Nice project with the ferrite setup. I put Super glue on a component on a PCB then soldered the component connection. I hit the glue with the soldering iron tip and a whiff of smoke from it went up my nostrils. I have a high pain threshold, but it was brutal. Now I only use Super glue far from solder connections.
I needed a custom adaptor to get from "Reverse SMB" plug to SMA receptacle. Well, reverse SMB doesn't exist except as a custom connector on this piece of military equipment. I used an SMB plug and a receptacle and swapped the center pins out, and then soldered it to the SMA connector, similar to what you did.
Got a good comment from @gorak9000 about testing to higher frequencies. So I did. It looks to me the terminator is good to 650 Mhz. These measurements were the worse case at 650 Mhz. Return Loss: -20.6 dB SWR: 1.206 Z = 44.6 ohms -j7.1 S21 Insertion Loss: -3.93 dB
it would be interesting to test it to a higher frequency, and see what frequency it's good to - it might be surprising how good it is! The quality of the SMA connectors themselves might be a bigger issue than the construction of the through terminator, depending on how good those connectors are.
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!
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.
Nice project with the ferrite setup. I put Super glue on a component on a PCB then soldered the component connection. I hit the glue with the soldering iron tip and a whiff of smoke from it went up my nostrils. I have a high pain threshold, but it was brutal. Now I only use Super glue far from solder connections.
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 just subscribe you after 1 min of watching the video . Looking forward to check rest of videos. 👍
You made my day! Thanks for subscribing. New video coming up soon, "DIY SMA RF Attenuators".
I needed a custom adaptor to get from "Reverse SMB" plug to SMA receptacle. Well, reverse SMB doesn't exist except as a custom connector on this piece of military equipment. I used an SMB plug and a receptacle and swapped the center pins out, and then soldered it to the SMA connector, similar to what you did.
That was clever Brian. Thanks for sharing!
Got a good comment from @gorak9000 about testing to higher frequencies. So I did.
It looks to me the terminator is good to 650 Mhz.
These measurements were the worse case at 650 Mhz.
Return Loss: -20.6 dB
SWR: 1.206
Z = 44.6 ohms -j7.1
S21 Insertion Loss: -3.93 dB
it would be interesting to test it to a higher frequency, and see what frequency it's good to - it might be surprising how good it is! The quality of the SMA connectors themselves might be a bigger issue than the construction of the through terminator, depending on how good those connectors are.
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!
How did you get the center pins to connect?
Did you bend them or cut them down?
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.
What are the ferrite devices with SMA connector?
I got them from DigiKey. Here is the link.
www.digikey.com/en/products/detail/fair-rite-products-corp/0444164181/8594097