazed at how Farhan was able to build the first rig using the parts
that he did. True ingenuity!! Over 1/2 of the orders so far are from
foreign countries, which really surprised me. 72, Doug

Re: Low cost frequency counter & Huff Puff stabiliser kit

hans.g0upl@...
 

Hi Steve

Okay, I think I know what your going to do. Had to think about it for a
few minutes, hi. The 11 MHz signal could be used as the CPU clock and
counted by one counter, while the 3 MHz signal was counted by the other
counter. The 32578 Hz crystal would be a seperate, external oscillator
and is slow enough it could be counted by pin change interupts to form
the time base without needing its own divider. But, the 11 MHz signal
is coming from the BFO which is stable so only has to be counted once.
Therefore, only a single counter might be need to count the BFO
frequency (aka internal CPU clock) and then switched to counting the
VFO. Now the time base could have its own event counter, making the
program a tad simpler.
That's roughly it ;-)

Oh, and here's another idea to make it even lower cost. You really
don't care exactly what frequency your at, so long as you know *about*
where you are. A row of six LEDs, set up as a bank of two and a bank of
four can indicate 100 kHz and 10 kHz digits in BCD format. I suppose
you could add 1 kHz digits too, but then you'd have to start
multiplexing due to lack of ports. LEDs cost a lot less than a LCD, are
easier to get and take up far less front panel space.
I did something very similar, without the microcontroller:
http://www.hanssummers.com/radio/sfreq/index.htm . Very low cost.

But I think this time there's an appetite for a real frequency display.

73 Hans
http://www.hanssummers.com

Re: Low cost frequency counter & Huff Puff stabiliser kit

jseager@...
 

Quoting Hans Summers <hans.g0upl@...>:

I am working on a frequency counter and
Huff Puff stabiliser kit for the BITX20...comments and feedback
on this idea...

Hi Hans. Nice to hear from you again! Some comments as asked:
1. Huff and Puff and a freq. readout are so useful that most builders
(kit and dead bug folk)will want them.
2. Ultra low cost sounds about right.
3. Many (i.e. I do) will want to convert their BITX to 18mHz. 'H and P'
will then be needed if you stick with the same i.f. Do you expect
your device to be happy to add 11 and 7 if the VFO is chased up to 7mHz?
4. The LCD seems a bit generous for size. Is there any chance of a
smaller one or is it a key feature? I shall pencil in 4 1/4" anyway.
5. How long until you have it ready for us?! (What about a few beta kits
for Rochdale?) 73 John G0UCP

Re: Low cost frequency counter & Huff Puff stabiliser kit

hans.g0upl@...
 

Hi John,

Thanks for the comments and suggestions!

Hi Hans. Nice to hear from you again! Some comments as asked:
1. Huff and Puff and a freq. readout are so useful that most
builders
(kit and dead bug folk)will want them.
Yes, response so far has been very favourable!

2. Ultra low cost sounds about right.
It depends on using an inexpensive microcontroller and trying to be
as minimalist as possible: smallest possible number of external and
inexpensive components, so that the PCB is also simple and small.
This includes avoiding buttons and switches. Ideally my dream is that
the thing should be "plug and play" as far as possible. No
configuration of IF offset or such. Just wire it up, and watch it go.
All of that makes it simpler to build and use, as well as cheaper ;-)

[To digress: I bought a Norcal40A kit at OzarkCon in April including
the audible frequency counter which speaks the frequency in CW into
the 'phones when you press a button. I STILL can't get it to accept
the desired I.F offset. It just ignores my commands. I don't like
that!]

3. Many (i.e. I do) will want to convert their BITX to 18mHz. 'H
and P'
will then be needed if you stick with the same i.f. Do you expect
your device to be happy to add 11 and 7 if the VFO is chased up
to 7mHz?

No! Unfortunately not. The device as I currently conceive it, should
work if all of the following conditions are true:

1. Received frequency = I.F. + VFO (i.e. in this case, IF is 11MHz
and VFO is 3MHz. Not 17MHz and 3MHz)

2. I.F. (i.e. BFO) <= 20MHz (the max clock freq of the ATtiny2313)

3. VFO < 1/2 I.F

In your example, 7MHz VFO is more than half the Intermediate
Frequency, which violates my rule 3.

HOWEVER, that said: I am very grateful for the comments, because they
will enable me to add extra features. I can imagine various
configuration options which would allow non-default behaviour. These
configuration options would be selected by wiring jumpers on the PCB.
For example: in your case, one might assume that a builder capable of
modifying from 14Mhz to 18MHz would also possess the necessary skills
to be able to implement a simple VFO divider - for example a 74HC74
divide-by-2. So I might be able to provide a jumper option which
tells the device that you have added an external division ratio, and
what that ratio is, and calculates the correct frequency accordingly.
Similarly, another jumper might cause subtraction of VFO from I.F
rather than addition, and so on.

4. The LCD seems a bit generous for size. Is there any chance of
a
smaller one or is it a key feature? I shall pencil in 4 1/4"
anyway.

The choice of target LCD is currently this one from AllElectronics:
http://www.allelectronics.com/cgi-bin/item/LCD-
111/365/24_X_1_LCD_.html primarily based on its incredibly low price
of US $1.50 in quantities of 10+. I believe the low price is due to
the fact that this LCD has a non-standard software interface, not
compatible with 95% of LCD modules on the market; and that the LCD
has an 0.05-inch pitch connector. Both of these failings can be
addressed easily in this case - the software isn't difficult and
mounting the PCB direct on the back of the LCD means no difficult-to-
source connectors will be required.

All of this is intended to help towards the goal of making the thing
DIRT CHEAP!

HOWEVER (again): I think that it ought to be possible in the software
to provide for both the unusual, and standard types of LCD interface.
Again, a PCB jumper could configure the ATtiny2313 at switch on, to
determine which kind of LCD it thinks it will talk to. That way, any
builders who want to get fancy and use a different LCD, for example
maybe with a backlight, could do so too without trouble.

5. How long until you have it ready for us?! (What about a few
beta kits
for Rochdale?)
I'll try. No promises though!

Thanks for the comments and keep them coming - that way I an try to
tailor the device to suit as many folks as possible.

72/3 Hans G0UPL
http://www.hanssummers.com

Re: Low cost frequency counter & Huff Puff stabiliser kit

Chris van den Berg
 

Hi John (and 'many';-) ),
the 18MHz band is so small you do not need a VFO. A VXO will do
perfectly. May be a bit difficult to find a X-tal that will bring you
in the desired part of the band (phone or CW) but after searching (and
digging in your shack) you may be find something.
VXO doe not give a frequency readout but is stable enough for SSB
operation. See you on 17,
best regards,
Chris.

3. Many (i.e. I do) will want to convert their BITX to 18mHz. 'H
and P'
will then be needed if you stick with the same i.f. Do you expect
your device to be happy to add 11 and 7 if the VFO is chased up to
7mHz?

73 John G0UCP

Re: Low cost frequency counter & Huff Puff stabiliser kit

Steven Weber <kd1jv@...>
 

Hans,

One more thought. Consider using a MEGA48 instead of the Tiny2313. The
price difference is small ($1.31/100 for the '2313 vs $1.56/100 for the
Mega48).

For an extra 25 cents you get 8 more I/O ports, a 32578 Hz compatable osc
with its own independant counter (that alone is worth it) and A/D converter
inputs. The A/D input would be handy to monitor the hufff and puff voltage
to check if it is in range.


72,
Steve, KD1JV
"Melt Solder"
White Mountains of New Hampshire
http://kd1jv.qrpradio.com

Re: Low cost frequency counter & Huff Puff stabiliser kit

hans.g0upl@...
 

Hi Steve

For an extra 25 cents you get 8 more I/O ports, a 32578 Hz compatable
osc
with its own independant counter (that alone is worth it) and A/D
converter
inputs. The A/D input would be handy to monitor the hufff and puff
voltage
to check if it is in range.
Thanks for the interesting idea. The ADC chanels also make possible
other things, such as: monitoring battery voltage, an S-meter, or power
output meter (PEP).

73 Hans G0UPL
http://www.hanssummers.com

Re: Low cost frequency counter & Huff Puff stabiliser kit

Jim Strohm <n6otq@...>
 

--- Hans Summers <hans.g0upl@...> wrote:


Thanks for the interesting idea. The ADC chanels
also make possible
other things, such as: monitoring battery voltage,
an S-meter, or power
output meter (PEP).
If you could get RX signal and power out signals
conditioned to comparable input levels, a single A/D
channel could serve as BOTH an S-meter and RF power
meter. Just multiplex it off of the keying line with
a couple of switching diodes.

Jim n6OTQ


____________________________________________________________________________________
Shape Yahoo! in your own image. Join our Network Research Panel today! http://surveylink.yahoo.com/gmrs/yahoo_panel_invite.asp?a=7

Re: Low cost frequency counter & Huff Puff stabiliser kit

Steven Weber <kd1jv@...>
 

Hans,

I have some spare MEGA48's on hand. If you'd like one to play with, I'd be
happy to send one off to you. I also have a number of AVR routines you
could use, binary to BCD, standard LCD driver, 16 bit multiply and divide
for RF power calculations and my huff n' puff.


72,
Steve, KD1JV
"Melt Solder"
White Mountains of New Hampshire
http://kd1jv.qrpradio.com

Re: Low cost frequency counter & Huff Puff stabiliser kit

jseager@...
 

Quoting vdberghak <vdberghak@...>:

..the 18MHz band is so small you do not need a VFO. A VXO will do
perfectly.

Hi Chris
It is true that a VXO will give you much of the band, and for
PSK even a xtal alone will do. But there is something a little
unpleasing about having all the action at one end of the dial.
A VFO with a stabiliser is preferable if it can be done.
I am confident that Hans will think of a way to fool his chip
(maybe he has already done so ) I am happy to wait!
Regards John G0UCP

Re: Low cost frequency counter & Huff Puff stabiliser kit

Arv Evans
 

John, Chris, Steve, etc.

It seems that if your BITX were to use a 22 MHz carrier oscillator and
n/2 pre-scaler for the 11 mHz IF frequency, then the AVR chip could run
at 22 MHz, placing it's frequency coverage into the range where counting
your 7 mHz VFO for 17 meters would be a possibility. Software in the
AVR could then halve the measured CPU clock to derive the transceiver IF
frequency and would be able to measure VFO output at up to maybe 9 mHz.
This is pushing a 20 mHz AVR chip a bit, but most would probably handle
it with minimal complaint. This would possibly also work for those BITX
units that use a 10 mHz IF, but it would be closer to the limits of VFO
measurement reliability.

Another alternative might be to put the n/2 prescaler on the VFO output
so the AVR would only have to read a 3.5 MHz signal and then software
double that for calculating the actual displayed frequency. This loses
a little resolution accuracy, but would still probably be adequate for
putting you on a specific frequency.

Arv
_._


jseager@... wrote:


Quoting vdberghak <vdberghak@... <mailto:vdberghak%40zonnet.nl>>:

..the 18MHz band is so small you do not need a VFO. A VXO will do
perfectly.

Hi Chris
It is true that a VXO will give you much of the band, and for
PSK even a xtal alone will do. But there is something a little
unpleasing about having all the action at one end of the dial.
A VFO with a stabiliser is preferable if it can be done.
I am confident that Hans will think of a way to fool his chip
(maybe he has already done so ) I am happy to wait!
Regards John G0UCP