I was just looking how to make some attenuators and I run into you again! You are just a wealth of great information and practical implementation ! I want to be sitting right next to you and try to catch some of your breadcrumbs! Thank you again! Stay safe and have a great weekend!

@rusty1187

3 жыл бұрын

LOL! Same! i was just going to type this into the search bar, when this video popped on next! Serendipity!

Wow, I always thought that making attenuators is a complicated science, especially getting a decent flat line frequency response. But your video proved to me that it can be quite easy, thanks!

@jamescollier3

6 ай бұрын

he's good, but now the hardest part is you can't say tee-pee lol

PI & T? Yes, I'd love some. On a more serious note, another excellent video.

I'm going to put a notebook together (with graph paper of course) and follow along with these videos and even build some of the stuff you've got here. Thanks for taking the time to make these!

Excellent video! Thanks for taking the time to make them. Your explanations are very clear and concise.

WOW!!!!!!! THANKS FOR WALKING US THRU YOUR NOTES,... EXCELLENT DESCRIPTIONS!!!... GREAT DEMO!!! THANKS!!!

Thank you for your time in a full explanation, your patience and knowledge is appreciated! 73 ' David K8KEM

Wow! Another great lesson. I keep coming back to your channel to learn and refresh my memory. I remember my college professor always telling me when dealing with RF circuits "Keep 'em short, neat and tidy." Great to see such accuracy by keeping these same principles in the 20dB attenuator you built. Now, if I can only find a good used RF spectrum analyzer to do the same thing....

@Bazzawombat

2 жыл бұрын

I used my Nano VNA to achieve what W2AEW showed, use log mag on Ch 1. Now where near as accurate as his spectrum analyzer, but never the less, you get a lot of "bang for buck" with the less than $100 nano VNA.

Fun: Yes that was ! I'm 77 years old and still enjoy tinkering around. 73 Leo

One trick I picked up for similar attenuators and terminations is to stack a number of smd resistors to get the desired value. 3 150 ohm larger ones make good 50 ohm terminations. For attenuators it is a good way to get more precise values and somewhat better frequency flatness. I am not sure why it works. Probably stacking helps reduce stray inductance. Made a small cal set with a power splitter like this for my VNA that turned out almost as god as the original N sized ones for that application. For some reason I had good luck with the 1218 size resistors.

Excellent. Amazing the bandwidth acheived!

Very informative! Never thought it could be so simple!

The best channel in youtube. Keep up the good work.

just found the channel, thanks for all the education you provide

Loving how you constructed the attenuator!

Very nice. Wonderful. Sometimes the simple things are so rewarding .... ! Make several videos this way for us, the guys like me, that sometimes need go back to the basics ....

What is fun is to do the exact same circuit with Long THC leads and see your high end response skew. Another nice video!

I must agree your videos are excellent I always look forward to the next one. Thanx Gary

Thank you for your video. Excellent! I need to make an attenuator. It so much cheaper than buying one. Thanks for the inspiration.

Thanks for the heads up once again Alan - almost purchased an attenuator on eBay but now I'll make my own. Thanks for explaining and your valuable time. 73 de GI8WFA.

Great explanation!

Que buen video, muy bien explicado. Necesito hacer un atenuador y me sirvió bastante tu enseñanza. Gracias

Thanks for the video, I really need an attenuator by tomorrow and amazon wouldn't get it to me soon enough. So this will work temporarily.

Another nice video!! I have done the same thing to make various values. I use the same type of connectors, but round. The attenuators fit perfectly inside brass tubing available at most hobby shops.

This is awesome! Thanks so much for explaining this.

Great video!! This video made me think about making a diy feedthrough 50ohm termination for my oscilloscope...🤔

It's still a very good video though. I did build the version with the series 120R resistors and the response was 20dB +/- 0.1dB to 3GHz on a VNA. The return loss at LF was 'only' about 40dB (because 120R isn't the ideal value of course) and it degraded to about 28dB by 3GHz. However, the resistors fractured when removing it so I would also advise soldering some additional bracing around the structure to protect against PCB flexing when twisting it during fitting/removal from a test setup :)

Great video ! Thanks so much

Thanks for your input. Traditionally, I have bought mostly HP and Textronix but Advantest seems like it's a top end unit from my limited observation. I too like the ole Tek 465B scopes. I was once a FE for DEC and traveled around the nation with the VAX/VMS platforms. During that time we ALWAYS drug 465B's around. Rumor was leaving it at the office could get you dismissed, mot sure that was true. Hi I appreciate your videos, some of it proved to be a good review and I have learned as well. 73

I love this videos. Thanks!

Thanks mate, You videos are priceless!

That's a good design, and a great construction technique! Thanks for sharing! I would not have thought to suspend surface mount components in the air like that, like old style leaded resistors, but it clearly works well.

@w2aew

Жыл бұрын

Yes, but not as robust mechanically - it's easy to delaminate a termination on a small SMT part with a little mechanical force.

Great Job and thank you. I give you an A++

Keep up the good work!

That is excellent and helps me alot thankyou!

Thanks for the video! Your soldering job was pretty interesting - surprised you managed to make that work lol.

thank you very much Sir for this video!

Excellent explanation as always , a very useful bit of diy . Similar video on DC blockers would be great , should you be looking for suggestions , given how expensive they are to buy off the shelf.

perfect! please do more vids on RF stuff

Good example of construction technique for RF stuff!

Great video, thank you for the info and saving me a couple of bucks :)

I recently decided to add an attenuator to my 1.5Kw 50ohm dummy load. I found an online PI attenuator calculator that allowed a different input and output impedance. I thought if I used 3 stages and lowered the impedance in each stage I could start with an input of 100K as to not effect 50 ohms of the dummy load(and also not have any real power attenuation in the first stage). I copied the formulas for the page into a spreadsheet so I could quickly change the input impedance/attenuation/output impedance and have the spreadsheet calculate the total impedance and the power dissipated in each resistor. Luckily I simulated the circuit and it was off by a factor of 100. Being it was only a large resistor network, I then calculated it with a DC input by hand with EET101 skills, this matched the simulator. After asking numerous times on online forums, I only got responses that it's the wrong way to do it. I finally built an current sense RF sampler with an PI attenuator(50 ohms in and out) on the output, I again missed and got 68db instead of 60, but the thing works and I'm tired of fighting it. But I've never been able to comprehend why the previous method didn't work(at least mathematically), my spreadsheet outputs the same values as the online calculators. Someone suggested that the online calculators are incorrect when the input and output impedance are not the same(even though they specify that is what they do) I finally left it as the calculators are wrong so I could sleep at night. chemandy.com/calculators/matching-pi-attenuator-calculator.htm care to take a shot at this? It's purely academic at this point, but somewhat important to my sanity. KO4SWI QRZ

Thank you so much for your videos! :)

You explained that so well, +++++

Nice video, thanks for sharing it :)

Great job...

amazing all that math looked so boring in the book..... but now it all makes sense now that you brought it to life. Thanks

Very interesting video, wonder how u soldered that !

Is there a reason to use matching parallel resistors or would it be better getting the higher accuracy of using 330 || 75 for the 61.1111Ω and 270 || 3000 for the 247.5Ω resistor? To reinforce the information presented here, I created a spreadsheet that calculates Pi and T attenuator resistor values and helps me select the best parallel or series resistors from my personal collection.

Many thanks

Sooo very true .. I strive to make one as good some day .. :) Practice makes perfect lol

Hi, what is the wattage on those resisters? Could you suggest a good way to seal the attenuator for use in a wireless test bed? And thank you for an excellent, helpful video.

Thanks for the video it came in handy the other day when i made a 30dB attenuator for a test fixture.. BTW I sent you a message on linkedin regarding a PCB i am wanting to send you.

Thanks soo muchhh

Wow, great tutorial! Finally I know what an attenuator is, and what it's for ;) You meant it's good for couple GHz, so essentially I can build attenuator for Wi-Fi antenna (if it's needed, (because I don't have that much experience in RF stuff as you have))?

Very nice..next topic on circulators pls

Thanks. When you speak of "going to ground", is that soldering to the chassis?

Fabulous as usual. How about this idea: use three quality (cermet) trimpots and then adjust them as precisely as indicated by the equations? It would be interesting to see the resulting bandwidth performance.

Thank you

Nice! I always thought that resistor has stray reactance that affect sigificantly when you vary the frequency...

@w2aew

Жыл бұрын

Yes, all components do have some parasitic reactance - the physical construction of the device will generally dictate the magnitude of this.

Great video! If you need to calibrate this to get an exact attenuation figure, what's the best way to do that? Would little trim pots be too lossy or noisy?

@Bazzawombat

2 жыл бұрын

I used a commercial 10db attenuator on my Nano VNA to check calibration.

thank you for video thats whats in toe works here

Thanks

Thanks very much I'm going to make me some attenuators

kindly explain how to measure self resonating frequency of capacitor

Hello W2AEW, can you pl explain how to design a DC block.

Thanks for sharing. Seems I had not seen this one. What controls how flatness of the response of the attenuator? Is this mainly the construction characteristics? Would shielding the whole thing help even more than just the solid ground plane? Also, are SMD resistors better for this purpose vs. through hole? If so, just due to their size? Thanks so much for the great videos you produce.

@w2aew

8 жыл бұрын

Physical construction is what will determine bandwidth and flatness. SMT is generally better because leaded parts typically have higher parasitic inductance. Design of good RF attenuators is an art.

Great!

@w2aew I love your videos they are very informing and explains everything in an excellent explanatory way. I have a question. How do you calculate the maximum effect these attenuators can handle? Regards Jacob, OZ2LT.

@w2aew

8 жыл бұрын

+Jacob Lindquist In general, the shunt resistors will dissipate the most power since they see the full power voltage on the input side of things. So, if you make all resistors of the same power rating, you can get a good estimate of total power rating by calculating the power in the first shunt resistor.

So clear and simple, I think I can do it. I need to cover 0-6ghz at 3watt 10 db 50ohms. how do I alter your example? eg instead of smd resistors do I use 2w resistors (old school) and how do i cover the 6ghz extent? Note I am adding this to a 30db unit to give me 40 db. thanks Troy

@w2aew

7 жыл бұрын

If you already have a 30dB pad, you can put the additional 10dB "after" that - by doing this, the 10dB pad doesn't need to be rated for the full power. Home-building a high power 6GHz attenuator is not a trivial task.

Thanks for video! What's the maximum bandwidth that normal 0603/0402 resistors can go to before the ESL is a an issue? I've been looking in Farnell at microwave resistors and they look quite expensive. Are they only required for over 4GHz for example?

@w2aew

10 жыл бұрын

It will depend on your layout, but I have seen them used up to several GHz.

Because for SMD, capacitive effects are more important than inductance?

Does it work at frequencies greater than 2.5GHz?

Hi, a little off topic but I have been looking for a spectrum analyzer with a tracking gen without the typical high cost. I have a great HP 8566B that covers almost DC to 20gigs but no TG. I can built an interface adapter and Phase Lock an external sig gen to the first LO but at best, I may have 80 dB of dynamic range. Are you pleased with the Advantest SA and any recommendations on a good SA that will go to 2 or 3 gigs?? Oh, I need the low range to be good at about 100 KHz 73,, Glenn WA4AOS

lol thank you. Colorimetry and details are tipical from Canon DSLR. nice video quality and nice stuff. You have a nice workshop...

Can you check a attenuator using a signal generator and a oscilloscope

What happens at lower frequencies? Is it linear all the way to DC?

sir im in a bit of a muddle i have a rf radio output 10 watts and a unit that takes 100 mw input or less to operate if not damage will be so can you give me a pi simpe circut values please

nice video. you have selected smd resistor I think 0805 package. I want to know do we have to consider wattage of resistor during selection. how it will impact the design.?

@w2aew

5 жыл бұрын

Yes, you certainly have to take into account the power rating of the resistors if you need an attenuator that works are high power levels.

I want to build one for input to ldmos hf amp covering 160m-6m I have a place on amp board for t attenuator what type of resistor should you use metal film or carbon film can’t get a good answer can you help

Nice

Thanks for this useful video. As a beginner in construction, please could you tell me if I could replace R3 in your Pi version with a potentiometer to make a variable attenuator?

@w2aew

3 жыл бұрын

Not really, for two reasons: 1) it won't be impedance matched (50 ohm input and output) if you change only one resistor, and 2) most potentiometers won't perform as well at high RF frequencies. If you don't care about high frequencies or impedance matching, then yes, it would work.

@acestudioscouk-Ace-G0ACE

2 жыл бұрын

@@w2aew Belated thanks for the reply, I appreciate it.

Hi, thank for your works. Can i mesure an attenuator without spectrum analyser ?? Thanks 73's

@w2aew

6 жыл бұрын

Sure, as long as you have a signal generator and a means of measuring the signal amplitude with the proper termination (scope, etc.).

I built this in LTSpice with a 1V generator and 50Ohm at the input and output and I'm getting 50mV at the output. This is a 20 ratio. What am I doing wrong??

I'm very impressed. Super great work ... I'm wondering if we measure the reflection S11 or s22 ... Are they gonna be good as well?? Or should they be close to zero as possible for an ideal attenuator or not? I really don't know.

@w2aew

Жыл бұрын

Yes, the S11 and S22 should be a very low reflection coefficient also.

What exactly is the difference between these networks and a voltage divider?

@w2aew

9 жыл бұрын

These are voltage dividers that also present the same impedance (matched to the source and load) at both ends.

@ahmetserdr2920

3 жыл бұрын

İnsertion loss just.

Alan, thanks for your generous contributions to the electronics and ham communities! I recently scored a Spinner 745359 100 W 40 dB attenuator. It measures an accurate 50 ohms at DC and NanoVNA sweeps show 50 ohms and excellent SWR in both directions. Does anyone know if this attenuator can accept high power input to either port? The datasheet I found is almost illegible and the sheet for the modern equivalent doesn't mention in/output, so I'm guessing they're symmetrical with regard to power handling but thought I's ask before using.

@w2aew

Жыл бұрын

I would think that if it isn't clearly marked, then it is symmetrical. Spinner is still in business, so you could email them and ask the question too.

@user-kp1ee4lb2d

Жыл бұрын

@@w2aew Spinner replied with datasheet and confirmation that the attenuator is bidirectional wrt power. Thanks for the nudge to contact them. After 30 years in science I don't even bother asking questions of manufacturers since they rarely reply unless I have a $ervice contract on the equipment. Good to see that some of the folks on the engineering side are friendlier.

Needless to say, it is very very clear and easy to follow, from design to test. NOW MY QUESTION. Is it mandatory to use the SMD resistors if I aim to use the attenuator at 500 Mhz? Can I use regular resistors? Thanks in advance. Manfred.

@w2aew

6 жыл бұрын

Hmmm - good question. If the leads are kept extremely short, you *might* be able to get away with leaded components. Worth a try....

Hi Allen, I am going to hook up my rig 870 IF out put to a RTL dongle with a rf 20 db attenuation do you think it is enough I am not going to damage the RTL's front end??

@w2aew

7 жыл бұрын

Based on the signal levels observed here, 20dB should be sufficient. kzread.info/dash/bejne/q2WYkpipiKrKfcY.html

Absolutely brilliant Alan. Thanks for sharing. Incidentally, I'm curious; some speccies have the option of a tg. On your Advantest how easy/difficult is it to install a tg? Or does the tg have to be installed during manufacture?

@w2aew

3 жыл бұрын

I think it depends on the particular brand/model.

@Testequip

3 жыл бұрын

@@w2aew Specifically on the Advantest model you have

@w2aew

3 жыл бұрын

@@Testequip I don't know, I purchased this one used and it already had the TG installed.

Hi, i would like to ask you some question since i have no idea about RF. First, can i build it with normal resistor or it should be better with smd resistor ? Second, will it work for the 5 -6 Ghz frequency . Thanks

@w2aew

9 жыл бұрын

At such high frequencies, it is imperative to keep leads lengths to a minimum, which is why SMDs work best.

Do these not require capacitive compensation as is used in scope probes?

@w2aew

5 жыл бұрын

In general, no - because the 50 ohm impedance dominates. At very very high frequencies, there may be some compensation or special design techniques employed to maintain a flat frequency response.

Can u pleas make the 2400Mhz band pass filter

Good video with perfect explanation. But your attenuator needs to be shielded, in order to protect it from unwanted oscillations/background RF signals. Otherwise your attenuator will not work properly. Also resistors need to be mounted correctly to make it more effective. Thanks!

@visionofwellboyofficial

6 жыл бұрын

the RF attenuator will work well if you mounted it correctly, because stray components (inductance/capacitance) are critical

I thought attenuation db rating is based on power, ie 20db (n=100), those n-formulas are for voltage db only?

@w2aew

9 жыл бұрын

You use 20*LOG() when calculating using voltages, and 10*LOG() when calculating using power.

Can we use (glass fiber boards) for rf pcb designs ??? how much is its dielectric constant I wanna design a coplanar pcb transmission line with glass fiber boards and I don't know how much is its dielectric constant....

How much power would an attenuator like this be good for on the input?

@w2aew

6 жыл бұрын

It depends entirely on the power rating of the resistors used. In this case, probably only 100mW or less.

can someone tell me why the equation of powerloss X(DB) is vin/vout? my understanding for calculation is output/input . thanks

@reeeeeeeeemmmmmmmmmm

4 жыл бұрын

It's just a matter of terminology; attenuation is vin/vout, gain is vout/vin. 20dB attenuation (vin/vout=10^(20/20)=10) is the same as -20dB gain (vout/vin=10^(-20/20)=0.1).

Hi. I know its been a long time but I saw one of your video's on the 0.1-2000MHz 30dB Low Noise RF Amplifier LNA Broadband Module Receiver P5O2 . but I can't find the video, if you could be so kind has to let me know which one it is. I think I've watched nearly all of your video's and learned a vast amount of information from them. Thanks.

@w2aew

6 жыл бұрын

I never did a video on an LNA, so you must be thinking of another channel.

@fenderblues1744

6 жыл бұрын

w2aew I have downloaded a lot of your videos, I like your voice and the way you present your videos and look forward to them. Thank you for replying so quickly. I will have to recheck other video channels. Thank you.

Alan, I can't tell from the video. Is that copper cladding on a glass substrate? I have a Radio Shack double clad board but it looks like copper over phenolic. I doubt it matters at the frequencies I'm using it at but I would like to make sure before a I commit a couple of connectors to building up a few attenuators. Rather do it right the first time. Btw my call is N1ABE.

@w2aew

7 жыл бұрын

Yes, it is an FR-4 board, which is basically fiberglass/epoxy resin. Since the PCB isn't being used to carry signals in a transmission line (it is only a ground plane in this case), I doubt that the loss of the substrate will affect operation at all.

@johnbrandolini2915

7 жыл бұрын

Thanks for the reply.