DIY 40dB RF Power Tap for Ham Radio
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- เผยแพร่เมื่อ 26 มี.ค. 2022
- Folks, in this video we perform a build of a DIY RF Power Tap for Ham Radio, if we build it right we should get about -40dB of attenuation off of the tap. We can use this tap to measure signals from devices like radios with instruments like an oscilloscope or spectrum analyzer without the worry of damage.
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Links to products in the video:
Project Box: www.amazon.com/dp/B015334J9Q/...
Silver Solder: www.amazon.com/dp/B08HJ92NRX/...
Resistors: www.amazon.com/dp/B01M5I0I3L/...
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This was terrifying to watch as an RF engineer
Well thank goodness you made it unscathed. Either way, thanks for watching.
Since you are an RF engineer, what would be better in this video which was so terrifying (to you) ? We are curious of your input for the sake of continuous improvement. Thanks, that'd be appreciated ;)
He comments and just leaves. I guess he's not only an RF engineer but also a crappy Elmer huh?
I was really hoping the “RF engineer” would have replied with something more helpful other than a hit-and-run comment. Oh well.
I suggest using some 00 steel wool to buff the surface of the brass before soldering. A little buff on the center conductor of the SO239 as well. I find it helps the solder adhere more securely. Edit: Brass often has a light layer of oxidation which can inhibit the soldering process. Also, using steel wool to prep PCB surfaces for soldering helps with kit building.
Thanks a really good idea, thanks Robert
I like the all parts you need in a box before you start... I always spend half my time looking for stuff midway through a build. Nice video Ape and looks/works well great build
I have to do that to be "organized"
Another good take on the project! Thanks for sharing and showing how you tested it with the NanoVNA.
You bet. thanks for checking it out Derk!
I made one of these for my TinySA a few months ago and it works great.
Nice, thanks for watching Rick.
Nice build. An option for the nut interference problem might be to tap threads in the box. No nutz needed.
Yeah, that might be the move.
Excellent craftsmanship and a nice project.
Thanks!
Thanks PM 👍
Nice video Ape. Nice design, well explained and really educational! Keep ‘em coming pal!
Glad you liked it Larry, thanks for watching!
right tool for the right job... tin snips, and where are your safety glasses with all that brass flying around... lol. great video.
Hey John, thanks for watching 👍
Cool Build Ape !
Thanks Chuck 👍
I've never seen a better solder!
Haha, thanks bro 👍
great video, I love build videos.
It was a fun and easy one, thanks for checking it out Thump
reply to comment to help out w/ the algorithms!
Nice video! See if that wiggly line was just noise (& putting the cover on reduces or eliminates it).
Yeah, I should have done that. I may do a follow up video as there were a few questions.
Yeah! This video is smok'in! :0
Ha, thanks for watching Larry.
I never knew that marker was called a chevron. I thought that was a gas station. LOL. Good video Ape. Learned a bit.
^ Chevron - or according to Dan Brown in The Davinci Code, They are Up for male and Down for female... so what does that make a Drill Sergeant?
Thanks for checking it out Kyle
The in & out markings of the 7805 voltage regulator in the schematic are the wrong away around.!!! 73's de LA3EQ -Jan
Hi Ape,
Great build and video. As soon as I saw the size of that box, I would have used a two hole chassis connector or a bulkhead connector. I also think a piece of single sided circuit board could be used instead of the brass strip, or even a piece of 14 or 12 gauge wire across the connectors. You and the family stay safe. 73 WJ3U
Thanks for the ideas Don, hope all is going well for you.
@@TheSmokinApe Hi Ape,
You know I've been trying to get a reverse mortgage. Was approved in December, but they are raking me over the coals and now saying I have too much debt. Getting depressed.
@@DonDegidio ugh, sorry to hear that Don
@@TheSmokinApe My sister even started a Gofundme to help.
I see no one commented on why the boxes are called "stomp boxes". It is because guitar effects pedals are housed in these type of boxes. You have to "stomp" the button on the top to initiate the effect. Hope that helps.
Cool, thanks man 👍
You're welcome.
The name stomp box comes from their useage as guitar effect boxes. I have noted while the Chinese boxes follow Hammond part numbers they do not always follow the sizings. Specifically the boxes are frequently shallower than the original, which is why the SO239's did not fit well. I took a slightly different tack and cut/filed the 4 hole flange down to a 2 hole flange similar to the 239 found on IC-7300's. Had you sourced the parts from Digikey, Mouser or the like you could have picked the correct components as specified while at the same time helping out local manufactures and suppliers.
I was trying to help out port workers and customs officers 👍
@@TheSmokinApe LOL
Thanks for the video! I was looking for such a power divider for other uses, and this was spot on!
I was curious if you had done a sweep of the SWR on the input and output ports? I would do that if I build mine, just to see if there are any 'bumps along the way'...
You know Jeff, I don't think I did and that's a great idea.
I'd be interested in seeing a frequency sweep of this to see what frequencies it's useful up to beyond HF.
I may do a follow up, there was a lot of questions. Thanks for checking it out John
12:30 Nibbler is the tool for this works, shears will do too but the nibbler won't bend edges of the sheet.
Ah, I think I have seen those in the past. Thanks!
It would be nice to see how it works in real life. It's one thing to look good on an analyzer but very different in actual use. Does it make the audio clearer is the true test. 👍
I might do a follow up video, there have been a few questions. Thanks for checking it out.
This device will allow the operator to adjust the mic gain up to the point just before the RF signal begins to flat top on the scope. In that sense, audio can be clearer for having used it. 73, kc4i
I wish you had also measured the input SWR with a 50 ohm dummy load on the output.
Fair point, sorry about that 👍
Good point. I always make sure my solder is "dry" before moving on. LOL You know as a builder myself I gotta rib ya a little. Serious question. With my lack of knowledge with inductors, since the brass plate is the inductor, does thickness of the brass matter and is it part of the calibration? Or is surface area what determines the amount if inductance introduced into the circuit. Hence the measurement of 1X1.5?
Hey BlueGoose, I would imagine that both size and thickness play a role 👍
How would this resistive RF tap compare to the performance of an inductive tap?
I haven’t compared them but I could add that to the video list 👍
Why add the brass plate? Does it have a purpose other than as a buss? Wouldn’t a 12 ga. Copper wire running between the center pins of the so-239 sockets, with the resistor leads soldered to it do the same thing?
I am under the impression, which may be incorrect that the brass plate acts as an inductor. Without the plate we would need to add a toroid.
@@TheSmokinApe - Thanks for the reply. My education is insufficient. I can understand capacitance between the brass plate and the “floor” of the metal box, but I’ll have to research how a flat plate works as an inductor. Thanks again. I enjoy your channel.
Thanks for watching Steve!
auto comment to help out w/ the algorithms!
Thanks!
You made all the mistakes so I don't have to! Thanks, nice project.
Awesome, thanks for watching G4LMN
Take a gander at these 🥜 😂😂😂
Haha
Jim did it better, #justsayin
He’s a talent
First. :-D
Lol