Topics

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

Ashhar Farhan
 

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 

Ashhar Farhan
 

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 

Gordon Gibby
 

​That would be fantastic....i'll be buying one immediately.

Gordon Gibby KX4Z



From: BITX20@groups.io <BITX20@groups.io> on behalf of Ashhar Farhan <farhanbox@...>
Sent: Friday, July 26, 2019 2:03 PM
To: BITX20@groups.io
Subject: Re: [BITX20] #Antuino: an update and a bit of bad news for those bought it at FDIM-2019
 
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 

 

link to the GLCD or compiled hex please? I did the hardware mods but don't have and cant find the GLCD modded lib.........
--
David

 N8DAH
Kit-Projects.com

Shop is open!

 

using the stock firmware looking good hope I can get the GLCD modded lib or someone with it is kind enough to post a hex. Here is the new sweep of the BCI filters much better over all readings by a large margin.


--
David

 N8DAH
Kit-Projects.com

Shop is open!

Ashhar Farhan
 

The glcd library is at http://www.hfsignals.com/wp-content/uploads/2019/07/glcd.zip
I will add it to the repo. It is ummodified from what you already have. Run the calibration once, though.

On Sat 27 Jul, 2019, 7:00 AM N8DAH, <Dherron@...> wrote:

using the stock firmware looking good hope I can get the GLCD modded lib or someone with it is kind enough to post a hex. Here is the new sweep of the BCI filters much better over all readings by a large margin.


--
David

 N8DAH
Kit-Projects.com

Shop is open!

Ashhar Farhan
 

I have added the glcd library to the repo.

- f

On Sat, Jul 27, 2019 at 7:34 AM Ashhar Farhan via Groups.Io <farhanbox=gmail.com@groups.io> wrote:
The glcd library is at http://www.hfsignals.com/wp-content/uploads/2019/07/glcd.zip
I will add it to the repo. It is ummodified from what you already have. Run the calibration once, though.

On Sat 27 Jul, 2019, 7:00 AM N8DAH, <Dherron@...> wrote:

using the stock firmware looking good hope I can get the GLCD modded lib or someone with it is kind enough to post a hex. Here is the new sweep of the BCI filters much better over all readings by a large margin.


--
David

 N8DAH
Kit-Projects.com

Shop is open!

iz oos
 

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 

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 

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

ohwenzelph
 

and where it says

“Replace Q2 (BFR93W) with 2N3904”

it should say Q3?

(or is it really Q2..? ? )

ohwenzelph
 

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

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 

f1mqj
 

Just some questions :
1 - why taking a si5351 which makes square waveform, despite a Ad9851 which makes sinus (less to no harmonic) as made on F4GOH and RA4NAL ?
https://hamprojects.wordpress.com/2015/06/21/hf-arduino-vna/
I know it is the DDS of Bitx and uBitx so easy to go on, but the square wave could be more a problem for VNA (and the cost doesn't seem to be very different)
2 - How many memory points do antuino record ? because that's the main difference between VNA able to be wideband
3 - is it compatible with DL2SBA software (if it'is of some interest) ?
Thanks in advance for answers that might be of interest to be put in the description (especialy 2 and 3)
best 73 - Remi

Ashhar Farhan
 

Remi,
The Si5351 is used because it goes all the way to 200 mhz and this design calls for three clocka.  It doesnt have any spurs. The square waves are not a problem as filter the required signal through six pols of crystal filters.
- f

On Sun 28 Jul, 2019, 3:43 PM f1mqj, <f1mqj.fr@...> wrote:
Just some questions :
1 - why taking a si5351 which makes square waveform, despite a Ad9851 which makes sinus (less to no harmonic) as made on F4GOH and RA4NAL ?
https://hamprojects.wordpress.com/2015/06/21/hf-arduino-vna/
I know it is the DDS of Bitx and uBitx so easy to go on, but the square wave could be more a problem for VNA (and the cost doesn't seem to be very different)
2 - How many memory points do antuino record ? because that's the main difference between VNA able to be wideband
3 - is it compatible with DL2SBA software (if it'is of some interest) ?
Thanks in advance for answers that might be of interest to be put in the description (especialy 2 and 3)
best 73 - Remi