Date   
Re: Bitx40 vs. uBitx

John KG9DK
 

I have been following this thread on Bitx40 vs. ubitx.  I understood the question to be a comparison between the Bitx40 and the ubitx 40m.  Anyway that would be my question....so are there any different between the performance of Bitx 40 and the ubitx 40m. Taking in the consideration  of   being in spec for the FCC rules too.
john kg9dk.

Re: IF OUT

Joe Puma
 

Thanks for the suggestions Iz, Ill be checking out the RTTY contest for sure and I do have a need for some 1:1 transformers, Ill order some and give it a go. One thing I did last night seems to make even more improvement to the Spurs. I used a piece of short coax RG179 for the antenna input from board to connector. Looks like it reduced the spurs a little.

 

 

This pic is from the other day.

 

 

 

This is with coax on Antenna connection

 

 

I can also see the little dip in the center which I get on my FT-840 from tapping IF there too. I was told that this is a product of the filter, or mixer, it matched the width of 15khz which one could assume is from the 45mhz filter.

 

 

 

Joe

 

 

Sent from Mail for Windows 10

 

From: iz oos
Sent: Wednesday, September 26, 2018 3:19 AM
To: BITX20@groups.io
Subject: Re: [BITX20] IF OUT

 

I would like to point out two tricks to reduce noise that worked for me using cheap sdr IF converters. First if you use a laptop, either use the battery (which will be eaten fast) or a power supply that has the ground wire as well. Also in some cases adding a 1:1 RF isolating transformer at the IF output made a huge difference and removed ground loops.

 

Il 26/set/2018 08:50, ha scritto:

Ok, interesting that a resistor may suffice. If you hear overload in the uBitx then you need the BCI filter or adding some preselection. If you see the overload in the RTL and you hear a clean signal in uBitx that is due to the extremely poor dynamic range of the dongle. This weekend there is the most important RTTY contest. It is a good test to see the difference between a good and a mediocre receiver.

 

Il 25/set/2018 22:43, "Joe Puma" <kd2nfc@...> ha scritto:

I do have a buffer board but its in the FT-840. I added a 220 ohm resistor in series and I am no longer effecting the radio receive with the SDR connected, not hearing a difference plugged/unplugged. The waterfall is a little cleaner. The spikes or spurs are a bigger issue right? I usually see that on my other rigs if I do use gain in the SDR or a LNA, but gain is 0 on the SDR, is there some gain coming from where I tapped?

 

I also get bad IMD, I hear radio stations in the background no matter where I tune and it gets worse from 40 and below. Ill be exploring that soon, the BCI filter should make for more improvement when I install it. I also removed the

 

Joe

 

 

 

 

Sent from Mail for Windows 10

 

From: iz oos
Sent: Tuesday, September 25, 2018 3:58 PM
To: BITX20@groups.io
Subject: Re: [BITX20] IF OUT

 

I think Joe uses a buffer board which should be the best way to tap it. And alternative is using another 3904 (emitter-follower) . The gain in the RTL I have can be reduced by 42db via the software.

 

Il 25/set/2018 21:32, "Joe Puma" <kd2nfc@...> ha scritto:

Thank you Allison. That sounds like a good experiment, I’ll give it a go. 

 

 

Joe

 

 


On Sep 25, 2018, at 12:58 PM, ajparent1/KB1GMX <kb1gmx@...> wrote:

Joe,

Keep in mind a RTL-SDR is not an insensitive receiver.  Its good enough on its own.
so putting the gain and mixers of the ubitx ahead of that means the noise floor is
increased by the effective gain or about 10-14db or so.  None of which helps hear
signals better as the IF amp it self has a noise figure of maybe 4-6DB.

So yes, much cruft.

To use it effectively as a panadaptor the SDR gain has to be turned down so the noise is
the baseline at or near the bottom of the spectrum display or a light background on the
waterfall.  Otherwise all you see is the noise and the signals will not stand out.

You likely need a buffer (or reduce loading) as well as tapping at that point is like putting
two load (resistors) in parallel and the receiver has less signal or effective gain.  The buffer
could be as simple as a series resistor from that point to the coax for the SDR.  Since the
SDR already sees too much cruft so lowering the signal (series resistor) will improve the
view and also lower the load on the IF to regain signal.  Values likely are in the range
of 50 to 500 ohms and try by substitution may be easiest way.  Its a useful experiment
and so try a 470 ohm for a starting point (may be too high).

Allison

 

 

Re: 2.8" Color TFT display with mouse control #ubitx

Jim Sheldon
 

Several have asked the question if a Teensy 3.5 will work with our BITeensio board for this application.  The answer is NO because, as far as we have been able to determine, USB "Host" mode only works on the Teensy 3.6. 

When they had the Teensy 3.5 manufactured, PJRC seems to have left some components off it so USB host mode couldn't be implemented though the traces appear to be on the board.  I don't know if those components could be added (you'd have to be pretty good with a very fine soldering iron and know what the components were) or if that would even make it work.  There might be some internal programming for the ARM processor as well that would have to be updated and I can't answer those questions.

When we designed the BITeensio to replace the Raduino and our own RadI2Cino cards we settled on the Teensy 3.6 as it was a good bit superior in speed and capability to the Teensy 3.5.  The only minor disadvantage is the 3.6 is NOT 5 volt compliant on any of its I/O like some of the I/O pins on the Teensy 3.5.  We didn't see this as a disadvantage though as most of the later crop of useful items run on 3.3V anyway and our color displays require 3.3V only.  This, plus the smaller footprint of the Teensy series made the Teensy 3.6  a much better choice as the BITeensio's MPU. 

The Teensy 3.6's on board 3.3V regulator has sufficient current handling capability to run the smaller 2.8" Color screen/back light, the 3.3V I2C bus, the Si5351a and the TSX0102 level shifter for the BITeensio's 5V I2C bus and still have some reserve.  Also, the Teensy 3.5 was not enough cheaper than the 3.6 to warrant using it so again, the answer is NO, the Teensy 3.5 will not work with the BITeensio card in any of our applications.

Jim Sheldon, W0EB
TSW Project Coordinator

Re: Current Draw & Power Output Question

iz oos
 

Indeed Russ, it may have been just by fluke but mine arrived perfectly aligned (actually almost perfectly, 100-150hz off the actual frequency) so I assumed that in most cases it was delivered calibrated.


Il 26/set/2018 16:10, "Russ Hines" <russ@...> ha scritto:
And right off the bat... I wonder why this is mentioned on the HF Signals website?

"The µBITX comes pre-aligned. You should do this only if you really think it is out of alignment."

http://www.hfsignals.com/index.php/ubitx-tuneup/

73,
Russ
WB8ZCC

Re: Current Draw & Power Output Question

Russ Hines
 

And right off the bat... I wonder why this is mentioned on the HF Signals website?

"The µBITX comes pre-aligned. You should do this only if you really think it is out of alignment."

http://www.hfsignals.com/index.php/ubitx-tuneup/

73,
Russ
WB8ZCC

PTT switching for amp

Carl
 

Hi, can someone tell me a simple way to add a ptt switching circuit for my amp please? Can I just use pins from the transmit relay? 

Thanks.

Re: Current Draw & Power Output Question

M Garza <mgarza896@...>
 

Doing a smoke test does not include setting the BFO!
No where on the site does it mention that the kit comes pre-calibrated.  The software is written to get the frequency close to being aligned.  Due to differences, some people have to calibrate.
As for the bias adjustment, if it was not transmitting, I would think it might need to be reset.  It is transmitting.  RV1 probably needs to be adjusted to get a little more drive.
There are alignment procedures for a reason.  Don't assume that the kit can be put together and you get instant use.  It has to be aligned.  Even the high $$ equipment has alignment procedures.

Marco - KG5PRT 

On Wed, Sep 26, 2018, 6:17 AM Timothy Fidler <engstr@...> wrote:
iz. don't confuse the poor bugg_r There is a procedure for set up .  he needs to follow the procedure to get optimum output in SSB.  Now you bring up a red herring.  What I would find annoying is to see that there appears to have been ZERO set up on the test bench in India (he mentions it did not Rx as received either). You wonder if it was even turned on  to check for smoke leaks ??

Re: Current Draw & Power Output Question

Timothy Fidler
 

iz. don't confuse the poor bugg_r There is a procedure for set up .  he needs to follow the procedure to get optimum output in SSB.  Now you bring up a red herring.  What I would find annoying is to see that there appears to have been ZERO set up on the test bench in India (he mentions it did not Rx as received either). You wonder if it was even turned on  to check for smoke leaks ??

Re: Current Draw & Power Output Question

iz oos
 

Why don't you measure the power and current draw in CW key down?


Il 26/set/2018 12:02, "Curt M." <Kc3hjp@...> ha scritto:
Thanks guys, I had sort of considered that the Bird 43 was probably not showing peak power being that it’s not capable of without the add on kit being done to the meter so that confirms my thoughts. Thanks 

I’m using a relatively new, Fluke meter that of course could have an issue but it jives with another meter that I have so I suspect it’s probably close enough. 

I may re-bias being that the uBitx was supposed to be in alignment when I received it and it was nowhere near being able to tune a signal when I first powered it up. I had to do the calibration and BFO adjustment before I could tune anything in. I suspect that it may have been skipped over when it came to factory setup. 

Re: Current Draw & Power Output Question

Curt M.
 

Thanks guys, I had sort of considered that the Bird 43 was probably not showing peak power being that it’s not capable of without the add on kit being done to the meter so that confirms my thoughts. Thanks 

I’m using a relatively new, Fluke meter that of course could have an issue but it jives with another meter that I have so I suspect it’s probably close enough. 

I may re-bias being that the uBitx was supposed to be in alignment when I received it and it was nowhere near being able to tune a signal when I first powered it up. I had to do the calibration and BFO adjustment before I could tune anything in. I suspect that it may have been skipped over when it came to factory setup. 

The Triple Scratch-Built BITX Club

Bill Meara
 

Re: Ashhar's satellite

iz oos
 

Good news. Would be nice Farhan could make a stand alone VHF UHF SSB/CW qrp rig to be used for sats, sota and contests in general.


Il 26/set/2018 00:55, "Bill Meara via Groups.Io" <n2cqr=yahoo.com@groups.io> ha scritto:
I've updated the blog post. 73  Bill N2CQR

On Tuesday, September 25, 2018, 6:47:52 PM EDT, Joe Puma <kd2nfc@...> wrote:


This is great. I have my turnstile antenna ready!  📡 Go Farhan!


Joe



On Sep 25, 2018, at 6:34 PM, Doug W <dougwilner@...> wrote:

Re: IF OUT

iz oos
 

I would like to point out two tricks to reduce noise that worked for me using cheap sdr IF converters. First if you use a laptop, either use the battery (which will be eaten fast) or a power supply that has the ground wire as well. Also in some cases adding a 1:1 RF isolating transformer at the IF output made a huge difference and removed ground loops.


Il 26/set/2018 08:50, ha scritto:

Ok, interesting that a resistor may suffice. If you hear overload in the uBitx then you need the BCI filter or adding some preselection. If you see the overload in the RTL and you hear a clean signal in uBitx that is due to the extremely poor dynamic range of the dongle. This weekend there is the most important RTTY contest. It is a good test to see the difference between a good and a mediocre receiver.


Il 25/set/2018 22:43, "Joe Puma" <kd2nfc@...> ha scritto:

I do have a buffer board but its in the FT-840. I added a 220 ohm resistor in series and I am no longer effecting the radio receive with the SDR connected, not hearing a difference plugged/unplugged. The waterfall is a little cleaner. The spikes or spurs are a bigger issue right? I usually see that on my other rigs if I do use gain in the SDR or a LNA, but gain is 0 on the SDR, is there some gain coming from where I tapped?

 

I also get bad IMD, I hear radio stations in the background no matter where I tune and it gets worse from 40 and below. Ill be exploring that soon, the BCI filter should make for more improvement when I install it. I also removed the

 

Joe

 

 

 

 

Sent from Mail for Windows 10

 

From: iz oos
Sent: Tuesday, September 25, 2018 3:58 PM
To: BITX20@groups.io
Subject: Re: [BITX20] IF OUT

 

I think Joe uses a buffer board which should be the best way to tap it. And alternative is using another 3904 (emitter-follower) . The gain in the RTL I have can be reduced by 42db via the software.

 

Il 25/set/2018 21:32, "Joe Puma" <kd2nfc@...> ha scritto:

Thank you Allison. That sounds like a good experiment, I’ll give it a go. 

 

 

Joe

 

 


On Sep 25, 2018, at 12:58 PM, ajparent1/KB1GMX <kb1gmx@...> wrote:

Joe,

Keep in mind a RTL-SDR is not an insensitive receiver.  Its good enough on its own.
so putting the gain and mixers of the ubitx ahead of that means the noise floor is
increased by the effective gain or about 10-14db or so.  None of which helps hear
signals better as the IF amp it self has a noise figure of maybe 4-6DB.

So yes, much cruft.

To use it effectively as a panadaptor the SDR gain has to be turned down so the noise is
the baseline at or near the bottom of the spectrum display or a light background on the
waterfall.  Otherwise all you see is the noise and the signals will not stand out.

You likely need a buffer (or reduce loading) as well as tapping at that point is like putting
two load (resistors) in parallel and the receiver has less signal or effective gain.  The buffer
could be as simple as a series resistor from that point to the coax for the SDR.  Since the
SDR already sees too much cruft so lowering the signal (series resistor) will improve the
view and also lower the load on the IF to regain signal.  Values likely are in the range
of 50 to 500 ohms and try by substitution may be easiest way.  Its a useful experiment
and so try a 470 ohm for a starting point (may be too high).

Allison

 

Re: IF OUT

iz oos
 

Ok, interesting that a resistor may suffice. If you hear overload in the uBitx then you need the BCI filter or adding some preselection. If you see the overload in the RTL and you hear a clean signal in uBitx that is due to the extremely poor dynamic range of the dongle. This weekend there is the most important RTTY contest. It is a good test to see the difference between a good and a mediocre receiver.


Il 25/set/2018 22:43, "Joe Puma" <kd2nfc@...> ha scritto:

I do have a buffer board but its in the FT-840. I added a 220 ohm resistor in series and I am no longer effecting the radio receive with the SDR connected, not hearing a difference plugged/unplugged. The waterfall is a little cleaner. The spikes or spurs are a bigger issue right? I usually see that on my other rigs if I do use gain in the SDR or a LNA, but gain is 0 on the SDR, is there some gain coming from where I tapped?

 

I also get bad IMD, I hear radio stations in the background no matter where I tune and it gets worse from 40 and below. Ill be exploring that soon, the BCI filter should make for more improvement when I install it. I also removed the

 

Joe

 

 

 

 

Sent from Mail for Windows 10

 

From: iz oos
Sent: Tuesday, September 25, 2018 3:58 PM
To: BITX20@groups.io
Subject: Re: [BITX20] IF OUT

 

I think Joe uses a buffer board which should be the best way to tap it. And alternative is using another 3904 (emitter-follower) . The gain in the RTL I have can be reduced by 42db via the software.

 

Il 25/set/2018 21:32, "Joe Puma" <kd2nfc@...> ha scritto:

Thank you Allison. That sounds like a good experiment, I’ll give it a go. 

 

 

Joe

 

 


On Sep 25, 2018, at 12:58 PM, ajparent1/KB1GMX <kb1gmx@...> wrote:

Joe,

Keep in mind a RTL-SDR is not an insensitive receiver.  Its good enough on its own.
so putting the gain and mixers of the ubitx ahead of that means the noise floor is
increased by the effective gain or about 10-14db or so.  None of which helps hear
signals better as the IF amp it self has a noise figure of maybe 4-6DB.

So yes, much cruft.

To use it effectively as a panadaptor the SDR gain has to be turned down so the noise is
the baseline at or near the bottom of the spectrum display or a light background on the
waterfall.  Otherwise all you see is the noise and the signals will not stand out.

You likely need a buffer (or reduce loading) as well as tapping at that point is like putting
two load (resistors) in parallel and the receiver has less signal or effective gain.  The buffer
could be as simple as a series resistor from that point to the coax for the SDR.  Since the
SDR already sees too much cruft so lowering the signal (series resistor) will improve the
view and also lower the load on the IF to regain signal.  Values likely are in the range
of 50 to 500 ohms and try by substitution may be easiest way.  Its a useful experiment
and so try a 470 ohm for a starting point (may be too high).

Allison

 

Re: Current Draw & Power Output Question

Timothy Fidler
 

Russ et AL , these are the Bias instructions  straight from the  ubitx website.

It would seem to me that the unit went in the box without bias being done.   Rebias (not sure about the Re.. it may never have been done ??) is at his own risk. It seems to be a ticklish operation as the bias limit resistors are a SNAFU it seems. They appear to have been specified on basis of what the 5V reggy could supply with the potentiometers bottomed out  and not on basis of keeping bias volts in a reasonable range.  The current the chap is quoting is so low cw the below that he might like to check his DVM is in fact in spec...OTOH.....

  • Switch off the rig
  • Locate the two PA bias presets (the blue square ones)
  • Set both the presets  to fully clockwise position, gently.
  • Attach a dummy load or a low SWR antenna and switch the rig on
  • Attach a current meter to the power supply so can monitor the current draw
  • Switch on
  • Press the PTT without speaking ( no modulation)
  • The current draw should be between 470 mA and 500 mA
  • Slowly increase one of the two presets until the current increases to by 100 ma
  • Do the same for the other preset (the total current should have increased by 200 ma now)

Re: Started my uBitx build

Joe Puma
 

Decided to do the Pop fix and it all went well. After looking at how others did the mod to a V3 board I opted to install the components underneath.

I must be missing something though because the side tone is low, inaudible. I changed the resistor R70 to 1k, is there another resistor that needs to be changed. I don’t CW but the keyer has its uses. I trigger my autotuner with it. Works like a charm.

Any way, no more Pop!

Joe

On Sep 20, 2018, at 6:40 PM, Joe Puma <@kd2nfc> wrote:

WSPR....nice touch!

I’ve made one phone QSO do far and a few WSPR beacons. Getting off to a good start so far.

One thing that’s noticeable is the I hear AM stations on the lower bands.

Joe
On Sep 18, 2018, at 9:28 PM, KD2NFC, Joe Puma <@kd2nfc> wrote:

I decided to start building my V3 uBitx I had since February. I was going to build It in a case but hobby funds are low at the moment so I decided to at least get the basics done in the plastic container it came in. I already replaced the audio chip, I had the WX one and I added a AGC that I purchased from one of our group members. I don’t have a power meter or swr but I’ve put it on a dummy load and tested current, I’m pulling 160ma when it’s on and when I yell it went up to. 600ma. I haven’t played with the 2 bias pots and audio driver. I also upgraded to the latest CEC firmware.

I’m interested in improving the power out and hope a good solution with minimal effort is available soon and I would also like to attack some of the IMD issues and spur issues i’ve been reading about. I eventually want to get the Nextion LCD (sp?) and add a dedicated raspberry pi to it with touchscreen and SDR and sound usb so I can do digital modes. But so far the receiver sounds wonderful it really sounds much better than my commercial Yaesu FT 840 which seems to have a lot of noise coming out compared to the uBitx. Btw I’m not sure if that mic is a good mic for the rig but I can hear myself from another radio and I can confirm that I at least hear my voice.

Anyway I really just wanted to show off these initial pictures with the group I’ll see you guys on the bands.

73
Joe
KD2NFC

<IMG_5871.jpg>



<IMG_5873.jpg>



<IMG_5872.jpg>



<IMG_5865.jpg>


Sent from my iPad


<image1.png>
<image2.png>

Re: Current Draw & Power Output Question

Russ Hines
 

Lurk mode: OFF

You did.
"On 40m it looked like my power was about 5w."

Let me preface the rest of my reply with this - every once in a while, I do something foolish.  Like make a post.  You open yourself up for more BS than need be.  Who needs that?  But since I'm seeing the same voices here most of the time, I thought I'd add a different one.  Mine.  Not concerned about the song, just hoping I'm in the same hymnal. ;-)

A stock Bird 43 displays average power but not PEP which is what you're kind of interested in for SSB.  Being that as it may, let's make some assumptions and take your 12v source voltage and multiply it by what you indicate your currents are:

12v x 166 mA is just under 2 watts.  From what I gather from your post, this is the DC power your radio uses during receive.

12v x 540 mA is about 6-1/2 watts.  This is the DC power consumption on transmit with no RF output.  THIS is actually what we call idle current.  We can set the operating point of the IRF510's looking at this current.

12v x 1.02 A is about 12 watts.  This is total DC power consumption during transmit.  With RF output. 

Okay so far?  Good deal.  From what I read on this forum, and based on measurements of my own uBitX, the 2 x  IRF510 final amp isn't terribly efficient at 12v, this drive and output power level, but again let's assume we're as efficient as we need be.  For SSB, class A/B finals are somewhere in the 50-55% range efficiency.  You're pipping your Bird wattmeter at 5 watts, so your DC-to-RF efficiency is around 42%.  In reality, it's probably worse, but you'll likely not pop the FET's at this level.

IMHO, not great, but not terrible.  Lots of assumptions.  But it's better than what I see on my rig right now (I'm still hacking on it, installed several of Allison's suggestions, more to go).

Wait, it gets better.  A Bird 43 isn't frequency selective and this radio has spurs/harmonics issues.  Some of that output is not on frequency, or maybe even on 40m.  How much?  Beats me, you'll have to measure it.  My radio's what I call reasonable, around -40 dBc according to my Rigol SA.  That's 40 dB down from carrier.  Not technically legal as far as "spurious radiation" is concerned.  But it gets much worse on 20m and higher, and at higher than 3 watts or so output.  Make another assumption and say several milliwatts.  You can read or let others here tell you about the gory details... and hem and haw about -43 dBc no doubt. ;-)

Better news is, you're making contacts with the rig and, it's hoped, having fun.  Could be worse, you could be an "appliance operator."  But you obviously chose a different path.  Good for you.

So, unless you want to improve what you have, get your hands dirty, and suffer slings and arrows from forum denizens, my suggestion is stay on 40m, stay at 5 watts or less, and sin no more.  Otherwise, jump in with more questions, heat up the soldering iron, and dive into your uBitX.

BTW, the short answer to your original question is, currents sound about right to me for a few (more than 2) watts RF out or so on this radio. YMMV.

Ain't radio fun?

Lurk mode: ON

73,
Russ
WB8ZCC

Re: Current Draw & Power Output Question

Curt M.
 

I should have mentioned that my tests were on 40m

Current Draw & Power Output Question

Curt M.
 

Hello everyone, I’m just curious what kind of current draw I should be seeing?  Here are my readings:

166mA Idling
540mA Keyed w/no audio
1.02A with loud hello into the mic

The reason I ask this is that I put my radio into my Bird 43 and a 25w dummy load on the other side of the meter. I was using the lowest HF slug that I had which is 25w. On 40m it looked like my power was about 5w. I was thinking that I should see closer to 10w running the radio on 12v. 

I’ve made about 10 contacts all over the US so I know I’m getting out but I thought I should see more power out. Not sure if I need to do the tune procedure on the RV1 & RV2 or not?

Curt

Re: Ashhar's satellite

Bill Meara
 

I've updated the blog post. 73  Bill N2CQR

On Tuesday, September 25, 2018, 6:47:52 PM EDT, Joe Puma <kd2nfc@...> wrote:


This is great. I have my turnstile antenna ready!  📡 Go Farhan!


Joe



On Sep 25, 2018, at 6:34 PM, Doug W <dougwilner@...> wrote: