Date   
Re: vfo cal.

MVS Sarma
 

https://petetest2017.files.wordpress.com/2019/01/micro-bitx-calibration-instructions.pdf

I got this link from a friend om mahesh vu2iia. It works. Whether stock or lees firmware  procedure is common . In stock you press rotary encoder and in lee firmware yiu use ptt. 

Please study, if it can support yoallthe best

On Thu, 18 Apr 2019, 8:13 pm Adrian Chadd <adrian@... wrote:
hi!

The 30 second overview:


If you can plug in your audio into a computer and run a spectrum analyser (eg fldigi) it's MUCH easier to calibrate the BFO by looking for the right passband with just normal noise from your antenna.

Then after that you can calibrate the VFO - yes it goes into TX mode but it won't transmit a carrier unless you press PTT.


-a


On Thu, 18 Apr 2019 at 07:05, Jack Purdum via Groups.Io <jjpurdum=yahoo.com@groups.io> wrote:
There are likely something like a bazillion posts here about calibrating the µBITX. Have you searched this group? Also, a valuable resource is ubitx.net, too.

Jack, W8TEE

On Thursday, April 18, 2019, 6:57:55 AM PDT, Raymond House <raymondh40@...> wrote:


Hello everyone,I'm Ray House, VE2OL, I have just completed assembling an Ubitx V5 with 3.5 in display. I am testing it with the original display and I find the VFO is out a lot, can someone point me towards info for it's calibration, if I go to 10mhz cal it goes into TX mode, is this normal? I have checked the wiki and this forum but found nothing on this, I'm sure it's just that I don't know where to look.Someone mentioned here that a new member should indicate what test gear he has, so, 100mhz storage scope,freq counter, function generator,RMS meter good to 10mhz and assorted VOM's. Any help will be greatly appreciated, thanks. 73

Re: vfo cal.

Raymond House
 

Thanks Jack and Adrian, I get it now and am calibrating it. Yes I will establish the BFO properly using FLDIGI, Good info and as Jack says lots of it on the cal procedure.


On Thu, Apr 18, 2019 at 10:43 AM Adrian Chadd <adrian@...> wrote:
hi!

The 30 second overview:


If you can plug in your audio into a computer and run a spectrum analyser (eg fldigi) it's MUCH easier to calibrate the BFO by looking for the right passband with just normal noise from your antenna.

Then after that you can calibrate the VFO - yes it goes into TX mode but it won't transmit a carrier unless you press PTT.


-a


On Thu, 18 Apr 2019 at 07:05, Jack Purdum via Groups.Io <jjpurdum=yahoo.com@groups.io> wrote:
There are likely something like a bazillion posts here about calibrating the µBITX. Have you searched this group? Also, a valuable resource is ubitx.net, too.

Jack, W8TEE

On Thursday, April 18, 2019, 6:57:55 AM PDT, Raymond House <raymondh40@...> wrote:


Hello everyone,I'm Ray House, VE2OL, I have just completed assembling an Ubitx V5 with 3.5 in display. I am testing it with the original display and I find the VFO is out a lot, can someone point me towards info for it's calibration, if I go to 10mhz cal it goes into TX mode, is this normal? I have checked the wiki and this forum but found nothing on this, I'm sure it's just that I don't know where to look.Someone mentioned here that a new member should indicate what test gear he has, so, 100mhz storage scope,freq counter, function generator,RMS meter good to 10mhz and assorted VOM's. Any help will be greatly appreciated, thanks. 73

Re: POP!!

Sam Tedesco
 

So, the onboard 5v reg was bad. Replaced it and the nano...and I'm still getting 12v to ground somewhere. Receive is perfect. TX immediately shuts the whole rig off. Was suspecting the 470uF caps at the finals but those seem ok. All relays and 3904s are ok. Any ideas?

Re: Confusing Directions

fejohnso
 

Martin:  I found this info from Jerry-KE7ER- very helpful when I wired up my BITX40. Hope it helps you.

Forrest, KC9JFX

On Wednesday, April 17, 2019, 7:27:00 PM EDT, Martin KM6TCD <peaceofandalus@...> wrote:


 
I'm trying to wire up the BITx40 and quickly reached the point where I was catching mistakes.
 
Called in a more experienced friend who said, "This doesn't make any sense!"
 
Colors of the wires don't match the description.
Photos of the boards don't match be board in front of us.
 
Has anyone run into this problem?
How did you solve it?
 
tks
KM6TCF

Re: POP!!

Adrian Chadd
 

hi,

disconnect the power rail to the finals (it's a separate pin on the ubitx.) Try again. that should isolate if it's something to do with the finals current draw or there's a short elsewhere.


-a


On Thu, 18 Apr 2019 at 08:25, Sam Tedesco <stedesco619@...> wrote:
So, the onboard 5v reg was bad. Replaced it and the nano...and I'm still getting 12v to ground somewhere. Receive is perfect. TX immediately shuts the whole rig off. Was suspecting the 470uF caps at the finals but those seem ok. All relays and 3904s are ok. Any ideas?

Re: burst of harmonics during CW key-down?

Jerry Gaffke
 

Adrian,

Thanks for posting your code!
Curious that it hadn't been addressed on the uBitx yet by anyone,
given that it was a known problem on the Bitx40.

Jerry, KE7ER


On Thu, Apr 18, 2019 at 12:39 AM, Adrian Chadd wrote:
ok, so i fixed it in my fork:
 
 
This /seems/ applicable to all versions of the ubitx (3, 4, 5.) It's a mostly straight port from the bitx40 fork that fixed it.
 
Ian and other firmware hackers - would you mind taking a look and see if it makes sense?
 
Thanks!

Re: Trial to control CW power (and reduce harmonics as a result) by unbalancing the 2nd mixer #ubitx

Jerry Gaffke
 

With John's mod of post    https://groups.io/g/BITX20/message/67981
any spurs and harmonics when operating CW should be
very similar to what is seen when operating SSB. 

If CW signal into the 45mhz IF is too large, distortion (and spurs) will increase.
To correct this, could replace R104 with something like a 5k pot,
top pin of pot to CW-KEY, bottom pin to ground, wiper pin to R105.
(Remember, with John's mod, R105 now goes to T4 pins 3,5.)
Adjust this pot such that CW transmit power is equal to SSB peak power.

If we are lucky, the mixer at D3,4 will want the same CW-KEY injection level
across all rigs, and we can use fixed resistors instead of a pot.
But that may well not be the case.

Jerry, KE7ER


On Wed, Apr 17, 2019 at 08:31 PM, John (vk2eta) wrote:
If someone with a spectrum analyzer could check the implications for the harmonics and spurs that would be a plus. I would expect in CW mode that the harmonic for 80, 40 and 30M bands would reduce, but some spurs to appear since we have the beat of two clocks now.  If there is interest I can modify Farhan's code to match that modification (or publish some code snippets).
 

Re: next ubitx

Curt
 

Short of doing lots of homebrew, we only get so many of these inside the radio experiences.  Hard to measure whether I spent more time on the K2 or the ubitx.  Of course the ubitx virtue is 'have it your way', while the caution of course is its key limitation. 

Given the challenge of our local builders - some of us doing just fine with transmit drive, others not so - an ALC circuit might indeed be a key addition (if you really sense the need).  Hint - the approach used by the K2 is documented in their manual - as I never 'broke' that part of the rig - I didn't learn about it.  Worth exploring what they did, even if there are unobtainium parts - actually I think they are garden variety. 

We should choose our battles carefully on what to do with the ubitx.  Certainly fix the low band harmonic spurious - very fixable.  I have taken a break from high band mixer spurs (the xtal filter fix wrecks low band CW).  It does mean if I build a clean PA for the lower bands - the combo should be clean, as my ubtix is now good on both CW/SSB up through 17m.  Whether I 'need' a 50 watt rig using ubtix is another story.  For now, enjoying the VK3YE AGC that works wonderfully, I am off buiiding the simple S-meter from an earlier SPRAT that is on the web.  If this rig had EVERY possible addition I don't think I would enjoy it any more.  Nice that many folk around the world can possess the same rig.  Maybe I should build that 40w PA so I can QSO with another ubitx in India when we get our next solar high. 

Don't lament what isn't easy to install -- thrive in the reachable possibilities. 

Curt

Re: Trial to control CW power (and reduce harmonics as a result) by unbalancing the 2nd mixer #ubitx

Jerry Gaffke
 

Could be that John's method of varying transmit power when transmitting CW
will make the use of fixed resistors to set the  D3,4 injection level OK.
But if that mixer or the crystal filter is getting overloaded on some rigs, 
may need the pot.


On Thu, Apr 18, 2019 at 09:38 AM, Jerry Gaffke wrote:
With John's mod of post    https://groups.io/g/BITX20/message/67981
any spurs and harmonics when operating CW should be
very similar to what is seen when operating SSB. 

If CW signal into the 45mhz IF is too large, distortion (and spurs) will increase.
To correct this, could replace R104 with something like a 5k pot,
top pin of pot to CW-KEY, bottom pin to ground, wiper pin to R105.
(Remember, with John's mod, R105 now goes to T4 pins 3,5.)
Adjust this pot such that CW transmit power is equal to SSB peak power.

If we are lucky, the mixer at D3,4 will want the same CW-KEY injection level
across all rigs, and we can use fixed resistors instead of a pot.
But that may well not be the case.

Jerry, KE7ER

Re: Trial to control CW power (and reduce harmonics as a result) by unbalancing the 2nd mixer #ubitx

Jerry Gaffke
 

I'm suspicious about the CW-KEY injection level because 
the Bitx40 saw significant variation between rigs when Allard did 
something similar to unbalance the modulator for CW transmissions.
This was solved by going to a fairly high level of injection,
pushing the power amp into non-linear operation.
So it's like all the simple QRP CW transmitters out there with a class C amp.
The Bitx40  transmit LPF seems to work well to remove any harmonics,
and the 40m bandpass filter between the Bitx40's  first mixer
and the power amp removes the spurs.
Neither of these is true of the uBitx, so we can't use the same trick.

Jerry, KE7ER


On Thu, Apr 18, 2019 at 10:29 AM, Jerry Gaffke wrote:
If we are lucky, the mixer at D3,4 will want the same CW-KEY injection level
across all rigs, and we can use fixed resistors instead of a pot.
But that may well not be the case.

Re: next ubitx

Michael Mitchell
 

I did not mean I was going to design the MAXbitx but maybe the original uBitx guys might do it. I mean most of the design is done just needs to be modulized and made legal.


On Thu, Apr 18, 2019 at 1:26 PM Curt via Groups.Io <wb8yyy=yahoo.com@groups.io> wrote:
Short of doing lots of homebrew, we only get so many of these inside the radio experiences.  Hard to measure whether I spent more time on the K2 or the ubitx.  Of course the ubitx virtue is 'have it your way', while the caution of course is its key limitation. 

Given the challenge of our local builders - some of us doing just fine with transmit drive, others not so - an ALC circuit might indeed be a key addition (if you really sense the need).  Hint - the approach used by the K2 is documented in their manual - as I never 'broke' that part of the rig - I didn't learn about it.  Worth exploring what they did, even if there are unobtainium parts - actually I think they are garden variety. 

We should choose our battles carefully on what to do with the ubitx.  Certainly fix the low band harmonic spurious - very fixable.  I have taken a break from high band mixer spurs (the xtal filter fix wrecks low band CW).  It does mean if I build a clean PA for the lower bands - the combo should be clean, as my ubtix is now good on both CW/SSB up through 17m.  Whether I 'need' a 50 watt rig using ubtix is another story.  For now, enjoying the VK3YE AGC that works wonderfully, I am off buiiding the simple S-meter from an earlier SPRAT that is on the web.  If this rig had EVERY possible addition I don't think I would enjoy it any more.  Nice that many folk around the world can possess the same rig.  Maybe I should build that 40w PA so I can QSO with another ubitx in India when we get our next solar high. 

Don't lament what isn't easy to install -- thrive in the reachable possibilities. 

Curt



--
WM4MM

Re: burst of harmonics during CW key-down?

John (vk2eta)
 

Thanks Adrian.

I understand the logic.

If you make actual measurements please let us know.

All the best,

73, John

Re: vfo cal.

Raymond House
 

Thank you MVS Sarma, a very excellent PDF on calibration, the best I have read so far, I'm keeping this one.Clear and concise step by step! Great. 73


On Thu, Apr 18, 2019 at 11:03 AM MVS Sarma <mvssarma@...> wrote:
https://petetest2017.files.wordpress.com/2019/01/micro-bitx-calibration-instructions.pdf

I got this link from a friend om mahesh vu2iia. It works. Whether stock or lees firmware  procedure is common . In stock you press rotary encoder and in lee firmware yiu use ptt. 

Please study, if it can support yoallthe best

On Thu, 18 Apr 2019, 8:13 pm Adrian Chadd <adrian@... wrote:
hi!

The 30 second overview:


If you can plug in your audio into a computer and run a spectrum analyser (eg fldigi) it's MUCH easier to calibrate the BFO by looking for the right passband with just normal noise from your antenna.

Then after that you can calibrate the VFO - yes it goes into TX mode but it won't transmit a carrier unless you press PTT.


-a


On Thu, 18 Apr 2019 at 07:05, Jack Purdum via Groups.Io <jjpurdum=yahoo.com@groups.io> wrote:
There are likely something like a bazillion posts here about calibrating the µBITX. Have you searched this group? Also, a valuable resource is ubitx.net, too.

Jack, W8TEE

On Thursday, April 18, 2019, 6:57:55 AM PDT, Raymond House <raymondh40@...> wrote:


Hello everyone,I'm Ray House, VE2OL, I have just completed assembling an Ubitx V5 with 3.5 in display. I am testing it with the original display and I find the VFO is out a lot, can someone point me towards info for it's calibration, if I go to 10mhz cal it goes into TX mode, is this normal? I have checked the wiki and this forum but found nothing on this, I'm sure it's just that I don't know where to look.Someone mentioned here that a new member should indicate what test gear he has, so, 100mhz storage scope,freq counter, function generator,RMS meter good to 10mhz and assorted VOM's. Any help will be greatly appreciated, thanks. 73

Re: vfo cal.

MVS Sarma
 

The creator of that article deserves the appreciation., 
Thanks Steve

Regards
Sarma vu3zmv

On Fri, 19 Apr 2019, 12:06 am Raymond House <raymondh40@... wrote:
Thank you MVS Sarma, a very excellent PDF on calibration, the best I have read so far, I'm keeping this one.Clear and concise step by step! Great. 73

On Thu, Apr 18, 2019 at 11:03 AM MVS Sarma <mvssarma@...> wrote:
https://petetest2017.files.wordpress.com/2019/01/micro-bitx-calibration-instructions.pdf

I got this link from a friend om mahesh vu2iia. It works. Whether stock or lees firmware  procedure is common . In stock you press rotary encoder and in lee firmware yiu use ptt. 

Please study, if it can support yoallthe best

On Thu, 18 Apr 2019, 8:13 pm Adrian Chadd <adrian@... wrote:
hi!

The 30 second overview:


If you can plug in your audio into a computer and run a spectrum analyser (eg fldigi) it's MUCH easier to calibrate the BFO by looking for the right passband with just normal noise from your antenna.

Then after that you can calibrate the VFO - yes it goes into TX mode but it won't transmit a carrier unless you press PTT.


-a


On Thu, 18 Apr 2019 at 07:05, Jack Purdum via Groups.Io <jjpurdum=yahoo.com@groups.io> wrote:
There are likely something like a bazillion posts here about calibrating the µBITX. Have you searched this group? Also, a valuable resource is ubitx.net, too.

Jack, W8TEE

On Thursday, April 18, 2019, 6:57:55 AM PDT, Raymond House <raymondh40@...> wrote:


Hello everyone,I'm Ray House, VE2OL, I have just completed assembling an Ubitx V5 with 3.5 in display. I am testing it with the original display and I find the VFO is out a lot, can someone point me towards info for it's calibration, if I go to 10mhz cal it goes into TX mode, is this normal? I have checked the wiki and this forum but found nothing on this, I'm sure it's just that I don't know where to look.Someone mentioned here that a new member should indicate what test gear he has, so, 100mhz storage scope,freq counter, function generator,RMS meter good to 10mhz and assorted VOM's. Any help will be greatly appreciated, thanks. 73

Attenuator function in CEC firmware #nextion #ubitx #firmware

Jack Brabham - KZ5A
 

I looked around but haven't found just how the "attenuator" function in the CEC firmware actually works.

I'm curious because I'm interested in the mod that puts a digital attenuator between the pre-drivers and the filters, using it as a varible attenuator on RX and using it to normaiize the output levels between bands on TX.

More to the point, I'm wondering if the Attn function can be utilized to control the digital attenuator on RX instead of whatever it does normally?

73 Jack KZ5A

JackAl Secondary source for download files

Jack Purdum
 

All:

Although our site has been restored with new security software, some of you have expressed concern about the site. We understand this completely. On the other hand, many of you want to download the updated files about the JackAl project. To that end, I have copied the relevant doc and source files to the JackAl@groups.io site. Look in the Files section under JackAl Documentation and Code Files.

Jack, W8TEE
Al, AC8GY

Re: Attenuator function in CEC firmware #nextion #ubitx #firmware

Tom, wb6b
 

Some time ago, a clever person on this list developed a method of adjusting the mixer frequencies to place the desired signal on the edge of the 45Mhz filter. That filter being much wider than the signal and having a more gradual drop-off (Than the 12Mhz filter for example) on the edges of the bandpass, could function as a variable gain stage by moving the desired signal progressively into the edge of the bandpass.

The CEC firmware incorporated this gain control method. This might be the attenuator function you are looking for.  It has been a while since I looked at this so I believe it was used to adjust output power, but I may be wrong. Might be a clever idea to try to measure the received signal and have the firmware adjust the mixer frequencies to act as an AGC. Maybe that is already being done.

Tom, wb6b

Re: Attenuator function in CEC firmware #nextion #ubitx #firmware

Jerry Gaffke
 

The clever person is John, VK2ETA.
Here's where it started:
    https://groups.io/g/BITX20/topic/16737180
    https://groups.io/g/BITX20/topic/17009424

And we have an active thread right now about doing this with CW:
    https://groups.io/g/BITX20/topic/30997272

And a mention of it yesterday here:
    https://groups.io/g/BITX20/message/67982

It works by adjusting the si5351 to move the frequency at which the desired signal
hits the 45mhz crystal filter.  The filter has shoulders gradual enough that this serves
as an effective attenuator.  Works great for transmitting, where you set it once based
on the operating frequency and desired output power.  Using this method to dynamically
shape the receive attenuation would be sort of possible but not very satisifying
since there would be a pop heard every time the si5351 is updated.

There have been a half dozen different schemes for implementing simple AGC schemes
on the uBitx (and Bitx40).  I'd recommend Don's (ND6T) scheme as was kitted up
by Kees (K5BCQ).    http://www.nd6t.com/uBITX/AGC.htm
The kits are no longer available, but would be simple enough to dead bug it.
Others here will have their own favorites.
They pretty much all rectify the recovered audio to determine the amount of attenuation,
applying a DC voltage to some attenuation device.
You could easily control that attenuation from a processor, perhaps using pulse-width-modulation
to determine the amount of attenuation, though better would be an small ADC hanging off the I2C lines.

Jerry, KE7ER

Re: Attenuator function in CEC firmware #nextion #ubitx #firmware

KE2GKB
 

Just to comment here and pass some info on, Don's (ND6T's) AGC is available as a kit from N8DAH and my Self over at https://shop.kit-projects.com We are still working on talking to Don to get him to update his web page. We have his blessing but nothing has been updated yet on his end.

-- Tim Keller - KE2GKB https://shop.kit-projects.com

Re: Attenuator function in CEC firmware #nextion #ubitx #firmware

John (vk2eta)
 

Thanks guys for the qualification, but luck had its place in that exercise.

Jack,

Here is the correct graph and if you follow the thread it shows the logic (the first graph is wrong by a factor of 10 on the horizontal axis): https://groups.io/g/BITX20/message/45700

If you follow the usage of the firstIFShift variable in the implementation below you will see the code that implements a stepped power setting per band so that I have three levels (low=5W, medium=10W and max=open). I simply use a set of 4 values for each levels which represent the shift in KHz at 4 frequencies, then I interpolate for frequencies in-between. Moves up and down a little due to the interpolation but it does the job. You could have one set of value per band if you wanted to be more precise.

There is even some dead code (commented out) in there for an automatic ALC as you find in commercial rigs. But it didn't play well with my ATU so I used a fixed ALC instead.

In the file section: https://groups.io/g/BITX20/files/Variations%20on%20KD8CEC%20Software%20%28by%20VK2ETA%29%20+%20ATU%20sketch

I also use the IF shift in reception to augment the range of my AGC and it does the job. But as Jerry mentioned it makes a small pop when adjusting the shift. Not annoying in my case as I only adjust when the ALC hits the top of its range and step back only when it reaches the bottom of its range. So it normally happens on very strong stations and once at the start and end of an over. Not a major at all, but you will notice it. That code in in there too.

If you have questions on the code please ask.

All the best,

73, John