Date   
Re: Need a replacement Raduino.

MVS Sarma
 

Congrats and all the best


On Thu, 17 Jan 2019, 3:38 am Billy Shepherd <dis60cd@... wrote:
Well good news. Was modding my bitx40 to remove "clicks" and shorted out the Raduino....so started looking for new one. However, I added a 2amp fuse when I built it and the fuse blew!!! All fine now :)

Re: Q11,Q31 change

jim
 

Not original ..Similar circuitry used back in the old discrete component op-amp days "level-shifter"

Jim

On Wednesday, January 16, 2019, 6:48:47 PM PST, Ashhar Farhan <farhanbox@...> wrote:


Hehe, pretty clever!

On Thu, 17 Jan 2019, 05:11 Jon Tabor <jonsmg@... wrote:
No worries.  You just got this Bitx40 user's hopes up for a fun new modification.

:)

-- 
Jon Tabor KI7JYE http://obsolete.site

On Wed, Jan 16, 2019 at 3:34 PM jim via Groups.Io <ab7vf=yahoo.com@groups.io> wrote:
Indeed ..sorry for the confusion

Jim

On Wednesday, January 16, 2019, 2:29:22 PM PST, Jon Tabor <jonsmg@...> wrote:


I'm guessing this is the uBitx, right?

--
Jon Tabor KI7JYE http://obsolete.site


Re: UBITX For sale

 

Ray,

Is this still available?  If so I will PayPal the money ASAP. What your PayPal account info?

73
John
WI6P

From JKL's iPad

On Jan 16, 2019, at 17:13, rf200655 <crf2@...> wrote:

have ubitx new in box got first part 2018 also have the ant pop board and agc boards by Kees .
take 100. for all including shipping by PayPal
good in qrz
Thanks
Ray
KC4DYM
ps Bad eye sight cant see to do all mods 75 yrs old cant complain

Re: Q11,Q31 change

 

Jim,

The MDS on a stock board is 0.100 uV on my bench. I used head phones for the test!
No enough gain for the speaker.

Raj

At 17-01-19, you wrote:
So ...Just because I could, I changed Q11 and Q31 to PNP types (2n3906) R11,31 to 10K R14,34 to 150 ohms ...

MDS (minimum detectable signal) by ear ~ 0.2 v P-P at VOL-H now is 0.1 uV ... listening to 'noon-time-net' sounds ok

Lots 'o good signals

Maybe not state o the art or accepted general practice , but I'm pretty much ok with that

Re: Q11,Q31 change

iz oos
 

Using an S3 (its output level around -107-109dbm) signal generator I can ear the signal as strong as all rigs I have (tabletop and cheap portables)


Il 17/gen/2019 08:16, "Raj vu2zap" <rajendrakumargg@...> ha scritto:
Jim,

The MDS on a stock board is 0.100 uV on my bench. I used head phones for the test!
No enough gain for the speaker.

Raj

At 17-01-19, you wrote:
>So ...Just because I could, I changed Q11 and Q31 to PNP types (2n3906) R11,31 to 10K R14,34 to 150 ohms ...
>
>MDS (minimum detectable signal) by ear ~ 0.2 v P-P at VOL-H now is 0.1 uV ...  listening to 'noon-time-net' sounds ok
>
>Lots 'o good signals
>
>Maybe not state o the art or accepted general practice , but I'm pretty much ok with that





Re: Q11,Q31 change

 

Thats a 20db larger signal, I can hear down to -127dbm.

Raj


At 17-01-19, you wrote:

Using an S3 (its output level around -107-109dbm) signal generator I can ear the signal as strong as all rigs I have (tabletop and cheap portables)

Il 17/gen/2019 08:16, "Raj vu2zap" < rajendrakumargg@...> ha scritto:
Jim,

The MDS on a stock board is 0.100 uV on my bench. I used head phones for the test!
No enough gain for the speaker.

Raj

At 17-01-19, you wrote:
>So ...Just because I could, I changed Q11 and Q31 to PNP types (2n3906) R11,31 to 10K R14,34 to 150 ohms ...
>
>MDS (minimum detectable signal) by ear ~ 0.2 v P-P at VOL-H now is 0.1 uV ...  listening to 'noon-time-net' sounds ok
>
>Lots 'o good signals
>
>Maybe not state o the art or accepted general practice , but I'm pretty much ok with that

Re: Q11,Q31 change

iz oos
 

Indeed I hear a clear signal, probably at 20db above noise floor, by ear, similarly to the other rigs. I have never found so far a receiver that had not enough sensitivity.


Il 17/gen/2019 09:14, "Raj vu2zap" <rajendrakumargg@...> ha scritto:
Thats a 20db larger signal, I can hear down to -127dbm.

Raj

At 17-01-19, you wrote:

Using an S3 (its output level around -107-109dbm) signal generator I can ear the signal as strong as all rigs I have (tabletop and cheap portables)

Il 17/gen/2019 08:16, "Raj vu2zap" < rajendrakumargg@...> ha scritto:
Jim,

The MDS on a stock board is 0.100 uV on my bench. I used head phones for the test!
No enough gain for the speaker.

Raj

At 17-01-19, you wrote:
>So ...Just because I could, I changed Q11 and Q31 to PNP types (2n3906) R11,31 to 10K R14,34 to 150 ohms ...
>
>MDS (minimum detectable signal) by ear ~ 0.2 v P-P at VOL-H now is 0.1 uV ...Ā  listening to 'noon-time-net' sounds ok
>
>Lots 'o good signals
>
>Maybe not state o the art or accepted general practice , but I'm pretty much ok with that

Electret mic amp with AGC from Adafruit

Daimon Tilley <daimontilley@...>
 

Anyone tried one of these?
https://www.adafruit.com/product/1713

Views welcome!

Cheers.

Daimon. G4USI

Re: Electret mic amp with AGC from Adafruit

Ian Reeve
 

Hi, I have tried the type with variable gain that is set by a skeleton preset pot.Far too much gain and the voltage supplied by the ubitx  is above the max quoted.There are various types of these mic boards and I have only experience of the type on a purple pcb but the difference is cosmetic only and I guess they will all have too much gain.what is needed I think is a buffer preamp with modest gain.M0IDR. Ian

On 17 Jan 2019 9:49 a.m., Daimon Tilley <daimontilley@...> wrote:
Anyone tried one of these?
https://www.adafruit.com/product/1713

Views welcome!

Cheers.

Daimon. G4USI

Re: Need a replacement Raduino.

Vic WA4THR
 

If you haven't already, upgrade the software to the Amunter sketch for the BitX40. It adds a lot of nice features, requires no circuit mods (although he describes a few easy ones that further improve it) and pretty much eliminates the tuning clicks.

=Vic=

Re: Q11,Q31 change

jim
 



On Wednesday, January 16, 2019, 11:16:17 PM PST, Raj vu2zap <rajendrakumargg@...> wrote:


Jim,

The MDS on a stock board is 0.100 uV on my bench. I used head phones for the test!
No enough gain for the speaker.

Raj

At 17-01-19, you wrote:
>So ...Just because I could, I changed Q11 and Q31 to PNP types (2n3906) R11,31 to 10K R14,34 to 150 ohms ...
>
>MDS (minimum detectable signal) by ear ~ 0.2 v P-P at VOL-H now is 0.1 uV ...  listening to 'noon-time-net' sounds ok
>
>Lots 'o good signals
>
>Maybe not state o the art or accepted general practice , but I'm pretty much ok with that





Re: Q11,Q31 change

jim
 

Thats good enough ...Mine was and has been effing deaf

Jim

On Wednesday, January 16, 2019, 11:16:17 PM PST, Raj vu2zap <rajendrakumargg@...> wrote:


Jim,

The MDS on a stock board is 0.100 uV on my bench. I used head phones for the test!
No enough gain for the speaker.

Raj

Re: Electret mic amp with AGC from Adafruit

Ted
 

These things actually work quite well, with a minimum of prep.  The board provides power to the mic element by itself (once you remove the one it comes with) and the  mic bias from the radio's mic input line can be isolated from this board's output with a capacitor.  I can testify that failure to do so adds to the world's waste disposal issues.

As to levels, I've just added a 5k (or 10k) trimmer to the board output, followed by the aforementioned isolation cap. Adjust for max modulation on a  long "FFIIIIIIVVE", etc and your normal voice will be subsequently kept at top level from 8" away or closer. The AGC board only needs the minimum gain level, which happens when the "g" (gain) terminal is jumpered to the 5v b+ input.


Ted
K3RTA

Re: Q11,Q31 change

iz oos
 

It happened to me, after I soldered an IF output cable for an SDR receiver, that the ubitx lost its good sensitivity and the S3 was just barely audible. That was because I fried a resistor at the emitter of one of the 3904s. Replacing the fried resistor, sensitivity was back to normal.


Il 17/gen/2019 11:23, "jim via Groups.Io" <ab7vf=yahoo.com@groups.io> ha scritto:
Thats good enough ...Mine was and has been effing deaf

Jim

On Wednesday, January 16, 2019, 11:16:17 PM PST, Raj vu2zap <rajendrakumargg@...> wrote:


Jim,

The MDS on a stock board is 0.100 uV on my bench. I used head phones for the test!
No enough gain for the speaker.

Raj

Re: Need a replacement Raduino.

MVS Sarma
 

At least, whether your lcd display is OK?
the nano could  well be barbered out of board using a narrow nipper and a new one inserted and re programmed.
 whether si5351 would    be working !!  well possible  as it works thro' a 3.3v regulator inside arduino nano..
Now that you have an item, perhaps lot of learning possible, restoring it.

all the best


Unexpected measurements

Peter Russell <peter.russell@...>
 

After replacing the bias preset (RV3) I have finally been able to set up the IRF510 currents and have pressed the key.

These are the CW results into a SWR/Power meter and 50 ohm load.....

Freq Total current Relative output

1.8 1.8A 0.1 Buzzing
3.6 1.9A 0.25 Buzzing
5.2 1.8A 0.6 Buzzing
7.05 1.8A 1.8 Buzzing
10.15 1.25A 3.0 Clean
14.2 1.7A 9.0 Buzzing
18.1 1.8A 6.0 Buzzing
21.2 1.6A 10.2 Clean
24.92 1.6A 10.0 Buzzing
28.2 1.4A 10.0 Clean

The output figures are relative - I don't have a calibrated power meter.
Listening with headphones, only 3 of the bands produce a clean sidetone, the rest are a nasty grating buzz. On 1.8Mhz the buzz comes on after a delay of about half a second.
These results are not what I would have expected, especially low power at low frequencies and high power at high frequencies.
(The drive preset is set at about mid range and hasn't been changed from its factory setting.)
This is a ubitx ver.4 board without any mods.

Anyone care to comment?

Peter G8FWY.



---
This email has been checked for viruses by AVG.
https://www.avg.com

Re: Unexpected measurements

Evan Hand
 

Peter,

I too had strange results when I first tried the uBitx, very similar, though not exact.  Would check that the SWR/Power meter is rated for the frequencies being measured.  the first one that I bought dropped off at lower frequencies.  Checked closely and it was a CB (11m) rated SWR meter.

As to the buzzing, I found that the volume control at minimum created the buzz on transmit (I had turned down the volume because the normal side tone is extremely loud). The other possibility is that the power supply is causing the buzz if it is close to max rated current.

Since it is connected to a dummy load, the other thing that I ran into that had similar symptoms is when connected to an off center fed dipole (OCFD).  The RF on the braid was getting back into the audio on the ubitx and causing buzz on CW, distorted audio on SSB.  Fixed with RF ferrites clamped on the coax and improved ground in the shack.

The above are my experiences, and may not relate to yours.

73
Evan
AC9TU

Re: Electret mic amp with AGC from Adafruit

Bob Lunsford <nocrud222@...>
 

Here's a cheap and dirty idea.

Couple one of these automatic gain mics to an
earphone on the audio out and then drive another
audio amp from the mic. And what do you have?

Audio Level AGC.

Bob — KK5R

--------------------------------------------

On Thu, 1/17/19, Daimon Tilley <daimontilley@...> wrote:

Subject: [BITX20] Electret mic amp with AGC from Adafruit
To: BITX20@groups.io
Date: Thursday, January 17, 2019, 4:49 AM

Anyone tried one of these?
https://www.adafruit.com/product/1713

Views welcome!

Cheers.

Daimon. G4USI

Cooling fan Shroud

_Dave_ K0MBT
 

Decided to put a cooling fan on my ubitx v4. A friend gave me a couple of squirrel cage fans.
On my other rigs I have gone with conventional fans. One of those was getting noisy and decided to replace it with my new fans.

I had to make a shroud to move the air onto the heatsinks. The fan is bolted to the back of the Indian case. It looks like they put in a port for a small conventional fan but that isn't what I have.

The print file and the fan used was here:
https://www.thingiverse.com/thing:3360539

Maybe someone will find it helpful. This forum is where I find many solutions to bitx radio issues.

Re: Unexpected measurements

_Dave_ K0MBT
 

I would be careful with putting out power on 160. The finals become very hot and blow fuses when I have tried.