Date   
Manual RF gain control

John T P
 

Dear OM Farhan,

Bitx RX works very good. Only issue when strong signals coming there is no way to attenuate it.
I suggest to add a pot, Voltage controlled power supply to RX side of RF Amp(Q1) & IF AMP(Q2) by using a 10K lin pot.
I think that should able to reduce the front end gain for strong signals very easily at low cost and effort.

Regards

VU2JON
JOHN T.P.
Tharayil House
Sree Ayyappa Road
Kuriachira
Thrissur-680 006 
Mobile: +91-960-5000-445 / 88-07-007-933

Re: Output Power is less than 3W

unnikrish7997@...
 

tried with  a dummy load. thus got the output power

Re: Output Power is less than 3W

Soundararajan Ra.
 

Same problem with me also RFvoltage at base of pre  driver transistor 200 mv in defective board where us working one 500 mv .



On May 3, 2017 9:06 PM, "Steve Greer" <km4ous@...> wrote:
Let's start with the basics.  Power supply voltage and amperage.  Type of antenna?  Have you tried into a 50 ohm dummy load?  All hams should have one.  Check into a dummy load and report back.

On Wed, May 3, 2017 at 11:33 AM, <unnikrish7997@...> wrote:

hello dear people,

My output power of my BitX 40 is less than 3W while checking an SWR meter. I preset to control volume is set to its maximum. One of my friend have the same problem.

Waiting for the answers.

regards 

Unni Krishnan 



Re: Output Power is less than 3W

Steve Greer
 

Let's start with the basics.  Power supply voltage and amperage.  Type of antenna?  Have you tried into a 50 ohm dummy load?  All hams should have one.  Check into a dummy load and report back.

On Wed, May 3, 2017 at 11:33 AM, <unnikrish7997@...> wrote:

hello dear people,

My output power of my BitX 40 is less than 3W while checking an SWR meter. I preset to control volume is set to its maximum. One of my friend have the same problem.

Waiting for the answers.

regards 

Unni Krishnan 


Re: Output Power is less than 3W

unnikrish7997@...
 

Please read preset to control voltage. 

Output Power is less than 3W

unnikrish7997@...
 

hello dear people,

My output power of my BitX 40 is less than 3W while checking an SWR meter. I preset to control volume is set to its maximum. One of my friend have the same problem.

Waiting for the answers.

regards 

Unni Krishnan 

Re: Baofeng microphone mod for BITX

amer1337@...
 

I tried using the baofeng electret mic, jumping leads to go right to the consensor so the ptt and mic dont share the same ground and if i whistle into the mic it puts power out but not while talking.

Re: Book by Jack and C Questions

Jack Purdum <econjack@...>
 

Hi Roy:

That's sincerely appreciated, Roy, but not necessary. Instead, give an extra dollar to your favorite charity, or the next time you're at a bar, buy a drink and raise a toast to K&R and Farhan. And trust me, I'm getting far more out of this than I'm putting in...this is really fun stuff to me!

Jack, W8TEE


From: Roy Appleton <twelveoclockhigh@...>
To: BITX20@groups.io
Sent: Wednesday, May 3, 2017 8:39 AM
Subject: Re: [BITX20] Book by Jack and C Questions

Jack, for those people that may have a copy of your book and would like to make a direct contribution to you for your unrealized financial benefits, do you have a PayPal account we contribute to? I'm serious. :-))

Roy
WA0YMH

On May 2, 2017 9:47 PM, "Jack Purdum via Groups.Io" <econjack=yahoo.com@groups.io> wrote:
Michael:

First, thanks for buying the book. I know there are a ton of illegal sites out there where you can download it for free. 

Second, since you have gone through the trouble of buying it, please read it from page 1 to the end...don't skip around. I have some different ways of teaching programming and touch on things like lvalues, rvalues, symbol tables, memory management and some other stuff that is usually considered a tad bit strange for an intro book. However, I've taught C since the early 1980's and I know what works and what doesn't work...for most people. The result is that I've developed some strange teaching stuff, like the Right-Left Rule, The Bucket Analogy, The Five Programming Steps, the N - 1 Rule, and some others, but they work. If you can stick with me through the first four chapters, some often scary stuff (e.g., pointers) becomes duck's soup because you've been properly prepared for it. When you're done, let me know what you think...good or bad. 

As to being "over your head"...nonsense! Anyone who is smart enough to get a radio license is more than smart enough to learn how to program. Enjoy the trip!

Jack, W8TEE



From: Michael Hagen <motdog@...>
To: BITX20@groups.io
Sent: Tuesday, May 2, 2017 5:23 PM
Subject: Re: [BITX20] Book by Jack and C Questions

Thanks for you and Jacks help on this.  I am convinced it is over my head.

I  saw these suffix items added to a numeric the first time in my old
life making a Si5351 Generator.  I just don't know why.

I have not seen it in other programming in the past.  So I just made
sure my variables were big (UL).  I just put the numbers in without SUFFIX?

So since I have ALWAYS seen a variable introduced with a type in front
of it, I was really perplexed about what seems redundant info added.

I realize breaking the rules for a variable such as you mentioned  (left
= right) would be problems.

I always define the variable with a type.  I understand if you get away
without it, probably some type of INT will be assigned by the compiler?

I guess I would have to know what the compiler did special when it sees
these on the end of a number.
I also assume the programmer always knows what his type is so as not to
cause errors.

Too bad I am retired and old, I would be working somewhere making money
and my brain would not be strained so much.
I would not have time to get so confused!

Thanks,
Can't wait for Jack's book!  Amazon FREE Shipping!
Mike, WA6ISP


On 5/2/2017 1:52 PM, Mark Pilant wrote:
> Hi Mike.
>
> > "unsigned long bfo_freq = 11998000UL;"
>
> Now for some compiler stuff :-)
>
> Compilers "generally" (dangerous word) have a "left side" and "right
> side"
> for an assignment ("=") statement.  As such, constants such as
> 11998000 can
> present a problem.
>
> Does is get promoted if the left side has a smaller allocation than the
> right side?  Such as a 16-bit unsigned int being assigned with the value
> 4912 which is the 32-bit value (0xB71330) truncated to 16-bits (0x1330).
> Going to a larger allocation is not usually an issue as nothing gets
> truncated.
>
> In an effort to make this unambiguous and perfectly clear to the
> programmer
> as well as the compiler, it is usually considered good practice to add
> the
> appropriate suffix to a constant value.  Most often, it it only on large
> constants, but you will sometimes see a coding standard which
> specifies the
> appropriate suffix to be added to any constant value.
>
> And what Jack said :-)  (Especially with signed / unsigned.)
>
> 73
>
> - Mark  N1VQW
>
>
>
>








Re: BITX QSO Night, Sunday, May 7, 9pm Local Time, 7.179 MHz

KC8WBK
 

I agree that we should try to use the best time for propagation.  However noise levels and propagation vary so much, the best strategy for QRP is always going to be jump in when conditions are good.

Let's see if the QSO night becomes popular, if so, we might add local sunset to the schedule.

Are the best conditions just after sunset?  From watching my WSPR beacon, I was spotted by stations to the east before dark, then later in the evening had long distance spots to the west.


Re: Book by Jack and C Questions

Michael Hagen
 

On 5/3/2017 5:47 AM, walter berkley wrote:
Could anyone mentioning a book ...PLEASE provide the name of the book...it would be very helpful !

Thank you walt

Re: BITX QSO Night, Sunday, May 7, 9pm Local Time, 7.179 MHz

Bob KV4PC
 

I think this is a great idea, and I intend to give it a try now and then. But being a QRP activity, we might want to reach for the maximum advantage.

Selecting a time near dusk in every time zone would add Greyline enhancement to the activity. My suggestion would be to try calling at local sundown, what ever the season might be. That 9 PM time will be good later this spring, but where I am located dusk is about 7:30 PM (CDT) right now.

Speaking as a JT Op with WAS on several bands, when I picked up Alaska and Hawaii on 80-20m was just as the terminator crossed the stations at those locations (usually in November or December). Thats also when I got JA, VK, and ZL.

Re: Book by Jack and C Questions

walter berkley
 

Could anyone mentioning a book ...PLEASE provide the name of the book...it would be very helpful !

      Thank you        walt

On May 3, 2017, at 8:38 AM, Roy Appleton <twelveoclockhigh@...> wrote:

Jack, for those people that may have a copy of your book and would like to make a direct contribution to you for your unrealized financial benefits, do you have a PayPal account we contribute to? I'm serious. :-))

Roy
WA0YMH

On May 2, 2017 9:47 PM, "Jack Purdum via Groups.Io" <econjack=yahoo.com@groups.io> wrote:
Michael:

First, thanks for buying the book. I know there are a ton of illegal sites out there where you can download it for free. 

Second, since you have gone through the trouble of buying it, please read it from page 1 to the end...don't skip around. I have some different ways of teaching programming and touch on things like lvalues, rvalues, symbol tables, memory management and some other stuff that is usually considered a tad bit strange for an intro book. However, I've taught C since the early 1980's and I know what works and what doesn't work...for most people. The result is that I've developed some strange teaching stuff, like the Right-Left Rule, The Bucket Analogy, The Five Programming Steps, the N - 1 Rule, and some others, but they work. If you can stick with me through the first four chapters, some often scary stuff (e.g., pointers) becomes duck's soup because you've been properly prepared for it. When you're done, let me know what you think...good or bad. 

As to being "over your head"...nonsense! Anyone who is smart enough to get a radio license is more than smart enough to learn how to program. Enjoy the trip!

Jack, W8TEE



From: Michael Hagen <motdog@...>
To: BITX20@groups.io
Sent: Tuesday, May 2, 2017 5:23 PM
Subject: Re: [BITX20] Book by Jack and C Questions

Thanks for you and Jacks help on this.  I am convinced it is over my head.

I  saw these suffix items added to a numeric the first time in my old
life making a Si5351 Generator.  I just don't know why.

I have not seen it in other programming in the past.  So I just made
sure my variables were big (UL).  I just put the numbers in without SUFFIX?

So since I have ALWAYS seen a variable introduced with a type in front
of it, I was really perplexed about what seems redundant info added.

I realize breaking the rules for a variable such as you mentioned  (left
= right) would be problems.

I always define the variable with a type.  I understand if you get away
without it, probably some type of INT will be assigned by the compiler?

I guess I would have to know what the compiler did special when it sees
these on the end of a number.
I also assume the programmer always knows what his type is so as not to
cause errors.

Too bad I am retired and old, I would be working somewhere making money
and my brain would not be strained so much.
I would not have time to get so confused!

Thanks,
Can't wait for Jack's book!  Amazon FREE Shipping!
Mike, WA6ISP


On 5/2/2017 1:52 PM, Mark Pilant wrote:
> Hi Mike.
>
> > "unsigned long bfo_freq = 11998000UL;"
>
> Now for some compiler stuff :-)
>
> Compilers "generally" (dangerous word) have a "left side" and "right
> side"
> for an assignment ("=") statement.  As such, constants such as
> 11998000 can
> present a problem.
>
> Does is get promoted if the left side has a smaller allocation than the
> right side?  Such as a 16-bit unsigned int being assigned with the value
> 4912 which is the 32-bit value (0xB71330) truncated to 16-bits (0x1330).
> Going to a larger allocation is not usually an issue as nothing gets
> truncated.
>
> In an effort to make this unambiguous and perfectly clear to the
> programmer
> as well as the compiler, it is usually considered good practice to add
> the
> appropriate suffix to a constant value.  Most often, it it only on large
> constants, but you will sometimes see a coding standard which
> specifies the
> appropriate suffix to be added to any constant value.
>
> And what Jack said :-)  (Especially with signed / unsigned.)
>
> 73
>
> - Mark  N1VQW
>
>
>
>










Re: Book by Jack and C Questions

Roy Appleton
 

Jack, for those people that may have a copy of your book and would like to make a direct contribution to you for your unrealized financial benefits, do you have a PayPal account we contribute to? I'm serious. :-))

Roy
WA0YMH

On May 2, 2017 9:47 PM, "Jack Purdum via Groups.Io" <econjack=yahoo.com@groups.io> wrote:
Michael:

First, thanks for buying the book. I know there are a ton of illegal sites out there where you can download it for free. 

Second, since you have gone through the trouble of buying it, please read it from page 1 to the end...don't skip around. I have some different ways of teaching programming and touch on things like lvalues, rvalues, symbol tables, memory management and some other stuff that is usually considered a tad bit strange for an intro book. However, I've taught C since the early 1980's and I know what works and what doesn't work...for most people. The result is that I've developed some strange teaching stuff, like the Right-Left Rule, The Bucket Analogy, The Five Programming Steps, the N - 1 Rule, and some others, but they work. If you can stick with me through the first four chapters, some often scary stuff (e.g., pointers) becomes duck's soup because you've been properly prepared for it. When you're done, let me know what you think...good or bad. 

As to being "over your head"...nonsense! Anyone who is smart enough to get a radio license is more than smart enough to learn how to program. Enjoy the trip!

Jack, W8TEE



From: Michael Hagen <motdog@...>
To: BITX20@groups.io
Sent: Tuesday, May 2, 2017 5:23 PM
Subject: Re: [BITX20] Book by Jack and C Questions

Thanks for you and Jacks help on this.  I am convinced it is over my head.

I  saw these suffix items added to a numeric the first time in my old
life making a Si5351 Generator.  I just don't know why.

I have not seen it in other programming in the past.  So I just made
sure my variables were big (UL).  I just put the numbers in without SUFFIX?

So since I have ALWAYS seen a variable introduced with a type in front
of it, I was really perplexed about what seems redundant info added.

I realize breaking the rules for a variable such as you mentioned  (left
= right) would be problems.

I always define the variable with a type.  I understand if you get away
without it, probably some type of INT will be assigned by the compiler?

I guess I would have to know what the compiler did special when it sees
these on the end of a number.
I also assume the programmer always knows what his type is so as not to
cause errors.

Too bad I am retired and old, I would be working somewhere making money
and my brain would not be strained so much.
I would not have time to get so confused!

Thanks,
Can't wait for Jack's book!  Amazon FREE Shipping!
Mike, WA6ISP


On 5/2/2017 1:52 PM, Mark Pilant wrote:
> Hi Mike.
>
> > "unsigned long bfo_freq = 11998000UL;"
>
> Now for some compiler stuff :-)
>
> Compilers "generally" (dangerous word) have a "left side" and "right
> side"
> for an assignment ("=") statement.  As such, constants such as
> 11998000 can
> present a problem.
>
> Does is get promoted if the left side has a smaller allocation than the
> right side?  Such as a 16-bit unsigned int being assigned with the value
> 4912 which is the 32-bit value (0xB71330) truncated to 16-bits (0x1330).
> Going to a larger allocation is not usually an issue as nothing gets
> truncated.
>
> In an effort to make this unambiguous and perfectly clear to the
> programmer
> as well as the compiler, it is usually considered good practice to add
> the
> appropriate suffix to a constant value.  Most often, it it only on large
> constants, but you will sometimes see a coding standard which
> specifies the
> appropriate suffix to be added to any constant value.
>
> And what Jack said :-)  (Especially with signed / unsigned.)
>
> 73
>
> - Mark  N1VQW
>
>
>
>






Re: Armored BitX40.

Gil F4WBY <gil@...>
 

Great, certainly better than nothing! I cringe every time I take my KX2
outside and it might rain... Hopefully I will be able to write the code
to drive the DDS module from the keypad...

Gil F4WBY.

peatmoss - ki6ssi wrote:

Same here, I'm putting the bitx in a Outdoor products waterproof box
with o ring. When you flip open the lid the panel has all connectors,
lcd and knobs facing up. This way it will be 100% waterproof when
closed. The drawback is its not waterproof when operating. I plan to use
it backpacking and if its raining I'll use it from inside the tent.

Re: VFO

F4HKA Jeremy
 

Hello,

I have found that document whiles ago describing how turining hte bitx20 to à 40m band usage.

73!
Jeremy F4HKA

On Wed, May 3, 2017 at 8:44 AM, John Backo via Groups.Io <iam74@...> wrote:
Sorry, guys.

The above calculation for the 20m rig assumes the same IF. If they are different,
the L value must be calculated for the new VFO coverage,
using  f^2  = 25330/ LC where f is in MHz, L in uH, and C in pF.

The same general considerations apply.

john
AD5YE




Re: BITX QSO Night, Sunday, May 7, 9pm Local Time, 7.179 MHz

Chris Viningre
 

This sounds like a fun event. I´ll try to remember to give it a try. 

Chris

WS5B

Re: complaint of PCB

Johnson
 

I first grounded the heatsink. Then i could understand my problem. Now it is not grounded. But IRF 510 is not available here. I can use only 530. what should i do? It stil burns

On Wed, May 3, 2017 at 1:02 PM, Ryan Flowers <geocrasher@...> wrote:
One person reported that the heat sink was grounded out on the PCB and they had to fix that before the problem was solved. I suggest you check that. The schematic is available on hfsigs.com, so check the connections and start tracing the circuit between r136 and the IFR510. Best of luck to you!
--
Ryan Flowers W7RLF

miscdotgeek.com

http://miscdotgeek.com/unofficial-bitx40-faq


Re: complaint of PCB

Ryan Flowers
 

One person reported that the heat sink was grounded out on the PCB and they had to fix that before the problem was solved. I suggest you check that. The schematic is available on hfsigs.com, so check the connections and start tracing the circuit between r136 and the IFR510. Best of luck to you!
--
Ryan Flowers W7RLF

miscdotgeek.com

http://miscdotgeek.com/unofficial-bitx40-faq

Re: VFO

John Backo
 

Sorry, guys.

The above calculation for the 20m rig assumes the same IF. If they are different,
the L value must be calculated for the new VFO coverage,
using f^2 = 25330/ LC where f is in MHz, L in uH, and C in pF.

The same general considerations apply.

john
AD5YE

Re: VFO

John Backo
 

Jorge:

200 pF. is too large a range for a 300 KHz VFO.

Assuming 200 pF as your capacitor and about 30 pF. stray capacitance,
The L value for 2.7 MHz is ~15 uH, as noted.

But if your capacitor has a minium value of about 20 pF, the same
15 uH will give you a high frequency of about 6.5 MHz.

You should use a much lower variable cap for that range, maybe 60 pF.

Better yet is to use a varicap and ~12v supply to the capacitor. That will
give you the range you want with less fuss (and probably much more stability).
Search for a Colpitts varicap oscillator for the details. It will involve using a
potentiometer. A 10-turn one is best, or even two for tuning and "bandspread";
a 10-turn main and one-turn fine tune pot.

On the other hand, if you are already using a 200 pF capacitor on 20m, a proper
inductance for 40m would be one about twice the value of the one you are already using.
Everything else should work out to be about the same. Of course, you will also need to change
the PBF and LPF as well. use the same procedure -- double the present 20m values for 40m.
That will put you in the ballpark.

john
AD5YE