Just checking in with you. We all really miss you, and hope you are doing OK. Even though you have a small channel, your content has been some of the very best in Ham Radio. So, hopefully you're not burnt out (you were running like a flaming torch Hi-Hi!) and have many more projects in the old noggin'! Take Care and 73 from DM-78...
Charlie, Thank you for all your videos. I have learned so much from you, so please keep up with your videos. I know u are busy but I am always checking in to see what's next.
Charlie -- Just checking in to see how you're doing. Hope all is going well in the real-world (if you can call it that!). Hope to see you back and building/sharing your work. Best of Luck & 73...
@@CharlieMorrisZL2CTM Moving is so much work! I can't even imagine moving again in my lifetime. I've accumulated a bunch of tools and equipment and animals now. I would just keep this place and rent or buy another. lol I sincerely wish you the best moving and pray it goes very well for you! as we get older it gets harder for sure. Oh, and also watch for more antenna room! lol
Hello Charlie. Hope you and yours are ok and well down under mate. I hear things here in the States about whats going on down there. I hope all is well and you return to your youtube channel as soon as you see fit. Take care mate and Merry Christmas. -73's
Great idea! I was thinking of an atu for a mag loop to do the same thing via LORA control. I can't find your blog to get circuit detailsvfrom your awesome projects. So the best!
Hi Charlie, hope everyone is well, as always some interesting projects on the go. I like the little display on the clock, shall have to look for some of those. I built a clock a few years ago with the DS3231, think there may even be a short clip on my RU-vid channel. And when I plugged it in after being sat in the corner for well over a year I found it had only lost around 30 seconds. Great little module. Anyway keep that solder flowing, 73 for now.
Thanks Brian. I must admit I have a few clocks here and there. The RTC clock at work keeps excellent time. Been ticking away for a couple of years now. Take care. Charlie
Hi Chalie, some good ideas there. just starting on a antenna switch relay box and the repair and re-boxing of a long wire ATU unit. So some RF work coming to my channel. Good luck with all the changes coming up and stay well. 73
Thanks David. I'm keen to give it a go and see what happens. I think I might get a second motor and have that drive a rotary switch. I can see some experimenting coming on!
That digi-mode board is really neat Charlie, physically, and in keeping the main PC free. I have to confess I cam out in a cold sweat at the thought of using 4 pole relays, I have had some horrors with 2 pole so will be very interested to see how they pan out. I have a relay switched SSB transceiver using relays around the IF strip, using N6QW's simple SSB design. Works really well. Hope the house move goes well, always fraught times!
Hi Charlie. I thought I'd just drop you a line about the antenna matcher idea. I use an old Racal matcher that was allegedly designed for use on ships. I could find no information on it so I had to reverse engineer it to figure out how to use it. It's not automatic but it is programmable so you can set a combination of L and C for each band and then simply switch bands, or a portion of a band. It works really well. The bit, which you may have already thought of, is that the inductances used are pretty much in a binary format once they get past 1uH. So the sequence is; 0.25uH, 0.5uH, 1uH, 2uH, 4uH, 8uH, 16uH and 32uH. For the capacitance it isn't so easy because I guesss the high voltage capacitors aren't available in strange values. For that side they chose 12pF, 24pF, 50pF, 100pF, 200pF, 400pF 800pF, 1600pF and 3200pF. I use this to match to an inverted L antenna at it's base with the controller in the shack. I've never needed more than the 800pF capacitance and I suspect that's because my garden is quite short so the antenna is likely to require inductance. To make it more versatile, I use the control lines for the 1600 and 3200pF capacitors to control the switching of a multiple position UnUn. Relays change the tappings on a trifilar coil giving me a great range of input and output impedances. If anything it might be too versatile as it can be difficult to work out what combination of L match and UnUn will work the best. I think writing code to do that would be one hell of a challenge but for the basic matcher/tuner without the UnUn it should be pretty conventional. Good luck. I hope this gives you some pointers. Oh, and if you decide to go down the stepper motor/ variable capacitor route, take a look at what people have done with automatic mag loop tuners. There's some good stuff out there.
Just built a stepper driver for tuning my loop antenna. Microstep give 3200 steps per rotation. Problem is switch mode stepper driver has amps switching at 400kHz! And the RF radiation is huge, and so cannot be used on RX. However work fine on TX, with tuning adjusted by either a AD8307 RF meter + short antenna, or by NanoVNA to display the SWR dip. Not tried auto tune yet...
Yay, another video! Funny you mention measuring IMD that way. Heretofore, I've used a cheap siggen and an attenuating combiner to do such tests. I recently bought the very same siglent you have there. This afternoon I compared the siglent with my combiner vs the internal signal combination feature, and I see a 5dB difference in the resulting IP3. My guess is that the isolation in my combiner isn't as good as what the generator does when it's set to combine them, and I'm likely getting a much more accurate measurement this way. My little dual gate mosfet VGA might have a 24dBm OIP3 instead of the 19dBm I previously thought!
Quite keen to see how you get on with the auto ant tuner, I don't want to buy the versions that have a dozen relays all operating even on receive drawing more power than the QRP transmitter. If you can achieve a low current in operation - that would be marvelous. Yep motor driven Cap and ferrite Rod inductor might be ideal. Tuning speed is not really important. I like seeing your projects. Thanks.
Just another thought - is it possible I wonder, to sense resonance another way than TX SWR? maybe measuring the reactive load and tuning for 50 ohms in Receive mode similar to how a VNA would?
Big shout for an ATU project - really would like to see that. I've always liked doing it in stepper motors but variable capacitors are shockingly expensive. I've personally found relay ATUs aren't as good as manual tuners - often can't get a match when the tuner can - so variable caps are much better
Hi Charlie! It's good to have you back. It sounds like you've got a lot planned. I'm particularly interested in the auto ATU as I've thought about building one myself. I love the clock as well. Will you post the code on your blog for that please? We're moving house soon so I feel your pain on that one. I'm loving the array of Siglents by the way too. Thanks for all you share with us. 73 Nick M0NTV.
Sounds fun! Can't wait to see what you find with the IF amps and how the project comes along. I see the serial adapter and wonder, have you ever thought about adding digital (CAT) control to your radio?
Hi Dennis. Yes I have tried CAT control and it worked quite well. There should be a video on that somewhere. I'm looking forward to the IF amps as well.
Charlie: Have you ever used analog-transmission-gates (i.e. 4016, 4066, 4051-4053--or even discrete FET's)? They do have some on resistance (aprox. 125 ohms) but they can handle signals up to 40 MHz. Maybe not appropriate where you are switching power but for analog-DC and low-level RF, I've found they work great. But the main reason I like them is for power savings and that they can be left in any configuration with just static voltage. Also, I've in the past used DIP reed-relays as their current draw is very low in comparison. Anyway, good luck dealing with the 'real-world' and best to ya! 73...
those big relays work nice for switch but are big. i did find some nice smal RF switches that can be controlled by arduino's :) examples: HMC321, HMC284, HMC252, HMC7992. they are between 2 and 8 ports and are between DC and up to 8GHz. they do not handle much power but are good for routing internal RF signals.
Be interested to know why you chose siglent over rigol for those shiney new test instruments, if that was even a consideration. I’m thinking of splashing out on similar stuff. I can’t afford Tektronix or Agilent stuff (who could as a hobbyist?)…. Be VERY interested in the 3rd intercept point measurements, how you take them, what they mean for your designs, and how you improve things in the light of the measurements you take.
In the end I went with a local supplier, as the support was excellent and the capabilities exactly what I was after. So far i am really pleased with all three units.
One big advantage the Siglents have over Rigol is they don't charge you for the cool features -- everything's enabled new in box. I'm talking about the oscilloscopes, BTW. Sure, you can hack the Rigol firmware, but why bother when a competitor makes a great product that doesn't need it? On the sig-gen, I found the Rigol's specs to be somewhat lackluster by comparison. E.g., harmonic distortion figures are usually about 10dB worse on the Rigols.
Instead of relays, how about fet switches? The 74AC4053 is a "triple pole double throw" (three SPDT) fet switch, and available in both DIP and SMT packages. Also cheap.
I'm fascinated by the desk clock you already built at 3:10 . Can you tell me more about it? Is that a magnifying lens in front of a smaller screen? Did it start life as a mini TV or similar?
The spec an is the Siglent SSA 3032X. So far I am enjoying it, noting that I am only using 1% of its capabilities. I'm looking forward to learning more about it, and how best to use it for simple circuit design.
I've been drooling over some TO-5 package Teledyne relays, but they're $50-$70US and I need to convince myself that I don't need them. Seeing you doing great work with cheap little relays will go a long way toward accomplishing that. 73 KD2TDE
Hello Charlie again, we missed you and thank you for coming back with new amateur radio projects. What happened to your page on qrz.com, it doesn't appear anymore? Thanks and greetings from Romania. 73!
Hi Alexandru. I took the QRZ page down as I didn't see the worth. I might look to revamp it and put it up again. The videos here and the blog are the main way i document each build.
@@CharlieMorrisZL2CTM I know that, thank you for this ! You are the best inspiration for Ham radio operator from entire world, who wishes to understand the secrets of radio communications and come to love this hobby, this passion. Thanks and greetings from Romania. 73!
Hi Charlie, your idea for a stepper motor driving the 3 gang cap is the most interesting. With a mix of single stepping it should be fast and with 16/32 micro stepping more accurate. This could have many spin offs including an auto mag loop tuner.
