Looking at this board more, and I'm just getting more dejected. I just noticed that what appears to be C95 is missing. Is it supposed to be? I'm about ready to throw this thing in the trash. What a waste of time and money... ? Kent W9WB On Fri, Dec 23, 2016 at 11:05 AM, Arv Evans arvid.evans@... [BITX20] < BITX20@...> wrote:
Roy
My post did cover all the transformers, and all the inductors. It even
told you that
the trifilar (3-wires twisted together) wound cores were FT37-43 types and
that the
single wire inductors are on T37-6 cores. All transformers and all
inductors except
T5, T6, and T7 are used in both transmit and receive modes. T5, T6, and
T7 are
part of the RF PA transmit section, and are broadband or transmission-line
transformers. They are wound exactly like the mixer transformers with 10
turns of
twisted wire on FT37-43 cores. There should be no guessing required to
determine
what these are and how they are wound.
Kent
The BITX-40 V3 design avoids having to align anything other than
possibility the VFO
to insure that it covers frequencies that are specific to your license
class and your
ITU region band designation. The L1, L2, L3 band pass filter is broad
enough to cover
the whole 7.0 to 7.3 MHz range. The mixer transformers and RF PA
transformers are
broadband transmission-line transformers which provide close to unity
coupling over
most of the HF range. The L6 and L7 low pass filter reduces harmonics and
other
spurious signals that are above 7.3 MHz. Only tuning you might need to
optimize
performance is some sort of ATU to insure that your antenna presents a 50
ohm impedance
to the BITX-40 v3 antenna connection.
There is some question about your glued-together L2 core. If the broken
and
repaired core still exhibits the same inductance as it did before being
broken all should
work fine. Possible problem though is if the glue introduces a gap in the
core material
it may affect the inductance, even if this gap is small. Replacing this
core and its
winding with a new and intact 6uh inductor should restore things to
normal. If you
have built a simple RF Detector probe you can measure transmit drive level
to the
RF PA section at low end of 40M and again at high end of 40M to see if
signal levels
are nearly the same. Use any voltage difference to calculate the db
(decibel) difference
which should be less than a couple of db.
?Arv K7HKL
_._
?
On Fri, Dec 23, 2016 at 4:11 AM, Kent Vanderploeg kvanderploeg@...
[BITX20] <BITX20@...> wrote:
So while I wait on replacement parts for L2, I'm trying to get some
learning experience out of the radio. I superglued L2 back together and it
looks pretty good, though I'm sure it's not ideal. I have been able to
hear some CW about 1/3 of the way of the tuning range.
I set up my FT-450D to listen and began transmitting on the BITX very
near the frequency where I heard the CW. It appears that my range is off
as the transmitting frequency at approx. 1/3 up the tuning range is
7.006MHz. Is there a simple process to align the TX with the SSB portion
of the band? I don't have any test gear other than a VOM and other
transceivers.
I'm sure this info is listed somewhere else in the Yahoo groups, but I
have no idea how to find it. I'm used to standard forums where info is
much more readily readable and searchable.
Kent
W9WB
On Dec 22, 2016 2:27 PM, "rjinspace@... [BITX20]" <
BITX20@...> wrote:
Arv.
Well, your writings cover the RX, but not the PA transformers T5, T6 and
T7 in
And it does not matter if I use a BITX20 v.3 PA PCB or a breadboard or
whatever - the whole point is that I cut and add traces / jumpers in order
to replicate the PA circuit in
_circuit.pdf. But the schematic as it is now is useless because one has
to guess that T5, T6 and T7 are transmission line transformers 10 turns
bifilar on FT37-43 or FT50-43? And the predriver and driver could be 28AWG
wire, but the output transformer should maybe use a thicker wire.
But I am now out of here. I have wasted enough time. IMO - the ONLY
solution is that ALL INDUCTORS AND TRANSFORMERS are specified IN THE
SCHEMATIC. Schematics that can not be built without guessing are not for me.
Just my opinion and choice - of course. Others may be fine guessing and
experimenting.
Thanks again Arv for your kind help.
Roy
[Non-text portions of this message have been removed]
|
Re: BITX40 goes Digital this Xmas!
Was ready to jump but couldn't when I finally stumbled on hfsigs.com a few days ago. Now have my order in, and very happy to have the Raduino upgrade coming with it.
I might hack it for 80m/40m/20m using one or two slide switches. Looks like just a matter of the rx and tx filters, and having the Raduino move the Si5351. Only issue I anticipate is possibly inadequate isolation between the switch contacts. Any recommendations there?
From the photos, looks like the board is around 4.5x5 inches. I happen to have a 5x7x2.5 inch hinged candy tin that could work, attach board and controls and connectors to a 5x7 scrap of PCB or alumuminum and drop it into the box using?magnets to hold it to the bottom of the box. Close the lid and all you see is a stock tin box, nothing to break. Anybody see a source for hinged rectangular boxes that might be a tighter fit? ?Though mine has room for batteries and EFHW tuner and a hank of antenna wire across the top,?which could be a good thing. Perhaps hfsigs.com could buy an appropriate tin box in bulk and make it available as an option when ordering.
Could have two 12v batteries normally operated in parallel.
For QRO, a break-before-make dpdt switch puts the batteries in series, the exciter running off of just the bottom battery and the final running from the series combination.
Jerry, KE7ER ? ?Flora OR, USA ?
|
A few thoughts and observations re. BITX-40v3
The BITX20 discussion group is now growing at a speed that equals what it
did in the early days of BITX20 design and construction.? I am seeing 5 to
20 new members added almost every day.? Most of this growth is due to
availability of the new BITX-40v3 from .
From some of the questions being posted it seems that several members may
be trying to build their own BITX-40 from the schematic provided by Farhan at
HFSigs.com.? This is commendable and a worthwhile project.? To provide some
information and answers for those builders... - All the inductors on the BITX-40v3 are wound on T37-2 or T37-6 cores.
Inductance for these is clearly labeled on the schematic.? Using the
stated inductance you can use the calculator at to find
how many turns and length of the wire to wind your own equivalent
inductors.
- All the transformers in the BITX-40v3 are wound on FT37-43 cores.?
These are broadband transmission-line transformers.? Windings are
trifilar using 10 turns of twisted together wire.? These do not have any
inductance shown on the schematic because they are effectively RFCs
(Radio Frequency Chokes) with close to unity coupling factor over most
of the HF range.? This applies to mixers and transformers in the RF PA
section.? If you really MUST have an inductance value for these transformers
you can go to and enter 10 turns for an FT37-43 core and
see that the inductance is 35 uh.? At 7 MHz this is an impedance of 1539?
ohms or way above the approximately 50 ohms for circuits that they are
coupling together.? The calculator is also useful because it
tells you that your 10-turn winding will take approximately 7 inches or 17.8
CM for each of the three wires you use to make up the trifilar winding.
- The BITX-40v3 is rather unique in that it has no tunable stages, other
than the VFO.? The two BPF (Band Pass Filters) are broad enough to
cover the full 7.0 to 7.3 MHz band.? The mixer transformers and those
in the RF PA section are broad banded enough to cover most of the
HF range.
- As with all BITX designs, it is imperative that you use an antenna that
presents an impedance close to 50 ohms at the transceiver antenna
connection.? Too low an impedance and the RF PA transistor may draw
excessive current and overheat.? Too high an impedance and the RF PA
transistor may go into oscillation and destroy itself.
- Some of the problems thus far discussed regarding commercially built BITX-40v3
boards seem to result from tinned leads on the FT47-43 transformers becoming
shorting together.? The leads are close together and the tinned part is sometimes
longer than necessary.? If the transformers have been bent over in shipping
or due to the board being dropped, it may be worthwhile to take a close
look at the transformer leads to insure that they are not shorted together.
- Transformers and inductors on the BITX-40v3 boards are not glued to the
PCB.? This provides easy means to modify the circuit to meet your particular
desires.? This is particularly useful if you need to change the VFO frequency
range.? After you are sure you have everything working the way you want you
can secure the VFO inductor, and other inductors and transformers, to the
PCB with melted wax, hot-melt glue, or other suitable adhesive.? Securing these
components to the board is not mandatory, but many may want to do it.
- It is possible to build SMT based circuits on cheap breadboards.? This
involves bridging gaps between pads with the SMT component and
connecting pads together with small diameter wire.
??? ? Cheap and frustrating to use
??? ? Better due to plated-thru holes
??? ? Wire for connecting components
SMT ICs and larger components can be mounted upside-down with
glue and connecting leads soldered to the exposed pins.
Others probably use different methods, but this seems to work for me.
- The original BITX-40v3 from uses a 270-degree potentiometer
to adjust VFO frequency.? There are a number of schemes to improve
frequency resolution.? Simplest is changing this potentiometer from the
single-turn unit to a 10-turn unit.? This potentiometer can be any value
between 10K and 100K.? It acts as a voltage divider to bias the varactor
(Voltage Variable Capacitor).? This potentiometer gets its voltage from U2
which is a 9 volt regulator.
Building your built-own from-scratch BITX is a fun and rewarding endeavor. Arv ?K7HKL _._
|
Re: Bitx40 varactor tuning/tuning dial?
I think I will get one of the "updated" BitX40 boards with the Raduino tuning.
Rich KC8MWG
On Friday, December 23, 2016 1:18 PM, "nd6t_6@... [BITX20]" wrote:
?
Rich,
I've tried an LED counter but much too noisy. May I suggest an analog voltmeter with the scale indicating your frequency? Puts you in the vicinity without any big modifications. Cheap, too. Just tie it to the wiper of the tuning pot, the "-" side to the ground side. If you wish not to re-write the meter scale then you could do a chart like the old HRO radios did (or the WWII freq meters).
-Don, ND6T
|
Re: Bitx40 varactor tuning/tuning dial?
Rich,
I've tried an LED counter but much too noisy. May I suggest an analog voltmeter with the scale indicating your frequency? Puts you in the vicinity without any big modifications. Cheap, too. Just tie it to the wiper of the tuning pot, the "-" side to the ground side. If you wish not to re-write the meter scale then you could do a chart like the old HRO radios did (or the WWII freq meters).
-Don, ND6T
|
Roy
My post did cover all the transformers, and all the inductors. ? It even told you that
the trifilar (3-wires twisted together) wound cores were FT37-43 types and that the
single wire inductors are on T37-6 cores.? All transformers and all inductors except
T5, T6, and T7 are used in both transmit and receive modes.? T5, T6, and T7 are
part of the RF PA transmit section, and are broadband or transmission-line
transformers.? They are wound exactly like the mixer transformers with 10 turns of
twisted wire on FT37-43 cores. ? There should be no guessing required to determine
what these are and how they are wound.
Kent
The BITX-40 V3 design avoids having to align anything other than possibility the VFO
to insure that it covers frequencies that are specific to your license class and your
ITU region band designation.? The L1, L2, L3 band pass filter is broad enough to cover
the whole 7.0 to 7.3 MHz range.? The mixer transformers and RF PA transformers are
broadband transmission-line transformers which provide close to unity coupling over
most of the HF range.? The L6 and L7 low pass filter reduces harmonics and other
spurious signals that are above 7.3 MHz.? Only tuning you might need to optimize
performance is some sort of ATU to insure that your antenna presents a 50 ohm impedance
to the BITX-40 v3 antenna connection.
There is some question about your glued-together L2 core.? If the broken and
repaired core still exhibits the same inductance as it did before being broken all should
work fine.? Possible problem though is if the glue introduces a gap in the core material
it may affect the inductance, even if this gap is small.? Replacing this core and its
winding with a new and intact 6uh inductor should restore things to normal.? If you
have built a simple RF Detector probe you can measure transmit drive level to the
RF PA section at low end of 40M and again at high end of 40M to see if signal levels
are nearly the same.? Use any voltage difference to calculate the db (decibel) difference
which should be less than a couple of db.
?Arv K7HKL
_._
?
On Fri, Dec 23, 2016 at 4:11 AM, Kent Vanderploeg kvanderploeg@... [BITX20] <BITX20@...> wrote:
?
So while I wait on replacement parts for L2, I'm trying to get some learning experience out of the radio. I superglued L2 back together and it looks pretty good, ?though I'm sure it's not ideal. I have been able to hear some CW about 1/3 of the way of the tuning range.?
I set up my FT-450D to listen and began transmitting on the BITX very near the frequency where I heard the CW.? It appears that my range is off as the transmitting frequency at approx. 1/3 up the tuning range is 7.006MHz.? Is there a simple process to align the TX with the SSB portion of the band? I don't have any test gear other than a VOM and other transceivers.
I'm sure this info is listed somewhere else in the Yahoo groups, ?but I have no idea how to find it.? I'm used to standard forums where info is much more readily readable and searchable.?
Kent W9WB?
|
Re: BITX40 goes Digital this Xmas!
The email that keeps getting chopped off is "hfsignals AT gmail DOT com"
73, Al - VE3RRD
|
|
|
Re: BITX40 goes Digital this Xmas!
Hi
I was wondering how tuning the DDS with a potentiometer compares with using a shaft encoder? Seems like the shaft encoder would allow finer tuning compared to the potentiometer.? Probably soon after the new boards arrived, someone will modify the code to use a shaft encoder.
Also, the the BITX40 operate from 7.0 to 7.3 MHz for us in the US?
Is USB possible? I would like to be able to use the BITX40 for PSK-31 and some of the other digital modes.
I have ordered the new radio. Looks like a fun project. Looking forward to opening up my PO Box and finding a package from VU land.
73 and thanks for all your good work.
Randy, K7AGE
On Fri, Dec 23, 2016 at 7:40 AM, Kenyw kenyw@... [BITX20] <BITX20@...> wrote:
?
hfsignals@...
-----Original Message-----
From: ohwenzelph@... [BITX20] < BITX20@...>
To: BITX20 < BITX20@...>
Sent: Fri, Dec 23, 2016 9:12 am
Subject: Re: [BITX20] Re: BITX40 goes Digital this Xmas!
?
For me it comes thru each time as hfsignals@...
Which does not work even if I try.
What comes after the "@"?
Tnx,
|
Re: BITX40 goes Digital this Xmas!
I see that the Arduino sketch comes preloaded on the Nano. Still, I would like to look at the code so I can use a different display.
Joel
KB6QVI
|
Re: BITX40 goes Digital this Xmas-got it: Gmail dot com
Don't know why I kept getting the "dot dot dots" after the @ If 14 dollars doesn't cover the Raduino, I will probably just order a whole 2nd kit. I already ordered a digital tuning solution from QRP-Labs for the first one plus parts to try and make the analog VFO stable. Jerry aa1of
|
|
|
Re: BITX40 goes Digital this Xmas!
toggle quoted message
Show quoted text
-----Original Message-----
From: ohwenzelph@... [BITX20] <BITX20@...>
To: BITX20
Sent: Fri, Dec 23, 2016 9:12 am
Subject: Re: [BITX20] Re: BITX40 goes Digital this Xmas!
?
For me it comes thru each time as hfsignals@...
Which does not work even if I try.
What comes after the "@"?
Tnx,
|
Re: BITX40 goes Digital this Xmas!
Hi Ashher,
Where do we get the Arduino sketch for the Raduino Nano? Do we make our own or use any existing sketch? I have the one I'm using now, but am curious if you have a different one.
Joel
KB6QVI
|
Re: BITX40 goes Digital this Xmas!
Link works perfectly for me Lawrence
On Fri, Dec 23, 2016 at 3:18 PM, Ken Hansen ken@... [BITX20] <BITX20@...> wrote:
?
Ashhar,
Am I reading this correctly, the new board will sport a digital display that shows operating frequency?
Could you provide more specifics about the functionality out-of-the-box the adds over that of the previous board? I am not asking about about potential possibilities, but included functions as delivered.
Thanks,
Ken Comrades,
The upgraded BITX40 has been released. Check , you may have to refresh the page with a Ctrl-R or something.
RADUINO! The new BITX sports the Raduino, a tiny board that carries a full Arduino Nano, a 16x LCD display and an Si5351a. The Raduino is fully open sourced and it will be available on github by the weekend. With this, the BITX40 is now capable of sporting dual VFOs, RIT, keyer, SWR meter, etc. No, these are not built-in. Instead, these are things that can be made with a few resistors and capacitors and some clever software added around the Raduino. I will document it fully in a few days. I am very excited with the possibilities of the Raduino.?
|
Re: BITX40 goes Digital this Xmas!
Ashhar,
Am I reading this correctly, the new board will sport a digital display that shows operating frequency?
Could you provide more specifics about the functionality out-of-the-box the adds over that of the previous board? I am not asking about about potential possibilities, but included functions as delivered.
Thanks,
Ken
toggle quoted message
Show quoted text
On Dec 23, 2016, at 1:29 AM, Ashhar Farhan farhanbox@... [BITX20] < BITX20@...> wrote: Comrades,
The upgraded BITX40 has been released. Check , you may have to refresh the page with a Ctrl-R or something.
RADUINO! The new BITX sports the Raduino, a tiny board that carries a full Arduino Nano, a 16x LCD display and an Si5351a. The Raduino is fully open sourced and it will be available on github by the weekend. With this, the BITX40 is now capable of sporting dual VFOs, RIT, keyer, SWR meter, etc. No, these are not built-in. Instead, these are things that can be made with a few resistors and capacitors and some clever software added around the Raduino. I will document it fully in a few days. I am very excited with the possibilities of the Raduino.?
|
Re: BITX40 goes Digital this Xmas!
For me it comes thru each time as hfsignals@... Which does not work even if I try. What comes after the "@"?
Tnx,
|
Re: BITX40 goes Digital this Xmas!
Cheers Tim, still couldn't see the whole address in your message, but was able to see it in the message list.
David
VK5PL
|
Re: BITX40 goes Digital this Xmas!
Any YouTube demo About digital version ? If so link please. VU2RJW
On Dec 23, 2016 5:59 PM, "Richard Knack ihc73scout2@... [BITX20]" < BITX20@...> wrote:
?
Awesome! I will certainly be ordering one soon. Glad I waited...
Rich KC8MWG
?
G'day - recently ordered BITX40 with analogue tuner and still awaiting delivery.? Now I am waiting for the Christmas digital version.? That's all my Christmases in one,
Thanks and regards - Noel? VK2CAO
|
Re: BITX40 goes Digital this Xmas!
Awesome! I will certainly be ordering one soon. Glad I waited...
Rich KC8MWG
On Friday, December 23, 2016 7:10 AM, "tupakihi@... [BITX20]" wrote:
?
G'day - recently ordered BITX40 with analogue tuner and still awaiting delivery.? Now I am waiting for the Christmas digital version.? That's all my Christmases in one,
Thanks and regards - Noel? VK2CAO
|
Don, ND6T
Joel Caulkins/N6ALT
Soundararajan Ra.