voltage reading for DSB 20 meter version


tem494@...
 

I just put together the 40-meter version of DSB and measured about a watt and a half. 
I then decided to pull my 20-meter version which has been sitting for a while I then checked the output on it wasn't getting .04 watts.
I tried to find any information on the message page for voltages for troubleshooting but could find none. If anyone has information to help troubleshoot the 
the twenty-meter version I would be appreciative to get that information.


Jim Allyn - N7JA
 

By DSB I am guessing you mean the D4D  -  double sideband for digital mode?  Since you have both the 20 meter version and the 40 meter version, you could start by measuring voltages in the functioning 40 meter radio and compare the voltage readings in the non-functioning 20 meter version.  As far as I know they are identical except for the component values in the low pass filter at the output and a few other frequency determining components.  Beyond that, you're probably looking for something in the Q3/Q4 circuitry, so I would start comparing voltages there.  Off the top of my head, I'll say you should have about .7 volts between base and emitter on both Q3 and Q4, and you should have 12 volts at the collector of Q4.


tem494@...
 

Thank you and yes it should have been the D4D.
I Will work on it tomorrow when I am a little fresher and maybe a little better attitude.
tom

On Sat, Feb 20, 2021 at 5:13 PM Jim Allyn - N7JA <jim@...> wrote:
By DSB I am guessing you mean the D4D  -  double sideband for digital mode?  Since you have both the 20 meter version and the 40 meter version, you could start by measuring voltages in the functioning 40 meter radio and compare the voltage readings in the non-functioning 20 meter version.  As far as I know they are identical except for the component values in the low pass filter at the output and a few other frequency determining components.  Beyond that, you're probably looking for something in the Q3/Q4 circuitry, so I would start comparing voltages there.  Off the top of my head, I'll say you should have about .7 volts between base and emitter on both Q3 and Q4, and you should have 12 volts at the collector of Q4.


Carl Weiberg
 

Hi all,
I just completed my 20m build and after countless CQ’ and checking PSKreporter I don’t believe the output of the transmitter to be anywhere near a watt. I checked for signal on my main HF receiver, and there is a signal. PSKreporter confirmed my HF rig reception as well. However it was very weak. I am running a EFHF with perfect SWR as well. I also have a 40m unit, and tested that last night and PSKreported shows receptions across out west in the evening, so the 40 has some output.

I do not have a qrp meter. Is there any way to determine true output on these units? The receivers work ok, not outstanding but enough to get reasonable reception. I am quite pleased. 

I run other QRP rigs, but nothing sub 1 watt.

Thanks!
Carl

iPhone Aloha

On Feb 20, 2021, at 5:48 PM, tem494@... wrote:


Thank you and yes it should have been the D4D.
I Will work on it tomorrow when I am a little fresher and maybe a little better attitude.
tom

On Sat, Feb 20, 2021 at 5:13 PM Jim Allyn - N7JA <jim@...> wrote:
By DSB I am guessing you mean the D4D  -  double sideband for digital mode?  Since you have both the 20 meter version and the 40 meter version, you could start by measuring voltages in the functioning 40 meter radio and compare the voltage readings in the non-functioning 20 meter version.  As far as I know they are identical except for the component values in the low pass filter at the output and a few other frequency determining components.  Beyond that, you're probably looking for something in the Q3/Q4 circuitry, so I would start comparing voltages there.  Off the top of my head, I'll say you should have about .7 volts between base and emitter on both Q3 and Q4, and you should have 12 volts at the collector of Q4.


--
CW


Nigel Young
 

Carl, you won't get anywhere near a Watt on 20m, on 40 you will but not on 20. I'm surprised you got nothing on reporter though. Maybe try again tonight. These units are just toys really but they work, I've had a lot of fun with mine. But trying for one what on 20 with a BD139 is impossible in my opinion and I would be very happy with half that on 20. But that's half the fun.

Nigel ZL1NAY

Kia Kaha


On Mon., 22 Feb. 2021, 5:15 am Carl Weiberg via groups.io, <carlweiberg=aol.com@groups.io> wrote:
Hi all,
I just completed my 20m build and after countless CQ’ and checking PSKreporter I don’t believe the output of the transmitter to be anywhere near a watt. I checked for signal on my main HF receiver, and there is a signal. PSKreporter confirmed my HF rig reception as well. However it was very weak. I am running a EFHF with perfect SWR as well. I also have a 40m unit, and tested that last night and PSKreported shows receptions across out west in the evening, so the 40 has some output.

I do not have a qrp meter. Is there any way to determine true output on these units? The receivers work ok, not outstanding but enough to get reasonable reception. I am quite pleased. 

I run other QRP rigs, but nothing sub 1 watt.

Thanks!
Carl

iPhone Aloha

On Feb 20, 2021, at 5:48 PM, tem494@... wrote:


Thank you and yes it should have been the D4D.
I Will work on it tomorrow when I am a little fresher and maybe a little better attitude.
tom

On Sat, Feb 20, 2021 at 5:13 PM Jim Allyn - N7JA <jim@...> wrote:
By DSB I am guessing you mean the D4D  -  double sideband for digital mode?  Since you have both the 20 meter version and the 40 meter version, you could start by measuring voltages in the functioning 40 meter radio and compare the voltage readings in the non-functioning 20 meter version.  As far as I know they are identical except for the component values in the low pass filter at the output and a few other frequency determining components.  Beyond that, you're probably looking for something in the Q3/Q4 circuitry, so I would start comparing voltages there.  Off the top of my head, I'll say you should have about .7 volts between base and emitter on both Q3 and Q4, and you should have 12 volts at the collector of Q4.


--
CW


Carl Weiberg
 

Hi Nigel,
Yes, I was thinking the 20m would put out somewhere around 500mw. My antenna on 20 meters with WSPR gets spot reports all over the US as well as Africa, South America on 1 watt. So antenna is not the issue.

All QRP is fun. On the 40 meter a few minutes after I finished it, I sent a CQ and got a QSO in a couple minutes. That was super exciting. So I assumed on 20 in the day on a weekend the same results. After many CQ’s and no reply or PSKreporter results I assumed the rig had an issue. But, I get a weak signal on my other receiver so I know some power is going out.

I am thinking of buying a qrp warmer from MFJ, but was hoping to find some other method to determine output.

Thanks,
Carl
K0CFW

iPhone Aloha

On Feb 21, 2021, at 12:14 PM, Nigel Young <multilec@...> wrote:


Carl, you won't get anywhere near a Watt on 20m, on 40 you will but not on 20. I'm surprised you got nothing on reporter though. Maybe try again tonight. These units are just toys really but they work, I've had a lot of fun with mine. But trying for one what on 20 with a BD139 is impossible in my opinion and I would be very happy with half that on 20. But that's half the fun.

Nigel ZL1NAY

Kia Kaha

On Mon., 22 Feb. 2021, 5:15 am Carl Weiberg via groups.io, <carlweiberg=aol.com@groups.io> wrote:
Hi all,
I just completed my 20m build and after countless CQ’ and checking PSKreporter I don’t believe the output of the transmitter to be anywhere near a watt. I checked for signal on my main HF receiver, and there is a signal. PSKreporter confirmed my HF rig reception as well. However it was very weak. I am running a EFHF with perfect SWR as well. I also have a 40m unit, and tested that last night and PSKreported shows receptions across out west in the evening, so the 40 has some output.

I do not have a qrp meter. Is there any way to determine true output on these units? The receivers work ok, not outstanding but enough to get reasonable reception. I am quite pleased. 

I run other QRP rigs, but nothing sub 1 watt.

Thanks!
Carl

iPhone Aloha

On Feb 20, 2021, at 5:48 PM, tem494@... wrote:


Thank you and yes it should have been the D4D.
I Will work on it tomorrow when I am a little fresher and maybe a little better attitude.
tom

On Sat, Feb 20, 2021 at 5:13 PM Jim Allyn - N7JA <jim@...> wrote:
By DSB I am guessing you mean the D4D  -  double sideband for digital mode?  Since you have both the 20 meter version and the 40 meter version, you could start by measuring voltages in the functioning 40 meter radio and compare the voltage readings in the non-functioning 20 meter version.  As far as I know they are identical except for the component values in the low pass filter at the output and a few other frequency determining components.  Beyond that, you're probably looking for something in the Q3/Q4 circuitry, so I would start comparing voltages there.  Off the top of my head, I'll say you should have about .7 volts between base and emitter on both Q3 and Q4, and you should have 12 volts at the collector of Q4.


--
CW


--
CW


tem494@...
 

Carl,Nigel
I measured my output on the 20 meter version with  a 4sqrp dummy load with tap to measure voltage 20 meter showed 1.4 volts squaring the voltage divided 100 gave me about .04 watts. Before putting it away I remember close to a watt output.
After finishing the 40 meter unit I measured about 13 volts at the dummy load.


On Sunday, February 21, 2021, Carl Weiberg via groups.io <carlweiberg=aol.com@groups.io> wrote:
Hi Nigel,
Yes, I was thinking the 20m would put out somewhere around 500mw. My antenna on 20 meters with WSPR gets spot reports all over the US as well as Africa, South America on 1 watt. So antenna is not the issue.

All QRP is fun. On the 40 meter a few minutes after I finished it, I sent a CQ and got a QSO in a couple minutes. That was super exciting. So I assumed on 20 in the day on a weekend the same results. After many CQ’s and no reply or PSKreporter results I assumed the rig had an issue. But, I get a weak signal on my other receiver so I know some power is going out.

I am thinking of buying a qrp warmer from MFJ, but was hoping to find some other method to determine output.

Thanks,
Carl
K0CFW

iPhone Aloha

On Feb 21, 2021, at 12:14 PM, Nigel Young <multilec@...> wrote:


Carl, you won't get anywhere near a Watt on 20m, on 40 you will but not on 20. I'm surprised you got nothing on reporter though. Maybe try again tonight. These units are just toys really but they work, I've had a lot of fun with mine. But trying for one what on 20 with a BD139 is impossible in my opinion and I would be very happy with half that on 20. But that's half the fun.

Nigel ZL1NAY

Kia Kaha

On Mon., 22 Feb. 2021, 5:15 am Carl Weiberg via groups.io, <carlweiberg=aol.com@groups.io> wrote:
Hi all,
I just completed my 20m build and after countless CQ’ and checking PSKreporter I don’t believe the output of the transmitter to be anywhere near a watt. I checked for signal on my main HF receiver, and there is a signal. PSKreporter confirmed my HF rig reception as well. However it was very weak. I am running a EFHF with perfect SWR as well. I also have a 40m unit, and tested that last night and PSKreported shows receptions across out west in the evening, so the 40 has some output.

I do not have a qrp meter. Is there any way to determine true output on these units? The receivers work ok, not outstanding but enough to get reasonable reception. I am quite pleased. 

I run other QRP rigs, but nothing sub 1 watt.

Thanks!
Carl

iPhone Aloha

On Feb 20, 2021, at 5:48 PM, tem494@... wrote:


Thank you and yes it should have been the D4D.
I Will work on it tomorrow when I am a little fresher and maybe a little better attitude.
tom

On Sat, Feb 20, 2021 at 5:13 PM Jim Allyn - N7JA <jim@...> wrote:
By DSB I am guessing you mean the D4D  -  double sideband for digital mode?  Since you have both the 20 meter version and the 40 meter version, you could start by measuring voltages in the functioning 40 meter radio and compare the voltage readings in the non-functioning 20 meter version.  As far as I know they are identical except for the component values in the low pass filter at the output and a few other frequency determining components.  Beyond that, you're probably looking for something in the Q3/Q4 circuitry, so I would start comparing voltages there.  Off the top of my head, I'll say you should have about .7 volts between base and emitter on both Q3 and Q4, and you should have 12 volts at the collector of Q4.


--
CW


--
CW


Nigel Young
 

Its hard Carl at those levels to measure accurate and I don't know of any commercial cheap gear that can do it unless you build it yourself. Well, it sounds like all is not lost yet. Remember the BD139 is only capable of 1 watt max in a RF situation, you could pair a couple up to increase the OP but then your sort of defeating the purpose of the kit. With mine on 40 from NZ I worked the Caribbean and well into the states but 20 is another matter, signals were well down and I managed South Asia from here with a simple dipole. Adam made great toy and it's been a lot of fun to see where you can be heard, and is ideal for field day trips as an extra bonus. I enjoyed the build and everything is there, take it for what it is and enjoy it. Keep trying on 20 though, it will come through.

Nigel ZL1NAY

Kia Kaha


On Mon., 22 Feb. 2021, 8:39 am Carl Weiberg via groups.io, <carlweiberg=aol.com@groups.io> wrote:
Hi Nigel,
Yes, I was thinking the 20m would put out somewhere around 500mw. My antenna on 20 meters with WSPR gets spot reports all over the US as well as Africa, South America on 1 watt. So antenna is not the issue.

All QRP is fun. On the 40 meter a few minutes after I finished it, I sent a CQ and got a QSO in a couple minutes. That was super exciting. So I assumed on 20 in the day on a weekend the same results. After many CQ’s and no reply or PSKreporter results I assumed the rig had an issue. But, I get a weak signal on my other receiver so I know some power is going out.

I am thinking of buying a qrp warmer from MFJ, but was hoping to find some other method to determine output.

Thanks,
Carl
K0CFW

iPhone Aloha

On Feb 21, 2021, at 12:14 PM, Nigel Young <multilec@...> wrote:


Carl, you won't get anywhere near a Watt on 20m, on 40 you will but not on 20. I'm surprised you got nothing on reporter though. Maybe try again tonight. These units are just toys really but they work, I've had a lot of fun with mine. But trying for one what on 20 with a BD139 is impossible in my opinion and I would be very happy with half that on 20. But that's half the fun.

Nigel ZL1NAY

Kia Kaha

On Mon., 22 Feb. 2021, 5:15 am Carl Weiberg via groups.io, <carlweiberg=aol.com@groups.io> wrote:
Hi all,
I just completed my 20m build and after countless CQ’ and checking PSKreporter I don’t believe the output of the transmitter to be anywhere near a watt. I checked for signal on my main HF receiver, and there is a signal. PSKreporter confirmed my HF rig reception as well. However it was very weak. I am running a EFHF with perfect SWR as well. I also have a 40m unit, and tested that last night and PSKreported shows receptions across out west in the evening, so the 40 has some output.

I do not have a qrp meter. Is there any way to determine true output on these units? The receivers work ok, not outstanding but enough to get reasonable reception. I am quite pleased. 

I run other QRP rigs, but nothing sub 1 watt.

Thanks!
Carl

iPhone Aloha

On Feb 20, 2021, at 5:48 PM, tem494@... wrote:


Thank you and yes it should have been the D4D.
I Will work on it tomorrow when I am a little fresher and maybe a little better attitude.
tom

On Sat, Feb 20, 2021 at 5:13 PM Jim Allyn - N7JA <jim@...> wrote:
By DSB I am guessing you mean the D4D  -  double sideband for digital mode?  Since you have both the 20 meter version and the 40 meter version, you could start by measuring voltages in the functioning 40 meter radio and compare the voltage readings in the non-functioning 20 meter version.  As far as I know they are identical except for the component values in the low pass filter at the output and a few other frequency determining components.  Beyond that, you're probably looking for something in the Q3/Q4 circuitry, so I would start comparing voltages there.  Off the top of my head, I'll say you should have about .7 volts between base and emitter on both Q3 and Q4, and you should have 12 volts at the collector of Q4.


--
CW


--
CW


Nigel Young
 

Tem that sounds about right, it's well down from 40 I know that much but still workable, I'm surprised Carl got nothing on the return reporter, maybe conditions? 



Kia Kaha


On Mon., 22 Feb. 2021, 9:00 am , <tem494@...> wrote:
Carl,Nigel
I measured my output on the 20 meter version with  a 4sqrp dummy load with tap to measure voltage 20 meter showed 1.4 volts squaring the voltage divided 100 gave me about .04 watts. Before putting it away I remember close to a watt output.
After finishing the 40 meter unit I measured about 13 volts at the dummy load.

On Sunday, February 21, 2021, Carl Weiberg via groups.io <carlweiberg=aol.com@groups.io> wrote:
Hi Nigel,
Yes, I was thinking the 20m would put out somewhere around 500mw. My antenna on 20 meters with WSPR gets spot reports all over the US as well as Africa, South America on 1 watt. So antenna is not the issue.

All QRP is fun. On the 40 meter a few minutes after I finished it, I sent a CQ and got a QSO in a couple minutes. That was super exciting. So I assumed on 20 in the day on a weekend the same results. After many CQ’s and no reply or PSKreporter results I assumed the rig had an issue. But, I get a weak signal on my other receiver so I know some power is going out.

I am thinking of buying a qrp warmer from MFJ, but was hoping to find some other method to determine output.

Thanks,
Carl
K0CFW

iPhone Aloha

On Feb 21, 2021, at 12:14 PM, Nigel Young <multilec@...> wrote:


Carl, you won't get anywhere near a Watt on 20m, on 40 you will but not on 20. I'm surprised you got nothing on reporter though. Maybe try again tonight. These units are just toys really but they work, I've had a lot of fun with mine. But trying for one what on 20 with a BD139 is impossible in my opinion and I would be very happy with half that on 20. But that's half the fun.

Nigel ZL1NAY

Kia Kaha

On Mon., 22 Feb. 2021, 5:15 am Carl Weiberg via groups.io, <carlweiberg=aol.com@groups.io> wrote:
Hi all,
I just completed my 20m build and after countless CQ’ and checking PSKreporter I don’t believe the output of the transmitter to be anywhere near a watt. I checked for signal on my main HF receiver, and there is a signal. PSKreporter confirmed my HF rig reception as well. However it was very weak. I am running a EFHF with perfect SWR as well. I also have a 40m unit, and tested that last night and PSKreported shows receptions across out west in the evening, so the 40 has some output.

I do not have a qrp meter. Is there any way to determine true output on these units? The receivers work ok, not outstanding but enough to get reasonable reception. I am quite pleased. 

I run other QRP rigs, but nothing sub 1 watt.

Thanks!
Carl

iPhone Aloha

On Feb 20, 2021, at 5:48 PM, tem494@... wrote:


Thank you and yes it should have been the D4D.
I Will work on it tomorrow when I am a little fresher and maybe a little better attitude.
tom

On Sat, Feb 20, 2021 at 5:13 PM Jim Allyn - N7JA <jim@...> wrote:
By DSB I am guessing you mean the D4D  -  double sideband for digital mode?  Since you have both the 20 meter version and the 40 meter version, you could start by measuring voltages in the functioning 40 meter radio and compare the voltage readings in the non-functioning 20 meter version.  As far as I know they are identical except for the component values in the low pass filter at the output and a few other frequency determining components.  Beyond that, you're probably looking for something in the Q3/Q4 circuitry, so I would start comparing voltages there.  Off the top of my head, I'll say you should have about .7 volts between base and emitter on both Q3 and Q4, and you should have 12 volts at the collector of Q4.


--
CW


--
CW


Carl Weiberg
 

Hi,
I just sent a 1 watt CQ on 20 with my other QRP and had a QSO with a Washington State from my Minnesota QTH. I also confirm PSKreporter from several coastal states. So it’s just the difference from a watt to a couple hundred milliwatts. I am taking the DSB out of enclosure to double check but I think it’s just the nature of the little rig. I have no complaints, as it’s well done, but I was caught by surprise that 20m is hard to work at sub 1 watt. 

iPhone Aloha

On Feb 21, 2021, at 2:15 PM, Nigel Young <multilec@...> wrote:


Tem that sounds about right, it's well down from 40 I know that much but still workable, I'm surprised Carl got nothing on the return reporter, maybe conditions? 



Kia Kaha

On Mon., 22 Feb. 2021, 9:00 am , <tem494@...> wrote:
Carl,Nigel
I measured my output on the 20 meter version with  a 4sqrp dummy load with tap to measure voltage 20 meter showed 1.4 volts squaring the voltage divided 100 gave me about .04 watts. Before putting it away I remember close to a watt output.
After finishing the 40 meter unit I measured about 13 volts at the dummy load.

On Sunday, February 21, 2021, Carl Weiberg via groups.io <carlweiberg=aol.com@groups.io> wrote:
Hi Nigel,
Yes, I was thinking the 20m would put out somewhere around 500mw. My antenna on 20 meters with WSPR gets spot reports all over the US as well as Africa, South America on 1 watt. So antenna is not the issue.

All QRP is fun. On the 40 meter a few minutes after I finished it, I sent a CQ and got a QSO in a couple minutes. That was super exciting. So I assumed on 20 in the day on a weekend the same results. After many CQ’s and no reply or PSKreporter results I assumed the rig had an issue. But, I get a weak signal on my other receiver so I know some power is going out.

I am thinking of buying a qrp warmer from MFJ, but was hoping to find some other method to determine output.

Thanks,
Carl
K0CFW

iPhone Aloha

On Feb 21, 2021, at 12:14 PM, Nigel Young <multilec@...> wrote:


Carl, you won't get anywhere near a Watt on 20m, on 40 you will but not on 20. I'm surprised you got nothing on reporter though. Maybe try again tonight. These units are just toys really but they work, I've had a lot of fun with mine. But trying for one what on 20 with a BD139 is impossible in my opinion and I would be very happy with half that on 20. But that's half the fun.

Nigel ZL1NAY

Kia Kaha

On Mon., 22 Feb. 2021, 5:15 am Carl Weiberg via groups.io, <carlweiberg=aol.com@groups.io> wrote:
Hi all,
I just completed my 20m build and after countless CQ’ and checking PSKreporter I don’t believe the output of the transmitter to be anywhere near a watt. I checked for signal on my main HF receiver, and there is a signal. PSKreporter confirmed my HF rig reception as well. However it was very weak. I am running a EFHF with perfect SWR as well. I also have a 40m unit, and tested that last night and PSKreported shows receptions across out west in the evening, so the 40 has some output.

I do not have a qrp meter. Is there any way to determine true output on these units? The receivers work ok, not outstanding but enough to get reasonable reception. I am quite pleased. 

I run other QRP rigs, but nothing sub 1 watt.

Thanks!
Carl

iPhone Aloha

On Feb 20, 2021, at 5:48 PM, tem494@... wrote:


Thank you and yes it should have been the D4D.
I Will work on it tomorrow when I am a little fresher and maybe a little better attitude.
tom

On Sat, Feb 20, 2021 at 5:13 PM Jim Allyn - N7JA <jim@...> wrote:
By DSB I am guessing you mean the D4D  -  double sideband for digital mode?  Since you have both the 20 meter version and the 40 meter version, you could start by measuring voltages in the functioning 40 meter radio and compare the voltage readings in the non-functioning 20 meter version.  As far as I know they are identical except for the component values in the low pass filter at the output and a few other frequency determining components.  Beyond that, you're probably looking for something in the Q3/Q4 circuitry, so I would start comparing voltages there.  Off the top of my head, I'll say you should have about .7 volts between base and emitter on both Q3 and Q4, and you should have 12 volts at the collector of Q4.


--
CW


--
CW


--
CW


Conor Farrell
 

Hi Carl,

I had a similar issue with one of my D4D kits: I wasn't being spotted
on pskreporter with one transceiver, but my other transceiver worked
great.

The problem for me was the solder joints for the hand-wound coils. The
wire on these coils is covered in enamel and in my case the enamel
prevented a good solder joint. If you didn't scrape the enamel off the
wire when you were assembling it, I suggest holding a hot soldering
iron tip to each joint until you see the enamel "boil" away. Do this
for each solder joint at the coils and try transmitting again.

Hope this helps.

Conor

On Sun, 21 Feb 2021 at 20:27, Carl Weiberg via groups.io
<carlweiberg=aol.com@groups.io> wrote:

Hi,
I just sent a 1 watt CQ on 20 with my other QRP and had a QSO with a Washington State from my Minnesota QTH. I also confirm PSKreporter from several coastal states. So it’s just the difference from a watt to a couple hundred milliwatts. I am taking the DSB out of enclosure to double check but I think it’s just the nature of the little rig. I have no complaints, as it’s well done, but I was caught by surprise that 20m is hard to work at sub 1 watt.

iPhone Aloha


Carl Weiberg
 

Hi Conor,
Yes, I carefully scraped the coating off. I tested each coil before as well. To be sure I just took the pcb out and under 30x checked each solder joint as well as all coils. To be sure again I resoldered the transformer. Put it back on air, been sending CQ’s no psk? Very puzzling. I suppose I could have a bad transistor. I am at a loss at this point on what to do next.

Any advice is greatly appreciated. I
Was hoping to take these rigs into the field for some fun. But need to see some results from my shack QTH.
Thanks,

iPhone Aloha

On Feb 21, 2021, at 2:42 PM, Conor Farrell <conchobhair.ofearghail@gmail.com> wrote:

Hi Carl,

I had a similar issue with one of my D4D kits: I wasn't being spotted
on pskreporter with one transceiver, but my other transceiver worked
great.

The problem for me was the solder joints for the hand-wound coils. The
wire on these coils is covered in enamel and in my case the enamel
prevented a good solder joint. If you didn't scrape the enamel off the
wire when you were assembling it, I suggest holding a hot soldering
iron tip to each joint until you see the enamel "boil" away. Do this
for each solder joint at the coils and try transmitting again.

Hope this helps.

Conor

On Sun, 21 Feb 2021 at 20:27, Carl Weiberg via groups.io
<carlweiberg=aol.com@groups.io> wrote:

Hi,
I just sent a 1 watt CQ on 20 with my other QRP and had a QSO with a Washington State from my Minnesota QTH. I also confirm PSKreporter from several coastal states. So it’s just the difference from a watt to a couple hundred milliwatts. I am taking the DSB out of enclosure to double check but I think it’s just the nature of the little rig. I have no complaints, as it’s well done, but I was caught by surprise that 20m is hard to work at sub 1 watt.

iPhone Aloha



--
CW


Jim Allyn - N7JA
 

On Sun, Feb 21, 2021 at 08:15 AM, Carl Weiberg wrote:
I do not have a qrp meter. Is there any way to determine true output on these units?
Measure the voltage on an oscilloscope and calculate the power from that.  Or make a diode peak detector and calculate the power from that.


Carl Weiberg
 

Thanks Jim. I am suspecting a bad BD139. They are cheap, I will do some measurements with the existing one and a new one. After that I have no idea what to check. After several examinations on top, bottom, all solder joints at magnification, for most of the day I am setting it aside. 

iPhone Aloha

On Feb 21, 2021, at 4:22 PM, Jim Allyn - N7JA <jim@...> wrote:

On Sun, Feb 21, 2021 at 08:15 AM, Carl Weiberg wrote:
I do not have a qrp meter. Is there any way to determine true output on these units?
Measure the voltage on an oscilloscope and calculate the power from that.  Or make a diode peak detector and calculate the power from that.

--
CW


Larry Lovell
 

I assume that the transmit light does illuminate properly.  Because the wattage is low, I placed my oscilloscope probe with a 10X on the antenna output.
On the software I pushed the TUNE control.  
Unfortunately, I don't know what the signal is supposed to look like but the voltage was about 4 volts PP sinusoidal.
If you do not see a sinusoidal wave at that point, move the scope probe to earlier in the circuit.
I have not found any source of explanation as to what the FT8 signal should look like on a scope.

On Sun, Feb 21, 2021 at 3:51 PM Carl Weiberg via groups.io <carlweiberg=aol.com@groups.io> wrote:
Thanks Jim. I am suspecting a bad BD139. They are cheap, I will do some measurements with the existing one and a new one. After that I have no idea what to check. After several examinations on top, bottom, all solder joints at magnification, for most of the day I am setting it aside. 

iPhone Aloha

On Feb 21, 2021, at 4:22 PM, Jim Allyn - N7JA <jim@...> wrote:

On Sun, Feb 21, 2021 at 08:15 AM, Carl Weiberg wrote:
I do not have a qrp meter. Is there any way to determine true output on these units?
Measure the voltage on an oscilloscope and calculate the power from that.  Or make a diode peak detector and calculate the power from that.

--
CW



--
Larry Lovell
73's N7RGW
http://QRVTronics.com
Cell: 214-697-1729


Carl Weiberg
 

Yes, it’s transmitting but virtually no power. 

iPhone Aloha

On Feb 21, 2021, at 5:08 PM, Larry Lovell <larry.lovell76@...> wrote:


I assume that the transmit light does illuminate properly.  Because the wattage is low, I placed my oscilloscope probe with a 10X on the antenna output.
On the software I pushed the TUNE control.  
Unfortunately, I don't know what the signal is supposed to look like but the voltage was about 4 volts PP sinusoidal.
If you do not see a sinusoidal wave at that point, move the scope probe to earlier in the circuit.
I have not found any source of explanation as to what the FT8 signal should look like on a scope.

On Sun, Feb 21, 2021 at 3:51 PM Carl Weiberg via groups.io <carlweiberg=aol.com@groups.io> wrote:
Thanks Jim. I am suspecting a bad BD139. They are cheap, I will do some measurements with the existing one and a new one. After that I have no idea what to check. After several examinations on top, bottom, all solder joints at magnification, for most of the day I am setting it aside. 

iPhone Aloha

On Feb 21, 2021, at 4:22 PM, Jim Allyn - N7JA <jim@...> wrote:

On Sun, Feb 21, 2021 at 08:15 AM, Carl Weiberg wrote:
I do not have a qrp meter. Is there any way to determine true output on these units?
Measure the voltage on an oscilloscope and calculate the power from that.  Or make a diode peak detector and calculate the power from that.

--
CW



--
Larry Lovell
73's N7RGW
http://QRVTronics.com
Cell: 214-697-1729

--
CW


Timothy Fidler
 

Take care , not all BD139s are created equal.    I Believe the Fairchild Stamped ones are reliable as RF amps and some others are not.

The die designs vary between Mfrs.

Same applies for the venerable  IRF 510.  VIshay ones are known good and that is all Qrp Labs (Hans) will supply or suggest as replacements.
some other ones will work and some are absolute rubbish at RF.   IRF oness are prob. ok.   And if buying from PRc don't forget the Chinos rebadge
a lot of stuff.
i believe IRF licenced the die design for Second sourcing.  Some of  the others are Improved versions that are perhaps not so improved. 

Mah tumpence worth , massah .   Tim Fid in Nz who is not always Pol correct. 


Carl Weiberg
 

Tim,
 is the IRF510 a direct sub for the 139? If so what is the difference and are any additional mods required for the 20m?

iPhone Aloha

On Feb 22, 2021, at 1:49 AM, Timothy Fidler <engstr@...> wrote:



Take care , not all BD139s are created equal.    I Believe the Fairchild Stamped ones are reliable as RF amps and some others are not.

The die designs vary between Mfrs.

Same applies for the venerable  IRF 510.  VIshay ones are known good and that is all Qrp Labs (Hans) will supply or suggest as replacements.
some other ones will work and some are absolute rubbish at RF.   IRF oness are prob. ok.   And if buying from PRc don't forget the Chinos rebadge
a lot of stuff.
i believe IRF licenced the die design for Second sourcing.  Some of  the others are Improved versions that are perhaps not so improved. 

Mah tumpence worth , massah .   Tim Fid in Nz who is not always Pol correct. 


--
CW


Timothy Fidler
 

sorry I mentioned the IRF 510 in passing as it has the same issue - the VIshay brand ones work well but some others are duds - after all it is a SMPS mosfet that  just happens to work at RF  . It is a MOSFET that is commonly used in  Ham designs for instance the  50 W Pa from QRP Labs uses two and reaches 40 W when put together by complete Muchkins. 

BBUT it is CW only and needs 5W drive.

There is a very good source (I think, I can't deal with him because he refused to do Oseas sales ) for  TO39  Bipolar Genuine RF parts
and that is Dan's small parts and kits..  Google him.  He often has parts like  MRF237 and other parts even  2n3053  (which is a reasonable HF transistor , much better than the BD139)  at good prices. for instance  four for USD 3 or something like that. 

Just about all of these RF small can devices will produce 1.5 W out at RF at about 10dB gain some will produce even 2.5 W RF as a class C amp with a heat sink .   Firstly if you are outside the US you need to find someone there who will do you a favour and tranship.  After that then go through is current list of goodies with datasheets avail from the WWW and find what suits you. 

Be aware all of these RF bipolars will have the Base as the centre conductor so if you have a board to suit a BD 139 you will have to do some twisting but with wired devices it is all possible. 

Since some of these will be very high gain devices you May be able to get two in parallel and really get power out of whatever is driving it.  But of course if you load up the driving stage too much doing that   you will in fact go backwards.  Experimenting is always fun.  If you know how to run LTspice  software  or can teach yerself it will all be a lot quicker. 

All off his stuff will be remainders in general and once it is gone, it is gone for good.



regards ,  TEF




 

Timothy E. Fidler : Engineer BE Mech Auckland 
Telephone Whangarei   022  691 8405
e: Engstr@...



----- Original Message -----
From:
crkits@groups.io

To:
<crkits@groups.io>
Cc:

Sent:
Mon, 22 Feb 2021 04:27:14 -0600
Subject:
Re: [crkits] voltage reading for DSB 20 meter version


Tim,
 is the IRF510 a direct sub for the 139? If so what is the difference and are any additional mods required for the 20m?

iPhone Aloha

On Feb 22, 2021, at 1:49 AM, Timothy Fidler <engstr@...> wrote:



Take care , not all BD139s are created equal.    I Believe the Fairchild Stamped ones are reliable as RF amps and some others are not.

The die designs vary between Mfrs

Same applies for the venerable  IRF 510.  VIshay ones are known good and that is all Qrp Labs (Hans) will supply or suggest as replacements.
some other ones will work and some are absolute rubbish at RF.   IRF oness are prob. ok.   And if buying from PRc don't forget the Chinos rebadge
a lot of stuff.
i believe IRF licenced the die design for Second sourcing.  Some of  the others are Improved versions that are perhaps not so improved. 

Mah tumpence worth , massah .   Tim Fid in Nz who is not always Pol correct. 


--
CW


Timothy Fidler
 

https://www.mouser.com/datasheet/2/268/2N4427-1593496.pdf 

Carl , this device is also avail frm the chap I mentioned to you.  

This has a guaranteed power gain of 10 dB at 175 Mhz which is of no interest to you but that suggests Gp might be 13 -14 dB easily at HF.

Now there is a power curve given and it shows  2 W out at 135 mW drive remember this is for class C operation and you have to have class A.

Let's say we put two in parallel assuming we can get 270mW out of our downstream power chain - that's quite an ask.  To do this properly we need to have 0.1 R emitter ballast resistors which can only be approx by say five off 1/4 w  1 ohm rs in parallel. Let's say that gives us a -1 dB on max possible power gain from this parallel operation.  so if we treat the Pout possible as  2 x 2 devices W x 0.5 factor for class B from class C  x 0.8  for the -1 dB drop we end up with 1.6 W out.  BUT BUT that should be pretty conservative given you are running at 14 Mhz .. you could easily manage 2.5-3 W out  , class B operation as long as you can keep the 4227s adequately cool with clip on head sinks which I think Diz sells but I am not sure about Dan. 


In order to physically fit these you will need likely have one above the board and one under the PCB which will mean a completely new case I guess.  Old story you can't make a silk purse out of a sow's ear without serious gold being expended.  what's serious.. based on what I see Dan wanting and some postage as long aas you can get cheap heat sinks - perhaps twelve dollars for the full change out .


Previous comments re spurious emissions still apply.

BTW this way to do this properly is with RF mosfets but that requires a complete circuit rebuild.

regards , TE Fidler