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Re: Newbie questions

Dominic Baines
 

Thanks Hans... probably explains it.

72

Dom
M1KTA


From: hanssummers2000 <hans.summers@...>
To: QRPLabs@...
Sent: Tue, 12 October, 2010 19:43:35
Subject: [QRPLabs] Re: Newbie questions



Hi Dom

When apply power the signal is spread over maybe 10Hz initially (wide band)
after couple seconds it calms down and is a single signal.
I wonder if that is AGC action? It'll be a massive signal into your receiver and

probably the AGC either in the receiver, or in Argo, will take a little time to
adjust to it.


That's my suggestion... other than that, not sure of any other possibilities!

72/3 Hans G0UPL
Re: Newbie questions

"hanssummers2000"
 

Hi Dom

When apply power the signal is spread over maybe 10Hz initially (wide band) after couple seconds it calms down and is a single signal.
I wonder if that is AGC action? It'll be a massive signal into your receiver and probably the AGC either in the receiver, or in Argo, will take a little time to adjust to it.

That's my suggestion... other than that, not sure of any other possibilities!

72/3 Hans G0UPL
Newbie questions

"Dominic"
 

Hi all,

Just managed to get a 30m kit built. Just testing into a dummy load right now.

When apply power the signal is spread over maybe 10Hz initially (wide band) after couple seconds it calms down and is a single signal.

Is this normal?

Run the output through a splitter/tap into a digital oscilloscope that also works as a spectrum analyser and I calculate 56mW out.

Argo displays nice clean signal abt 4Hz wide.

PSU BTW is an ATX PSU, added lots of chokes and RF clean now. 5.12V
I can see small variations in the signal though and if I monitor the output using ARGO.

72

Dom
ON/M1KTA
Final amplifier Bias

"Yannick (XV4TUJ)"
 

Hi.

Having few spare time in october I just finished assembling the beacon kit.
Everything seems running ok but I am not happy with the 2N7000 bias setting.
Running the beacon at 5-6V, even with the potentiometer fully clockwise turned, I have more than 6V peak-to-peak on a 50r load.
Nothing bad but the FET is running too hot for me. The documentation states that it should not get noticeably warm...

What can I check / do ?

Thanks by advance for your help.
73,
Yan.
---
Yannick DEVOS - XV4TUJ
(Blog in french)
(web page in english)
Beacon on air test

"PaulG"
 

Beacon was on the air last night with 3 sec dots on about 10.14070. Using the CW mode (upper side) on a FT-1000 to read the Freq. Keyer seems stable and is reverting to a 12 wpm ID every 10 min or so then returning to 3 sec dot mode. Ant is not well matched yet, but will remember to use the peak V and not the P-P V for power computation.

Paul K3PG
Re: Beacon is running

"hanssummers2000"
 

Hi Paul

Thanks for your comments. The beacon has been running for several days now and the final seems ok temp wise with the output at 5.08V. I used this table of RF volts into 50 ohms

As others already noted, the table is peak voltage, not peak-to-peak. That's where the missing division by 2 comes from.

Also bear in mind that table is for 50 ohm load. You were using 36 ohms so it needs to be adjusted.

One problem I am seeing is the keyer often 'locks' up after sending the call once or a few times. Once though it ran all nite and was still keying. I wonder if it is related to the supply ? I am using an old Heathkit Reg P/S IP-18 that seems stable and clean.
This seems to happen sometimes and I think is due to the floating inputs. My recommendation is to ground any of the pins 5, 6 and 7 which you haven't tied to +Vcc. That normally will address this problem.

73 de Hans G0UPL
Power Calculations

"PaulG"
 

OK on the power formula and the P-P vs. Peak Volts. Will work on antenna connection and move it to the slow speed.

Paul K3PG
Re: Beacon is running

Stephen Farthing
 

Guys,

FWIW the formula for calculating RF power into a 50 ohm load from the peak to peak voltage observed on a scope is :-

Power = 2.5 x (Peak to peak voltage squared) milliwatts

So if you have a peak to peak voltage 0f 5 volts :-

Power = 2..5 (5x5)

Power = 2.5 x 25

Power = 62.5 milliwatts

I am happy to post a graph of Power vs Peak to Peak voltage in the files section if it makes things simple for the numerically challenged..

72/3 de Steve G0XAR





On 4 October 2010 16:52, PaulG <pgerhardt@...> wrote:
?


Hans

Thanks for your comments. The beacon has been running for several days now and the final seems ok temp wise with the output at 5.08V. I used this table of RF volts into 50 ohms



to determine the approximate power output. I will have to find a real 50 or 51 ohm load resistor and measure it again.

One problem I am seeing is the keyer often 'locks' up after sending the call once or a few times. Once though it ran all nite and was still keying. I wonder if it is related to the supply ? I am using an old Heathkit Reg P/S IP-18 that seems stable and clean.


--- In QRPLabs@..., "hanssummers2000" wrote:
>
>
> Hi Paul
>
> Congrats on finishing the kit. Yes, the transistor can get a bit hot when tuned for maximum output and it is best to turn the trimmer pot a bit back towards the "cold" end (ground) to lower the output a bit and feel more comfortable.
>
> 5.08V p-p into 36 ohms is not 250mW according to my calcs, it's 90mW. I think you have missed a divide-by-2 somewhere.
>
> Another thing to bear in mind is that the output low pass filter is designed for 50 ohm termination, I'm not sure what would change if you use 36 ohms.
>
> 72/3 Hans G0UPL
>
>
> --- In QRPLabs@..., "PaulG" wrote:
> >
> > Got the kit running on the bench still on 12 wpm with 36 ohm dummy load I am getting 5.08V p to p output on the scope. This is somewhere around 250 mw and is set somewhat below max output as max output causes the transistor to run pretty warm. I also found out that you can reverse voltage the PIC enough to cause a 2nd degree burn on the finger and it still seems to be working. I am letting it run overnight or for a few days before I put the antenna on it. Before it started working I had a bad looking sine wave at very low level. Also the final was amplifying this spurious signal. After poking and prodding and reheating some connections it starting running properly.
> >
> > Pix of it on bench at
> >
>




--
It is vain to do with more that which can be done with less.
Re: Beacon is running

Arv Evans
 

开云体育

Hello

Seems that there is some confusion regarding how to measure RF power.
There are several voltage measurement methods, including:
  • Average voltage

  • RMS voltage

  • Peak volts

  • Peak-to-Peak volts.
The chart that Paul noted shows the first 3 measurements but doesn't show
power converted from peak-to-peak voltage as you would see with a full-wave
rectifier or on an oscilloscope display.? If using peak-to-peak voltages it seems
one would want to divide-by-two, then use the peak volts part of the chart.

Arv
_._


On 10/04/2010 09:52 AM, PaulG wrote:

?


Hans

Thanks for your comments. The beacon has been running for several days now and the final seems ok temp wise with the output at 5.08V. I used this table of RF volts into 50 ohms



to determine the approximate power output. I will have to find a real 50 or 51 ohm load resistor and measure it again.

One problem I am seeing is the keyer often 'locks' up after sending the call once or a few times. Once though it ran all nite and was still keying. I wonder if it is related to the supply ? I am using an old Heathkit Reg P/S IP-18 that seems stable and clean.

--- In QRPLabs@..., "hanssummers2000" wrote:
>
>
> Hi Paul
>
> Congrats on finishing the kit. Yes, the transistor can get a bit hot when tuned for maximum output and it is best to turn the trimmer pot a bit back towards the "cold" end (ground) to lower the output a bit and feel more comfortable.
>
> 5.08V p-p into 36 ohms is not 250mW according to my calcs, it's 90mW. I think you have missed a divide-by-2 somewhere.
>
> Another thing to bear in mind is that the output low pass filter is designed for 50 ohm termination, I'm not sure what would change if you use 36 ohms.
>
> 72/3 Hans G0UPL
>
>
> --- In QRPLabs@..., "PaulG" wrote:
> >
> > Got the kit running on the bench still on 12 wpm with 36 ohm dummy load I am getting 5.08V p to p output on the scope. This is somewhere around 250 mw and is set somewhat below max output as max output causes the transistor to run pretty warm. I also found out that you can reverse voltage the PIC enough to cause a 2nd degree burn on the finger and it still seems to be working. I am letting it run overnight or for a few days before I put the antenna on it. Before it started working I had a bad looking sine wave at very low level. Also the final was amplifying this spurious signal. After poking and prodding and reheating some connections it starting running properly.
> >
> > Pix of it on bench at
> >
>
Re: Beacon is running

"PaulG"
 

Hans

Thanks for your comments. The beacon has been running for several days now and the final seems ok temp wise with the output at 5.08V. I used this table of RF volts into 50 ohms



to determine the approximate power output. I will have to find a real 50 or 51 ohm load resistor and measure it again.

One problem I am seeing is the keyer often 'locks' up after sending the call once or a few times. Once though it ran all nite and was still keying. I wonder if it is related to the supply ? I am using an old Heathkit Reg P/S IP-18 that seems stable and clean.

--- In QRPLabs@..., "hanssummers2000" <hans.summers@...> wrote:


Hi Paul

Congrats on finishing the kit. Yes, the transistor can get a bit hot when tuned for maximum output and it is best to turn the trimmer pot a bit back towards the "cold" end (ground) to lower the output a bit and feel more comfortable.

5.08V p-p into 36 ohms is not 250mW according to my calcs, it's 90mW. I think you have missed a divide-by-2 somewhere.

Another thing to bear in mind is that the output low pass filter is designed for 50 ohm termination, I'm not sure what would change if you use 36 ohms.

72/3 Hans G0UPL


--- In QRPLabs@..., "PaulG" <pgerhardt@> wrote:

Got the kit running on the bench still on 12 wpm with 36 ohm dummy load I am getting 5.08V p to p output on the scope. This is somewhere around 250 mw and is set somewhat below max output as max output causes the transistor to run pretty warm. I also found out that you can reverse voltage the PIC enough to cause a 2nd degree burn on the finger and it still seems to be working. I am letting it run overnight or for a few days before I put the antenna on it. Before it started working I had a bad looking sine wave at very low level. Also the final was amplifying this spurious signal. After poking and prodding and reheating some connections it starting running properly.

Pix of it on bench at

Re: Beacon is running

"hanssummers2000"
 

Hi Paul

Congrats on finishing the kit. Yes, the transistor can get a bit hot when tuned for maximum output and it is best to turn the trimmer pot a bit back towards the "cold" end (ground) to lower the output a bit and feel more comfortable.

5.08V p-p into 36 ohms is not 250mW according to my calcs, it's 90mW. I think you have missed a divide-by-2 somewhere.

Another thing to bear in mind is that the output low pass filter is designed for 50 ohm termination, I'm not sure what would change if you use 36 ohms.

72/3 Hans G0UPL

--- In QRPLabs@..., "PaulG" <pgerhardt@...> wrote:

Got the kit running on the bench still on 12 wpm with 36 ohm dummy load I am getting 5.08V p to p output on the scope. This is somewhere around 250 mw and is set somewhat below max output as max output causes the transistor to run pretty warm. I also found out that you can reverse voltage the PIC enough to cause a 2nd degree burn on the finger and it still seems to be working. I am letting it run overnight or for a few days before I put the antenna on it. Before it started working I had a bad looking sine wave at very low level. Also the final was amplifying this spurious signal. After poking and prodding and reheating some connections it starting running properly.

Pix of it on bench at

Beacon is running

"PaulG"
 

Got the kit running on the bench still on 12 wpm with 36 ohm dummy load I am getting 5.08V p to p output on the scope. This is somewhere around 250 mw and is set somewhat below max output as max output causes the transistor to run pretty warm. I also found out that you can reverse voltage the PIC enough to cause a 2nd degree burn on the finger and it still seems to be working. I am letting it run overnight or for a few days before I put the antenna on it. Before it started working I had a bad looking sine wave at very low level. Also the final was amplifying this spurious signal. After poking and prodding and reheating some connections it starting running properly.

Pix of it on bench at

Rainy day kit building

"PaulG"
 

With the rain coming up the East Coast I broke out my QRSS Beacon kit and got it started. On step 4 of the build I see a signal on the scope but can't find it on the rx or counter. Seem to have a signal at both the osc and the buffer. Am winding the rest of the coils and will add the final soon.

Kit was picked up at FDIM. I can hear the low level tone at step 1 as well.

Finished an end fed tuner matcher by KI6J and I may try it out with the QRSS Beacon if I can get it running...

Paul K3PG
I Hab 2 Balloon Launch and Beacon

"Ken Evans"
 

Just a reminder that the Iowa High Altitude Balloon (iHAB) project will
launch their second balloon with QRP beacon on Saturday. This launch is
sponsored by QRP ARCI.

The launch is scheduled for October 2, 2010 at 14:00Z (9AM CDT) from the
Ottumwa Industrial Airport (OTM) IHCC North Campus Aviation Building.
Preflight will begin at 13:00Z (8AM CDT). Should weather prevent the launch,
the fall back date will be Saturday, October 9, 2010 at the same times.

The QRP Beacon (1.6 watts) will be on 14.059.0 MHz signing (the QRP ARCI
Club call sign) "K6JSS iHAB 2". Post your spots of the beacon online at
www.qrpspots.com

A certificate will be available to people who provide a reception report.
Reports and requests for certificates should be sent to balloon@..."

Please go to for more information on the flight and
special recognition for reception reports.


Ken Evans, W4DU
President QRP ARCI
Re: Just finished soldering...

"Brad WF7T"
 

Sage advice Yan, and I will investigate. I did stumble upon the WSPR info and it started my thought process. Thank you for the PowerSDR article...I will glean what I can and get this puppy on the air!

73 Brad WF7T
Nashville EM66

--- In QRPLabs@..., "Yannick" <yannick.devos@...> wrote:

Hi Brad,

The easiest : tune to WW-V on 10 MHz and 15MHz. You should have a sharp carrier and will be able to notice your VFO error on two points.
If you are not able to receive WW-V or WW-H, there is other reference signal other the world in Russia for example.
Broadcast signals can also be used but their accuracy is worst. Ok in many cases but perhaps not precise enough for QRSS.

Here some tips :
(for WSPR but Ok for Argo)
(for PowerSDR)

73,
Yan.
---
Yannick DEVOS - XV4TUJ
(Blog in french)
(web page in english)

--- In QRPLabs@..., "Brad WF7T" <brad.wf7t@> wrote:

Update: To clarify, I need to "calibrate" ARGO in order to understand where my signal is being transmitted. Any pointers will be appreciated! 73 Brad



--- In QRPLabs@..., "Brad WF7T" <brad.wf7t@> wrote:

...my version of the QRSS board for 30M. Nice quick build and after a little bit of fiddling with the gimmick capacitor I have a nice 5Hz shift as seen in Argo while transmitting through a dummy load.

Using an IC-7600 through an EDZ for my monitoring setup as I set my final frequency I can actually see my signal (success!) Having only a few minutes of experience with Argo, I am wondering where I want to my signal to show in order to be in that 10.140.00 through 10.140.10 window? Assume I tune my RX rig to 10.140.00 USB.

I do not have a frequency counter handy, so I need to set my final frequency using my rig. I am pretty sure I can get the signal right in there, just having brain problems and will appreciate any pointers on using a rig to adjust my final frequency.

73 Brad WF7T
Re: Just finished soldering...

"Yannick"
 

Hi Brad,

The easiest : tune to WW-V on 10 MHz and 15MHz. You should have a sharp carrier and will be able to notice your VFO error on two points.
If you are not able to receive WW-V or WW-H, there is other reference signal other the world in Russia for example.
Broadcast signals can also be used but their accuracy is worst. Ok in many cases but perhaps not precise enough for QRSS.

Here some tips :
(for WSPR but Ok for Argo)
(for PowerSDR)

73,
Yan.
---
Yannick DEVOS - XV4TUJ
(Blog in french)
(web page in english)

--- In QRPLabs@..., "Brad WF7T" <brad.wf7t@...> wrote:

Update: To clarify, I need to "calibrate" ARGO in order to understand where my signal is being transmitted. Any pointers will be appreciated! 73 Brad



--- In QRPLabs@..., "Brad WF7T" <brad.wf7t@> wrote:

...my version of the QRSS board for 30M. Nice quick build and after a little bit of fiddling with the gimmick capacitor I have a nice 5Hz shift as seen in Argo while transmitting through a dummy load.

Using an IC-7600 through an EDZ for my monitoring setup as I set my final frequency I can actually see my signal (success!) Having only a few minutes of experience with Argo, I am wondering where I want to my signal to show in order to be in that 10.140.00 through 10.140.10 window? Assume I tune my RX rig to 10.140.00 USB.

I do not have a frequency counter handy, so I need to set my final frequency using my rig. I am pretty sure I can get the signal right in there, just having brain problems and will appreciate any pointers on using a rig to adjust my final frequency.

73 Brad WF7T
Re: Just finished soldering...

"Brad WF7T"
 

Update: To clarify, I need to "calibrate" ARGO in order to understand where my signal is being transmitted. Any pointers will be appreciated! 73 Brad

--- In QRPLabs@..., "Brad WF7T" <brad.wf7t@...> wrote:

...my version of the QRSS board for 30M. Nice quick build and after a little bit of fiddling with the gimmick capacitor I have a nice 5Hz shift as seen in Argo while transmitting through a dummy load.

Using an IC-7600 through an EDZ for my monitoring setup as I set my final frequency I can actually see my signal (success!) Having only a few minutes of experience with Argo, I am wondering where I want to my signal to show in order to be in that 10.140.00 through 10.140.10 window? Assume I tune my RX rig to 10.140.00 USB.

I do not have a frequency counter handy, so I need to set my final frequency using my rig. I am pretty sure I can get the signal right in there, just having brain problems and will appreciate any pointers on using a rig to adjust my final frequency.

73 Brad WF7T
Just finished soldering...

"Brad WF7T"
 

...my version of the QRSS board for 30M. Nice quick build and after a little bit of fiddling with the gimmick capacitor I have a nice 5Hz shift as seen in Argo while transmitting through a dummy load.

Using an IC-7600 through an EDZ for my monitoring setup as I set my final frequency I can actually see my signal (success!) Having only a few minutes of experience with Argo, I am wondering where I want to my signal to show in order to be in that 10.140.00 through 10.140.10 window? Assume I tune my RX rig to 10.140.00 USB.

I do not have a frequency counter handy, so I need to set my final frequency using my rig. I am pretty sure I can get the signal right in there, just having brain problems and will appreciate any pointers on using a rig to adjust my final frequency.

73 Brad WF7T
QRP Labs online shop

"hanssummers2000"
 

All

I have the online shop up and running, please scroll down to the bottom of the left hand menu on my website home page or visit to see the shop directly. I've added a components section too where you can buy spare parts for the beacon kits (crystals, toroids, transistors, PCB's). I hope this helps.

73 Hans G0UPL
Re: 20m inductor values

"hanssummers2000"
 

Hi all

This may save you some time. The beacon design uses the standard harmonic
output filter designs used by the GQRP club documented here
. So a good starting point will be the one
for 20 meters. You might find that the 2n7000 will not put out much output
power at 20 Meters, but hey, this is QRSS and we dont need much output power
:-)...
Please note people, that you may also need to reduce the value of the capacitors in the base/emitter of the Colpitts oscillator. They are 220pF in the 30m version. I think for 20m I think I would be tempted to start with a first guess of 150pF and see if that worked.

73 Hans G0UPL
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