I'm going to try and play with a class D audio module with built-in programmable AGC parameters. This coupled with a $3 arduino nano clone could make a nice up-grade for the BITX40?
WA6TKD | | | | | | Adafruit Industries, Unique & fun DIY electronics and kits Stereo 2.8W Class D Audio Amplifier - I2C Control AGC - TPA2016 ID: 1712 - A mini class D wit... | | | | Preview by Yahoo | | | ?
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BITX 40 - DDS right connection
Hi Ashhar, i have two questions: 1. when connect ?DDS or External VFO do I need to desolder only the L4 coil and disconnect the tuning potentiometer?
2. I have replaced the six resistor to 220 values to try to reduce the drift, unfortunately it work good in rx but less in tx mode becuse the temperature increase ... now i go to move to dds, the uestion is: ?It is better to resolder the old resistors with 100 ohm vlues or i can continue to use the present values of 220??
Thanks for replay.? I do some QSO with success. Thank you again for the project.
Giuseppe, IK8YFW
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BITX40 SMD Board#579 Setup
I have a question on setting up my BITX40 board.? I plan to use the onboard VCO and use the unit on 40M LSB only.? I'm going to use the "FLL Freq Counter IK3OIL (BUILT) for my Digi readout.? I'm going to power the FLL with two 9VDC batteries in parallel with an on / off switch, and use a 13.8VDC car battery jumper case for the power supply.? After reading all the posts on this new board I have a question.
I'm not sure how to connect my "FLL Freq Counter IK3OIL" to the BITX40.? I know where the + wire goes, but not where the - wire goes.? Also, ?just how do I connect the 0.047uf capacitor.? The cap has a + and - wire.? Does it go in series with the + line or in parallel?across the two lines, and what direction for the + side?
This is going to be a fun project for this winter.? Thanks in advance.
Ralph? K1KOB??
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Hi!
Lets see how much all these mods improve the audio quality. Lately we have been working with TDA2822, these chips are easily available as they are widely used in USB pc ?speakers. They are dual amps and can be used in bridged BTL configuration. Further in radio application one section can used as an af preamp while the second one as af pa. these chips are less noisy than the 386.?
73's
Rahul VU3WJM
On Sunday, 27 November 2016 11:15 PM, "Joel Caulkins caulktel@... [BITX20]" wrote:
?
Thanks Rahul,
That's another possibility I hadn't thought of yet. I have seen VK3YE do that before on his audio amps. I would have rather had a TDA7052A, but you can't have everything:-) Joel Caulkins KB6QVI
?
Hi!
While doing these mods try a 1nf cap in series with 10k resistor between pin 1 and 5 this also helps with the audio.
73's
Rahul VU3WJM
?
Thanks Joel.
I removed the cap at Pin1 & 8 long ago and that helped a lot. I'll try the 470 later today.
Hope you had a good Thanksgiving.
73 Ken
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Thanks Rahul,
That's another possibility I hadn't thought of yet. I have seen VK3YE do that before on his audio amps. I would have rather had a TDA7052A, but you can't have everything:-) Joel Caulkins KB6QVI
toggle quoted message
Show quoted text
On Nov 27, 2016, at 9:22 AM, Rahul Srivastava vu3wjm@... [BITX20] < BITX20@...> wrote:
?
Hi!
While doing these mods try a 1nf cap in series with 10k resistor between pin 1 and 5 this also helps with the audio.
73's
Rahul VU3WJM
?
Thanks Joel.
I removed the cap at Pin1 & 8 long ago and that helped a lot. I'll try the 470 later today.
Hope you had a good Thanksgiving.
73 Ken
|
Hi!
While doing these mods try a 1nf cap in series with 10k resistor between pin 1 and 5 this also helps with the audio.
73's
Rahul VU3WJM
On Sunday, 27 November 2016 10:43 PM, "Ken Chase chase8043@... [BITX20]" wrote:
?
Thanks Joel.
I removed the cap at Pin1 & 8 long ago and that helped a lot. I'll try the 470 later today.
Hope you had a good Thanksgiving.
73 Ken
|
Thanks Joel.
I removed the cap at Pin1 & 8 long ago and that helped a lot. I'll try the 470 later today.
Hope you had a good Thanksgiving.
73 Ken
On Sun, Nov 27, 2016 at 11:50 AM, Joel Caulkins caulktel@... [BITX20] <BITX20@...> wrote:
?
Hi Ken,
No I haven't had much time over the holiday with my Family being around, however, the first thing I'm going to do is change that 450mfd snubber cap on the output of the LM386 to a 220. If you remove the cap between pins 1 and 8 of the 386 chip that will lower the gain and make it sound better already, (mine was distorting real bad), then change the 450 to a 220 for less bass. Hopefully it won't go into oscillation. Joel Caulkins KB6QVI
?
Hi Joel
Did you ever check out the caps for the bassy audio?
73 Ken
|
Hi Ken,
No I haven't had much time over the holiday with my Family being around, however, the first thing I'm going to do is change that 450mfd snubber cap on the output of the LM386 to a 220. If you remove the cap between pins 1 and 8 of the 386 chip that will lower the gain and make it sound better already, (mine was distorting real bad), then change the 450 to a 220 for less bass. Hopefully it won't go into oscillation. Joel Caulkins KB6QVI
toggle quoted message
Show quoted text
On Nov 27, 2016, at 8:15 AM, Ken Chase chase8043@... [BITX20] < BITX20@...> wrote:
?
Hi Joel
Did you ever check out the caps for the bassy audio?
73 Ken
|
Hi Joel
Did you ever check out the caps for the bassy audio?
73 Ken
On Wed, Nov 23, 2016 at 8:30 PM, Joel Caulkins caulktel@... [BITX20] <BITX20@...> wrote:
?
Ken,
Ive noticed the same thing about the bassy audio, i was going to change some cap values to see if i could improve it. Ill let you know how it comes out.
Joel KB6QVI
?
I've finally hooked up a 5351 to the Bitx40. In testing I noticed two things(not related to the 5351)
The audio is very 'bassy' sounding. Is there some way to improve the quality or does the BFO have to be moved slightly?
As I tune the vfo from the lower end of the band and up, the closer I get to the end of the band, signal ?strength drops. Is this due to the BPF?
73
Ken VA3ABN.
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LED-LDR audio AGC for BitX
Tried uploading a circuit to Files but it didn't work. ?
Anyway it's in this video along with a description and a demonstration.?
An LED, LDR, one transistor and little else.?
73, Peter VK3YE
| | | | | | An automatic gain control using one transistor, one LED and one LDR. Video describes circuit and gives a demonstration with a BitX HF transceive... | | | | Preview by Yahoo | | |
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Re: Additional Power Amp?
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Re: Additional Power Amp?
Pardon but,
2P being power our or power in?
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---<farhanbox@...> wrote : We starting including the resistors after the reports of the drift. the pads are big enough for you to solder regular 1/4 watt in place of wthe smd resistors (in manhattan style). if you do really want them, drop a mail to and they will post a 'pinch' of them to you for free, though the cost of postage is prohibitive but they have agreed to bear it.? - f
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No problem I have some. Will do that tomorrow. Thanks ?
toggle quoted message
Show quoted text
From: BITX20@... [mailto:BITX20@...]
Sent: Saturday, November 26, 2016 11:38 PM
To: BITX20@...
Subject: Re: [BITX20] Bitx 40 board.? ? we starting including the resistors after the reports of the drift. the pads are big enough for you to solder regular 1/4 watt in place of the smd resistors (in manhattan style). if you do really want them, drop a mail to and they will post a 'pinch' of them to you for free, though the cost of postage is prohibitive but they have agreed to bear it. ? On Sun, Nov 27, 2016 at 9:53 AM, Arv Evans arvid.evans@... [BITX20] <BITX20@...> wrote: ? Mark. K3MRK
Either 10K or 100K, or anything in between, will work fine for the tuning pot.? A 10-turn type pot makes tuning much easier if you Resistors for decreasing heat generation are 220 ohms. ? On Sat, Nov 26, 2016 at 8:56 PM, 'Mark W' k3mrk1@... [BITX20] <BITX20@...> wrote: ? No I did not receive any resistors. What size are they? I¡¯ll try to find some. I also noticed that my tuning pot is 10k. The board info on the website says it should be 100k. Which is correct? I have received my enclosure and am almost done installing. Mark K3MRK ? ? ? ? mark,
you must have received a strip of 220 ohm resistors in the pack. if you replace the 100 ohm emitter resistors of the six amps with these, the drift will drastically reduce. the details are on the blog.
- f On 25-Nov-2016 4:58 am, "Mark Walton k3mrk1@... [BITX20]" <BITX20@...> wrote: >?
> ?
>
> It might be worse since there is no enclosure at all. Maybe not really warming up at all. I'm hoping the enclosure itself will have some heat retention. There are some transistors that can be used as heaters. I'll wait till I get the enclosure and see how it is. I realize that this circuit is prone to some drift on warm-up, but I think mine may be excessive. Bad cap? I haven't really started digging in yet. I have all the parts for a DDS and may just go that way from the start. I'm no engineer and will have to figure out how that is done as well.
> Mark
> K3MRK
>
>
> On Nov 24, 2016 4:21 PM, "Thomas Noel tnoel@... [BITX20]" <BITX20@...> wrote: >>?
>> ?
>>
>> What would happen if you added an intentional heater to the enclosure? I'm thinking of something like the flat stick-on pads used to warm reptile tanks, stuck on the underside of the radio enclosure? Thinking a giant version of an oven controlled crystal oscillator?
>>
>> Tom
>> KF7RSF
>>
>> Sent from my iPhone
>>
>> On Nov 24, 2016, at 12:53, Mark Walton k3mrk1@... [BITX20] <BITX20@...> wrote:
>> >>> ?
>>>
>>> I recently received my BitX-40 board. Until I get the enclosure, I only hooked it up for receive. Worked right out of the box. The only issues I've found is the drift is pretty bad even after being powered up for an hour. What should I be looking at to try to improve the stability? I do plan to build a DDS VFO for it over the winter.
>>> The only other issue is the running is very touchy. I have coming a multiturn pot to fix that.
>>> Any ideas on the drift?
>>> Other than that , I'm very happy with the board and look forward to building onto it in the near future.
>>> Thanks
>>> Mark. K3MRK
>
>
> ? ?
|
Thanks Arv, Are they SMD resistors? If so, what size are they? Physical size. I don¡¯t work with SMD enough to tell by looking. I have a multiturn pot on the way. My tuning is super touchy. It takes quite a while to tune a signal in correctly. I literally have to tap the shaft to fine tune. Thanks for the info Mark K3MRK ? ?
toggle quoted message
Show quoted text
From: BITX20@... [mailto:BITX20@...]
Sent: Saturday, November 26, 2016 11:24 PM
To: BITX20@...
Subject: Re: [BITX20] Bitx 40 board.? ? Mark. K3MRK
Either 10K or 100K, or anything in between, will work fine for the tuning pot.? A 10-turn type pot makes tuning much easier if you Resistors for decreasing heat generation are 220 ohms. ? On Sat, Nov 26, 2016 at 8:56 PM, 'Mark W' k3mrk1@... [BITX20] <BITX20@...> wrote: ? No I did not receive any resistors. What size are they? I¡¯ll try to find some. I also noticed that my tuning pot is 10k. The board info on the website says it should be 100k. Which is correct? I have received my enclosure and am almost done installing. Mark K3MRK ? ? ? ? mark,
you must have received a strip of 220 ohm resistors in the pack. if you replace the 100 ohm emitter resistors of the six amps with these, the drift will drastically reduce. the details are on the blog.
- f On 25-Nov-2016 4:58 am, "Mark Walton k3mrk1@... [BITX20]" <BITX20@...> wrote: >?
> ?
>
> It might be worse since there is no enclosure at all. Maybe not really warming up at all. I'm hoping the enclosure itself will have some heat retention. There are some transistors that can be used as heaters. I'll wait till I get the enclosure and see how it is. I realize that this circuit is prone to some drift on warm-up, but I think mine may be excessive. Bad cap? I haven't really started digging in yet. I have all the parts for a DDS and may just go that way from the start. I'm no engineer and will have to figure out how that is done as well.
> Mark
> K3MRK
>
>
> On Nov 24, 2016 4:21 PM, "Thomas Noel tnoel@... [BITX20]" <BITX20@...> wrote: >>?
>> ?
>>
>> What would happen if you added an intentional heater to the enclosure? I'm thinking of something like the flat stick-on pads used to warm reptile tanks, stuck on the underside of the radio enclosure? Thinking a giant version of an oven controlled crystal oscillator?
>>
>> Tom
>> KF7RSF
>>
>> Sent from my iPhone
>>
>> On Nov 24, 2016, at 12:53, Mark Walton k3mrk1@... [BITX20] <BITX20@...> wrote:
>> >>> ?
>>>
>>> I recently received my BitX-40 board. Until I get the enclosure, I only hooked it up for receive. Worked right out of the box. The only issues I've found is the drift is pretty bad even after being powered up for an hour. What should I be looking at to try to improve the stability? I do plan to build a DDS VFO for it over the winter.
>>> The only other issue is the running is very touchy. I have coming a multiturn pot to fix that.
>>> Any ideas on the drift?
>>> Other than that , I'm very happy with the board and look forward to building onto it in the near future.
>>> Thanks
>>> Mark. K3MRK
>
>
> ?
|
we starting including the resistors after the reports of the drift. the pads are big enough for you to solder regular 1/4 watt in place of the smd resistors (in manhattan style). if you do really want them, drop a mail to and they will post a 'pinch' of them to you for free, though the cost of postage is prohibitive but they have agreed to bear it.
- f
On Sun, Nov 27, 2016 at 9:53 AM, Arv Evans arvid.evans@... [BITX20] <BITX20@...> wrote:
?
Mark. K3MRK
Either 10K or 100K, or anything in between, will work fine for the
tuning pot.? A 10-turn type pot makes tuning much easier if you
have one available.?
Resistors for decreasing heat generation are 220 ohms.
Arv? K7HKL
_._
|
Mark. K3MRK
Either 10K or 100K, or anything in between, will work fine for the
tuning pot.? A 10-turn type pot makes tuning much easier if you
have one available.?
Resistors for decreasing heat generation are 220 ohms.
Arv? K7HKL
_._
On Sat, Nov 26, 2016 at 8:56 PM, 'Mark W' k3mrk1@... [BITX20] <BITX20@...> wrote:
?
No I did not receive any resistors. What size are they? I¡¯ll try to find some. I also noticed that my tuning pot is 10k. The board info on the website says it should be 100k. Which is correct? I have received my enclosure and am almost done installing. Mark K3MRK ? ? ? ? mark,
you must have received a strip of 220 ohm resistors in the pack. if you replace the 100 ohm emitter resistors of the six amps with these, the drift will drastically reduce. the details are on the blog.
- f On 25-Nov-2016 4:58 am, "Mark Walton k3mrk1@... [BITX20]" <BITX20@...> wrote: >?
> ?
>
> It might be worse since there is no enclosure at all. Maybe not really warming up at all. I'm hoping the enclosure itself will have some heat retention. There are some transistors that can be used as heaters. I'll wait till I get the enclosure and see how it is. I realize that this circuit is prone to some drift on warm-up, but I think mine may be excessive. Bad cap? I haven't really started digging in yet. I have all the parts for a DDS and may just go that way from the start. I'm no engineer and will have to figure out how that is done as well.
> Mark
> K3MRK
>
>
> On Nov 24, 2016 4:21 PM, "Thomas Noel tnoel@... [BITX20]" <BITX20@...> wrote: >>?
>> ?
>>
>> What would happen if you added an intentional heater to the enclosure? I'm thinking of something like the flat stick-on pads used to warm reptile tanks, stuck on the underside of the radio enclosure? Thinking a giant version of an oven controlled crystal oscillator?
>>
>> Tom
>> KF7RSF
>>
>> Sent from my iPhone
>>
>> On Nov 24, 2016, at 12:53, Mark Walton k3mrk1@... [BITX20] <BITX20@...> wrote:
>> >>> ?
>>>
>>> I recently received my BitX-40 board. Until I get the enclosure, I only hooked it up for receive. Worked right out of the box. The only issues I've found is the drift is pretty bad even after being powered up for an hour. What should I be looking at to try to improve the stability? I do plan to build a DDS VFO for it over the winter.
>>> The only other issue is the running is very touchy. I have coming a multiturn pot to fix that.
>>> Any ideas on the drift?
>>> Other than that , I'm very happy with the board and look forward to building onto it in the near future.
>>> Thanks
>>> Mark. K3MRK
>
>
>
|
No I did not receive any resistors. What size are they? I¡¯ll try to find some. I also noticed that my tuning pot is 10k. The board info on the website says it should be 100k. Which is correct? I have received my enclosure and am almost done installing. Mark K3MRK ? ?
toggle quoted message
Show quoted text
From: BITX20@... [mailto:BITX20@...]
Sent: Thursday, November 24, 2016 8:48 PM
To: BITX20@...
Subject: Re: [BITX20] Bitx 40 board.? ? mark,
you must have received a strip of 220 ohm resistors in the pack. if you replace the 100 ohm emitter resistors of the six amps with these, the drift will drastically reduce. the details are on the blog.
- f On 25-Nov-2016 4:58 am, "Mark Walton k3mrk1@... [BITX20]" <BITX20@...> wrote: >?
> ?
>
> It might be worse since there is no enclosure at all. Maybe not really warming up at all. I'm hoping the enclosure itself will have some heat retention. There are some transistors that can be used as heaters. I'll wait till I get the enclosure and see how it is. I realize that this circuit is prone to some drift on warm-up, but I think mine may be excessive. Bad cap? I haven't really started digging in yet. I have all the parts for a DDS and may just go that way from the start. I'm no engineer and will have to figure out how that is done as well.
> Mark
> K3MRK
>
>
> On Nov 24, 2016 4:21 PM, "Thomas Noel tnoel@... [BITX20]" <BITX20@...> wrote: >>?
>> ?
>>
>> What would happen if you added an intentional heater to the enclosure? I'm thinking of something like the flat stick-on pads used to warm reptile tanks, stuck on the underside of the radio enclosure? Thinking a giant version of an oven controlled crystal oscillator?
>>
>> Tom
>> KF7RSF
>>
>> Sent from my iPhone
>>
>> On Nov 24, 2016, at 12:53, Mark Walton k3mrk1@... [BITX20] <BITX20@...> wrote:
>> >>> ?
>>>
>>> I recently received my BitX-40 board. Until I get the enclosure, I only hooked it up for receive. Worked right out of the box. The only issues I've found is the drift is pretty bad even after being powered up for an hour. What should I be looking at to try to improve the stability? I do plan to build a DDS VFO for it over the winter.
>>> The only other issue is the running is very touchy. I have coming a multiturn pot to fix that.
>>> Any ideas on the drift?
>>> Other than that , I'm very happy with the board and look forward to building onto it in the near future.
>>> Thanks
>>> Mark. K3MRK
>
>
>
|
Thanks!? That made the rx spot on. ?I'll check tx tomorrow. ?
I also noticed that my DDS has a rit set. I turned that off. ?That should help.?
Thanks for a making the board available. This has been a fun project.?
toggle quoted message
Show quoted text
On Nov 26, 2016, at 9:00 PM, Ashhar Farhan farhanbox@... [BITX20] < BITX20@...> wrote:
?
bill,
i should permanently document this somewhere. the LSB pass band of a ladder filter is invariably below the marked frequency. so, if you set the dds for exactly 12 mhz, it won't be precise.
the most accurate way is to measure the bfo frequency on your board. the rule of thumv is to set the IF frequency to 11.99850 Mhz
- f
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Joel Caulkins/N6ALT
Todd K7TFC