#159

[@LeeKirkman88]

Yes there's always videos showing you how to use equipment but they never explain how to hook things up and that's pretty important. Good informative video.

[@BrockNanson]

This is great and answers many questions I had... as well as several I didn't know I needed to ask! If only the profs I had back in my university days had been able to present ideas as effectively as Peter does - those years would have been more enjoyable and far less frustrating!

[@mikefinn2101]

Thanks for that very valuable video. I just bought a spectrumanalyser and glad you made this video sure help more than you know. saved me from damaging my new Rigol. Wish others were as kind as you are and donate so much of your expertise to help others. I am so Grateful many thanks God Bless 73s wb7qxu

[@patrick4228]

Brilliant! Absolutely brilliant! Thank you for this very informative video. Finally no more guesswork in my mind about the proper way of doing this kind of measurements! 73

[@TRXLab]

glad that you liked it. Thanks for watching 73

[@larryk4mu240]

Hi Peter, a very superb explanation of how to make sure everyone can avoid overloading their test equipment. Great tips to follow. I enjoyed the video very much. 73

[@TRXLab]

Glad that you like it Larry! Thanks for watching 73

[@johnc4414]

Hi Peter. You made the selection of attenuators for different equipment with different input level ratings made sense for me. Thank you. John C

[@TRXLab]

Glad that the video made sense to you. Thanks for stepping in 73

[@TheRadioShop]

Thanks for sharing tis vital bit of information Peter. It should help lots of folks out. I see you have the same test radio on the bench I do 73 my friend.

[@TRXLab]

Thank you my friend for stepping by! 73

[@jansb984]

Absolutely perfect. I can even understand the extra time you are taking to explain it all. Sometimes I do tend to fall to sleep but this is due to my work schedule. Seriously, I put a piece of wire into my Rhode & Schwarz FS300 and "listen" to my dummy load on TRX. Regards, vk2fex

[@karlmartell9279]

He sounds like some lost tourist on a sightseeing tour.

[@jansb984]

@@karlmartell9279 Well - No. This subject is not easy to explain to anyone that is a novice in the subject lesson. I do enjoy it for factor(s) such as remainders of something I may have forgotten over years. There is a balance between benefits of being on the air and doing diagnostic of your own RF equipment. They are both as important and the confrontation here is about the LAB and the RIG or the other way around if you please. Both are just as important as each other. In my opinion, TRX is an essential LAB tool for every Ham who cares and Peter does the very best job to this effect. 73s, vk2fex

[@RC-Heli835]

@@karlmartell9279 English is not his native language and so ah yah! You have to turn the speed up to 1.5 X. What's funny though it makes the camera angles change rather quick.

[@TheDefpom]

Very thorough video Peter, good work.

[@TRXLab]

Glad that you like it 73

[@stefanosimpsi6621]

Thanks Peter for simple explanation.

[@TRXLab]

You are welcome Stefano! 73

[@Rob-du9ui]

Thank you Peter. I found the information regarding the maths especially useful.

[@TRXLab]

Ah okay and I thought that this is more the critical part of this video...Thanks for watching and comment 73

[@dennisqwertyuiop]

Great video, thank you for taking time to do videos, they are the best

[@TRXLab]

Thanks for the kind words Dennis! 73

[@user-su5sq5ib3i]

I love your videos and appreciate them very much

[@clytle374]

Thanks. Good clarification and refresher course

[@TRXLab]

Thanks for watching

[@bundylovess]

Thanks Peter just what Iv have been searching for big thumbs up 👍

[@TRXLab]

Thanks for feed back. Glad that it is of any need for you! 73

[@g1fsh]

Thsnks Peter that was very well explained by u. Very helpfull and a great video as always.

[@TRXLab]

Thank you Garry! All the best 73

[@snellsentinel6485]

Meny thanks, & seasons greetings kind regards from New Zealand snell

[@TRXLab]

You are welcome! Season greetings and all the best. 73

[@peterjones3245]

Another priceless gem for us (old) radio repairers. I guess the same techniques would apply to connecting an oscilloscope to the Tx? Thank you Peter.

[@ot7e]

Thanks Peter for this usefull video, great tips and very well explained. 73

[@TRXLab]

Thanks for watching Mathieu! 73

[@alessandrozax]

Good explanation..other simple solution is inside of your previous video where you have show us how to pick up a signal via inductive way (ex. toroid). Have a nice day !! '73

[@TRXLab]

Thank you Alessandro. 73

[@robertcalkjr.8325]

Nice lesson, Peter. Thanks.

[@TRXLab]

Thanks Robert! 73

[@berniken6511]

Nice video Peter very informative as usual.........................Thank you.........................Berni

[@TRXLab]

Thank you Berni ! 73

[@musb748]

Super presentation! What about the CMS54 R&S ?

[@Mschasz3129]

Only wish I had the test equipment you have. But then again I'd have to take a few classes to know what heck to do with all of it.

[@TRXLab]

LOL, well I guess all different equipment has been used in one or the other video... so you can train yourself ;-)

[@theDaftman]

Old video i know, been looking for a Watt To dBm Conversion Table like the on in your video, seen loads but not as good as the one you have, any links to the one you have. excellent video as always thanks.

[@nettrobber]

Hello Peter, thanks for sharing. Just a question about the Power calculation, the voltage written on the measuring device is related to as a peak voltage then the power calculation should not be P=(Epk/sqrt(2))^2/Z =E^2/(2.Z) as we are taking this way the Erms value? and not only P=U^2/Z Then for the measuring device accepting only a 3v maximun input voltage, the related max power should be 90mW which is ca. 20dBm Then the attenuation required should be at least 20dBmin? Or that is totally wrong ? ;) thanks

[@andrewverran3498]

Great video...a question....if someone gave me an in line vented barrel type attenuator ,similiar but smaller than the one you are using, if the attenuation value information isnt on the attenuator how can you calculate its value?? Cheers

[@TRXLab]

you can test it. Put a known accurate level in and simply test the output level. The difference is the attenuation level....

[@adhiwibowo488]

what is spectrum analyzer do you use? the brand I mean. I saw it was connected to a PC monitor? THank you

[@TRXLab]

Signal hound

[@s7courier]

Nice video. Did you build the 600 watt dummy load that is in the video. I can not seem to find any online with test ports attached out oft box. Thanks for a great video.

[@TRXLab]

No my attenuator is this www.apitech.com/globalassets/documents/products/rf-microwave-microelectronics-power-solutions/rf-components/attenuators/fixed/wmod53.pdf

[@EI6DP]

How did you get 100w on AM from your FT747

[@Artelisys]

Peter, Thank You for your time! Your videos are just great; could you do a segment on the main pieces of equipment you have in your shop? I have basic electronics background, nothing close to what would be called an electronic technician working in the RF field. I would however, like to know the basic equipment required to repair and align radios up to 30Mhz. Would be nice to include equipment in the 2m and 7cm band too. I see some really affordable equipment on ebay that I could get started in, but would like to know the basics. Maybe a more advanced than your #50 video in regards to a first lab on a budget. Equipment that is required to repair the RF Amps on TX and RX, alignment of radios that are off frequency, alignment of meters and receive (AF, etc). Like I said, I know enough to get in trouble, just need a little bit more to know how to get myself out of trouble. Thanks!

[@TRXLab]

Hi Billy, yes you are right a good idea for a video but to many projects going on in the moment so I have to postpone it sorry. Thanks for watching and comment 73

[@Artelisys]

No worries, I do not expect you to drop anything you are doing at the moment; at some point in the future, it would be nice. Thank You!

[@jerrymoats971]

HELLO PETER. LOVE YOUR VIDEOS. IN THIS VIDEO YOU SHOW A HARD COPY OF YOUR CONVERSION CHART. I HAVE LOOKED ALL OVER THE INTERNET FOR A PRINTABLE VERSION EXACTLY LIKE YOURS BUT CAN NOT FIND ANYTHING CLOSE. DO YOU KNOW WHERE I CAN GET THE EXACT SAME CHART AS YOURS? THANKS JERRY

[@TRXLab]

Hi Jerry, the chart is done by myself. Use this link kzbin.infocommunity

[@robertruth3281]

What a wonderful presentation. I admire your knowledge and your skills at making difficult concepts look easy. I do have one thing that I can not understand. When using attenuators to reduce the signal, how do you know what the power dissipation requirements are for the attenuators? I will try to describe what I mean. With your 600 W dummy load, which has a -40 db attenuator built in.... you still need 10 more db of attenuation to reduce the 50 dbm to 0dbm. How do you know what power handling is required of the 10 db inline attenuator? It would seem to me that with the RF padded down you are not going to be dissipating much power in the string of attenuators. Is that true or am I misunderstanding? Thank you very much for what you do here. Bob

[@andrewverran3498]

Is there any problem with putting say 3 T bnc connectors after the attenuation to send the output to 3 devices, say scope, counter and spectrum ananlser,basically is the attenuated signals dbm value comprimised if split out to 3 peices of test equiptment? Thanks in advance

[@TRXLab]

no that is not possible since you are still in the 50Ohm world. If you split off your levels on the following meters reads wrong.

[@andrewverran3498]

@@TRXLab i will have to investigate, would be great ti get the same radio output simultaneously to my scope , counter and SA... 73s

[@michaeldotc2254]

Great Video Peter! I love seeing how the test equipment is connected to the radio. So many videos just show meter readings and never explain how the radio is connected. I do not own a dummy load with a test port but I do have a Bird watt meter with a rf sensing slug. Will that work in place of the dummy load test port?

[@TRXLab]

Do you mean a sample port? Well you can see signals but you can't do quality y measurements. 73

[@carlospopelier]

howmuch attenuation in de spectrumanalyzer itself ?

[@theobosters8487]

did you make the dummyload yourself, can't find a good dummyload with attenuation on the internet.

[@TRXLab]

no that would not be linear up to 3 GHZ. search for Weinschel

[@theobosters8487]

@@TRXLab do you have a type number, can't find any Dummyload with the attenuator from weinschel its one or the other but not what you say.

[@freeman1990]

Hello, Where I can buy Spectrum analyzer like yours ? I mean the 1 which monitor.

[@LeeKirkman88]

Yes the driver puts out a small amount of power, To drive the output transistors or mosfets so the spectrum analyser picks up the smallest of signals even from the driver.

[@giuseppecuffaro-1398]

So the point is to always be at 0dbm?

[@dennisqwertyuiop]

one more question, the att. 10 db on the sig hound connected to the dc block,, what is the power ratting on it,,, would it have to be 10 watts ? Thanks Peter

[@TRXLab]

100W=50dBm-40dB big attenuator =10dBm at the little 10db attenuator . 10dBm= 10mW so no problem at all. The maximum rating is 2Watt.

[@stargazer7644]

41:26 "counter is not heated up" It is connected to an external reference. The counter is dead on.

[@mrkattm]

Peter nice "back to basics" video, you did a awesome job. One question, do the through attenuators that you demonstrated in your video act exactly like a 50 ohm dummy load or do you need to terminate the through attenuators with 50 ohms when not connected to a piece of equipment?

[@TRXLab]

Hi Michael, yes it is a 50 Ohm dummy with test port so no need to connect anything else....73

[@itdevops]

Hi what do you think the hp8922m for test ? For radio. Ty

[@andrewverran3498]

Watched this many times now ..brilliant.. I know you are very bust but at some stage could you address beginners trap of confusion between a tone in the Audio domain vs the tone in the Waveform domain, Mavbe in the 2 tone ssb test and an S9 alighnment... Thnanks in advance.

[@TRXLab]

Well from my point of view you can use both signal or tone but I admit that tones is more regular used in the audio domain...

[@gixerags750]

How do calculate the watt value for a SSB signal for the formula??? PEP AVG ??

[@TRXLab]

in video #42 you'll find all the answers...

[@hancecrawford]

peter 100w = 70.7 Volt did you mean 70.7 mv what does dbm mean? very interesting how you derive at the readings from the input to a radio back to are old friend Ohms Law

[@TRXLab]

Hi John no 70,7 Volt is right for 100 Watt @50 ohm. And dBm stands for decibel milliwatt reference... we never lose the old friend ohms law...LOL 73

[@WaterWhiteTuber]

Hi Peter (or anyone). OK, I have what may seem like a dumb question. Your equipment has upper and lower signal limits. What happens when you use an oversize attenuator? Does it completely squash the signal and display zero on your equipment or is it possible for the reading to exceed the lower limit of the test equipment and present a risk of harming the equipment? In other words, I think I'm asking: do you need to take bandwidth into account when selecting an attenuator? Thank you in advance.

[@TRXLab]

Well it is like I have explained it for the counter. If you go down below the sensitivity level of the unit you don't get a reading out of it. For SA's it is more that you reduce the dynamic range too much. Too much attenuation never can harm the equipment but always avoid to much power! Bandwidth needs to be taken into account not to warp your reading! You have seen the sticker on my 1odB attenuator showing 2.3Ghz I believe...If you go higher you warp your reading...

[@WaterWhiteTuber]

Fantastic. Thank You 73

[@williamcolvin3609]

I know you enjoy building your own test equipment,are you familiar with the T747 Tester for microphones. They work great - but I was wondering how hard it would be to add a modulation meter to show the amount of modulation a microphone is putting out. That way you could see how much increase there is over different microphones,stock,noise canceling,different brand,different element and amplified it is hard to tell just listening. Thanks for any help you can give it will be appreciated.

[@TRXLab]

William you are still in the audio domain so a little millivoltmeter would do the trick. To get more sensitivity sometimes it makes sense to use a uA meter. This instrument will give you the required reading. May be you need an instrument amplifier depending of the source. Some microphones are producing a very tiny signal...73

[@williamcolvin3609]

I understand from Buddy at The Radio Shop - that you have one of the T747 Testers you have modified to be able to connect a larger variety of microphones. I looked for it in your videos,but did not see it. What would be best - to add an external speaker with the meter in that enclosure across the speaker terminals?

[@karlmartell9279]

Simply plug in the cable and press "ON" could blow up your valuable device. So first watch here!

[@ahmadshwayat9840]

Thanks for the video.

[@TRXLab]

Thanks for watching

[@yTb2801082331]

Good evening! May I know the model of your S.A., please ?

[@TRXLab]

Hi Andrea, in video #77 you'll find all the answers 73

[@yv5grb]

Thanks, very useful as always, 73

[@TRXLab]

Thank you Eduard ! 73

[@SP9DR]

Peter fantastic video as always. By the way, can you tell me what is the model of the audio interface sitting on top of Agilent meter?

[@TRXLab]

Thank you! Yes it is a Terra Tec Audio-Interface: DMX 6Fire USB. 73

[@fiszczenko]

Hey. Good explanation :) Can you tell me model of that dummy load?

[@TRXLab]

Thanks! While I was preparing the video I was looking for the sticker on the dummy but it is gone and I can't really remember the brand. I believe it was a Weinschel... 73

[@The-Weird-Show]

I want to add a nice spectrum anylyzer to my rodecaster pro 2 for my podcast...

[@dixsusu]

Hi Peter ,great video, what spectrumanalyser are you using please?

[@TRXLab]

All you need you find in video #77

[@radiotestfr1232]

Hi, thanks for all. Do you have a link to the conversion table ? Pls. 73's

[@TRXLab]

Hi Stephane, use this great web page...www.random-science-tools.com/electronics/dBm-Watts-volts.htm

[@jfrede1976]

Nice sticker on the Clock ;-)

[@TRXLab]

Yeah I'm burning the midnight oil

[@Standing-Wave]

Another brilliant video!!!!! 73 De N0ZFG

[@TRXLab]

Thank you glad that you like it 73

[@sethlavinder]

So what exactly is that “test port” dummy load device called? Is this simply a fixed attenuator designed to dissipate a 100 watt RF signal? Where do I find one that doesn’t cost more than my spectrum analyzer did? I tried to google such a device and Pasternack came back with what I believed to be the device for about $1,700 which is what I paid for my Siglent analyzer back in May 2017.

[@TRXLab]

It is called Fixed Coaxial Attenuators with test port. You can get it on different power levels . This devices are expensive and yes they might be even more expensive than a low end SA. Look around on ebay or HAM fairs...73

[@reallybadaim118]

Nice watt meter to!

[@TRXLab]

Yeah a very nice LP500...

[@jhorieboif5016]

thank you

[@TRXLab]

Thanks for stepping by 73

[@TheRangerDale]

Peter could you pass on the Program your using on the computer as a SpectrumAnalyser ? By the way good video well explained .. Email via QRZ ..

[@TRXLab]

Hi Dale, you can download the software on signal hound web page for free. signalhound.com/ But you need a signal hound spectrum analyser to use it...73

[@TKomoski]

Very interesting demo *Peter* , is it preferred to use a DC block attenuation pad that is close to 0 dbm? Also what is the purpose of testing a radio at it's maximum power level not at 10 db down? I like the demo's but I much prefer the repair video's that's just me. Thanks again for latest video and look forward to the next installment from TRX Bench, *_Cheer's 73_*

[@TRXLab]

Hi Tom, the DC block should have no insertion loss and we should always test radios at full power as there they show there real behaviour... And repair videos will come as well :^) Cheers and 73

[@israelhershkovits5675]

It is a real high le el rf skilled information 4z4RE

[@TRXLab]

was it to complicated to follow? Thanks for comment. 73

[@berndreiner7159]

Warum klebst du uhrzeit und datum am Bildschirm ab... 😐😐😐

[@ichbinsnun9140]

Es ist so anstrengend, diesem so schlechten Englisch zu folgen. Mach es doch einfach in Deutsch. Right?

[@baghdadiabdellatif1581]

Thank you