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I'm so glad you found the video useful! Thank you for subscribing and 73's to you also!

Thank you RMD for your interesting comment!

Thanks for opining Paolo!

You see it right! Its nickle plated hardware that was exposed to the elements for 2 years. It's easy to change it out to stainless steel fasteners if I ever use it outdoors again.

Thanks Ape!

For sure! What we have today, in the world of amateur radio, is far different than what I used to see 50 years ago.

@@rfburns3472 yeah technology doesn't hang about for anyone. has come a long way. 73

Thank you for your detailed reply. You are so right! Everything can look rosey on the transmitter side of a tuner with what one may see as a "good match". But, what about the antenna side? lol

Umm, how may RF paths are there between a radio and an antenner.?

Hello and welcome! The pole at the top of the DPDT switch has a 150 pf capacitor used to couple the RF energy to the diodes for rectification.

@@rfburns3472 Thanks rfburns 3472 I don't mean the capacitor in front of the diode, I mean the ON/OFF SWITCH between the rotary potentiometer and the ampere display on the diagram! It also says 150 but without a designation...? Sorry for my bad English, but great video and great idea with these two measuring probes! 73 Daniel

@@ugiukito9449 OK Daniel I understand now. It's a 150 ohm resistor and switch that will change the sensitivity of the potentiometer adjustment. It's optional and only needed if you have very high currents coming from the toroid sensors.

The Adruino is a good idea Lugeix. My design is simple and based on the "KISS" method.

Can't seem to find it. But thanks for sharing.

Great suggestion Rafael. Here is what I measured from the low inductive carbon resistor load. 1 Mhz 433 ohms -j2.0 ending at 30 Mhz with 433 ohms -j18.6

I really would like to do the video. Just need to figure out how to do the camera shots hopefully soon.

I got them from DigiKey. Here is the link. www.digikey.com/en/products/detail/fair-rite-products-corp/0444164181/8594097

www.nextpcb.com/blog/what-is-an-unun-rf-antenna-unun#:~:text=An%20Unun%2C%20short%20for%20Unbalanced,suited%20for%20the%20transmission%20lines.

Thank you for your comment! Yes, I will add to the description the information you requested and the resistor values and order numbers from DigiKey hopefully this week.

@@rfburns3472 Brilliant! thank you very much for the details and your dedication! 73 de vk3OLA

@@lmantuano6986 Your absolutely welcome OM! Please let me know how it works out for you.

Nice video. Very good results up to a certain freq for these DIY attenuators. There are a few chinese ones out there and most likely are the same but you saved money and have the possibility of customize the attenuation value to your needs. About the HP attenuator, don’t forget to account for the two BNC to SMA adapters, especially if they’re not good quality.If you calibrate the vna WITH those using a double female BNC I believe you should get better results out of the HP. Best wishes Diego

@@IZ0MTW Thank you Diego! Yes, the connectors can be a real concern especially at those VHF/SHF frequencies.

Yes sir, stripping the chassis was not a whole lot of fun. The fun begins when you start to assemble it as if it was a Heath Kit type radio!

You're very welcome Pat!

So glad you found out about the issue. I came close to replacing mine!

You made my day! Thanks for subscribing. New video coming up soon, "DIY SMA RF Attenuators".

I am glad you liked it. And....Ape's the man! Learned a lot from his channel.

The center pins were cut down to a stub. The 4 mounting posts were cut down so they do not interfer or touch the toroid. I used an epoxy glue to hold the connector in place.

That was a good catch! The generator was set for 75 ohms since my attenuator was 75 ohms which may have scewed the results a bit.

@@rfburns3472 If you get a chance, could you just do say a single ‘S-9’ measurement; I’m really interested to see what the difference might be? Tnx & 73…

@@SpinStar1956 There is a S9 measurement in the video. Can you please clarify your request?

@@rfburns3472 well your generator was set to 75 Ohms and the Swan is 50 Ohms, then I would think there would be an error. I was thinking that you could make a single-point S-9 measurement with the generator properly set to 50 Ohms to gauge the amount of error when it was inadvertently set to 75 Ohms.

@@SpinStar1956 Gottcha. If I get time, I will recheck it this weekend. I too am interested in what the difference might be.

Perhaps your right. I am planing on changing out the hardware using stainless steel. I then will see if there is any difference looking at the antenna with the VNA. Anyone else care to comment on this?

@@rfburns3472 Yes, I would suggest using brass hardware. 👍

@@rfburns3472well, here you’re checking the transformation ratio of 49. It is obvious that when you connect the wire (the real antenna) you’ll have different results. The complex impedance of the real antenna on its own installation will be all over the place and the transformer will transform (lower) that value closer to 50ohm for the radio or an antenna matching unit. (This was for the guy who commented first). I have an antenna like this myself. 54 meters of wire starting from the roof, going up to a tree and then down to the end of the property. In my case on few bands I’m lucky to have already a good match, for the other bands where swr is little high I then use the “tuner”. Otherwise one could buy a remote antenna tuner, place it outside and start the random lenght of wire out of it. This way it’ll adapt the LC network to give you always the best matching transformer at the antenna point. 73 Diego

I couldn't agree with you more. I will take your suggestion to heart and see if I can improve my video's.

I created the schematic from various designs published long ago. For this passive device, a 50 ohm resistor is not recommended due to heavily loading down the sensitivity of the meter. In some designs, you may also note a diode placed across the meter to protect it from excessive current damage. But, this too decreases the sensitivity of the meter and is unnecessary if you exercise care and set the pot all the way down before energizing the coax under test. The 10 turn winding, on this toroid, presents very poor impedance match across the HF spectrum and therefore, the toroid if needed should be terminated with a 50 ohm resistor. See my video where I implemented this. th-cam.com/video/DrjW_t_1qq0/w-d-xo.html

Thank you sir. Your video's are truly apprecated and inspiring!

It really does...glad you enjoyed it! And, thank you for subscribing.

Thanks!

Appreciate the comment. Glad you liked it John.

Hi John. Let me know how your CMC tester works out for you. And, I had a "duh" moment when I wrote Db instead of dB. Graham Bell?

Maybe a bit too much variance in content with my videos could be part of the issue. But, thanks John for your coment and subscription!

Thanks for sharing your experience John. SG is nasty stuff to inhale or get fumes into your eyes. Only a fly spec of the glue is needed.

I got it on eBay and the seller provided a link for wiring instructions and schematic. He is not there anymore, but plenty other sellers are. Do a eBay search on 10W QRP Radio HF SW CW telegraph Transmitter 5-9MHz HF Power Amplifer DIY kits

Thank you for your kind words. I hope to do some more vid's on DIY projects. Also, I may do a followup vid on how to construct those split toroidal transformers with the SMA connectors.

Yup, it was a surprise for me, albeit a pleasant one at that! BTW, your videos are well done and the info I've gotten from them has really helped me understand the operational use of my new NanoVNA. Keep it up!

I agree. And, I did the FW flash. Thanks for you input.

Ape, I found the problem leading to a fix. I will share it in a followup video.

@@rfburns3472 awesome 👍

That was clever Brian. Thanks for sharing!

You make a good point Gorak. I retested it through 300 Mhz and results were very good. I tried to go beyond 300 mhz but my NanoVNA has an issue that will not allow for this. You can see what happens when I tried to do so in my next video. I think its defective.

@@rfburns3472 I tried to leave a comment on that video too, but youtube deleted it. You need to verify that the firmware you loaded is right for the H4, and that you have a real H4 and not a clone. Because it works at some frequencies and goes haywire afterwards points to a hardware incompatibility with the firmware. OR it really is defective. It's too bad you didn't try a full span it's capable of sweep before you upgraded the firmware. That would've been very helpful in figuring out if it's a firmware or hardware problem

Good advice. I went to nanovna.com which recomended AliExpress and the Zeenko store which I purchsed it from. I trust its not a clone. www.aliexpress.us/item/3256801087059810.html?spm=a2g0o.order_list.order_list_main.57.7e5f1802vGTljd&gatewayAdapt=glo2usa As for the H4 firmware, I did get the lastest file from Github......NanoVNA.H4.v1.2.20.dfu And, you are so correct that I should have tested it through its full frequency range when I first got it. Thanks for helping!

@@rfburns3472 If it's a true H4, you can also try the dislord firmware - if you see the same problem there, I'd say it's faulty and should be exchanged for a functional one!

I will take a look at that Jim and let you know. Glad you got one built.

I´ll answer my self here.. I connected this to my Pixie... But started to transmit imediarly even if i didnt key the pixie.

Sorry Jim I do not recall the input power. I need to get it out on the bench and test it.

Glad to hear that! It was a fun conversion and quite a stealthy appearance at that.

In his video's, Charles says he dosen't make any money off of the plans. In my case, he charged $15 including postage. Got all the parts for less than $80 from Digikey and eBay. It took me 3 weeks working daily about 4 hours a day. Quite a bit of time was used for preparing the unit for wiring. It was a fun project! I use the radio almost every day.

@@rfburns3472 Thank you. My 348R is in pretty bad shape with things missing. I was about to go for doing this conversion until near the end of the video where I learned an outboard audio amplifier would be necessary. So I dropped the idea.

@@totallysmooth1203 Yes that was a bit disappointing for me also. But, I may try one of those cheap audio amps from China so it can drive a speaker. Charles had mentioned in his videos to not to use a digital amp. Analog would be best for not transferring noise into the receiver. The receivers front end is very sensitive.

Hi Ed. I will take a look for it. Its yours if i still have it!

Thank you kindly!

There are very nice radios. Compact and solid.