Date   
Re: calibrating ubitx to www

_Dave_ K0MBT
 

Personally I don't like to calibrate on wwv. I never seem to get it right and end up zero beating on an audio tone. I usually find a stronger shortwave broadcast with voice only. In theory wwv is probably more accurate. I also use headphones when zerobeating as the low frequency response is much better than the speaker.

The main reason that I have switched to the kd8cec firmware as it doesn't move the frequency scale to 10mhz.

I listen to both sides of the sideband alternately. It gets interesting if you have to vary the vfo too much as it moves the bfo off considerable and the sensitivity goes way down. One of my used radios that I bought had the bfo set to the wrong side of the carrier and there was a lot of attenuation going on. He thought that there was an issue with the receiver circuit. As a matter of fact two of my radios purchased use had almost identical operator error.

There are a lot of hams that pretty well panic when the radio doesn't work. It is broke or trashed in their minds. Yet these are many of the same operators who will change circuitry, displays and firmware on their radio before they even turn it on. I like many, test with it stock then change one thing and retest. To my understanding the radio boards are 100 percent tested for function before they leave India. 4 of 5 of the BITX radios that I got were in not running condition purchased used.

Am not being critical of the radio, I really love them. Between my wife (N0BEX) and I, we have somehow ended up with 4 uBITX and one BITX40.

It is a bit concerting to see the list traffic fall off recently. Maybe it is just summer.

Re: Operating uBITZ

Liam Kingsmill <lumetters1@...>
 

Mark, Darwin, Olivier ... Thank you!

Re: calibrating ubitx to www

terryhugheskirkcudbrifght@...
 

hi
what radio station did you use and how do you calibrate the ubitx

the calibrate option on the menu only seems to work for www on 10 mhz

terry gm4dso

Re: #Antuino: an update and a bit of bad news for those bought it at FDIM-2019

Ashhar Farhan
 

Thats right!


On Sat 27 Jul, 2019, 4:30 PM iz oos, <and2oosiz2@...> wrote:

Great news! Would the final production of Antuino embed all the hardware and firmware improvements, tested and calibrated at the factory before shipping?


Il 26/lug/2019 20:03, "Ashhar Farhan" <farhanbox@...> ha scritto:
I'll add two things :
1. I have worked on this with Raj, who went potty trying to figure this out. I am driving down to bangalore, on sunday, we will together review these changes (two pairs of eyes are better than one). 
2. I hope to have the final production Antuinos up on the website by the end of next week, two months late! Expect the price to be $100 inclusive of shipping.
- f 

On Fri, Jul 26, 2019 at 10:46 PM Ashhar Farhan via Groups.Io <farhanbox=gmail.com@groups.io> wrote:
Peeps,
The Antuino has been in use for over a few months now. We had produced 100 of them that were sold at the FDIM. These work quite well for an SWR meter and Antenna Analyzer, but they were sub-optimal for serious RF work. For those who bought it for SWR measurements, you can continue to use it. For those who want to improve it, read on.

It was noticed that the db scale was not accurate. Antuino was designed to be an accurate and precise instrument. The db readings should be within +/- 1 db accuracy. However, they tended to vary by as much as 2 db on the upper range of power measurments. This was finally tracked down to having too much gain. I had prototyped the original with 2N3904 transistors but in production we used BFR93W as I guessed it would have 'better' performance. It turned to be a bad choice. The higher gain resulted in compression of signals above -30 dbm. This restricted the useful range of the Antuino to about 50 db. 

I am attaching the new (Version 2.1, it is a minor edit of the V2 that was sold at the FDIM). In summary, these are the changes:
1. The new software with a cleaner way to calibrate is on https://github.com/afarhan/antuinov2.1. Please upgrade to it even if you don't want to carry out the other hardware modifications.
2. Replace the Q1 and Q3 transistors to 2N3904. Although the PCB pads are SMT, you can solder the leaded type by twisting the legs around.
3. In the first IF amplifier (that immediately follows the mixer), we decrease the emitter resistor (R18) from 100 ohms to 51 ohms (you can also parallel a regular 1/4 watt 100 ohms with the original 100 ohms to get to 51 ohms). We also parallel the (R19) 220 ohms collector load with a 10 uh inductor (you can use 10 turns on FT 37-43), the exact value is not important.
4. In the second and third IF amplifiers, we replace the 100 ohms emitter resistors (R7, R34) with 10 ohms and remove the 4.7 ohm resistors (R32, R4).
5. In the last IF amplifier, we change the load resistor(R33) from 51 ohms to 220 ohms.

You need a few 10 ohms resistors and a 220 ohm resistor. You can resuse the R31 at R18.


Attached are the images and the circuit.

73, f 

Re: calibrating ubitx to www

Tom, wb6b
 

Hi,

Unless the firmware has been changed from when I calibrated my uBITX you can tune around to find another signal to calibrate on. There is another member in the group that pointed out the higher the frequency used to calibrate to the better. So, 15 MHz would be an improvement. 

When I was a kid, using WWB to zero beat to was easy. Now days, with all the various modulations added to their carrier, it is much more difficult to figure out just when you have obtained zero beat. It can be done with some practice, but still may take several attempts to get it right.

Tom, wb6b

Re: calibrating ubitx to www

Tom, wb6b
 

On Sat, Jul 27, 2019 at 09:00 AM, Tom, wb6b wrote:
using WWB to zero beat to was easy.
That should be WWV.

Tom, wb6b

Re: calibrating ubitx to www

terryhugheskirkcudbrifght@...
 

hi tom

are you using kd8cec firmware or the original cos it seems that the cec firmware only allows 10 m hz www

i may have to reload the original firm ware

the problem is here in the uk 10 m hz is not heard 15 mhz www is just about audible

terry gm4dso

Re: calibrating ubitx to www

terryhugheskirkcudbrifght@...
 

hi again
i have just heard www on 10 m hz and the dial frequency was 10 m hz so all ok

band must have changed

i am still interested to know which version of the firmware you use

terry
gm4dso

µBITX Centerpiece of the Station

Arvo W0VRA
 

80m-70cm, with the µBITX as the workhorse.

Re: µBITX Centerpiece of the Station

Jim
 

Nice set up!

Re: #Antuino: an update and a bit of bad news for those bought it at FDIM-2019

ohwenzelph
 

On the hfsigs site link where it talks about correcting the Dayton version and says

Hardware Modifications

Here is the updated circuit with the changes marked out (in addition to replacing Q1, Q2 with ”

i assume it it should say Q3 instead of 2

Re: #Antuino: an update and a bit of bad news for those bought it at FDIM-2019

ohwenzelph
 

and where it says

“Replace Q2 (BFR93W) with 2N3904”

it should say Q3?

(or is it really Q2..? ? )

Re: #Antuino: an update and a bit of bad news for those bought it at FDIM-2019

ohwenzelph
 

In the picture it looks like #8 points to probably Q3 

Re: About case

George
 

 Hi Mike? good result, could you please tell me where did you get the case? It is good for this transceiver I think. Best regards.

FYI: Time Stations

Jeffrey Benedict
 

FYI:  There is a list of time stations on the following link.  North Americans may be able to get CHU, the Canadian station.  It is not on 2.5, 5, 10. 15. and 20.  See the list for their frequencies.

http://www.dxinfocentre.com/time.htm
--
Jeff, K7AIL  CN87

raoul@...

Re: #Antuino: an update and a bit of bad news for those bought it at FDIM-2019

Ashhar Farhan
 

You are right. It is a typo.


On Sun 28 Jul, 2019, 7:22 AM ohwenzelph via Groups.Io, <Ohwenzelph=yahoo.com@groups.io> wrote:
In the picture it looks like #8 points to probably Q3 

Re: FYI: Time Stations

Jeffrey Benedict
 

CHU is on 3.3, 7.85 and 14.67 Mhz
--
Jeff, K7AIL  CN87

raoul@...

Re: calibrating ubitx to www

Tom, wb6b
 

On Sat, Jul 27, 2019 at 09:35 AM, <terryhugheskirkcudbrifght@...> wrote:
are you using kd8cec firmware or the original
Currently I use an older version of the CEC firmware, just before the Nextion display support was added. 

I originally calibrated my uBITX with the factory firmware. I believe I did some additional calibrations by changing values with the CEC firmware or the "Memory Manager" utility. But that was long enough ago that I don't recall exactly.

Tom, wb6b

Re: FYI: Time Stations

Wayne Leake
 

back in the 1950's, I used to receive CHU on 7.85Mhz, as well as 2.5Mhz, 5.0Mhz 10.0Mhz and maybe higher WWV signals.
 I lived in Syracuse NY at the time, and used a wire antenna, with a very old,but still good Philco Model 620.
 The Philco was a good Superhet multi band, with RF amp as well as mixer, IF amp, diode detector, plus triode audio amp and pentode audio output.
 Was AM only,so I could not listen to SSB, and CW was not my thing.
 Regardless, I was able to set my watch and clock by either CHU or WWV
 Wayne WA2YNE

Re: FYI: Time Stations

Buddy Brannan
 

CHU used to be on 7335, not 7850, didn’t it? Can’t recall which other of their transmissions moved, if any, but I do recall there being a bit of uproar when they were proposing eliminating 7335.


Buddy Brannan, KB5ELV - Erie, PA
Email: buddy@...
Mobile: (814) 431-0962

On Jul 28, 2019, at 12:20 AM, Wayne Leake <wayneleake@...> wrote:

back in the 1950's, I used to receive CHU on 7.85Mhz, as well as 2.5Mhz, 5.0Mhz 10.0Mhz and maybe higher WWV signals.
I lived in Syracuse NY at the time, and used a wire antenna, with a very old,but still good Philco Model 620.
The Philco was a good Superhet multi band, with RF amp as well as mixer, IF amp, diode detector, plus triode audio amp and pentode audio output.
Was AM only,so I could not listen to SSB, and CW was not my thing.
Regardless, I was able to set my watch and clock by either CHU or WWV
Wayne WA2YNE