Charlie, I've been watching your videos for over a year now and I have to tell you this is pure HF circuit porn. It's just so entertaining. I can't get enough and I have my ideas on what I want to build and it will probably be a phasing rig eventually to morph into a multi-band HF rig.
I really appreciate you documenting these builds! Not only are they entertaining, I find the discussion of circuit theory invaluable. Last year while watching your QRP SSB build I was motivated to start building my own first homebrew SSB rig. Cheers and 73 From Oregon.
@@CharlieMorrisZL2CTM Right now it's a great little AM/SSB receiver that covers 80m 40m and 20m. I've been distracted learning CW, but will finish the PA and get it on the air before too long.
I'm really looking forward to some of the videos coming in this series. Especially interested in the discrete mixers and the crystal filter you talked about. Thanks for making these videos!
Charlie, I've been watching your videos for well over 2 years now, and feel that they are coming across exactly as you wish them to. Never saw your videos as anything but informative ideas. None of us are 'experts', but we all improve our level of competence by sharing our activities and ideas as you do! Cheers!
Thank you, Charlie. I don't care where you start or what project you select. it is all great! Thank you for the inspiration. you have helped me tremendously.
I find your videos inspiration to get the soldering iron out. Great to see an idea become a project and then see the results even if the results are not 100% perfect. So much more interesting than someone presenting a polished result with no mention of the development process.
For the band pass filter, look at qrp labs. The have inexpensive filters, and very detailed instructions for those to allow the assembly and also the homebrewer.
Hi Charlie. I enjoy your videos documenting your thoughts and projects. I keep telling myself as I am now retired I should get it in gear and do a little home brewing of my own. I just seem to be unmotivated to clean my work area to do it. GL & 73 Albert WB8FEQ
Get into Albert. As you can see from my work bench you don't need a lot at all. I certainly enjoy the challenge of trying to make it all work. 73 Charlie ZL2CTM
Looking forward to this build and planning to follow with the build. like Yakov very interested in building mixers using discrete components. thnx again keep it up 73s
I really appreciate that you are taking the simple route. Discrete components are fun to build with :-) I'll be interested in your use of semiconductors for the transformers. I wasn't aware that that was even an option. I'm right in the middle of planning out the modifications of my bitx40 which I just posted on my channel, and the builds actually have a lot in common in the sense of keeping it simple.
You just do things your way. It is inspirering and cosy. Love your videos. My own approach is a little different. I make schedules on my PC and cubber prints. I find that proces very interesting. And I am a clumsy builder on Vero boards. I allways ruin it by disasterrous shortings. I go for the touch screen and a bigger Arduino, because it is possible to build in so many nice functions. Aaaand I go for metal cases. I have some lying that I made myself many years ago on technical school. I will not build many rigs but only one. I will then improve on that one for the years to come. Hopefully a never ending story. Again thank you for your videos. I highly apprechiate them. 73 René, OZ1JPD.
Thanks René. I'll use the LCD first then the touch screen. My main focus for this build is simple, easy and hopefully not too expensive. Thanks for the feedback.
Hi Charlie Morris! May I have the first quaestions on this topic. What does SSB mean? It stands for "Single Side Band", doesn't it? And the PD block after IF2. What is it? A mixer? So your Radio Station would be "DOUBLE SUPERHET"? Thanks for your works and attentions!
@@CharlieMorrisZL2CTM This is the best US regen I have ever seen RCA's RAL. ua-cam.com/video/kercAWZPS-c/v-deo.html And here are the best German ones ua-cam.com/video/r19nbag65po/v-deo.html www.kriegsfunker.com/radios/lo6k39a.html
nice demonstration...excellent explanation...i have a one question sir...what are the antenna type and its characteristics???? if it is possible then please make a separate video for antenna designing for the SSB rig....
@@CharlieMorrisZL2CTM I have no direct experience, but have noticed FST3253 bus switch used in several designs. This guy: martein.home.xs4all.nl/pa3ake/hmode/switches.html has seriously tested a whole lot of them and settled on FSA3157 in his very high performance design. Also, have seen common old CD4066 being used although I suspect that performance would not be high, but available from Jaycar. Cheers, Steve
I'll be following you all the way Charlie! I've taken the disclaimer on board and as a returner to amrad and homebrew will be interested to see how this develops. Very much like the parameters of cheap and accessible parts but wonder if you would consider an option for the bigger display? Given that many hams are "mature", many may think the added cost of a larger screen is worth it in order to help old eyes.
@@CharlieMorrisZL2CTM Thanks, Charlie. I mentioned it because it was a criticism of the Xiegu G90..."great little rig, shame about the display". Thanks for all the work you put in and share.
I've bought Si5351 chips from Mouser or Digikey for under a buck each (cheaper from Mouser if I buy 10 at a whack), and solder them to breakout boards from ebay. I have a TON of 25mhz crystals. So I can build up a Si5351 for about $2. They are possible to solder by hand.
@@CharlieMorrisZL2CTM Adafruit's boards are about $8 each, add a few bucks for the SMA connectors. Ebay China sellers have them for less. Using breakout boards about 12mm square takes up less board space, but I'm using the usual wire lead crystals instead of SMT ones. Some of the Chinese made boards might be using surplus Si5351's (overstock) that were factory configured to a non-standard I2C address. That would cause a bit of head scratching to get them to work, but there is an arduino sketch that will scan the I2C bus to look for such things.
Please note for this transceiver schematic you NEED another BPF before the PA (one per band). The reason is that the output of the diode ring mixer has many unwanted products. If you just amplify them without filtering not only your PA performance will be not great because of wasted energy and IMD products but also you will transmit something like ~0.1W of power outside of amateur radio bands, even if you have a good BPF before the antenna. I know this because I tried this approach recently and the spectrum analyzer clearly showed the result. This is the reason why there are usually 2 IFs in SSB rigs, because no one wants two sets of BPF for every of 8+ bands. Speaking of PA, you can easily get 5-10W class AB using 13.8 V and 3 stages 2N2222 -> 2N2219A -> IRF510. Check out the schematics by VK3HN , e.g. vk3hn.wordpress.com/2020/03/29/pocket-sized-homebrew-40m-cw-qrpp-qrp-transceiver/ BD139 although is cheap doesn't work well above 7 Mhz. 2N2219A works quite well up to 17-15 meters. 73s de R2AUK
Thanks for that. I typically do just that for the reasons you point out. In one approach I shared the BPF between RX and TX. We'll see what happens this time. 73 Charlie ZL2CTM
Hi Charlie, I would like to see you do a video on switching methods (possibly part of the next build, or before) and why you choose not to use some methods. I think it would be beneficial to everyone and would possibly advance any future builds. If you want to switch RF signals there are 3 main methods that i can think of ( mux chips, pin diodes and relays). These are worth looking at if you want to reduce some of those QRP radios even smaller. Best regards Simon M6FJW
Hi Simon. I did experiment with diode switching a couple of years back. There should be videos on it. I must admit I found the saving in space did not outweigh the extra complexity in switching the diodes and losses across them. While a relay adds a potential mechanical failure condition, I do like their simplicity. I'll add revisiting diodes switching to the list of future things to look at.
Hi Simon. RF switching is something I’m currently experimenting with. I’ve also taken inspiration and advice from VK3HN. I’ve successfully switched RF paths using the SA630. I’m about to test the NC7SB3157 to switch a set of BPF. I’m going to select the individual NC7SB3157 using a PCF8574. I mention all of this only to add to the pool of knowledge/experiences.
@@CharlieMorrisZL2CTM No i haven't seen your video's on diode switching. While diodes can be used there are some things to consider, Like the type of diode. A pin diode is about the best of the diodes to experiment with. NO matter what you use for switching there will always be some losses. With relays and RF signals you can still get RF feedback due to RF jumping across the contacts ( at some frequencies ). The basic point is this each different type of switching has it's place. For Home Brew / DIY QRP Radio's that is going to mean a relay on the output of the power amp. The other methods wont be suitable. ( they wouldn't handle the power levels from the output stage). Now Diode switching ( pin diodes are the best type of diode for switching signals) has been used for some years now and is a proven technique. Yes the diode method has a few things to consider, The voltage and the current required to keep the diode fully open so the signal remains above the cut-off of the diode. Example: diode has a cut-off of 10 micro amps, you wouldn't try running the diode at 10 micro amps when you have a sinewave involved. Due to voltage fluctuations, it will fluctuate the current too. If the diode is turning on and off due to the RF signal this increases losses. So a rule of thumb is the cut-off voltage plus half the bias voltage plus 10% ( so the lowest part of the signal remains above the cut-off of the diode). Notice: the above example is here for clarity and education purposes and NOT to make anyone look stupid in anyway. Yes diodes are a little more complicated ( require a few more components, usually around 5 very small components), But a relay at least some of the time would require transistor switching ( if you required MCU / Processor control). So as we all can see yes even the humble relay can get more complicated if we are not careful. The final methods are transistors ( there are some with no gain and just switching capability) and mux IC's sometimes have a high on state resistance so careful selection would be required. as with all the methods there will be stray capacitances/ internal capacitances that will effect it at some frequencies making further losses due to reactance that can get over looked at times. While this shouldn't be a problem when dealing with signals on HF that doesn't mean we can ignore it entirely . Best regards Simon M6FJW
@@nevmarr Have you looked at devices like the FST3253 it's like a 2 pole and 4 way switch that is in essence controlled by a binary input on 2 pins. these 2 pins control both halves of the dual Mux. the insertion resistance is 2 ohms but if you parallel both sides up you can get approximately 1 ohm insertion resistance. They are suitable for AC and DC signals ( some mux chips are DC only ), They are a reasonable switch that last time i looked are easily available online. For RF signals i wouldn't use some of the other MUX chips due to the on state resistance being a lot higher than the FST 3253 device and possibly not suited to AC signals. Some of the softrock ensemble radio's use an FST3253 to switch up to 4 bandpass filters which is why i have mentioned it here for your consideration and experimentation. Well happy experimenting Best regards Simon M6FJW
@@simonmichaeluk Thanks Simon. I hope Charlie doesn't mind too much that this thread is a bit off topic :) I've not used the 3253 but I'll add it to my list for future trials. I have been suspicious of many of the MUX because I can't tell from the datasheet if they can handle AC/RF - as you note, a lot seem to be DC only devices. I gravitated towards the 3157 because the datasheet said it was good for 250MHz. Many thanks for your comments. As Charlie often says, it's all learning here.
Sounds like an interesting experiment to compare some random crystals to some specially selected ones, I really do want to see how much difference it makes. You also mentioned the SDR did you ever look at the link I sent that used an initial mixer and a fixed quadrature frequently.
My thoughts Charlie are with the diode mixer and 24v supply, will this be a 24 v mixer. I like the lcd displays but have you considered the old 7 segment displays for a retro effect? The laptop ps's are switchers so you may want to check for emi suppression though for 80 mtrs noise may not be the problem.
Thanks for all that. The mixers will be passive at this stage. I understand J310s are quite hard to come by, so making up a pseudo dual gate MOSFET is not an option. We'll see how it all plays out :o)
Hey Charlie! Thanks for this really good video series! 'Coudn't be better explained' is my humble appreciation for your series. 1. While trying to buy the NE5534 i found a large number of variants with suffixes. Could you please help with the exact suffix. 2. The FRS relays are also hard to come by. Could you suggest alternatives? Looking forward to your next video in this series!! Thanks & 73
Hi Rajaram. Thanks for the feedback. The NE5534s I have here are from Texas Instruments. They are marked: 25AC1LM NE5534AP. As for the relays, any DPDT should work. I had 12VDC ones in the junk box so used them. You also use 5VDC and modify the switching voltage as required. Hope this helps. Charlie
Very interested to see this one through! I plan to do something similar, but need to learn more :) Have you considered ne602 for mixer? Will there be a need for filtering si5351 harmonics?
Hi Vojislav. Yes, I have used NE612 and NE602s in the past and they work well here where we don't have an abundance of high power transmitters. There should be a few videos on their use here. As for the Si5351, no, I'll keep the square wave output as is. Check out: ua-cam.com/video/WwJKxvz7qbs/v-deo.html&feature=emb_logo
Charlie, I've been watching your videos for over a year now and I have to tell you this is pure HF circuit porn. It's just so entertaining. I can't get enough and I have my ideas on what I want to build and it will probably be a phasing rig eventually to morph into a multi-band HF rig.
Fantastic. That's great to hear thanks. Keep us posted on how you get on.
I really appreciate you documenting these builds! Not only are they entertaining, I find the discussion of circuit theory invaluable. Last year while watching your QRP SSB build I was motivated to start building my own first homebrew SSB rig. Cheers and 73 From Oregon.
That's great to hear Theo. Did you get the radio on the air, or at least receiving?
@@CharlieMorrisZL2CTM Right now it's a great little AM/SSB receiver that covers 80m 40m and 20m. I've been distracted learning CW, but will finish the PA and get it on the air before too long.
I'm really looking forward to some of the videos coming in this series. Especially interested in the discrete mixers and the crystal filter you talked about. Thanks for making these videos!
My pleasure Yakov.
Charlie,
I've been watching your videos for well over 2 years now, and feel that they are coming across exactly as you wish them to. Never saw your videos as anything but informative ideas.
None of us are 'experts', but we all improve our level of competence by sharing our activities and ideas as you do!
Cheers!
Thanks for the feedback Christina. Much appreciated.
Awesome videos! No need to apologize for unconventional approaches - that's what makes it fun and exciting! Looking forward to the next ones.
Cheers Scott. Much appreciated.
Thank you, Charlie. I don't care where you start or what project you select. it is all great! Thank you for the inspiration. you have helped me tremendously.
My pleasure Curt. Thanks for the feedback, I really do appreciate it.
I find your videos inspiration to get the soldering iron out. Great to see an idea become a project and then see the results even if the results are not 100% perfect. So much more interesting than someone presenting a polished result with no mention of the development process.
Cheers. To me they are a bit like crystal sets of my youth. Nice and simple. I still remember the thrill of hearing something.
Hey I love your videos, I like seeing how other people do these kind of things, I especially like how you go through your thinking process. Keep it up
I appreciate that Michael. I certainly enjoy it. It's not for everyone, but that's fine. Each to their own as they say.
Build cw trx abt 30yrs ago. Now started again with a 6 band cw ssb rig. Audio amp and rf amp (2sc2166 10w) done. Still have few 2sc1969😁😁
For the band pass filter, look at qrp labs. The have inexpensive filters, and very detailed instructions for those to allow the assembly and also the homebrewer.
Thanks Robert. I'll take another look.
Hi Charlie. I enjoy your videos documenting your thoughts and projects. I keep telling myself as I am now retired I should get it in gear and do a little home brewing of my own. I just seem to be unmotivated to clean my work area to do it. GL & 73 Albert WB8FEQ
Get into Albert. As you can see from my work bench you don't need a lot at all. I certainly enjoy the challenge of trying to make it all work. 73 Charlie ZL2CTM
Wow, all of that sounds really interesting. Thanks Charlie! Cheers, Ian
Thanks Ian. Hopefully it will all work!
Looking forward to this build and planning to follow with the build. like Yakov very interested in building mixers using discrete components.
thnx again keep it up
73s
Thanks Khalid. Hopefully, the 1N5711s will turn up soon.
I really appreciate that you are taking the simple route. Discrete components are fun to build with :-) I'll be interested in your use of semiconductors for the transformers. I wasn't aware that that was even an option. I'm right in the middle of planning out the modifications of my bitx40 which I just posted on my channel, and the builds actually have a lot in common in the sense of keeping it simple.
Great to hear. I'm having fun!
You just do things your way. It is inspirering and cosy. Love your videos.
My own approach is a little different. I make schedules on my PC and cubber prints. I find that proces very interesting. And I am a clumsy builder on Vero boards. I allways ruin it by disasterrous shortings.
I go for the touch screen and a bigger Arduino, because it is possible to build in so many nice functions. Aaaand I go for metal cases. I have some lying that I made myself many years ago on technical school. I will not build many rigs but only one. I will then improve on that one for the years to come. Hopefully a never ending story.
Again thank you for your videos. I highly apprechiate them.
73 René, OZ1JPD.
Thanks René. I'll use the LCD first then the touch screen. My main focus for this build is simple, easy and hopefully not too expensive. Thanks for the feedback.
Looking forward the build!
Thanks Andy
Looking forward to seeing the build.
Thanks Bob. Hopefully, I can make it all work.
@@CharlieMorrisZL2CTM So do I :-))
Hi Charlie Morris! May I have the first quaestions on this topic. What does SSB mean? It stands for "Single Side Band", doesn't it? And the PD block after IF2. What is it? A mixer? So your Radio Station would be "DOUBLE SUPERHET"? Thanks for your works and attentions!
Woo hoo - looks like a great design we can all follow along with ! !
I hope so Chris. That will be the aim!
@@CharlieMorrisZL2CTM :-)
I would love to see you take on a high performance, regenerative or super regen based transciever
Hi Stephen. I must do a regen at some stage. I'll add it to the list.
@@CharlieMorrisZL2CTM This is the best US regen I have ever seen RCA's RAL.
ua-cam.com/video/kercAWZPS-c/v-deo.html
And here are the best German ones
ua-cam.com/video/r19nbag65po/v-deo.html
www.kriegsfunker.com/radios/lo6k39a.html
nice demonstration...excellent explanation...i have a one question sir...what are the antenna type and its characteristics???? if it is possible then please make a separate video for antenna designing for the SSB rig....
Thank you! Looking forward for next interesting piece of HF:)
Cheers. Just working on the crystal filter now.
Looking forward to updates!
Cheers Tony.
Using an analogue-switch IC as a mixer might be interesting in a future project.
Thanks Stephen. I've also added that top the list of things to look at in the future. Do you have a part number in mind?
@@CharlieMorrisZL2CTM I have no direct experience, but have noticed FST3253 bus switch used in several designs.
This guy: martein.home.xs4all.nl/pa3ake/hmode/switches.html has seriously tested a whole lot of them and settled on FSA3157 in his very high performance design.
Also, have seen common old CD4066 being used although I suspect that performance would not be high, but available from Jaycar.
Cheers,
Steve
Sounds good Charlie - as always.
Cheers Harry.
I'll be following you all the way Charlie! I've taken the disclaimer on board and as a returner to amrad and homebrew will be interested to see how this develops. Very much like the parameters of cheap and accessible parts but wonder if you would consider an option for the bigger display? Given that many hams are "mature", many may think the added cost of a larger screen is worth it in order to help old eyes.
Yes, I will add a larger display once the initial 'simple' version is made. I'll mention that in the next video.
@@CharlieMorrisZL2CTM Thanks, Charlie. I mentioned it because it was a criticism of the Xiegu G90..."great little rig, shame about the display". Thanks for all the work you put in and share.
I've bought Si5351 chips from Mouser or Digikey for under a buck each (cheaper from Mouser if I buy 10 at a whack), and solder them to breakout boards from ebay. I have a TON of 25mhz crystals. So I can build up a Si5351 for about $2. They are possible to solder by hand.
That's interesting. $2 is a great price for a nice stable VFO. I must admit I take the easy way out and buy the boards.
@@CharlieMorrisZL2CTM Adafruit's boards are about $8 each, add a few bucks for the SMA connectors. Ebay China sellers have them for less. Using breakout boards about 12mm square takes up less board space, but I'm using the usual wire lead crystals instead of SMT ones. Some of the Chinese made boards might be using surplus Si5351's (overstock) that were factory configured to a non-standard I2C address. That would cause a bit of head scratching to get them to work, but there is an arduino sketch that will scan the I2C bus to look for such things.
Please note for this transceiver schematic you NEED another BPF before the PA (one per band). The reason is that the output of the diode ring mixer has many unwanted products. If you just amplify them without filtering not only your PA performance will be not great because of wasted energy and IMD products but also you will transmit something like ~0.1W of power outside of amateur radio bands, even if you have a good BPF before the antenna. I know this because I tried this approach recently and the spectrum analyzer clearly showed the result. This is the reason why there are usually 2 IFs in SSB rigs, because no one wants two sets of BPF for every of 8+ bands. Speaking of PA, you can easily get 5-10W class AB using 13.8 V and 3 stages 2N2222 -> 2N2219A -> IRF510. Check out the schematics by VK3HN , e.g. vk3hn.wordpress.com/2020/03/29/pocket-sized-homebrew-40m-cw-qrpp-qrp-transceiver/ BD139 although is cheap doesn't work well above 7 Mhz. 2N2219A works quite well up to 17-15 meters. 73s de R2AUK
Thanks for that. I typically do just that for the reasons you point out. In one approach I shared the BPF between RX and TX. We'll see what happens this time.
73
Charlie ZL2CTM
Hi Charlie,
I would like to see you do a video on switching methods (possibly part of the next build, or before) and why you choose not to use some methods. I think it would be beneficial to everyone and would possibly advance any future builds. If you want to switch RF signals there are 3 main methods that i can think of ( mux chips, pin diodes and relays). These are worth looking at if you want to reduce some of those QRP radios even smaller.
Best regards
Simon M6FJW
Hi Simon. I did experiment with diode switching a couple of years back. There should be videos on it. I must admit I found the saving in space did not outweigh the extra complexity in switching the diodes and losses across them. While a relay adds a potential mechanical failure condition, I do like their simplicity. I'll add revisiting diodes switching to the list of future things to look at.
Hi Simon. RF switching is something I’m currently experimenting with. I’ve also taken inspiration and advice from VK3HN. I’ve successfully switched RF paths using the SA630. I’m about to test the NC7SB3157 to switch a set of BPF. I’m going to select the individual NC7SB3157 using a PCF8574. I mention all of this only to add to the pool of knowledge/experiences.
@@CharlieMorrisZL2CTM
No i haven't seen your video's on diode switching. While diodes can be used there are some things to consider, Like the type of diode. A pin diode is about the best of the diodes to experiment with. NO matter what you use for switching there will always be some losses. With relays and RF signals you can still get RF feedback due to RF jumping across the contacts ( at some frequencies ). The basic point is this each different type of switching has it's place. For Home Brew / DIY QRP Radio's that is going to mean a relay on the output of the power amp. The other methods wont be suitable. ( they wouldn't handle the power levels from the output stage). Now Diode switching ( pin diodes are the best type of diode for switching signals) has been used for some years now and is a proven technique. Yes the diode method has a few things to consider, The voltage and the current required to keep the diode fully open so the signal remains above the cut-off of the diode.
Example: diode has a cut-off of 10 micro amps, you wouldn't try running the diode at 10 micro amps when you have a sinewave involved. Due to voltage fluctuations, it will fluctuate the current too. If the diode is turning on and off due to the RF signal this increases losses. So a rule of thumb is the cut-off voltage plus half the bias voltage plus 10% ( so the lowest part of the signal remains above the cut-off of the diode).
Notice: the above example is here for clarity and education purposes and NOT to make anyone look stupid in anyway.
Yes diodes are a little more complicated ( require a few more components, usually around 5 very small components), But a relay at least some of the time would require transistor switching ( if you required MCU / Processor control). So as we all can see yes even the humble relay can get more complicated if we are not careful.
The final methods are transistors ( there are some with no gain and just switching capability) and mux IC's sometimes have a high on state resistance so careful selection would be required. as with all the methods there will be stray capacitances/ internal capacitances that will effect it at some frequencies making further losses due to reactance that can get over looked at times. While this shouldn't be a problem when dealing with signals on HF that doesn't mean we can ignore it entirely
.
Best regards
Simon M6FJW
@@nevmarr Have you looked at devices like the FST3253 it's like a 2 pole and 4 way switch that is in essence controlled by a binary input on 2 pins. these 2 pins control both halves of the dual Mux. the insertion resistance is 2 ohms but if you parallel both sides up you can get approximately 1 ohm insertion resistance. They are suitable for AC and DC signals ( some mux chips are DC only ), They are a reasonable switch that last time i looked are easily available online. For RF signals i wouldn't use some of the other MUX chips due to the on state resistance being a lot higher than the FST 3253 device and possibly not suited to AC signals. Some of the softrock ensemble radio's use an FST3253 to switch up to 4 bandpass filters which is why i have mentioned it here for your consideration and experimentation.
Well happy experimenting
Best regards
Simon M6FJW
@@simonmichaeluk Thanks Simon. I hope Charlie doesn't mind too much that this thread is a bit off topic :) I've not used the 3253 but I'll add it to my list for future trials. I have been suspicious of many of the MUX because I can't tell from the datasheet if they can handle AC/RF - as you note, a lot seem to be DC only devices. I gravitated towards the 3157 because the datasheet said it was good for 250MHz. Many thanks for your comments. As Charlie often says, it's all learning here.
Sounds like an interesting experiment to compare some random crystals to some specially selected ones, I really do want to see how much difference it makes. You also mentioned the SDR did you ever look at the link I sent that used an initial mixer and a fixed quadrature frequently.
Yes I did thanks Brian. That looked quite interesting.
My thoughts Charlie are with the diode mixer and 24v supply, will this be a 24 v mixer. I like the lcd displays but have you considered the old 7 segment displays for a retro effect? The laptop ps's are switchers so you may want to check for emi suppression though for 80 mtrs noise may not be the problem.
Thanks for all that. The mixers will be passive at this stage. I understand J310s are quite hard to come by, so making up a pseudo dual gate MOSFET is not an option. We'll see how it all plays out :o)
Perhaps you could add "digital pots" to the list of things to try please?
That's a great idea. I've added it the list, but I'll defer it to the next build. Could be a nice AGC alternative. Bit like a volume regulator.
Hey Charlie! Thanks for this really good video series! 'Coudn't be better explained' is my humble appreciation for your series. 1. While trying to buy the NE5534 i found a large number of variants with suffixes. Could you please help with the exact suffix.
2. The FRS relays are also hard to come by. Could you suggest alternatives? Looking forward to your next video in this series!! Thanks & 73
Hi Rajaram. Thanks for the feedback. The NE5534s I have here are from Texas Instruments. They are marked: 25AC1LM NE5534AP. As for the relays, any DPDT should work. I had 12VDC ones in the junk box so used them. You also use 5VDC and modify the switching voltage as required. Hope this helps. Charlie
@@CharlieMorrisZL2CTM Thanks a ton!
Very interested to see this one through! I plan to do something similar, but need to learn more :) Have you considered ne602 for mixer? Will there be a need for filtering si5351 harmonics?
Hi Vojislav. Yes, I have used NE612 and NE602s in the past and they work well here where we don't have an abundance of high power transmitters. There should be a few videos on their use here. As for the Si5351, no, I'll keep the square wave output as is. Check out: ua-cam.com/video/WwJKxvz7qbs/v-deo.html&feature=emb_logo
Really love these videos Charlie. Have you thought about trying a 2M SSB transceiver?
Hi. No, I mainly stick with HF. One of these day I might look into a SSB VHF rig. Thanks for the feedback.
A 16X4 wouldn't be too much more in cost.
Yes I agree. I think I'll use the 16x2 first, then change it at the end. My main focus is cost.