Date   
Re: New file uploaded to BITX20@groups.io

Michel Dupuy
 

Hello Allen. Very good the file for the Nextion 35 B. I noticed a small problem: The S / Meter never exceeds the S9 even on a very QRO signal. It looks like it's stuck at S9. Thank you for the work.
Michel F1GTX

Re: Raduino fix leads to no receive uBitx #radiuno #ubitx

ludwig_t@...
 

Hi Gordon,

I measured mine without any load and I had way too low output level on CLK2 and CLK1. It was a bit dependent from the frequency I tune in. Then I modified the code in the ubitx_si5351.ino inreasing the drive of the clock outputs. The DC voltage supply for the SI5351 supplies 3.3V, so there seems to be no problem.

I measured now with a HP54510A oscilloscope which has a greater bandwith than the Philips PM3335 analog scope I used before. I also used better oscilloscope probes to measure. Now I get 1.26Vrms when I tune on 10m band and 1.85Vrms on 80m. This should be okay. Now my receiving noise is also a bit louder on all bands but I still not receive any SSB Signal.

Re: uBitX for sale

Ryan Benteman AD0TZ
 

Its back on the market!  

Re: receive works great, but no trans power, #ubitx-help

Jerry Gaffke
 

Yes, an RF probe is a good idea to have around when debugging a uBitx.

That looks like a reasonable circuit, but good luck finding a GEX66.
Seems to be a germanium point contact diode from 50 years ago, meant for UHF,
5v max reverse voltage.
I'd just use a Schottky diode such as the 1n5711 or a BAT54*.
And maybe adjust those cap values, 100pf at the input seems low for under 100mhz. 

See this post, and the thread around it.
    https://groups.io/g/BITX20/message/52563

Jerry



On Sun, Jul 15, 2018 at 09:47 PM, Clark Martin wrote:
Build yourself an RF Probe such as at: http://www.qsl.net/g3pto/probe.html.  You can use it to trace the signal (or lack thereof) through the transmit path.
 

Re: Q70 replacement

Tom Cooper
 

With RX voltage of 13.6, the Q70 collector voltage is 4.67 on the 2sc945.

I should mention that I added a 16K resistor from the base to ground when Q70 was a 2n3904, which was suggested by W3JDR to reduce distortion.  I did not remove that resistor.

73,

Tom  W1EAT

Re: New file uploaded to BITX20@groups.io

Allen Merrell
 

Thanks Michel, I don't have my smeter together yet but I think I can fix this problem pretty easy. It should go all the way out to the +20, did you calibrate your s meter using Ian's procedure?  I will definitely check into it. I need to get s meter together. I thank you for bringing this to my attention.
--
Allen  Merrell

Re: Q70 replacement

Jer Tres
 

Where does one get a 2SC945?

Re: Q70 replacement

M Garza <mgarza896@...>
 

I would look at old 10 & 11M equipment.  The NTE equivalent is a NTE 85.

Good luck,

Marco - KG5PRT 


On Mon, Jul 16, 2018, 9:42 AM Jer Tres <ownselv@...> wrote:
Where does one get a 2SC945?

Re: Q70 replacement

R. E. Klaus
 

Used to use a lot of them in repairing audio gear in the 80's and 90's. We got them from MCM Electronics then. Probably discontinued now, so probably have to get them off Amazon or eBay. Google shows several returns for them.
 

Re: #bitx40help #radiuno #bitx40help #radiuno

g3srq@...
 

Read all the posts with interest...Just waiting for my uBITX to arrive....Thanks Guys....Ray G3SRQ/F5VKX

Re: receive works great, but no trans power, #ubitx-help

Don - KM4UDX
 

Clark & Jerry -- thank you for the guidance! 

I think I'm getting in over my head here. I'll try some more basic debugging, but if I can't figure it out, I may have to put it in the dump and call it a "lesions learned" experience.

The ratio of working/communicating is getting way too high. I'm sadden that so many other uBitx folks are working the world, but I can't get out of my workbench. sigh. 

Don

Ubitx version 4.3

p.gould1@...
 

Hi all.
Just received and built the latest ubitx, and have encountered a couple of seeming problems.
It is all wired up according to specification.
First problem is that there is little or no audio on rx , and the sidetone volume is fine
Secondly that when using straight key the first key down isn't recognised, there is a pause then a dash before it catches up with what is being sent,
Resulting in corrupt call signs etc. it's ok then as long as I don't pause in sending!
And hopefully and lastly the bandwidth of the received stations are enormous so if trying to contact them , where to put the frequency is a matter of guess work.
Hope this makes sense, and the answer is simple enough for my grey cells to contemplate.
Best regards
Paul......M6FEU

Re: Ubitx version 4.3

Jerry Gaffke
 

Enormous bandwidth?
Are you using this rig mostly for CW?
It is primarily designed for SSB use, CW is an afterthought.
The crystal filter is around 2khz wide, as required for SSB use.
The easiest solution for CW would be to add an external filter between headphone jack and headphones.

There are updates to the the firmware should solve the keying issue for you, check out the KD8CEC firmware.


On Mon, Jul 16, 2018 at 08:22 AM, p.gould1@... wrote:
Hi all.
Just received and built the latest ubitx, and have encountered a couple of seeming problems.
It is all wired up according to specification.
First problem is that there is little or no audio on rx , and the sidetone volume is fine
Secondly that when using straight key the first key down isn't recognised, there is a pause then a dash before it catches up with what is being sent,
Resulting in corrupt call signs etc. it's ok then as long as I don't pause in sending!
And hopefully and lastly the bandwidth of the received stations are enormous so if trying to contact them , where to put the frequency is a matter of guess work.
Hope this makes sense, and the answer is simple enough for my grey cells to contemplate.
Best regards
Paul......M6FEU

Re: receive works great, but no trans power, #ubitx-help

Bo Barry <wn4ghv@...>
 

Please post the link to the guide again. Tnx Bo W4GHV 

Re: Q70 replacement

Kevin Rea
 

Here on eBay.
https://www.ebay.com/itm/100-x-2SC945-C945-BIPOLAR-TRANSISTORS-NPN-TO-92-50V-USA-SELLER-Free-Shipping/323210926653?epid=1113025015&hash=item4b40df5a3d%3Ag%3A6MkAAOSwBahVT88a&LH_PrefLoc=1&_nkw=2SC945&_from=R40&rt=nc

Re: uBitX for sale

Ryan Benteman AD0TZ
 

Sold.  

Re: BITX QSO Afternoon/Evening, Sunday, July 15, 3PM & 7PM Local Time, 7277 kHz in North America, 7177 kHz elsewhere.

James Lynes
 

Heard N2CQR calling CQ once around 7:32 EDT here in WCF. Then faded into the ether...

James
KE4MIQ

Re: receive works great, but no trans power, #ubitx-help

Jerry Gaffke
 

I certainly wouldn't dump it.
Could sell it on the forum here.
Could state your location in the forum, see if others live close.
Could haul it into a local ham club meeting, see if anybody is 
interested in helping you debug it.
Could park it on the shelf for a week or two, then take another look.

Could be as simple as a bad connection at the antenna BNC connector.
The BNC socket provided with the kit is not machined to tight enough tolerances,
in many cases the middle pin does not make contact.
That was a problem with my uBitx, and others here have reported the same issue.
Try adding wires to go around that BNC connector directly to your dummy load.

Another common point of failure is the torroid transformers, inspect them closely.
Could be that the enamel wasn't scraped off the wire somewhere, and so the solder joint isn't working.
Or a broken wire, they are kind of heavy so rough handling while shipping can break them.
Following the schematic, check with an ohmmeter.

##############
We should have a standard procedure for checkout out the transmitter.
Something like this:

Build a specific version of the diode RF probe, driving A7 for voltage readings to the LCD.
Create special Raduino firmware to support the debug procedure.

Set up the rig to transmit CW at 7mhz, disconnect PA-PWR to the IRF510's so they don't burn up.
Verify DC and AC levels using DVM and the RF probe at all points through T2, Q90, Q911, Q912, Q92,93,96,97.
Compare your readings with a chart for a properly functioning rig.

Apply PA-PWR, add a dummy load, measure power at IRF510 drains and at the dummy load.

Drive mike input from sidetone, go to special code that puts rig in SSB transmit mode with sidetone operating.
Verify DC and AC levels through Q6, D6, Q40,41,42, Q20,21,22
(The remainder of the transmitter was already checked out in CW mode.)

Something similar could be done for the receiver.
Perhaps generate 7mhz on CLK0 (normally the BFO) and apply that through an attenuator to the antenna port.
Trace this using the RF probe all the way through the 45mhz and 12mhz crystal filters to D5.
Now restore the BFO to 12mhz, disconnect it from the antenna, and unbalance the first mixer using CW-KEY.
Inject 45mhz at CLK2, and verify the product detector and audio chain.
Again, we need to compile a list of expected DC and AC voltages at each stage.

Parts for a good 12W dummy load (parallel four of Mouser part number 283-200-RC) 
plus a diode RF probe (1n5711 or similar, a couple caps and resistors) plus appropriate attenuators (a few resistors)
would cost about $1.  Could be included with every kit.

This capacitance meter using a Nano might also be of interest:
    https://groups.io/g/BITX20/message/52471

Am curious if anybody has a good way to measure inductance using the Nano.
I'd probably measure a 100pf cap using the above capacitance meter, then sweep a parallel combination
of the inductor being tested plus the 100pf cap using an output from the si5351 through a series resistor.
Look for the lowest freq dip using the RF probe.  Other caps such as 10pf, 1nf, ... might also be of use
depending on the size of the inductor.
The si5351 can go from about 4khz to 200mhz, up to 290mhz if pressed.

Jerry, KE7ER


On Mon, Jul 16, 2018 at 07:59 AM, Don - KM4UDX wrote:
Clark & Jerry -- thank you for the guidance! 

I think I'm getting in over my head here. I'll try some more basic debugging, but if I can't figure it out, I may have to put it in the dump and call it a "lesions learned" experience.

The ratio of working/communicating is getting way too high. I'm sadden that so many other uBitx folks are working the world, but I can't get out of my workbench. sigh. 

Re: Question about Nextion display and firmware

Bo Barry <wn4ghv@...>
 

Mike, I think he wanted a hex file compiled on a mega2560 not nano.
  I was going to do that and give him the link to the uploader program. Bo W4GHV 

Re: receive works great, but no trans power, #ubitx-help

Gordon Gibby
 

If the ham radio operator has another receiver,  they can use it to listen for signal at earlier stages.  

CW would allow them to know exactly what frequency to listen for on earlier stages.  

The way you eat an elephant is one stage at a time.   




On Jul 16, 2018, at 12:50, Jerry Gaffke via Groups.Io <jgaffke@...> wrote:

I certainly wouldn't dump it.
Could sell it on the forum here.
Could state your location in the forum, see if others live close.
Could haul it into a local ham club meeting, see if anybody is 
interested in helping you debug it.
Could park it on the shelf for a week or two, then take another look.

Could be as simple as a bad connection at the antenna BNC connector.
The BNC socket provided with the kit is not machined to tight enough tolerances,
in many cases the middle pin does not make contact.
That was a problem with my uBitx, and others here have reported the same issue.
Try adding wires to go around that BNC connector directly to your dummy load.

Another common point of failure is the torroid transformers, inspect them closely.
Could be that the enamel wasn't scraped off the wire somewhere, and so the solder joint isn't working.
Or a broken wire, they are kind of heavy so rough handling while shipping can break them.
Following the schematic, check with an ohmmeter.

##############
We should have a standard procedure for checkout out the transmitter.
Something like this:

Build a specific version of the diode RF probe, driving A7 for voltage readings to the LCD.
Create special Raduino firmware to support the debug procedure.

Set up the rig to transmit CW at 7mhz, disconnect PA-PWR to the IRF510's so they don't burn up.
Verify DC and AC levels using DVM and the RF probe at all points through T2, Q90, Q911, Q912, Q92,93,96,97.
Compare your readings with a chart for a properly functioning rig.

Apply PA-PWR, add a dummy load, measure power at IRF510 drains and at the dummy load.

Drive mike input from sidetone, go to special code that puts rig in SSB transmit mode with sidetone operating.
Verify DC and AC levels through Q6, D6, Q40,41,42, Q20,21,22
(The remainder of the transmitter was already checked out in CW mode.)

Something similar could be done for the receiver.
Perhaps generate 7mhz on CLK0 (normally the BFO) and apply that through an attenuator to the antenna port.
Trace this using the RF probe all the way through the 45mhz and 12mhz crystal filters to D5.
Now restore the BFO to 12mhz, disconnect it from the antenna, and unbalance the first mixer using CW-KEY.
Inject 45mhz at CLK2, and verify the product detector and audio chain.
Again, we need to compile a list of expected DC and AC voltages at each stage.

Parts for a good 12W dummy load (parallel four of Mouser part number 283-200-RC) 
plus a diode RF probe (1n5711 or similar, a couple caps and resistors) plus appropriate attenuators (a few resistors)
would cost about $1.  Could be included with every kit.

This capacitance meter using a Nano might also be of interest:
    https://groups.io/g/BITX20/message/52471

Am curious if anybody has a good way to measure inductance using the Nano.
I'd probably measure a 100pf cap using the above capacitance meter, then sweep a parallel combination
of the inductor being tested plus the 100pf cap using an output from the si5351 through a series resistor.
Look for the lowest freq dip using the RF probe.  Other caps such as 10pf, 1nf, ... might also be of use
depending on the size of the inductor.
The si5351 can go from about 4khz to 200mhz, up to 290mhz if pressed.

Jerry, KE7ER


On Mon, Jul 16, 2018 at 07:59 AM, Don - KM4UDX wrote:
Clark & Jerry -- thank you for the guidance! 

I think I'm getting in over my head here. I'll try some more basic debugging, but if I can't figure it out, I may have to put it in the dump and call it a "lesions learned" experience.

The ratio of working/communicating is getting way too high. I'm sadden that so many other uBitx folks are working the world, but I can't get out of my workbench. sigh.