OK, thanks Jack.? As I said, my testing methods were primitive and just a first glance.? I'll dig into the details next week when I get back to the workbench.? I may have something messed up on the board or in my testing.
Dave, W0DF
|
Dave:
Dennis has posted the spectrum traces for the VFO and they all look within specs to me.
Jack, W8TEE
|
Yes... And Dave, If you haven't done so yet, you may have to run the formula that Jack describes in the QST article in order to get the VFO calibrated perfectly. We breadboarded this project every step of the way... adding one piece at a time once parts started arriving from China. When the DDS board arrived, we hooked it up to the Nano and tested the output. With a small antenna coupled to the DDS and a portable shortwave radio's antenna, we fired it up and looked for a carrier. With the VFO dialed up to 7.040, we found ?the carrier way off frequency. Of course, we weren't expecting perfection since this was the DDS right out of the box and the code directly from Farrukh's website. No modifications other than some customized splash screen elements were made to the code at this point.
We ran the formula for calculating the Tuning Constant and made the correction in the code. Once we did that, problem solved. Solid carrier on 7.040 and the 49-er is pretty much dead on frequency as well Aaron - N2HTL
toggle quoted message
Show quoted text
?
Don't forget that the crystal on the DDS board may not be exact and you should expect some deviation. The article details how to correct for the "slop" you may find.
73, Jack, W8TEE
?
Thanks for the response Aaron.? I haven't had time to investigate what is happening yet and won't get a chance to do that until next week sometime as I'm getting ready for a short trip.? My DDS is off a couple hundred cycles, but I will correct that next week also.? I'll keep you posted on what I find.
Dave, W0DF
?
Hi Dave. I have to admit that I haven't but I certainly will now. When I fired up the DDS controlled 49-er for the first time, I checked it against my frequency counter to see what it was doing. I was quite pleased that the VFO was showing 7.100 and the frequency counter was showing the output on 7.099.4 or something to that effect. I made the test which the radio putting a signal out directly into my 40m dipole and not into a dummy load since it was such a quick test.
While I'm not sure testing for harmonics on a frequency counter is the best method, I can tell you that over the summer I built a two tube QRP crystal controlled 40m transmitter into a coffee can. When I fired that thing up for the first time, it was radiating harmonics STRONGER on 14.110 rather than on 7.110 - which is the crystal I had installed. Turns out the coil I was using was too small, the wrong diameter, and my tap was in the wrong spot. Once I corrected the coil, the radio operated where if was designed to.
My point is that the frequency counter caught it right away that the transmitter was way off and in danger of getting me in serious trouble. Aaron - ?N2HTL
?
Has anyone looked at the harmonics on their 49er.? I must admit that my testing method is primitive but looking at the 2nd and third harmonics on my K3/P3 panadapter, the 2nd and 3rd harmonics on mine are progressively stronger than the fundamental.? I have my 49er (Frog Sound) xcvr terminated in a 50 ohm dummy load sitting on the desk next to my K3 that is terminated in either another 50 ohm dummy load or a ground mounted vertical antenna that is roughly 30 feet or so from the K3.? In both cases, the harmonics on 20 and 15 meters are stronger that the 40 meter signal, somewhat stronger on 20 meters and much stronger on 15.? Has anyone else checked this?
Dave, W0DF
|
Don't forget that the crystal on the DDS board may not be exact and you should expect some deviation. The article details how to correct for the "slop" you may find.
73, Jack, W8TEE
From: "David Fine dfine01@... [SoftwareControlledHamRadio]"
To: "SoftwareControlledHamRadio@..." <SoftwareControlledHamRadio@...>
Sent: Wednesday, April 13, 2016 7:55 AM
Subject: Re: [SoftwareControlledHamRadio] 49er Harmonics
?
Thanks for the response Aaron.? I haven't had time to investigate what is happening yet and won't get a chance to do that until next week sometime as I'm getting ready for a short trip.? My DDS is off a couple hundred cycles, but I will correct that next week also.? I'll keep you posted on what I find.
Dave, W0DF
On Tuesday, April 12, 2016 11:03 PM, "AaronHev aaronhev@... [SoftwareControlledHamRadio]" wrote:
?
Hi Dave. I have to admit that I haven't but I certainly will now. When I fired up the DDS controlled 49-er for the first time, I checked it against my frequency counter to see what it was doing. I was quite pleased that the VFO was showing 7.100 and the frequency counter was showing the output on 7.099.4 or something to that effect. I made the test which the radio putting a signal out directly into my 40m dipole and not into a dummy load since it was such a quick test.
While I'm not sure testing for harmonics on a frequency counter is the best method, I can tell you that over the summer I built a two tube QRP crystal controlled 40m transmitter into a coffee can. When I fired that thing up for the first time, it was radiating harmonics STRONGER on 14.110 rather than on 7.110 - which is the crystal I had installed. Turns out the coil I was using was too small, the wrong diameter, and my tap was in the wrong spot. Once I corrected the coil, the radio operated where if was designed to.
My point is that the frequency counter caught it right away that the transmitter was way off and in danger of getting me in serious trouble. Aaron - ?N2HTL
?
Has anyone looked at the harmonics on their 49er.? I must admit that my testing method is primitive but looking at the 2nd and third harmonics on my K3/P3 panadapter, the 2nd and 3rd harmonics on mine are progressively stronger than the fundamental.? I have my 49er (Frog Sound) xcvr terminated in a 50 ohm dummy load sitting on the desk next to my K3 that is terminated in either another 50 ohm dummy load or a ground mounted vertical antenna that is roughly 30 feet or so from the K3.? In both cases, the harmonics on 20 and 15 meters are stronger that the 40 meter signal, somewhat stronger on 20 meters and much stronger on 15.? Has anyone else checked this?
Dave, W0DF
|
Thanks for the response Aaron.? I haven't had time to investigate what is happening yet and won't get a chance to do that until next week sometime as I'm getting ready for a short trip.? My DDS is off a couple hundred cycles, but I will correct that next week also.? I'll keep you posted on what I find.
Dave, W0DF
On Tuesday, April 12, 2016 11:03 PM, "AaronHev aaronhev@... [SoftwareControlledHamRadio]" wrote:
?
Hi Dave. I have to admit that I haven't but I certainly will now. When I fired up the DDS controlled 49-er for the first time, I checked it against my frequency counter to see what it was doing. I was quite pleased that the VFO was showing 7.100 and the frequency counter was showing the output on 7.099.4 or something to that effect. I made the test which the radio putting a signal out directly into my 40m dipole and not into a dummy load since it was such a quick test.
While I'm not sure testing for harmonics on a frequency counter is the best method, I can tell you that over the summer I built a two tube QRP crystal controlled 40m transmitter into a coffee can. When I fired that thing up for the first time, it was radiating harmonics STRONGER on 14.110 rather than on 7.110 - which is the crystal I had installed. Turns out the coil I was using was too small, the wrong diameter, and my tap was in the wrong spot. Once I corrected the coil, the radio operated where if was designed to.
My point is that the frequency counter caught it right away that the transmitter was way off and in danger of getting me in serious trouble. Aaron - ?N2HTL
?
Has anyone looked at the harmonics on their 49er.? I must admit that my testing method is primitive but looking at the 2nd and third harmonics on my K3/P3 panadapter, the 2nd and 3rd harmonics on mine are progressively stronger than the fundamental.? I have my 49er (Frog Sound) xcvr terminated in a 50 ohm dummy load sitting on the desk next to my K3 that is terminated in either another 50 ohm dummy load or a ground mounted vertical antenna that is roughly 30 feet or so from the K3.? In both cases, the harmonics on 20 and 15 meters are stronger that the 40 meter signal, somewhat stronger on 20 meters and much stronger on 15.? Has anyone else checked this?
Dave, W0DF
|
Hi Dave. I have to admit that I haven't but I certainly will now. When I fired up the DDS controlled 49-er for the first time, I checked it against my frequency counter to see what it was doing. I was quite pleased that the VFO was showing 7.100 and the frequency counter was showing the output on 7.099.4 or something to that effect. I made the test which the radio putting a signal out directly into my 40m dipole and not into a dummy load since it was such a quick test.
While I'm not sure testing for harmonics on a frequency counter is the best method, I can tell you that over the summer I built a two tube QRP crystal controlled 40m transmitter into a coffee can. When I fired that thing up for the first time, it was radiating harmonics STRONGER on 14.110 rather than on 7.110 - which is the crystal I had installed. Turns out the coil I was using was too small, the wrong diameter, and my tap was in the wrong spot. Once I corrected the coil, the radio operated where if was designed to.
My point is that the frequency counter caught it right away that the transmitter was way off and in danger of getting me in serious trouble. Aaron - ?N2HTL
toggle quoted message
Show quoted text
?
Has anyone looked at the harmonics on their 49er.? I must admit that my testing method is primitive but looking at the 2nd and third harmonics on my K3/P3 panadapter, the 2nd and 3rd harmonics on mine are progressively stronger than the fundamental.? I have my 49er (Frog Sound) xcvr terminated in a 50 ohm dummy load sitting on the desk next to my K3 that is terminated in either another 50 ohm dummy load or a ground mounted vertical antenna that is roughly 30 feet or so from the K3.? In both cases, the harmonics on 20 and 15 meters are stronger that the 40 meter signal, somewhat stronger on 20 meters and much stronger on 15.? Has anyone else checked this?
Dave, W0DF
|
Has anyone looked at the harmonics on their 49er.? I must admit that my testing method is primitive but looking at the 2nd and third harmonics on my K3/P3 panadapter, the 2nd and 3rd harmonics on mine are progressively stronger than the fundamental.? I have my 49er (Frog Sound) xcvr terminated in a 50 ohm dummy load sitting on the desk next to my K3 that is terminated in either another 50 ohm dummy load or a ground mounted vertical antenna that is roughly 30 feet or so from the K3.? In both cases, the harmonics on 20 and 15 meters are stronger that the 40 meter signal, somewhat stronger on 20 meters and much stronger on 15.? Has anyone else checked this? Dave, W0DF
|
Re: DDS VFO voltage adjustment
Good to hear! That was one of the design goals that the three of us shot for when we started the project. As I mentioned in the article, we wanted a VFO that would be capable of powering older rigs, which tend to need more drive than modern rigs. Dennis did the original design for the Arduino Projects book and Farrukh expanded it with a second buffer. The result is a pretty functional VFO for a variety of rigs. Glad you got it working.
Jack, W8TEE
From: "Aaron Heverin aaronhev@... [SoftwareControlledHamRadio]"
To: SoftwareControlledHamRadio@...
Sent: Tuesday, April 12, 2016 10:58 AM
Subject: Re: [SoftwareControlledHamRadio] DDS VFO voltage adjustment
?
Thanks for the reply, Jack. I successfully made the adjustment to 4 vDC using an RF probe and my VTVM. And Farrukh is absolutely correct... you need to give R1 quite a few turns in order to see any sort of variance on the meter.?
Once I had R1 adjusted for 4V, I decided to take this experiment up a notch. I took the output of J3 and fed it into my Globe Chief Model 90 transmitter. I dialed up the DDS VFO to 7.106 and keyed the transmitter. Adjusting the oscillator tuning on the transmitter was a bit different that if there was a crystal in rig, but once I had a peak, I switched to transmit and keyed the rig. Wow! It loaded up perfectly to its full 30 watts out. I tried various frequencies up and down the CW portion of the 40m band and it worked flawlessly. If it wasn't for the fact that I need to get ready for our radio club's hamfest this evening, I'd be making contacts all afternoon!
So not only do we have a really sweet QRP rig, but we also have a digital VFO for use on crystal-controlled transmitters. It doesn't get any better than this.
Aaron - N2HTL
|
Re: DDS VFO voltage adjustment
Thanks for the reply, Jack. I successfully made the adjustment to 4 vDC using an RF probe and my VTVM. And Farrukh is absolutely correct... you need to give R1 quite a few turns in order to see any sort of variance on the meter.?
Once I had R1 adjusted for 4V, I decided to take this experiment up a notch. I took the output of J3 and fed it into my Globe Chief Model 90 transmitter. I dialed up the DDS VFO to 7.106 and keyed the transmitter. Adjusting the oscillator tuning on the transmitter was a bit different that if there was a crystal in rig, but once I had a peak, I switched to transmit and keyed the rig. Wow! It loaded up perfectly to its full 30 watts out. I tried various frequencies up and down the CW portion of the 40m band and it worked flawlessly. If it wasn't for the fact that I need to get ready for our radio club's hamfest this evening, I'd be making contacts all afternoon!
So not only do we have a really sweet QRP rig, but we also have a digital VFO for use on crystal-controlled transmitters. It doesn't get any better than this.
Aaron - N2HTL
?
Got this today:
Hi Jack,
There are two pots on the DDS VFO board. R1 adjusts the GAIN of the RF buffer amplifier and hence the AMPLITUDE of the sine wave output on J3. R8 is for calibration of battery/power supply voltage sample into Nano analog input A7. If we add the code for A7 analog input, we can display the power supply voltage as part of the initial splash screen.
If the J3 output sine wave amplitude on a DDS VFO board does not change from 0 to 4V pk-pk when R1 is adjusted something must be wrong with the buffer amplifier circuit. It is also possible the person is not aware that R1 is multi-turn (>10 turns) pot, and they are only turning it one rotation. There are no hard stops at the end of the multi-turn travel range of R1. Only very soft clicks. So the person might keep turning it towards 0V position without realizing it has reached the 0V position, unless they are looking at J3 output on a scope or DVM.
73, Farrukh
?
Thanks for the relay, Jack. And therein lies the rub. Rotating R1 has no effect whatsoever on the output... but I'm not thoroughly convinced that I tested the output voltage at the right spot on the DDS board. Having Farrukh's input on this would be a huge help. I'm actually experimenting with this now... documenting everything as I go.?
And did I tell you I LOVE this thing? :-)
Aaron - N2HTL
On Mon, Apr 11, 2016 at 9:52 PM, Jack Purdum jjpurdum@... [SoftwareControlledHamRadio] <SoftwareControlledHamRadio@...> wrote:
?
Aaron:
Once again, I'm the software guy, not the one who designed the board; that was done by Farrukh and he is better able to answer these types of questions. That said, I do know that the pots can be used to change the drive on J3. The fact that you are getting 5W out suggests that maybe it's being over-driven, since it is a 3W transceiver. I'd back that down a little, as I do not know the power rating on the final transistor.?
Farrukh: any ideas on this?
73, jack, W8TEE
?
Jack, and all... As you know, I'm in the process of putting together a very detailed construction manual for the radio which will be handed out to everyone who takes on the project as part of the class in our club. I wanted to ask you about the voltage adjustment of R1.?
I've been putting my prototype of the radio through some serious testing the past few days. My goal is to also use the DDS VFO to drive some of the older transmitters I have in my collection. But for the 49-er, I see that you indicate that J3 should be used to connect the 49-er to the DDS board at J6. If I'm understanding your instructions correctly, J3 is supposed to have a 4v peak-to-peak voltage on it via the buffer amp on the DDS board. This voltage can be adjusted with R1.?
As it stands now, I'm not seeing any difference in the performance of the 49-er both in receive and transmit by using either J2 or J3 on the DDS board. According to the schematic, J2 is coming directly from pin 20 on the DDS through C2, while J3 goes through the buffer amp and supplies the 4 volts voltage. I attempted to view the output voltage at J3 but saw absolutely no difference when I adjusted R1. In fact, with either J2 or J3 feeding the 49-er, I still had 5 watts output power on the radio.
Can you please clarify exactly where this voltage measurement would be taken? I simply took it directly from J3 and ground but saw nothing but a few milliwatts of DC voltage regardless of the rotation of R1.
Thank you and best 73s.
-- Aaron
|
Re: DDS VFO voltage adjustment
Got this today:
Hi Jack,
There are two pots on the DDS VFO board. R1 adjusts the GAIN of the RF buffer amplifier and hence the AMPLITUDE of the sine wave output on J3. R8 is for calibration of battery/power supply voltage sample into Nano analog input A7. If we add the code for A7 analog input, we can display the power supply voltage as part of the initial splash screen.
If the J3 output sine wave amplitude on a DDS VFO board does not change from 0 to 4V pk-pk when R1 is adjusted something must be wrong with the buffer amplifier circuit. It is also possible the person is not aware that R1 is multi-turn (>10 turns) pot, and they are only turning it one rotation. There are no hard stops at the end of the multi-turn travel range of R1. Only very soft clicks. So the person might keep turning it towards 0V position without realizing it has reached the 0V position, unless they are looking at J3 output on a scope or DVM.
73, Farrukh
From: "Aaron Heverin aaronhev@... [SoftwareControlledHamRadio]"
To: SoftwareControlledHamRadio@...
Sent: Monday, April 11, 2016 10:17 PM
Subject: Re: [SoftwareControlledHamRadio] DDS VFO voltage adjustment
?
Thanks for the relay, Jack. And therein lies the rub. Rotating R1 has no effect whatsoever on the output... but I'm not thoroughly convinced that I tested the output voltage at the right spot on the DDS board. Having Farrukh's input on this would be a huge help. I'm actually experimenting with this now... documenting everything as I go.?
And did I tell you I LOVE this thing? :-)
Aaron - N2HTL
|
Re: DDS VFO voltage adjustment
Thanks for the relay, Jack. And therein lies the rub. Rotating R1 has no effect whatsoever on the output... but I'm not thoroughly convinced that I tested the output voltage at the right spot on the DDS board. Having Farrukh's input on this would be a huge help. I'm actually experimenting with this now... documenting everything as I go.?
And did I tell you I LOVE this thing? :-)
Aaron - N2HTL
?
Aaron:
Once again, I'm the software guy, not the one who designed the board; that was done by Farrukh and he is better able to answer these types of questions. That said, I do know that the pots can be used to change the drive on J3. The fact that you are getting 5W out suggests that maybe it's being over-driven, since it is a 3W transceiver. I'd back that down a little, as I do not know the power rating on the final transistor.?
Farrukh: any ideas on this?
73, jack, W8TEE
?
Jack, and all... As you know, I'm in the process of putting together a very detailed construction manual for the radio which will be handed out to everyone who takes on the project as part of the class in our club. I wanted to ask you about the voltage adjustment of R1.?
I've been putting my prototype of the radio through some serious testing the past few days. My goal is to also use the DDS VFO to drive some of the older transmitters I have in my collection. But for the 49-er, I see that you indicate that J3 should be used to connect the 49-er to the DDS board at J6. If I'm understanding your instructions correctly, J3 is supposed to have a 4v peak-to-peak voltage on it via the buffer amp on the DDS board. This voltage can be adjusted with R1.?
As it stands now, I'm not seeing any difference in the performance of the 49-er both in receive and transmit by using either J2 or J3 on the DDS board. According to the schematic, J2 is coming directly from pin 20 on the DDS through C2, while J3 goes through the buffer amp and supplies the 4 volts voltage. I attempted to view the output voltage at J3 but saw absolutely no difference when I adjusted R1. In fact, with either J2 or J3 feeding the 49-er, I still had 5 watts output power on the radio.
Can you please clarify exactly where this voltage measurement would be taken? I simply took it directly from J3 and ground but saw nothing but a few milliwatts of DC voltage regardless of the rotation of R1.
Thank you and best 73s.
|
Another possibility that I think I remember me doing was putting an electrolytic in backwards and that cut the audio in the next stage. We I heard that, I said: "No way...I'm too careful." Way. I had one in backwards. I replaced it and things were as they should have been.
Jack, W8TEE
From: "Aaron Heverin aaronhev@... [SoftwareControlledHamRadio]"
To: SoftwareControlledHamRadio@...
Sent: Monday, April 11, 2016 6:01 PM
Subject: Re: [SoftwareControlledHamRadio] Re: It's Alive !
?
Norbert,
One test I did make was to disconnect the speaker, plug in the headphones, and pull the DDS board and check for hiss. It was still there. The I pulled the oscillator chip - U2 (LM 602) and still had hiss. So my thinking is that the DDS board and the local oscillator are clean and the hiss is coming directly from the LM-386 or some part in the audio amplifier circuit. I'm picking up a couple of spare LM-386 chips from a friend at our club's hamfest tomorrow so I'll give a replacement a try and report back. My problem is I tend to take a lot of these electronic components at face value... meaning if they're new, they must be perfect. I've found many times that this isn't always the case.?
I'm actually putting the radio together as part of a class a friend and I will be teaching at our radio club. In the past he's found several LM386 chips that have been brand new, but not very strong and the source for either distortion or hiss. We actually built an audio distribution amplifier for several operators to be able to wear headphone while working a special event like Field Day or Museum Ships Weekend. Had had a single input into the amp with three outputs... each controlled with a small LM386 amplifier. Sure enough, one of the outputs was lousy very distorted and hissy. I replaced the chip and all was well. I'm not saying that this is the cause of the hiss I'm experiencing, but without switching out a component or two, you're just guessing.?
Also, on the DDS board, make sure you're feeding pin J6 on the 49-er from pin J3 on the DDS board. In case you didn't see this part in Jack's manual, it's on page 20, second paragraph. I have to admit, I missed this the first time and relied solely on the schematic for the hook-up procedure.
Likewise, make sure you've got the antenna connections to the 49-er correct. If you're holding the 49-er with the sockets J2 and J4 directly in front of you, J4 will be on the left side. If you refer to the A10 in the assembly instructions, you'll see a layout of the 49-er board and then we'll both be on the same page. The center conductor for the antenna output at J4, will be the RIGHT pin, the ground connection is the left pin. Try reversing the the connection you made - if you haven't done so already and see if that brings in the signals.?
On 40 right now, the band is flooded with very strong CW signals. I've got somebody at 7.050 that's about 10 over (could be W1AW for that matter). I've made several contacts with the rig this afternoon and am really pleased. In fact, I just worked K3SEW and we were both 59+. Now if only the snow and rain would stop I'd take this thing outside, throw a wire up into a tree, and make the world go away for an hour or so while I enjoy QRP CW bliss.
Aaron - N2HTL
|
Re: DDS VFO voltage adjustment
Aaron:
Once again, I'm the software guy, not the one who designed the board; that was done by Farrukh and he is better able to answer these types of questions. That said, I do know that the pots can be used to change the drive on J3. The fact that you are getting 5W out suggests that maybe it's being over-driven, since it is a 3W transceiver. I'd back that down a little, as I do not know the power rating on the final transistor.?
Farrukh: any ideas on this?
73, jack, W8TEE
From: "aaronhev@... [SoftwareControlledHamRadio]"
To: SoftwareControlledHamRadio@...
Sent: Monday, April 11, 2016 6:19 PM
Subject: [SoftwareControlledHamRadio] DDS VFO voltage adjustment
?
Jack, and all... As you know, I'm in the process of putting together a very detailed construction manual for the radio which will be handed out to everyone who takes on the project as part of the class in our club. I wanted to ask you about the voltage adjustment of R1.?
I've been putting my prototype of the radio through some serious testing the past few days. My goal is to also use the DDS VFO to drive some of the older transmitters I have in my collection. But for the 49-er, I see that you indicate that J3 should be used to connect the 49-er to the DDS board at J6. If I'm understanding your instructions correctly, J3 is supposed to have a 4v peak-to-peak voltage on it via the buffer amp on the DDS board. This voltage can be adjusted with R1.?
As it stands now, I'm not seeing any difference in the performance of the 49-er both in receive and transmit by using either J2 or J3 on the DDS board. According to the schematic, J2 is coming directly from pin 20 on the DDS through C2, while J3 goes through the buffer amp and supplies the 4 volts voltage. I attempted to view the output voltage at J3 but saw absolutely no difference when I adjusted R1. In fact, with either J2 or J3 feeding the 49-er, I still had 5 watts output power on the radio.
Can you please clarify exactly where this voltage measurement would be taken? I simply took it directly from J3 and ground but saw nothing but a few milliwatts of DC voltage regardless of the rotation of R1.
Thank you and best 73s.
|
DDS VFO voltage adjustment
Jack, and all... As you know, I'm in the process of putting together a very detailed construction manual for the radio which will be handed out to everyone who takes on the project as part of the class in our club. I wanted to ask you about the voltage adjustment of R1.?
I've been putting my prototype of the radio through some serious testing the past few days. My goal is to also use the DDS VFO to drive some of the older transmitters I have in my collection. But for the 49-er, I see that you indicate that J3 should be used to connect the 49-er to the DDS board at J6. If I'm understanding your instructions correctly, J3 is supposed to have a 4v peak-to-peak voltage on it via the buffer amp on the DDS board. This voltage can be adjusted with R1.?
As it stands now, I'm not seeing any difference in the performance of the 49-er both in receive and transmit by using either J2 or J3 on the DDS board. According to the schematic, J2 is coming directly from pin 20 on the DDS through C2, while J3 goes through the buffer amp and supplies the 4 volts voltage. I attempted to view the output voltage at J3 but saw absolutely no difference when I adjusted R1. In fact, with either J2 or J3 feeding the 49-er, I still had 5 watts output power on the radio.
Can you please clarify exactly where this voltage measurement would be taken? I simply took it directly from J3 and ground but saw nothing but a few milliwatts of DC voltage regardless of the rotation of R1.
Thank you and best 73s.
|
Norbert,
One test I did make was to disconnect the speaker, plug in the headphones, and pull the DDS board and check for hiss. It was still there. The I pulled the oscillator chip - U2 (LM 602) and still had hiss. So my thinking is that the DDS board and the local oscillator are clean and the hiss is coming directly from the LM-386 or some part in the audio amplifier circuit. I'm picking up a couple of spare LM-386 chips from a friend at our club's hamfest tomorrow so I'll give a replacement a try and report back. My problem is I tend to take a lot of these electronic components at face value... meaning if they're new, they must be perfect. I've found many times that this isn't always the case.?
I'm actually putting the radio together as part of a class a friend and I will be teaching at our radio club. In the past he's found several LM386 chips that have been brand new, but not very strong and the source for either distortion or hiss. We actually built an audio distribution amplifier for several operators to be able to wear headphone while working a special event like Field Day or Museum Ships Weekend. Had had a single input into the amp with three outputs... each controlled with a small LM386 amplifier. Sure enough, one of the outputs was lousy very distorted and hissy. I replaced the chip and all was well. I'm not saying that this is the cause of the hiss I'm experiencing, but without switching out a component or two, you're just guessing.?
Also, on the DDS board, make sure you're feeding pin J6 on the 49-er from pin J3 on the DDS board. In case you didn't see this part in Jack's manual, it's on page 20, second paragraph. I have to admit, I missed this the first time and relied solely on the schematic for the hook-up procedure.
Likewise, make sure you've got the antenna connections to the 49-er correct. If you're holding the 49-er with the sockets J2 and J4 directly in front of you, J4 will be on the left side. If you refer to the A10 in the assembly instructions, you'll see a layout of the 49-er board and then we'll both be on the same page. The center conductor for the antenna output at J4, will be the RIGHT pin, the ground connection is the left pin. Try reversing the the connection you made - if you haven't done so already and see if that brings in the signals.?
On 40 right now, the band is flooded with very strong CW signals. I've got somebody at 7.050 that's about 10 over (could be W1AW for that matter). I've made several contacts with the rig this afternoon and am really pleased. In fact, I just worked K3SEW and we were both 59+. Now if only the snow and rain would stop I'd take this thing outside, throw a wire up into a tree, and make the world go away for an hour or so while I enjoy QRP CW bliss.
Aaron - N2HTL
?
You've been writing about this for over a week. Have you tried what has been suggested (i.e., replacing the LM386, checking the transistors, etc.)? Have you tried different sets of headphones rather than external speakers? Are the voltages on the transistors correct?
Jack, W8TEE
?
Hi!
I played with the radio for a while yesterday and I'm having some difficulty copying other stations. I hear them very low, like "far away" , fainting.?I'm noticing a lot of the "hiss" noise that Aaron described earlier.?I double checked the antenna connection and everything is OK.?
I switched to my FT817 and there were some strong signals that I could barely hear with the 49er.?
No noise when I turn the radio On ?and the antenna is not connected. The noise appears right after the splash screen and it becomes louder if I increase the volume on the external speaker.?
I did tried transmitting and was able to hear myself on another radio. Everything seems to be working fine except for that little issue I'm having when receiving other stations.?Any suggestions ???
I'm using a 12v battery.?
Regards Norbert
PS - My 49er is from ebay (vendor tianlo_go)
|
You've been writing about this for over a week. Have you tried what has been suggested (i.e., replacing the LM386, checking the transistors, etc.)? Have you tried different sets of headphones rather than external speakers? Are the voltages on the transistors correct?
Jack, W8TEE
From: "wp3dx@... [SoftwareControlledHamRadio]"
To: SoftwareControlledHamRadio@...
Sent: Monday, April 11, 2016 3:18 PM
Subject: [SoftwareControlledHamRadio] Re: It's Alive !
?
Hi!
I played with the radio for a while yesterday and I'm having some difficulty copying other stations. I hear them very low, like "far away" , fainting.?I'm noticing a lot of the "hiss" noise that Aaron described earlier.?I double checked the antenna connection and everything is OK.?
I switched to my FT817 and there were some strong signals that I could barely hear with the 49er.?
No noise when I turn the radio On ?and the antenna is not connected. The noise appears right after the splash screen and it becomes louder if I increase the volume on the external speaker.?
I did tried transmitting and was able to hear myself on another radio. Everything seems to be working fine except for that little issue I'm having when receiving other stations.?Any suggestions ???
I'm using a 12v battery.?
Regards Norbert
PS - My 49er is from ebay (vendor tianlo_go)
|
Hi!
I played with the radio for a while yesterday and I'm having some difficulty copying other stations. I hear them very low, like "far away" , fainting.?I'm noticing a lot of the "hiss" noise that Aaron described earlier.?I double checked the antenna connection and everything is OK.?
I switched to my FT817 and there were some strong signals that I could barely hear with the 49er.?
No noise when I turn the radio On ?and the antenna is not connected. The noise appears right after the splash screen and it becomes louder if I increase the volume on the external speaker.?
I did tried transmitting and was able to hear myself on another radio. Everything seems to be working fine except for that little issue I'm having when receiving other stations.?Any suggestions ???
I'm using a 12v battery.?
Regards Norbert
PS - My 49er is from ebay (vendor tianlo_go)
|
Thanks for the quick reply Jack. Guess I must have missed that file.? I think I have enough parts in the junk box to put one together.? I'll let you know the results. Dave, W0DF
|
There are photos of a BCI filter that should work with the Forty-9er posted on this site along with the values. It will be less expensive to make, since the CQ article is for 100W and uses hand-wound toroids. The parts are:
2 ? 1500pF ceramic caps 2 ? ? 560pF ? ? ? ? ? ?" 2 ? ? ?1.8uH inductor, axial lead 1 ? ? ?1.5uH ? ? ? ? ? ?"
The inductors and capacitors can all be purchased from Tayda Electronics (http://www.taydaelectronics.com/) for about a dime each. Connect it between the BNC and antenna connector on the Forty-9er. The insertion loss is about 0.04dB, so you won't even know its there. Take a look at the photos.
Jack, W8TEE
From: "dfine01@... [SoftwareControlledHamRadio]"
To: SoftwareControlledHamRadio@...
Sent: Sunday, April 10, 2016 1:08 PM
Subject: [SoftwareControlledHamRadio] Re: Forty-9er BCI Filter
?
Jack,
Is there a schematic/parts list available for the BCI filter available yet, or are you waiting for the article to appear in CQ? (which month??)?? I just let my subscription expire and will have to renew or pick one up at the local parts house tomorrow if the is in the current month??? I am experiencing some minor BCI with the 49er.
Dave
|
Hola!
Dennis and Jack, I was able to fix the "increments" issue with the new code from Jack. I ended up using the file named TempVFOCode.ino and I replaced the rotary.h and rotary.cpp (lower case) in the Rotary library. I unplugged the Nano from the VFO board and loaded the new code. If I remember correctly, ?is not a good idea to load the code with the Nano mounted on the VFO board.?I put it back together and Bingo the increments are working when I push the encoder, Thanks for the help. ?
Aaron, I still hear the stations "far away". Yes, I saw your posting about the reversed wiring colors on J2 and J4 and mine also came like that. I reversed J2 with the Red + to be on the left side. For the antenna?I'm using a small piece of coax from the 49er to the BNC jack, not sure if that makes a difference. I'm going to try your recommendation by reversing the antenna leads on the board. Right now the center conductor of the coax is on the left side of J4 (looking at it with the spk and key jacks being on the bottom and J2 and J4 towards the top side of the board).?
I have not tried TX yet.?
I'll keep you posted.?
73s Norbert -KP4WK?
|
jjpurdum