Date   
Re: #Bitx40 Mic Pre-amp MAX9812 #bitx40

 

I had reports of it being muddy. I will try and make another recording w/o it and try and get it posted when I have more time to play with it. Over all it seems to be an improvement but will have to find a way to add this to the audio chain if I want to continue doing digital. At the moment its just in the mic housing.
--
David

 N8DAH
Kit-Projects.com

Re: Nextion Display

Jack, W8TEE
 

Fred:

Are you running the Nextion from the STM32? No driver issues?

Jack, W8TEE



From: Dr Fred Hambrecht <w4jle@...>
To: BITX20@groups.io
Sent: Wednesday, January 31, 2018 2:13 PM
Subject: [BITX20] Nextion Display

I may be late to the party, but I have just discovered the NEXTION display. I am using it on my BitX. What makes it really neat is the software that can be downloaded from the manufacturer's site. It takes all the pain out of graphics programming. I have also replaced the UNO with an STM32 as in addition to the normal stuff I have added a GPS module to display time/location/grid square data as well as using the 1PPS to do a continuous correction to the SI oscillator. The higher resolution allows calculating the SWR etc with much finer gradations.  I will be adding a filter board from a CODAN that will allow all band operation.(bought for $12.00 on EBay). Amazing what is available to the homebrewer today!


Re: Bitx40 USB mod

KC9SGV <kc9sgv@...>
 

Might be my problem too as discussed in another thread here today.
Missed that C91/91 removal in the latest sketch comments.
KC9SGV

On Wed, Jan 31, 2018 at 1:38 PM, N8DAH <Dherron@...> wrote:
Yes to your question C91/91 will attenuate the usb signal to much so they should be removed. You do not have to change firmware or go to V2 for this to work
--
David

 N8DAH
Kit-Projects.com


Re: Spare/replacement part

Jerry Gaffke
 

The inductors for the Bitx40 are described by Farhan at the bottom of
    http://www.hfsignals.com/index.php/2017/11/23/bitx40-circuit-description/

If you want to buy cores, I'd first look at     http://www.kitsandparts.com/
Buy his $12 SWR meter here   http://www.kitsandparts.com/bridge1.4.php
if wishing to justify the shipping charge.
Prices are shown when you click "Place Order".

But most likely the old core is just fine.

Jerry


On Wed, Jan 31, 2018 at 11:33 am, Michael Davis wrote:
T2 on my Bitx40 is intermittent. By that I mean, if I nudge it my receiver cuts out, if I move it, it comes back on. I have re-soldered the circuit board connections and have removed T2 from an old Bitx40 board. The leads are short and before I attempt to unsolder the bad T2, I though I'd ask if there is a way to buy a spare. I am going to examine the connections more closely with my computer microscope first. Is T1 identical to T2? Any others on the board identical. Thanks

Re: Bitx40 USB mod

 

I am running a old Alpha version of 1.18 I have not upgraded in a long time.
--
David

 N8DAH
Kit-Projects.com

Re: Bitx40 USB mod

Allard PE1NWL
 

Although not strictly required, it is recommended to remove C91/C92 for better performance in USB mode.
C91/C92 used to be required for the analog VFO. You can safely remove them when the Raduino is used instead of the original analog VFO.

In USB mode, the VFO operates at 19 MHz instead of 5 MHz in LSB mode. At 19 MHz, the two capacitors attenuate the VFO signal too much. It is possible, to some extend, to compensate for this by increasing the VFO drive level (in the SETTINGS menu). But removing the capacitors gives better results.

73 Allard PE1NWL

Re: Nextion Display

Jerry Gaffke
 

Which STM32?  
There's a whole bunch of them, from Arm Cortex M0's to M7F's.
The M0 is extremely cheap, can be well under a buck for the chip.
The M7F has caches,memory mapping, and floating point, 216mhz clock. 

I'm currently playing with a "Blue Pill", has the STM32F103C8, $2 on ebay
    http://wiki.stm32duino.com/index.php?title=Blue_Pill
Has the M3 core at 72mhz,  64meg of flash, 20meg of ram, 12bit ADC.
Otherwise much like like the Nano, IO is primarily 3.3v with some 5v tolerant pins.

Get one that reads "PC13" in the silk towards the lower right corner (most these days do).
I got it to speak Arduino with some messing around, though not all the libraries are supported.
Arduino is a good way to get your feet wet, I may move on to the Atollic Eclipse IDE someday.

Jerry, KE7ER


On Wed, Jan 31, 2018 at 11:13 am, Dr Fred Hambrecht wrote:
I have also replaced the UNO with an STM32

Re: MAX9814 mic preamp and DC bias capacitor

jlco001@...
 

I used another mic housing with a DPDT switch and wired it so voltage is supplied only when PTT is engaged. I am using a CR2032 3v button cell. Seems to work fine, but I have not compared the stock vs. preamp mic with anyone on the air yet. Definitely has more avg power on the watt meter. I can hear some peaks come thru the speaker when transmitting. I may try installing a pot to dial back the gain.

Jeff
AD6RH

Re: Care and Feeding of SMD Parts

Thomas Sharka
 

I find it's easier to get the strip started if I put down a strip of double-sided sticky tape on a piece of cardboard, put the carrier for the SMD on the strip and use a small piece of tape on the edge of the strip to lift up the plastic covering. Keeps the strips for my project from wandering off and it holds the carrier and parts down for easy access with my tweezers. lifting up just enough of the covering to expose one part at a time prevents them from blowing away.
 


Sent from Yahoo Mail. Get the app


On Wednesday, January 31, 2018 1:38 PM, Clark Martin <kk6isp@...> wrote:


I’ve been working with SMDs for a few years now and have lost several.  If the get pressed right they fly off just like a tiddily wink.  They also tend to adhere to tweezers, probes and soldering irons with very little effort.  If it’s a cap or resistor I just fetch another one it’s not worth the effort of a futile search.

One thing I do to try to minimize losses is to limit the number of loose parts I have out to two.  If I need to install more than that I’ll do two at a time and tack solder them into place.


Clark Martin
KK6ISP

On Jan 31, 2018, at 8:44 AM, Ken KM4NFQ <km4nfq@...> wrote:


To use a component, I press it from the plastic side, through the paper side with tweezers, then put the freed component on the solder-pasted pads. I work over an aluminum tray covered with a cloth. I haven't lost a component yet. Of course, I have only recently started working with SMDs, so take that with a grain of salt. :)



Re: MAX9814 mic preamp and DC bias capacitor

Arvo W0VRA
 

I'm working on something similar.  It looks like Q6 is part of the µB's mic pre.  When TX goes high, Q6 turns on and passes the signal into the mixer and so on.  RX also goes low and turns off Q70.  So if you wanna skip the µB's mic pre you have to turn off that signal during RX.  This is because TX and RX share all that mixing and filtering and modulating stuff that I don't quite understand yet.

If someone who knows what they are talking about can confirm this, I'll give myself another high five.

Re: uBITX Firmware (CEC) 0.30 released (Test version). #ubitx

Je
 

Congratulations to the author at first glance seems OK. But what is the 14.150k on the first line of the display?

ubitx relay substitute

denm178@...
 

Would the Ormon G5V-2-H-DC12  relay be a valid replacement for the relays in the ubitx?

Re: ubitx relay substitute

Allard PE1NWL
 

The relays in the ubitx are the same as the ones used in the BitX40.
I used Zettler AZ822-2C-12DE as a replacement:

https://www.conrad-electronic.co.uk/ce/en/product/507425/?insert=89&insertNoDeeplink&productname=PCB-relays----12-Vdc----2-A----2-change-overs----Zettler-Electronics

73 Allard PE1NWL

On Wed, January 31, 2018 21:44, denm178@... wrote:
Would the Ormon G5V-2-H-DC12  relay be a valid replacement for the
relays
in the ubitx?

Re: ubitx relay substitute

Allard PE1NWL
 

The relays in the ubitx are the same as the ones used in the BitX40.
I used Zettler AZ822-2C-12DE as a replacement:

https://www.conrad-electronic.co.uk/ce/en/product/507425/?insert=89&insertNoDeeplink&productname=PCB-relays----12-Vdc----2-A----2-change-overs----Zettler-Electronics

73 Allard PE1NWL

On Wed, January 31, 2018 21:44, denm178@... wrote:
Would the Ormon G5V-2-H-DC12  relay be a valid replacement for the
relays
in the ubitx?

Re: #Bitx40 Mic Pre-amp MAX9812 #bitx40

 

This is w/o the pre-amp .....might just stick with the slight yell to get the audio out. I like the idea of not having to shout but do not like the audio from this version of preamp
--
David

 N8DAH
Kit-Projects.com

Re: Modular BiTX40

ON6RF
 

Hi Mike,
Thank you so much for sharing this with me! Congrats to the whole group!

As for the board corrections, I'll integrate them in the next revision as soon as I manage to finish building V1 ;)
What I'd like to do for the next version is make it µBitX-compatible: build one configuration, you get a single-band 20-40BitX, build another one, you get a µBitX. Probably make all the modules the same size might also be a good idea...

I'd love to receive a motherboard, if you don't mind shipping it to Belgium; I can't seem to find your e-mail address though...

Manoel
ON6RF

Re: Audio gone on new ubitx

Erik Hokansson
 

I do have 12v at pin 2.. I was able to key up the P tt and use a keyer to transmit...they key word there is "was"..now the display just reflects the u bitx version and stays there 

Re: Software support Request for Full QSK BITX40

Jerry Gaffke
 

Gary,

With no load at the antenna port, the simulation shows an IRF510 drain current that stays near the quiescent 100ma
with perhaps 20ma pk-pk of RF riding on top of it.  (An initial spike that I'm ignoring here, as we would be increasing 
drive at audio rates.)    The drain current never goes toward zero, even when Q13 is driven with 400mv pk-pk.
Gate voltage is quite distorted, but does get down to 1.2v which should be enough to shut down the IRF510.
I'd guess that as the IRF510 shuts down the drain voltage rises, the gate-drain capacitance causes the gate voltage to rise,
and so the IRF510 continues to conduct.     When operating more slowly the IRF510 does indeed shut down as Vgs rises.

Jerry


On Wed, Jan 31, 2018 at 09:40 am, Jerry Gaffke wrote:
One major conundrum: 
When the Bitx40 IRF510 turns off and the magnetic field collapses that energy needs some place to go,
the induced emf in T7 will create voltage spikes that rise as high as it needed till it finds a load, 
perhaps arcing across the transformer.  But my LTSpice simulation of the Bitx40 final with no load
shows no such spike, the output voltage remains pretty much determined by the turns ratio
as if T7 were a straight up forward transformer.

Re: Nextion Display

Jerry Gaffke
 

Scratch that.
The STM32F103C8 has a measly 64kbytes of flash, 20kbytes of ram.
For megabytes, you'll have to shell out $5 for the RasberryPi-zero.


On Wed, Jan 31, 2018 at 12:14 pm, Jerry Gaffke wrote:
I'm currently playing with a "Blue Pill", has the STM32F103C8, $2 on ebay
    http://wiki.stm32duino.com/index.php?title=Blue_Pill
Has the M3 core at 72mhz,  64meg of flash, 20meg of ram, 12bit ADC.
Otherwise much like like the Nano, IO is primarily 3.3v with some 5v tolerant pins.

Re: Spare/replacement part

James Lawrie
 

Check to see if coils are touching any smts. One of my bitx coils was soldered to a resistor, I guess during final assembly it was up against it and got hot enough to stick. I’m going one by one checking missing parts, bad solder joint, etc.

Hope this helps


On Jan 31, 2018, at 13:33, Michael Davis <maddmd818@...> wrote:

T2 on my Bitx40 is intermittent. By that I mean, if I nudge it my receiver cuts out, if I move it, it comes back on. I have re-soldered the circuit board connections and have removed T2 from an old Bitx40 board. The leads are short and before I attempt to unsolder the bad T2, I though I'd ask if there is a way to buy a spare. I am going to examine the connections more closely with my computer microscope first. Is T1 identical to T2? Any others on the board identical. Thanks