Re: Building my own ubitx - question about mixers and mixer transformers
Most any level 7 mixer should work, such as the ADE-1 or SBL-1. ?The commercial ones are designed to give a flat response up to a ghz or two, so an appropriately hand built design appropriate for the operating frequency may outperform it, though choosing the correct core and number of windings is not something I'll be giving advice on. ?If you check the datasheets, you will see that the commercial mixer schematic is identical to what Farhan has on his diode ring mixers, so the same method of transmitting CW should work. ?The dual diode modulator on the uBitx is operating at 12mhz, and can be identical to what is on the Bitx40.?
There are a few issues with the uBitx as it now stands.?
With a 45mhz IF and a high side VFO, the receiver will be susceptible to images in the FM broadcast band. ?For example, when receiving at 25mhz, the vfo will be at 45+25 = 70mhz. ? An FM transmitter at 70+25 = 95mhz would be received as an image. ?So if you have strong FM broadcast transmitters in your area, you might consider upping the IF frequency some from 45 mhz. ?That would also make it easier to build a suitable front end lowpass filter that still lets through a 10m signal.
The second harmonic out of the push-pull IRF510's is not sufficiently attenuated unless you happen to have a spectrum analyzer handy to get the balance right. ?So, for example, you will likely need separate lowpass filters on 80 and 40 meters to be legal. ?Use C0G or NP0 caps in those filters and anywhere the actual capacitance value is critical, and the caps in in the lowpass filters need to be good for several hundred volts.
There might be some trouble with crosstalk when using all three outputs from the Si5351, especially if the SI5351 outputs are set to the higher drive levels. ?Will certainly work, though might give us extra birdies.
Farhan is still developing the uBitx, but has encouraged scratch builds as a way of getting more information on possible issues.
I think it will prove to be a very nice rig, better in many ways than the Bitx40 has been.
Jerry, KE7ER
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On Wed, May 31, 2017 at 08:55 am, David Feldman wrote:
1. I could not find specification for the transformers used in ubitx (alongside the BAT45S diodes), but I did eventually track down a mention from bitx40 on hfsigs.com as follows: ? ?T1,T2,T4,T5,T6,T7 : 10 turns trifilar on FT 37-43 core
Is this appropriate for the ubitx frequency regime (12 and 45 MHz)?
?
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Re: Building my own ubitx - question about mixers and mixer transformers
Dave WB0GAZ
In the early days of BITX most of us built our own transceivers that loosely followed the
original design by Farhan.? Historical information on those builds cover most of your
questions and can be found by browsing back over the group discussions.? - You can build your own mixers.? These might be simple as-built units with
1N4148 diodes and FT37-43 transformers.? !0 turns may be a bit much
for operation at the upper extremes of HF range, but you can test this by
measuring input versus output of the transformers with an appropriate load.
- Many of the commercial mixers can be used (SBL, etc.).? Almost all should
perform adequately.? There is much room for discussion (argument...?)
about whether commercial mixers or carefully built homemade mixers are
best.? Lower threshold diodes should require less LO drive voltage.? Carefully
matched diodes and transformer windings should also improve performance.
- Binocular transformers do find use in the RF PA of may QRP rigs.? You can
use stacks of conventional toroidal cores as work-alike alternatives.? Same
winding technique is used for both binocular cores and stacked toroid cores.
There are many myths, opinions, facts, and opinionated facts regarding which mixer is best or worse.? I personally would build my own carefully designed mixers, but leave
room for substituting alternative mixers for testing and evaluation purposes.? This
way you can determine for yourself which is best for you.? It may be that the best?
HF mixer will be different from the best BFO mixer.? It is probably not a one-size-fits-all
situation.
Arv
_._
On Wed, May 31, 2017 at 9:55 AM, David Feldman via Groups.Io <wb0gaz@...> wrote: Hello (and thanks to the moderator for approving my request to join)!
I am implementing my own ubitx and have a couple of questions about the mixers and mixer transformers (which don't seem to be specified on the project website):
1. I could not find specification for the transformers used in ubitx (alongside the BAT45S diodes), but I did eventually track down a mention from bitx40 on as follows:
T1,T2,T4,T5,T6,T7 : 10 turns trifilar on FT 37-43 core
Is this appropriate for the ubitx frequency regime (12 and 45 MHz)?
2.
There were some mentions of "tv transformer cores" - binocular - but no specification or identifier.
Are these a suitable alternative?
3.
Could I use packaged minicircuits mixers (such as ADE-1 or similar Level-7 mixer) in lieu of the transformer+bat45s design?
If so, how do I "unbalance" the ADE-1 for CW transmit in the 45 MHz-to-RF mixer stage? Would injecting a positive bias voltage into the IF port work (if so, recommended voltage, current and means to isolate normal RF flow)?
Thanks very much, looking forward to this project!!
73 Dave WB0GAZ wb0gaz@...
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D7/C130 connected incorrectly
It appears from the BITX40v3 schematic that D7 & C130 should not be connected between +12v and ground but instead across pins 8 and 9 of K1.? Just like D6 and C164 are connected across pins 8 and 9 of K2.
?
High voltage spikes could result went the PPT control line is opened.? Also D7 will be damaged if the 12v power leads are accidentally reversed.
?
I apologize if this has already been corrected but I didn't see a previous post and the schematic is still wrong.
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Re: Signal Meter and 10m conversion for Bitx40 ?
Here's a very simple S-meter: ?
I suppose you could read it from the Arduino through an analog pin, and maybe convert
the linear reading over to something logarithmic (traditionally 6 dB difference per S unit).
Print the result to the display using printLine2() in the sketch.
But that diode detector is not going to be very sensitive.
A more accurate S-meter could be had by using an AD8307 (or AD8307 if you can deal with the pin spacing.)
Not only does it have a 90 dB dynamic range, the output is logarithmic. ?
Those parts are good down to DC, could be used after the audio pre-amp if you need the gain.
As far as hitting other bands, you would need to replace the bandpass filter at L1,L2,L3 and the lowpass filter at L6,L7.
Also adjust the Arduino sketch to move the VFO frequency appropriately.
Power from the IRF510 will be down some when operating at 10 meters, and could be you will have trouble
with the current board layout at those higher frequencies.
Allard's sketch allows you to choose LSB or USB operation.
Jerry, KE7ER
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On Wed, May 31, 2017 at 08:05 am, Jim McKay wrote:
I am looking for software and hardware advice to add a signal meter (ideally on the Raduino?1602 LCD - bottom line?) and also to convert the radio to 10m USB.
?
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Building my own ubitx - question about mixers and mixer transformers
Hello (and thanks to the moderator for approving my request to join)!
I am implementing my own ubitx and have a couple of questions about the mixers and mixer transformers (which don't seem to be specified on the project website):
1. I could not find specification for the transformers used in ubitx (alongside the BAT45S diodes), but I did eventually track down a mention from bitx40 on hfsigs.com as follows:
T1,T2,T4,T5,T6,T7 : 10 turns trifilar on FT 37-43 core
Is this appropriate for the ubitx frequency regime (12 and 45 MHz)?
2.
There were some mentions of "tv transformer cores" - binocular - but no specification or identifier.
Are these a suitable alternative?
3.
Could I use packaged minicircuits mixers (such as ADE-1 or similar Level-7 mixer) in lieu of the transformer+bat45s design?
If so, how do I "unbalance" the ADE-1 for CW transmit in the 45 MHz-to-RF mixer stage? Would injecting a positive bias voltage into the IF port work (if so, recommended voltage, current and means to isolate normal RF flow)?
Thanks very much, looking forward to this project!!
73 Dave WB0GAZ wb0gaz@...
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Re: How to pronounce "BITX"?
I like BIT-X "bit-ex"
Sent from my iPhone
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On May 30, 2017, at 3:55 PM, Vince Vielhaber <vev@...> wrote:
I pronounce it the same as Jack does.
Vince - patiently awaiting DHL with my Bitx40 - KA8CSH.
On 05/30/2017 03:49 PM, Jack Purdum via Groups.Io wrote:
I like "bit-X"
Your friendly Name-Nazi
------------------------------------------------------------------------
*From:* Ashhar Farhan <farhanbox@...>
*To:* [email protected]
*Sent:* Tuesday, May 30, 2017 3:38 PM
*Subject:* Re: [BITX20] How to pronounce "BITX"?
americans have taken on saying 'bee-tex', while some others , notably
the english and their indian cousins, say 'by-tex'. we havent had any
name nazis here yet. choose your own!
- f
On Wed, May 31, 2017 at 12:31 AM, John <easydogxray@...
<mailto:easydogxray@...>> wrote:
Hi All,
Is there a correct pronunciation of BITX? I've been calling it
"Bittex" but I wonder if there's an official pronunciation.
Thanks and 73,
John G4EDX
Nottingham, England
--
Michigan VHF Corp.
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Signal Meter and 10m conversion for Bitx40 ?
Hello everyone,
I am hoping someone can help me with 2 modifications for my BiTX40.
I am looking for software and hardware advice to add a signal meter (ideally on the Raduino?1602 LCD - bottom line?) and also to convert the radio to 10m USB.
Can anyone offer advice, please?
Thank you?
Jim
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BITX QSO Night, Sunday, June 4, 7pm Local Time, 7277 kHz in North America, 7177 kHz elsewhere
BITX QSO Night, Sunday, June 4, 7pm Local Time, 7277 kHz in North America, 7177 kHz elsewhere
Join us as we make contacts from BITX40 to BITX40 on 7277 kHz in the 40 meter band!
To participate, call CQ BITX at 7pm sharp, your local time, on Sunday. Call off and on for about 15 minutes. It is helpful if you call CQ BITX with your name and location.? Repeat your call a number of times if conditions are weak.
This is a worldwide event at 7pm in each time zone.? You may participate in any time zone, regardless of your location, so you may wish to call in at 6pm, 7pm and 8pm, your local time, to contact hams in adjacent time zones.
Report your QSO's, discuss propagation, noise, signal reports, audio reports, antenna type, etc. in this thread.
This is an undirected, scheduled event.? The BITX QSO Night relies on you to call CQ BITX to initiate contacts with other stations, so warm up that final and transmit a few calls at 7pm on Sunday.? Talk to you then!
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Re: Raduino_v1.13 with scan function released
Yes I believe the general recommendation should be 10K instead of 47K.
So that it gives sufficient drive in all cases.
I will update the instructions accordingly.
73 Allard PE1NWL
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On Wed, May 31, 2017 14:40, Jerry Gaffke via Groups.Io wrote: Some have found that they need a smaller resistor value than Allard's 47k
to get 5 watts out, some have gone as low as 10k. ??That's a better
solution than turning up R136. ??That variation is due to how the BFO
lands on the edge of the crystal filter, so different rigs wind up with
different drive levels into the IRF510. ??My guess is that everybody could
do just fine using 10k and thus drive the IRF510 relatively hard, since
the IRF510 does not have to be a linear amp when transmitting CW. ??Though
Q13 is already out beyond its dissipation limits, as is R141. ??So those
parts might possibly blow with too high of a drive level, though nobody
has reported a problem like that recently.
I'll let somebody who has gotten around to doing it give advice on how to
get digital modes going.
On Tue, May 30, 2017 at 11:42 pm, John Smith wrote:
When you say BFO is on the skirt of the filter, do you mean CW will need
to be turned up?
And with clean CW we drive it really hard.--- How hard?
Do you offer any words of advice about safely interfacing with isolated
audio and switches? I am planning on something like Easy Digi from
scratch
with a DB9 breakout board with screw terminals, plus the two audio cable
connections. Do I need pots for audio levels? Or do you think in windows
audio settings will be enough.
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Re: Raduino_v1.13 with scan function released
Some have found that they need a smaller resistor value than Allard's 47k to get 5 watts out, some have gone as low as 10k. ?That's a better solution than turning up R136. ?That variation is due to how the BFO lands on the edge of the crystal filter, so different rigs wind up with different drive levels into the IRF510. ?My guess is that everybody could do just fine using 10k and thus drive the IRF510 relatively hard, since the IRF510 does not have to be a linear amp when transmitting CW. ?Though Q13 is already out beyond its dissipation limits, as is R141. ?So those parts might possibly blow with too high of a drive level, though nobody has reported a problem like that recently.
I'll let somebody who has gotten around to doing it give advice on how to get digital modes going.
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On Tue, May 30, 2017 at 11:42 pm, John Smith wrote:
When you say BFO is on the skirt of the filter, do you mean CW will need to be turned up?
And with clean CW we drive it really hard.--- How hard?
Do you offer any words of advice about safely interfacing with isolated audio and switches? I am planning on something like Easy Digi from scratch with a DB9 breakout board with screw terminals, plus the two audio cable connections. Do I need pots for audio levels? Or do you think in windows audio settings will be enough.
?
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Re: Raduino_v1.13 with scan function released
OK thanks, updated the text slighty as follows:
FUNCTION BUTTON WIRING:
Connect a momentary pushbutton between pin A3 (connector P1, orange wire)
and ground.
And the pin layout picture:
PIN LAYOUT:
73 Allard PE1NWL
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On Wed, May 31, 2017 06:43, John Smith via Groups.Io wrote: I was happy with a SSB Transceiver to go with my CW transceiver, but I
can't help thinking I am missing a great opportunity to try digital very
cheaply with the Bit-X 40. Especially since Allard has made it so easy
with enabling the functions in the code and tweaking them so they work and
work well. Thanks for that.
But I don't know what kind of CW this is. Is it MCW or regular (No Oo
Card) CW? Non engineer needs simple answer.
And now for some friendly feedback. Allard, would you consider changing
the "Function Button Wiring" instruction to include the 8 pin connector in
addition to the orange wire. Both connectors have an orange wire, and I
had to look up Randy's Raduino Pin Out PDF to find out which one has Pin
A3.
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Re: How to pronounce "BITX"? Thanks!
Wow! I never thought there would be such a big response to my question!
Thanks for all the replies, and it seems that there are plenty of quite acceptable pronunciations. B. I. T. X. seems a bit formal to me, Bittex now sounds like that stuff they put in liquids to stop people drinking them, so I'm going with By Tex from now on.
73 all,
John G4EDX/G4JBC
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Re: Raduino_v1.13 with scan function released
I have meanwhile updated the code so that the display now shows the actual
frequency during both TX and RX.
Will be included in the next version v1.14, along with some other
improvements - to be released soon.
73 Allard PE1NWL
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On Wed, May 31, 2017 02:07, Jerry Gaffke via Groups.Io wrote: I have no idea what commercial rigs do these days. ??But I'd think that in
all cases the display should show the transmit carrier frequency whether
transmitting or receiving. ?? (The carrier is suppressed when in SSB mode,
but the carrier is still the frequency that gets displayed.) ?? ?? The vfo
would have to move to one side by an amount equal to the sidetone
frequency (as set during configuration) when receiving in CW mode. ??
Which side it gets moved to is determined by whether we are in UCW or LCW
mode. ??Of course, Receive Incremental Tuning can be used to adjust the
vfo further during receive. ??I'd prefer that the main display always show
the transmit frequency, but with an RIT delta frequency shown in the
bottom line of the display if RIT is enabled.
??
On Tue, May 30, 2017 at 03:53 pm, Allard PE1NWL wrote:
So the actual transmitted frequency is indeed a few hundred hertz off
the
dial frequency as shown on the display. This may be confusing for some.
I
will see if I can improve this in the next version so that the dial
frequency is updated during TX (same as in some commercial rigs).
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Re: How to pronounce "BITX"?
Listen to how Ashhar Farhan pronounces BITX at:
the podcast:
"BEE EYE TEE EX"
B I T X.
However, like many Americans, I pronounce it, "bit-ex,"
even though I know it is actually pronounced "B I T X"
by Mr. Farhan.
73 DE KM4NFQ
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Re: Step by step raduino software install instructions
For window 7 with 32 bit computer what are the steps to be followed. followed
Soundar vu2rjw
i have got it working at last. i downloaded the driver from GOGO:TRONICS
thanks for the info from everybody
73's de terry gm4dso
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Re: Raduino_v1.13 with scan function released
When you say BFO is on the skirt of the filter, do you mean CW will need to be turned up?
And with clean CW we drive it really hard.--- How hard?
Do you offer any words of advice about safely interfacing with isolated audio and switches? I am planning on something like Easy Digi from scratch with a DB9 breakout board with screw terminals, plus the two audio cable connections. Do I need pots for audio levels? Or do you think in windows audio settings will be enough.
I would appreciate a link for what others have done here in the digital sub group, or what have you.?
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Re: How to pronounce "BITX"?
I've been used to pronouncing 'Bittix'.
Probably cause is that the seperate 'X' is pronnounced as ' ix ' in Dutch.
What's in a name..??
73, Alex
PA1FOX
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Re: How to pronounce "BITX"?
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Re: Raduino_v1.13 with scan function released
The audio oscillator approach generates regular CW as well. ?I was moaning a bit there about all those other potential sources of dirt in our CW transmissions, but if done correctly there's nothing wrong with the audio oscillator approach. ?Especially at QRP power levels.
Jerry, KE7ER
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On Tue, May 30, 2017 at 10:41 pm, Jerry Gaffke wrote:
Allard's solution is regular CW. ?It should give a cleaner signal than the audio oscillators that are often used with the Bitx transceivers,
?
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Re: Raduino_v1.13 with scan function released
Allard's solution is regular CW. ?It should give a cleaner signal than the audio oscillators that are often used with the Bitx transceivers, since those will have signals with a residual carrier and opposite sideband and some distortion due to a not so perfect audio sine wave and distortion in the mike amp and distortion in the modulator and typically no key shaping. ?Only downside I see to Allard's current CW transmit solution is that the BFO is on the skirt of the crystal filter, so CW output power may need to be adjusted at R136. ?However, Allard is looking into generating the BFO from the Si5351's CLK0, which would allow the sketch to move the BFO such that it is centered in the crystal filter passband when transmitting CW (if that all somehow fits in the Nano). ? When transmitting clean CW like this we can drive that IRF510 pretty hard since it no longer needs to be a linear amp.
.
Going digital using a PC sound card on the Bitx40 should be about as easy as any SSB transmitter. ?The PC must somehow tell the Bitx40 when to transmit. ?Some here have reported success with using the Bitx40 for digital modes.
Jerry, KE7ER
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On Tue, May 30, 2017 at 09:43 pm, John Smith wrote:
Is it MCW or regular (No Oo Card) CW?
?
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K7IOW
Allard PE1NWL
Soundararajan Ra.