Re: Raduino V1.01 vs V1.14 Birdie at 7.200
On Mon, June 12, 2017 09:10, OZ9AEW wrote: bitx is 100% stock except from a 7808 with .1uf and 2200uf on both input
and output placed between on/off and Raduino board, it reduce tuning click
to nearly nothing, but that 7.200MHz Birdie is really strong !
I have think about rewire everything with shielded cable and solder them
instead of use connectors Adding capacitors as you did can indeed reduce the tuning click issues, but will not have an effect on the 7199 kHz birdie. Regarding the birdie: Have you already tried different VFO drive levels? In early raduino versions the drive level was set to 2mA, as from v1.05 the default became 4mA but you change change it in the SETTINGS menu (possible values are 2,4,6,8mA). The correct setting of the drive level can have a great effect on the strength of the birdie in LSB mode. It seems there is some variability between BitX radios, most have best results with 4mA but in some cases a different value is better. 73 Allard PE1NWL
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Have you got the diagram for the interface by any chance and has anyobe heard about the release date for the uBitx yet
On 12 Jun. 2017 4:11 pm, "Ashhar Farhan" < farhanbox@...> wrote: it might be a good idea to just remive the rf amps before the mixer. there is too mucb gain for a 7 mhz radio.
- f
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Re: BITX QSO Night, Sunday, June 11, 7pm Local Time, 7277 kHz in North America, 7177 kHz elsewhere
no luck here .... have someone on a langue I do not understand here with 9++?
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Re: Raduino V1.01 vs V1.14 Birdie at 7.200
bitx is 100% stock except from a 7808 with .1uf and 2200uf on both input and output placed between on/off and Raduino board, it reduce tuning click to nearly nothing, but that 7.200MHz Birdie is really strong !
I have think about rewire everything with shielded cable and solder them instead of use connectors
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Checked the relay Virtual VRS2H on my board is not polarised.
I have some other brands, checked one I had handy a Panasonic and it is
polarised.
BITX40's both relays are wired opposite of each other.
At 12-06-2017, you wrote:
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You're probably right.
So Matt's TX rail probably never saw power during the mishap, and none of
those parts behind it got damaged.
We're assuming it was a battery lead reversal that blew D7.
?
?
On Sun, Jun 11, 2017 at 08:49 pm, Raj vu2zap wrote:
- The relays are polarized type, they have a magnet inside to reduce
operating current.
- They wont operate with reversed voltage.
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it might be a good idea to just remive the rf amps before the mixer. there is too mucb gain for a 7 mhz radio.
- f
On 12 Jun 2017 11:37 a.m., "Jerry Gaffke via Groups.Io" <jgaffke= [email protected]> wrote: If incoming signals are too strong to go through the receiver without distortion, you need to reduce the gain.? The bitx40 has an audio gain control already, that happens at the tail end of the radio.? For really strong signals, we're better off with an RF gain control, RF gain happens at the front end of the receiver near the antenna.? That way we don't overload all those parts of the receiver that happen before the audio gain control.
The first link talks about many different methods of gain control, including two methods of RF gain control.? The one by Don Cantrell where you mess with power into the existing amplifier at Q1 is an elegant solution that probably works just fine.? The second link is Don's blog post about it.? The second RF gain control method is described in post 20538 and 20541 where you add a 10k pot between K2 pin 14 and K1 pin 12, that is a trace that is only used during receive and not during transmit.? The second method is a bit harder to do well, because if you mount the 10k RF gain pot on the front panel it really should have two pieces of coax off to where you cut that trace between K1 and K2 since it is sometimes dealing directly with an extremely low level received signal from the antenna.
Adding a 240 ohm resistor at the antenna might work well enough if you have an antenna tuner between that and the rig to match the rig's 50 ohm transmitter.? I suppose if you are talking to somebody close you want to reduce transmitted power anyway.? But you will be wasting most of the power from the transmitter, better to reduce mike gain (or R136) if you want to cut transmitter power.
?
Jerry
On Sun, Jun 11, 2017 at 10:13 pm, John Smith wrote:
Your first link was about amplified audio, and the second was more like what I am talking about with attenuation of RF. When a strong station comes on, they sound distortedly loud even when I turn the volume almost all the way down. My experiment with the resistor softened them enough to eliminate the distortion and sound like most other stations. And I like the audio gain as is from stock. I need it for QSO night.?
On that second link, do you have other ideas along these lines? Or is that my best bet?
?
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If incoming signals are too strong to go through the receiver without distortion, you need to reduce the gain. ?The bitx40 has an audio gain control already, that happens at the tail end of the radio. ?For really strong signals, we're better off with an RF gain control, RF gain happens at the front end of the receiver near the antenna. ?That way we don't overload all those parts of the receiver that happen before the audio gain control.
The first link talks about many different methods of gain control, including two methods of RF gain control. ?The one by Don Cantrell where you mess with power into the existing amplifier at Q1 is an elegant solution that probably works just fine. ?The second link is Don's blog post about it. ?The second RF gain control method is described in post 20538 and 20541 where you add a 10k pot between K2 pin 14 and K1 pin 12, that is a trace that is only used during receive and not during transmit. ?The second method is a bit harder to do well, because if you mount the 10k RF gain pot on the front panel it really should have two pieces of coax off to where you cut that trace between K1 and K2 since it is sometimes dealing directly with an extremely low level received signal from the antenna.
Adding a 240 ohm resistor at the antenna might work well enough if you have an antenna tuner between that and the rig to match the rig's 50 ohm transmitter. ?I suppose if you are talking to somebody close you want to reduce transmitted power anyway. ?But you will be wasting most of the power from the transmitter, better to reduce mike gain (or R136) if you want to cut transmitter power.
?
Jerry
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On Sun, Jun 11, 2017 at 10:13 pm, John Smith wrote:
Your first link was about amplified audio, and the second was more like what I am talking about with attenuation of RF. When a strong station comes on, they sound distortedly loud even when I turn the volume almost all the way down. My experiment with the resistor softened them enough to eliminate the distortion and sound like most other stations. And I like the audio gain as is from stock. I need it for QSO night.?
On that second link, do you have other ideas along these lines? Or is that my best bet?
?
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Your first link was about amplified audio, and the second was more like what I am talking about with attenuation of RF. When a strong station comes on, they sound distortedly loud even when I turn the volume almost all the way down. My experiment with the resistor softened them enough to eliminate the distortion and sound like most other stations. And I like the audio gain as is from stock. I need it for QSO night.?
On that second link, do you have other ideas along these lines? Or is that my best bet?
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Show quoted text
On Sun, Jun 11, 2017 at 09:31 pm, Jerry Gaffke wrote:
Not quite sure what you're trying to do, but here's some links on implementing an RF gain control.
? /g/BITX20/topic/4238539
???
?
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Not quite sure what you're trying to do, but here's some links on implementing an RF gain control. ? /g/BITX20/topic/4238539???
On Sun, Jun 11, 2017 at 09:21 pm, John Smith wrote:
I previously made the FLDGI CW keying circuit, and it works great. But better than that is using the rig controls for serial port PTT. Tests with the relay module and the Usb to serial adapter Indicates it's working very well. Next is the audio. I plan to use the Easy Digi schematic design for the audio connections with 600ohm audio transformers, and a 2kR across the lines and a 104C on the + line, of the radio side. The only hard part seems to be wiring all those stereo audio mini jacks. 3 on both the interface box, and the radio enclosure. Audio in, out, and PTT, and hard wire the audio adapter. Plus Allard's new wires from the Nano.
Has anyone thought about RF signal attenuation? I tried a 240ohm resistor inline with the antenna to better handle the bigger stations near by. It gave me the results I was looking for, but again it seems too easy for a proper solution. If there is nothing wrong with that, I might use a switch to bring it in and out of circuit.
I just happened to think that the attenuation would be both ways. Humm.
?
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I previously made the FLDGI CW keying circuit, and it works great. But better than that is using the rig controls for serial port PTT. Tests with the relay module and the Usb to serial adapter Indicates it's working very well. Next is the audio. I plan to use the Easy Digi schematic design for the audio connections with 600ohm audio transformers, and a 2kR across the lines and a 104C on the + line, of the radio side. The only hard part seems to be wiring all those stereo audio mini jacks. 3 on both the interface box, and the radio enclosure. Audio in, out, and PTT, and hard wire the audio adapter. Plus Allard's new wires from the Nano.
Has anyone thought about RF signal attenuation? I tried a 240ohm resistor inline with the antenna to better handle the bigger stations near by. It gave me the results I was looking for, but again it seems too easy for a proper solution. If there is nothing wrong with that, I might use a switch to bring it in and out of circuit.
I just happened to think that the attenuation would be both ways. Humm.
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You're probably right.
So Matt's TX rail probably never saw power during the mishap, and none of those parts behind it got damaged.
We're assuming it was a battery lead reversal that blew D7.
?
?
toggle quoted message
Show quoted text
On Sun, Jun 11, 2017 at 08:49 pm, Raj vu2zap wrote:
The relays are polarized type, they have a magnet inside to reduce operating current.
They wont operate with reversed voltage.
?
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Re: BITX QSO Night, Sunday, June 11, 7pm Local Time, 7277 kHz in North America, 7177 kHz elsewhere
N9ARZ was 59 here in Coralville, IA but didn't hear me. Maybe next time.
John AD0RW
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The relays are polarized type, they have a magnet inside to reduce operating current.
They wont operate with reversed voltage.
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Show quoted text
At 12-06-2017, you wrote: The NPN's powered from the "TX" 12v rail do not get power unless the PTT switch is pressed to transmit.
I suggest you concentrate on the receiver first.
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Colour TFT + Touch controlled VFO/BFO
I have put preliminary information on my cheap Mcufriend 2.4" TFT based VFO/BFO with touch controls at vu2spf.blogspot.com
More pictures and program to follow. Soon I will be uploading its video too.
73
VU2SPF
SP Bhatnagar
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Re: Calling West Coast BITX operators
I had a QSO with Don ND6T in California about half
an hour early... my first one with someone using a
BITX40! I'm still waiting for my BITX40, so I was
running 100W. Don was fairly weak... about 43.
I later heard K7RTV, KG7UMW and N6QW although I
thought I heard him saying he was not QRP. I heard
ND6T again in a QSO during which he peaked up to 59.
There were quite a few weaker stations whose call
signs I couldn't copy.
--
73 Keith VE7GDH
CN88
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Reverse polarity protection is a must. I have always put a diode in my designs. Does not cost much.
First thing I did before powering up the BITX40!
Raj
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At 11-06-2017, you wrote: My curiosity overcame me. Pulled the LM7805 from my Raduino (so I was sure I was working with the same manufacturer that hfsigs uses) and verified proper operation with 12v in, saw 5v out. Reversed the 12v leads into the LM7805, put on the safety goggles, and powered up. Was powering from a 2.5 amp 12v supply. The reversed LM7805 was sucking enough current to pull down my 12v switcher to -5v going into the LM7805, saw -2v going out of the LM805. Could well be more than -2v going out if I had used a beefier 12v supply. Regardless, -2v is sufficient to damage some parts behind the LM7805. After a few seconds the LM7805 got hot enough to vent and stink up the room.
So, the LM78** parts offer little to no protection from reversed power supply leads. Not surprising, they were designed 40 years ago when such niceties would have been too expensive to include. A reversed power supply to the rig could easily blow the Nano on the Raduino. The Nano has an internal 3.3v regulator that may or may not save the Si5351, but no guarantees. The LM78L09 powering the analog VFO and LM78L05 for the IRF510 bias likely have the same issue.
The LM2940* family of regulators does offer reverse polarity protection and has a lower dropout voltage. However it is twice as expensive ($1.00 vs $0.50 from mouser for 10), they recommend at least 22uf on the LM2940* output to maintain stability. As mentioned previously, having an LM2940-12 at the main Bitx40 supply going into the board would protect us from reversed power leads, and also avoid trouble from supplies that exceed 12v such as a stack of 4 lithium batteries. The IRF510 should be powered separately, as we may want considerably higher voltages and currents there and the IRF510 is plenty cheap.
I am left very curious if Matt's Raduino is still functional. Does the display come up if you apply 12v to it?
Jerry, KE7ER
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Please see the link given below
Thank you 73 Ameer Khan VU3SQM
On 12-Jun-2017 7:42 AM, "John Smith via Groups.Io" <johnlinux77= [email protected]> wrote: Does anyone know if those cheap Usb sound card adapters offer any isolation between PC and radio? I plan to try out these things with my isolated interface for digital modes. The plan is to use an Usb to serial adapter for the PTT, and one of these sound card dongles for audio, and a Usb to DIP adapter (exposed PCB) to pick up power for a 5V relay module with opto isolation. All on a 4 way Usb hub. The object is to have one connection to PC. And just hoping I can get away without the audio transformers for the lines in and out.
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Re: BITX QSO Night, Sunday, June 11, 7pm Local Time, 7277 kHz in North America, 7177 kHz elsewhere
After weeks of trying I finally had some success! First QSO with Rick WB0NPM then Don ND6T. I also hear a few others but can't make them out. Rick mentioned an early net 8AM on 7186, may give that a try.
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I had one that looked similar to your Ebay post and it didn't have any isolation between the computer ground and the audio in and out ground. I did the VOX interface as well. I intend my Bitx to be mostly portable so I skipped the transformers in this one to save space and just added a resister and some caps to get some DC isolation. We will see if that was a mistake but it seems to be working fine as of now.
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I have worked with a lot of cheapy ones from aliexpress they wont have any isolation. I use a vox interface just for that. It does add more cables to the mess but it works.
Gl
73
David
N8DAH
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Allard PE1NWL
Raj vu2zap
SP Bhatnagar
Jeff
N8DAH