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.
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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
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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
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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)
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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)
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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)
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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
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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
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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
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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?
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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
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Re: It's Alive ! [1 Attachment]
Norbert, Were you able to figure out the issue you were having with receiving stations and the fact they sounded "far away?" I'm not sure how the individual parts in your 49-er kit were put into the packaging, but on mine, the cables for J2 (power in) and J4 (antenna out) were wired backwards IF you want to use a standard of the red wire being "+" and the black wire being "-".
If I had made the antenna connection to J4 with the way my cables were assembled, the center conductor of the coax going to my antenna would be coming off the ground of the 49-er - which was the red wire at J4. After I fixed the issue, I experimented with switching the wires around at J4 (since I was using clip leads at the time I did the first test), and sure enough, the signals I was hearing sounded like they were being picked up by an antenna that was nothing more than a 3 foot piece of coax. I used a sharp soldering pick to push the two pins out of the white molex connector and simply reversed them.
Hope you get your radio on the air and can make a few contacts with it. We should try a sched!
Aaron - N2HTL
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[Attachment(s) from wp3dx@... [SoftwareControlledHamRadio] included below]
OK guys, I managed to put everything together and so far is looking good.?
It powered up fine, so far I'm noticing that the encoder "step" function is not working when I push it down. It does move up and down with no problems. ?
I can hear stations but they are very low, I hear them like far away if you know what I mean.? I tried an external speaker and also with the headphones.?
For the enclosure I ended up using an old Netgear router that wasn't working. I stripped everything out and managed to fit the VFO board and the 49er inside. It actually looks good.?
For power I used an SLA 12V battery.
I have not tried transmitting yet.?
I've been on this for a few hours now, tomorrow is another day, Good Night Everybody !?
Cheers !? Norbert
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See my last post. If you downloaded the rotary file from the website listed in the vfo sketch, the increment function will NOT work.? Get the rotary files that Jack posted a few days ago and that will solve your problem.
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SUCCESS AT LAST!!!!!!
After weeks of trying to figure out what I did wrong, my DDS VFO is working flawlessly and the increment problem has been solved. I replaced the rotary files downloaded from github with the ones Jack sent me and it now works.
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OK guys, I managed to put everything together and so far is looking good.?
It powered up fine, so far I'm noticing that the encoder "step" function is not working when I push it down. It does move up and down with no problems. ?
I can hear stations but they are very low, I hear them like far away if you know what I mean. ?I tried an external speaker and also with the headphones.?
For the enclosure I ended up using an old Netgear router that wasn't working. I stripped everything out and managed to fit the VFO board and the 49er inside. It actually looks good.?
For power I used an SLA 12V battery.
I have not tried transmitting yet.?
I've been on this for a few hours now, tomorrow is another day, Good Night Everybody !?
Cheers !? Norbert
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Re: 40m QRP Transmitter Success
Am having some success making contacts with the 49-er transceiver this evening due to the SKCC Weekend Sprint contest going on at the moment. Just to clarify the setup on this end, the 49-er is taking power from the DDS board, but THAT is being powered by a 12v gel cell. No wall-warts being used. I noticed that as soon as I apply power, the hiss starts immediately...very loud. After the splash screen goes away and the frequency display is active, CW signals are heard with very little band noise but the hiss is still there. I'm listing at the moment using a pair of ear buds and over-the-ear headphones - switching back and forth. Aaron - N2HTL
On Fri, Apr 8, 2016 at 11:42 PM, Aaron Heverin <aaronhev@...> wrote: Thanks, Jack. I suppose that's another issue too, isn't it? 40m has been very rough lately for hearing any sort of signals worth copying. I've got the radio on now and there are LOADS of CW signals on the band. In fact, it's copying a signal on 7.054 that's very loud... but there still seems to be excessive amounts of hiss present. If I switch from the amplified speaker to the headphones, the CW signals are almost too faint to copy unless you really concentrate. Too much work there since I'm still trying to bring my CW skills way up from where they were back in 1981.
I was thinking about the LM386 being a bit suspect and I started tearing my parts drawers apart trying to find another. I've got more laying around here someplace but can never find one when I need it. :-)
And you're absolutely right about the Pixie. I built it and put it on the air several times and made some contacts with it... but the darned thing is so susceptible to the strong AM broadcast stations in my neck of the woods (even with a band-pass filter in line) that it's not much fun to use. Been in a box for the past two years.
73s.
Aaron - N2HTL
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Re: How do I power the 49er ?
My apologies to the group. It appears this thread has be hijacked to continue the discussion about the hiss issue I'm having with my 49-er. I have some additional information but I'll put it out on the thread I started regarding the issue - ?"40m QRP Transceiver Success." Many thanks... and apologies again.
Aaron - N2HTL
On Sat, Apr 9, 2016 at 10:47 PM, Aaron Heverin <aaronhev@...> wrote: Thanks, Dave. Well... that's exactly what I'm using - a 12 volt gel cell. Heavy bugger but it's working great. The radio itself is working perfectly. The rotary encoder is tuning as it should. 40m is loaded with signals tonight. In fact, I'm making some contacts during the SKCC Weekend Sprint with the radio right now. I'm just trying to get to the bottom of the the excessive hiss coming from the audio output. Unfortunately, I don't have another LM386 chip on hand to see if perhaps the chip is weak in some way.? Aaron - N2HTL
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Re: How do I power the 49er ?
Thanks, Dave. Well... that's exactly what I'm using - a 12 volt gel cell. Heavy bugger but it's working great. The radio itself is working perfectly. The rotary encoder is tuning as it should. 40m is loaded with signals tonight. In fact, I'm making some contacts during the SKCC Weekend Sprint with the radio right now. I'm just trying to get to the bottom of the the excessive hiss coming from the audio output. Unfortunately, I don't have another LM386 chip on hand to see if perhaps the chip is weak in some way.? Aaron - N2HTL
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Aaron,? I am using a 12 volt gel cell battery to power my 49er and I'm using Yamaha CM-500 headphones.? I don't know if the earbuds would make a difference or not, but as Jack just said, wall warts are generally junk and plagued with noise and are not acceptable for use on the 49er.
Also, regarding the rotary encoder, I originally tried to use one of the encoders with the resistors on the circuit board.? It was one that came with one of the Arduino starter kits.? It did not work.? I don't know if it was a bad encoder (suspect it was), or if it was incompatible in some way.? I had some that were stand alones (not on a PCB) without the resistors that I had purchased from Adafruit, they worked fine.
Dave, W0DF
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I have a Jetstream 30A power supply with adjustable output voltage. I run it at 13.8V for my 100W rig, but 12V for my Forty-9er. Wall warts can be very noisy and so can some cheap 12V supplies. If you have a scope, look at the output.
Jack, W8TEE
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What are you using to power the 49er with, battery, wall wart, 12 volt supply???
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Hi Dave. Just disconnected the antenna and there's a lot of hiss on the output. Of course, the band is flooded with signals tonight due to the SKCC Weekend Sprint going on so it's much busier than it was last night. But regardless, with just a pair of earbuds on, it's very hissy. On very weak signals, the hiss makes it very hard to copy any weak signals.
Aaron - N2HTL On Sat, Apr 9, 2016 at 10:02 PM, dfine100@... [SoftwareControlledHamRadio] <SoftwareControlledHamRadio@...> wrote:
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Aaron,
What does the audio sound like with the antenna disconnected?? Are you hearing 40 meter band noise, or are you hearing audio hiss from within the 49er circuitry. I have one working and it does not have hiss when the antenna is disconnected.? Also, what are using for the 12 volt power supply?
Dave, W0DF
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Hello Norbert. I'm glad you found the solution. Was just about to respond when I read your latest post. Glad you got it resolved.?
I was wondering if you could do me a small favor. Once you power up the 49-er and get a chance to test it out, would you please report your findings on the quality of the signals coming from the audio output of the 49-er? I'm chasing down an issue with what seems to be excessive hiss - not band noise - coming from mine and since I've never assembled a 49-er before, I'm not sure how it's supposed to sound. Having another example to compare mine to would be a great help in determining if anything isn't right here.
Many thanks... and best 73s.
Aaron - N2HTL
On Sat, Apr 9, 2016 at 9:28 PM, wp3dx@... [SoftwareControlledHamRadio] <SoftwareControlledHamRadio@...> wrote:
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Got it, in finding some minor differences between the instructions in the QST and Farruk's link. I re-read the whole thing and page 22 on the QST instructions clearly states;
"12V power for the Forty-9er is taken from pins 1 and 3 of the J1 header on the Nano/VFO board."
Regards Norbert
-- Aaron
-- Aaron
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Re: How do I power the 49er ?
Aaron,? I am using a 12 volt gel cell battery to power my 49er and I'm using Yamaha CM-500 headphones.? I don't know if the earbuds would make a difference or not, but as Jack just said, wall warts are generally junk and plagued with noise and are not acceptable for use on the 49er.
Also, regarding the rotary encoder, I originally tried to use one of the encoders with the resistors on the circuit board.? It was one that came with one of the Arduino starter kits.? It did not work.? I don't know if it was a bad encoder (suspect it was), or if it was incompatible in some way.? I had some that were stand alones (not on a PCB) without the resistors that I had purchased from Adafruit, they worked fine.
Dave, W0DF
On Saturday, April 9, 2016 9:32 PM, "Jack Purdum jjpurdum@... [SoftwareControlledHamRadio]" wrote:
?
I have a Jetstream 30A power supply with adjustable output voltage. I run it at 13.8V for my 100W rig, but 12V for my Forty-9er. Wall warts can be very noisy and so can some cheap 12V supplies. If you have a scope, look at the output.
Jack, W8TEE
From: "dfine100@... [SoftwareControlledHamRadio]"
To: "SoftwareControlledHamRadio@..."
Sent: Saturday, April 9, 2016 10:19 PM
Subject: Re: [SoftwareControlledHamRadio] Re: How do I power the 49er ?
?
What are you using to power the 49er with, battery, wall wart, 12 volt supply???
On Saturday, April 9, 2016 9:15 PM, "Aaron Heverin aaronhev@... [SoftwareControlledHamRadio]" wrote:
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Hi Dave. Just disconnected the antenna and there's a lot of hiss on the output. Of course, the band is flooded with signals tonight due to the SKCC Weekend Sprint going on so it's much busier than it was last night. But regardless, with just a pair of earbuds on, it's very hissy. On very weak signals, the hiss makes it very hard to copy any weak signals.
Aaron - N2HTL
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Re: How do I power the 49er ?
Sorry... forgot to answer that question. I'm using a 12v, 8aH battery. It's the same one I use when I take my other rigs portable. Aaron - N2HTL
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I have a Jetstream 30A power supply with adjustable output voltage. I run it at 13.8V for my 100W rig, but 12V for my Forty-9er. Wall warts can be very noisy and so can some cheap 12V supplies. If you have a scope, look at the output.
Jack, W8TEE
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What are you using to power the 49er with, battery, wall wart, 12 volt supply???
?
Hi Dave. Just disconnected the antenna and there's a lot of hiss on the output. Of course, the band is flooded with signals tonight due to the SKCC Weekend Sprint going on so it's much busier than it was last night. But regardless, with just a pair of earbuds on, it's very hissy. On very weak signals, the hiss makes it very hard to copy any weak signals.
Aaron - N2HTL On Sat, Apr 9, 2016 at 10:02 PM, dfine100@... [SoftwareControlledHamRadio] <SoftwareControlledHamRadio@...> wrote:
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Aaron,
What does the audio sound like with the antenna disconnected?? Are you hearing 40 meter band noise, or are you hearing audio hiss from within the 49er circuitry. I have one working and it does not have hiss when the antenna is disconnected.? Also, what are using for the 12 volt power supply?
Dave, W0DF
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Hello Norbert. I'm glad you found the solution. Was just about to respond when I read your latest post. Glad you got it resolved.?
I was wondering if you could do me a small favor. Once you power up the 49-er and get a chance to test it out, would you please report your findings on the quality of the signals coming from the audio output of the 49-er? I'm chasing down an issue with what seems to be excessive hiss - not band noise - coming from mine and since I've never assembled a 49-er before, I'm not sure how it's supposed to sound. Having another example to compare mine to would be a great help in determining if anything isn't right here.
Many thanks... and best 73s.
Aaron - N2HTL
On Sat, Apr 9, 2016 at 9:28 PM, wp3dx@... [SoftwareControlledHamRadio] <SoftwareControlledHamRadio@...> wrote:
?
Got it, in finding some minor differences between the instructions in the QST and Farruk's link. I re-read the whole thing and page 22 on the QST instructions clearly states;
"12V power for the Forty-9er is taken from pins 1 and 3 of the J1 header on the Nano/VFO board."
Regards Norbert
-- Aaron
-- Aaron
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Re: Lead Free Soldering - Some lessons here may transfer over to building your circuits.
I'll second Jack's recommendation on the Radio Shack solder.? That is all I use on circuit boards.? It is great stuff.? If I ever run out, I may have to quit the hobby.
Dave. W0DF
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Re: How do I power the 49er ?
I have a Jetstream 30A power supply with adjustable output voltage. I run it at 13.8V for my 100W rig, but 12V for my Forty-9er. Wall warts can be very noisy and so can some cheap 12V supplies. If you have a scope, look at the output.
Jack, W8TEE
From: "dfine100@... [SoftwareControlledHamRadio]"
To: "SoftwareControlledHamRadio@..."
Sent: Saturday, April 9, 2016 10:19 PM
Subject: Re: [SoftwareControlledHamRadio] Re: How do I power the 49er ?
?
What are you using to power the 49er with, battery, wall wart, 12 volt supply???
On Saturday, April 9, 2016 9:15 PM, "Aaron Heverin aaronhev@... [SoftwareControlledHamRadio]" wrote:
?
Hi Dave. Just disconnected the antenna and there's a lot of hiss on the output. Of course, the band is flooded with signals tonight due to the SKCC Weekend Sprint going on so it's much busier than it was last night. But regardless, with just a pair of earbuds on, it's very hissy. On very weak signals, the hiss makes it very hard to copy any weak signals.
Aaron - N2HTL
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Re: Lead Free Soldering - Some lessons here may transfer over to building your circuits.
I never use lead-free solder. I prefer 62/36/2 in a .022" diameter (2% silver). It melts like a dream at low temps. Radio Shack carried it, but it's getting tough to find. I found 7 spools on eBay and bought all 7. If you still have a RS in business, see if they still have some. It so, buy it...and I'll buy it from you if you don't want it.
Jack, W8TEE
From: "white512@... [SoftwareControlledHamRadio]"
To: SoftwareControlledHamRadio@...
Sent: Saturday, April 9, 2016 4:02 PM
Subject: [SoftwareControlledHamRadio] Lead Free Soldering - Some lessons here may transfer over to building your circuits.
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I rarely use lead free solder - my fav is 63/37 or 60/40. However recently the PCB in my A/C and Heat Pump started twinking out.?
After troubleshooting the obvious (connectors, sensors, relays) I surmised a cold solder joint. Careful inspection under a 30X jewelers loupe didn't reveal any obvious breaks or bad solder joints. But since I had taken it out I decided to re-solder every connection on the PCB. ?
I wasn't able to get good wetting with my workhorse soldering pencil. Instead, I noted that it only came up to about 275 degrees C when measured using a K type thermocouple - I have a new tip on order as it appears it has degraded over the years. Certainly still good for basic 60/40 solder but not satisfactory due to the heat I needed to transfer to many of the more substantial component connectors on the PCB and the obvious lead free solder. Even my more rugged Weller soldering gun struggled a tad.
So, if you suspect lead free solder, be prepared to crank up the temp to 325 C. or more. Am also now looking into a more versatile temperature controlled soldering pencil. ?I am posting this as I'm seeing more and more commercial PCBs with lead free solder.
Oh, the AC/Heat Pump works fine now.
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jjpurdum