开云体育

ctrl + shift + ? for shortcuts
© 2025 开云体育
  1. BITX20
  2. Messages
Expanded Topics Messages Polls
Date
Re: A little off topic, but does anyone know?

 

Another screw thread site


73
Larry

On Fri, Jul 21, 2017 at 7:52 AM, John P <j.m.price@...> wrote:
I recently got a couple of Jennings vacuum variable capacitors on eBay, which I hope to use on the magnetic loop antenna I'm building to go with my Bitx-40.

One is missing the threaded rod adjustment shaft. I cannot for the life of me figure out what the thread is. The shaft is 1/4", but the thread count is neither 24 or 28, which would be standard for a 1/4" rod. I tried putting some graphite on it then pressing it on a piece of paper so I could see the thread marks (looks like //////////) and when I count how many I come up in an inch, I get 28, so it's close to that, but not exact. Any help would be appreciated. If anyone knows the specifications, or has a spare, please?let me know.

Thanks
--
John - WA2FZW


Re: Park ops today

 

p.s. this is NOT npota or national parks on the air
Park ops today

 

Going to head out to the park today with the Bitx and my FT-891 will be on 40m psk and ssb as well as 20m ssb and psk if I can setup the laptop.

?

?73

?? David

??? N8DAH
SolderSmoke Podcast #198

 


Re: Finished to build but LCD noise.

 

开云体育

Thanks Jack
73 Carlos
?

Sent: Saturday, July 29, 2017 12:05 PM
Subject: Re: [BITX20] Finished to build but LCD noise.
?
I'll try to get that done this weekend and then post it.

Jack, W8TEE


From: CX8ABF Carlos Molina <cx8abf@...>
To: [email protected]
Sent: Saturday, July 29, 2017 10:55 AM
Subject: Re: [BITX20] Finished to build but LCD noise.
?
Please Jack,
send us the schematic of the modified PSU.
?
73 Carlos
CX8ABF
?
Sent: Saturday, July 29, 2017 11:44 AM
Subject: Re: [BITX20] Finished to build but LCD noise.
?
I had the same noise problem with my TFT display. Because of all the add-on boards that Dennis is working on, I needed additional takeoff points for +/-12V (mainly for BITX40, PA, and Dennis' boards) and +/- 8V (the TFT and my DDS). My original design for the PS introduced a ground loop into the circuit and updating the display created an ugly "whoosing" sound. (Hey! What do I know? I'm a software guy.) Under the guidance of Al Peter, AC8GY, I redid the PS (see picture) to eliminate the ground loop. The power comes into the pins on the left, and the yellow pins at the top of the board are +12V feeds (black is GND), the middle yellow pins are +8V for my PCB (less stress on the Mega), and the bottom single set is for the PA. The lone yellow pin near the top right feeds into pin A14 on the Mega to monitor the supply voltage (which might be a battery) on the display. Now there is no interference when tuning.

Jack, W8TEE


From: Mvs Sarma <mvssarma@...>
To: [email protected]
Sent: Saturday, July 29, 2017 5:22 AM
Subject: Re: [BITX20] Finished to build but LCD noise.
?
the power supply going to raduino has to be filtered at -close to raduino? by say 100uF and? 0.1? disc cap or MLC cap.
?
?
On Sat, Jul 29, 2017 at 1:52 PM, <qrper72@...> wrote:

I've finished the Bitx40 experimental project today. I added the AF-AGC and LM386 POP limitter with raduino v1.20.1 (Thanks Allard). And I also added the DuinoVOX for Digital Mode operation. It's a great radio but the problem is only the "LCD noise" when increasing the AF volume. hi... Can I reduce this noise? Or I have to use the analog VFO? Any suggestions welcome.

ja9mat Hidehiko.




--
Regards
Sarma
?



Virus-free.


Re: Front End Protection Diodes?

David
 

As a newbie about to put the radio together I would love a list of hacks all on one sheet and ideally a reference to a document with an explanation or directions. Seems like a file for this could be put in a folder on the group site.

Sent from my iPhone
Re: Finished to build but LCD noise.

Jack Purdum
 

I'll try to get that done this weekend and then post it.

Jack, W8TEE


From: CX8ABF Carlos Molina <cx8abf@...>
To: [email protected]
Sent: Saturday, July 29, 2017 10:55 AM
Subject: Re: [BITX20] Finished to build but LCD noise.

Please Jack,
send us the schematic of the modified PSU.
?
73 Carlos
CX8ABF
?
Sent: Saturday, July 29, 2017 11:44 AM
Subject: Re: [BITX20] Finished to build but LCD noise.
?
I had the same noise problem with my TFT display. Because of all the add-on boards that Dennis is working on, I needed additional takeoff points for +/-12V (mainly for BITX40, PA, and Dennis' boards) and +/- 8V (the TFT and my DDS). My original design for the PS introduced a ground loop into the circuit and updating the display created an ugly "whoosing" sound. (Hey! What do I know? I'm a software guy.) Under the guidance of Al Peter, AC8GY, I redid the PS (see picture) to eliminate the ground loop. The power comes into the pins on the left, and the yellow pins at the top of the board are +12V feeds (black is GND), the middle yellow pins are +8V for my PCB (less stress on the Mega), and the bottom single set is for the PA. The lone yellow pin near the top right feeds into pin A14 on the Mega to monitor the supply voltage (which might be a battery) on the display. Now there is no interference when tuning.

Jack, W8TEE


From: Mvs Sarma <mvssarma@...>
To: [email protected]
Sent: Saturday, July 29, 2017 5:22 AM
Subject: Re: [BITX20] Finished to build but LCD noise.
?
the power supply going to raduino has to be filtered at -close to raduino? by say 100uF and? 0.1? disc cap or MLC cap.
?
?
On Sat, Jul 29, 2017 at 1:52 PM, <qrper72@...> wrote:

I've finished the Bitx40 experimental project today. I added the AF-AGC and LM386 POP limitter with raduino v1.20.1 (Thanks Allard). And I also added the DuinoVOX for Digital Mode operation. It's a great radio but the problem is only the "LCD noise" when increasing the AF volume. hi... Can I reduce this noise? Or I have to use the analog VFO? Any suggestions welcome.

ja9mat Hidehiko.




--
Regards
Sarma
?



Virus-free.


Re: raduino v1.20.1 (respect frequency limits) released

 

?
Thanks Allard.
73 - LU5DNM
?
Norberto Modanesi
San Nicolás

----- Original Message -----
Sent: Saturday, July 29, 2017 2:50 AM
Subject: Re: [BITX20] raduino v1.20.1 (respect frequency limits) released

This is what I have for 80m it came from a mkars 80 its basically a 80m bitx ?see photos of bpf mod and lpf mod?

On 29 Jul 2017 06:39, "Allard PE1NWL" <pe1nwl@...> wrote:
On Tue, July 25, 2017 16:21, Norberto Modanesi wrote:
> Hi Allard:
> Is it possible to change the LOWEST_FREC limit to 3500KHz to have the 80m
> band?

I've never tried it but it should basically be possible.
However note that the standard filters are dimensioned for the 40m band,
so some additional hardware modification is required.

73 Allard PE1NWL
Re: Finished to build but LCD noise.

 

开云体育

Please Jack,
send us the schematic of the modified PSU.
?
73 Carlos
CX8ABF
?

Sent: Saturday, July 29, 2017 11:44 AM
Subject: Re: [BITX20] Finished to build but LCD noise.
?
I had the same noise problem with my TFT display. Because of all the add-on boards that Dennis is working on, I needed additional takeoff points for +/-12V (mainly for BITX40, PA, and Dennis' boards) and +/- 8V (the TFT and my DDS). My original design for the PS introduced a ground loop into the circuit and updating the display created an ugly "whoosing" sound. (Hey! What do I know? I'm a software guy.) Under the guidance of Al Peter, AC8GY, I redid the PS (see picture) to eliminate the ground loop. The power comes into the pins on the left, and the yellow pins at the top of the board are +12V feeds (black is GND), the middle yellow pins are +8V for my PCB (less stress on the Mega), and the bottom single set is for the PA. The lone yellow pin near the top right feeds into pin A14 on the Mega to monitor the supply voltage (which might be a battery) on the display. Now there is no interference when tuning.

Jack, W8TEE


From: Mvs Sarma <mvssarma@...>
To: [email protected]
Sent: Saturday, July 29, 2017 5:22 AM
Subject: Re: [BITX20] Finished to build but LCD noise.
?
the power supply going to raduino has to be filtered at -close to raduino? by say 100uF and? 0.1? disc cap or MLC cap.
?
?
On Sat, Jul 29, 2017 at 1:52 PM, <qrper72@...> wrote:

I've finished the Bitx40 experimental project today. I added the AF-AGC and LM386 POP limitter with raduino v1.20.1 (Thanks Allard). And I also added the DuinoVOX for Digital Mode operation. It's a great radio but the problem is only the "LCD noise" when increasing the AF volume. hi... Can I reduce this noise? Or I have to use the analog VFO? Any suggestions welcome.

ja9mat Hidehiko.




--
Regards
Sarma
?



Virus-free.

Re: Finished to build but LCD noise.

Jack Purdum
 

I had the same noise problem with my TFT display. Because of all the add-on boards that Dennis is working on, I needed additional takeoff points for +/-12V (mainly for BITX40, PA, and Dennis' boards) and +/- 8V (the TFT and my DDS). My original design for the PS introduced a ground loop into the circuit and updating the display created an ugly "whoosing" sound. (Hey! What do I know? I'm a software guy.) Under the guidance of Al Peter, AC8GY, I redid the PS (see picture) to eliminate the ground loop. The power comes into the pins on the left, and the yellow pins at the top of the board are +12V feeds (black is GND), the middle yellow pins are +8V for my PCB (less stress on the Mega), and the bottom single set is for the PA. The lone yellow pin near the top right feeds into pin A14 on the Mega to monitor the supply voltage (which might be a battery) on the display. Now there is no interference when tuning.

Jack, W8TEE?


From: Mvs Sarma <mvssarma@...>
To: [email protected]
Sent: Saturday, July 29, 2017 5:22 AM
Subject: Re: [BITX20] Finished to build but LCD noise.

the power supply going to raduino has to be filtered at -close to raduino? by say 100uF and? 0.1? disc cap or MLC cap.
?

On Sat, Jul 29, 2017 at 1:52 PM, <qrper72@...> wrote:

I've finished the Bitx40 experimental project today. I added the AF-AGC and LM386 POP limitter with raduino v1.20.1 (Thanks Allard). And I also added the DuinoVOX for Digital Mode operation. It's a great radio but the problem is only the "LCD noise" when increasing the AF volume. hi... Can I reduce this noise? Or I have to use the analog VFO? Any suggestions welcome.

ja9mat Hidehiko.




--
Regards
Sarma
?



Virus-free.

PowerSupplyModule.jpg

Re: A little off topic, but does anyone know?

 





_._

On Sat, Jul 29, 2017 at 5:37 AM, John P <j.m.price@...> wrote:
On Fri, Jul 21, 2017 at 06:19 am, John wrote:
Do you know where the capacitors were manufactured?
?
The British Standard Fine (BSF) thread is 1/4" x 26 threads per inch.?
Well, thanks again John for trying to help, but the BSF threaded rods arrived yesterday, and it turns out that that isn't the right answer either. I'm really starting to think Jennings used a proprietary thread; although, I can't imagine why they would do that.
Have to see if I can find a 6mm coarse bolt and try that. I have my doubts though, as the shaft I have is definitely 1/4" according to 2 sets of calipers.

?
--
John - WA2FZW


Re: A little off topic, but does anyone know?

John P
 

Thanks Larry!
--
John - WA2FZW
Re: A little off topic, but does anyone know?

 



Eham.net has some comments that could help

73
Larry

On Fri, Jul 21, 2017 at 7:52 AM, John P <j.m.price@...> wrote:
I recently got a couple of Jennings vacuum variable capacitors on eBay, which I hope to use on the magnetic loop antenna I'm building to go with my Bitx-40.

One is missing the threaded rod adjustment shaft. I cannot for the life of me figure out what the thread is. The shaft is 1/4", but the thread count is neither 24 or 28, which would be standard for a 1/4" rod. I tried putting some graphite on it then pressing it on a piece of paper so I could see the thread marks (looks like //////////) and when I count how many I come up in an inch, I get 28, so it's close to that, but not exact. Any help would be appreciated. If anyone knows the specifications, or has a spare, please?let me know.

Thanks
--
John - WA2FZW


Re: A little off topic, but does anyone know?

John P
 

On Fri, Jul 21, 2017 at 06:19 am, John wrote:
Do you know where the capacitors were manufactured?
?
The British Standard Fine (BSF) thread is 1/4" x 26 threads per inch.?
Well, thanks again John for trying to help, but the BSF threaded rods arrived yesterday, and it turns out that that isn't the right answer either. I'm really starting to think Jennings used a proprietary thread; although, I can't imagine why they would do that.
Have to see if I can find a 6mm coarse bolt and try that. I have my doubts though, as the shaft I have is definitely 1/4" according to 2 sets of calipers.

?
--
John - WA2FZW
Re: On the subject of fake IRF510

chris gress
 

I just got 10 x irf510 from ma components in the UK cost ?7.55 via amazon so fast got them in 24hrs they look the same as fitted in the bitx 40 so I think there good stock?

On 26 Jul 2017 17:36, "chris gress" <Chrisg0wfh@...> wrote:
I just ordered 2 of the ones with the display them China things don't last long I have found so I will have a back up they
Look cool anyway?

On 26 Jul 2017 13:57, "Curt M." <Kc3hjp@...> wrote:
After whatever went on with the first Bitx40 that I was shipped and especially after it appeared that the Radrino got whacked during troubleshooting when I switched from 12v to 13.8v I'm exclusively on 12V now.? I use the 15Ah Bioenno battery that I bought for my FT-817ND which puts out about 13.4v so I installed a voltage converter/stabilizer between the battery and the radio.? I set it for around 12.1v with no load.? See links below...

I purchased two different ones to try.? With the first one which has a display, I set it for 12.1v and the voltage drops to just under 12v when I power the Bitx on.? When I key up and talk the voltage does not go any lower than the initial voltage drop.? Actually 12.1v was the highest I could get when adjusting the output because the device can only control at a minimum of 1v difference between the input and output. ?not sure what happened to the other .2v but either way it seems fine.? What's nice is that this device gives you a pretty clear indication that you are really transmitting because you see the fluctuations in current as you are talking into the mic.? I haven't checked what happens to the voltage with the second one but measuring the power output of the Bitx on the Bird 43, the power output using either one shows that I'm putting out about as close to 6 watts as it could be without the needle actually covering the 6 indicator so I suspect that either of these are fine.? I built the radio with it only ever being a QRP radio so what appears to be about 5.9 watts is more than I was expecting.? Also, these devices do not appear to induce any type of noise into the receive or transmit of the radio.? For everyday use I may stay with the one that doesn't have the display because I can leave it connected to the battery at all times without the load of the LCD and backlight drawing from the battery.? Having the one with the display will allow me to have a quick indication of what's going on with the radio if I ever question if the final has gone defective.

?

?


IMG_20170729_115755.jpg

Re: W8TEE Corrected Code Rel 3

 

Today the new AD9850 DDS has arrived and now everything is working again as it should.
I let the Diodes in series with the AD9850 Vcc supply jumpered, because it really runs "hotter" for me (as described in the shematic).
And ~4,6V on TP4 is Ok for the DDS.
Thank you Jack and Mike for your encouragement.

73, Matt
Re: Finished to build but LCD noise.

 

the power supply going to raduino has to be filtered at -close to raduino? by say 100uF and? 0.1? disc cap or MLC cap.
?

On Sat, Jul 29, 2017 at 1:52 PM, <qrper72@...> wrote:

I've finished the Bitx40 experimental project today. I added the AF-AGC and LM386 POP limitter with raduino v1.20.1 (Thanks Allard). And I also added the DuinoVOX for Digital Mode operation. It's a great radio but the problem is only the "LCD noise" when increasing the AF volume. hi... Can I reduce this noise? Or I have to use the analog VFO? Any suggestions welcome.

ja9mat Hidehiko.




--
Regards
Sarma
?
Finished to build but LCD noise.

 

I've finished the Bitx40 experimental project today. I added the AF-AGC and LM386 POP limitter with raduino v1.20.1 (Thanks Allard). And I also added the DuinoVOX for Digital Mode operation. It's a great radio but the problem is only the "LCD noise" when increasing the AF volume. hi... Can I reduce this noise? Or I have to use the analog VFO? Any suggestions welcome.

ja9mat Hidehiko.

IMG_0226.JPG
IMG_0229.JPG

Re: raduino v1.20.1 (respect frequency limits) released

chris gress
 

For the bpf you can use the 100pf that are fitted but c4 you will need to add 20pf on the bottom of the PCB ?c1 and c7 you need to remove and on lpf remove l6 l7 and c160 and c163 mine is not air tested but should work fine?

On 29 Jul 2017 06:51, "chris gress" <Chrisg0wfh@...> wrote:
This is what I have for 80m it came from a mkars 80 its basically a 80m bitx ?see photos of bpf mod and lpf mod?

On 29 Jul 2017 06:39, "Allard PE1NWL" <pe1nwl@...> wrote:
On Tue, July 25, 2017 16:21, Norberto Modanesi wrote:
> Hi Allard:
> Is it possible to change the LOWEST_FREC limit to 3500KHz to have the 80m
> band?

I've never tried it but it should basically be possible.
However note that the standard filters are dimensioned for the 40m band,
so some additional hardware modification is required.

73 Allard PE1NWL
Re: raduino v1.20.1 (respect frequency limits) released

chris gress
 

This is what I have for 80m it came from a mkars 80 its basically a 80m bitx ?see photos of bpf mod and lpf mod?

On 29 Jul 2017 06:39, "Allard PE1NWL" <pe1nwl@...> wrote:
On Tue, July 25, 2017 16:21, Norberto Modanesi wrote:
> Hi Allard:
> Is it possible to change the LOWEST_FREC limit to 3500KHz to have the 80m
> band?

I've never tried it but it should basically be possible.
However note that the standard filters are dimensioned for the 40m band,
so some additional hardware modification is required.

73 Allard PE1NWL




IMG_20170726_190104.jpg
IMG_20170726_190034.jpg
IMG_20170729_064833.jpg

85261 - 85280 of 115908