What do i need for making and design RF circuits? - Page 1
Forum section: electronics / beginners

author: rozeh
author_rank: Regular Contributor
timestamp: August 31, 2013, 09:02:44 am
content: Hi everybodyi want to start to make RF circuit. so, i have a question:What device and software i need for design and make RF circuit?logic analyzer? oscilloscope? HFSS software? SWR meter? PWR meter?...any suggestion?

author: bookaboo
author_rank: Frequent Contributor
timestamp: August 31, 2013, 09:42:04 am
content: Depends a lot on exactly what you want to do and in what volume.There are prebuilt radio modules for lots of applications. Unless you have something really specific or are trying to learn they are the most efficient way of getting something up and running.In the UK you have LPRS, Radiometrix, RFsolutions, warwickwireless. Also I think quasar do hobby kits.In most cases you won't need spectrum analyzers or SWR meters (though they come in handy), you will still need a scope to check data in and out etc.

author: ElectroIrradiator
author_rank: Frequent Contributor
timestamp: August 31, 2013, 09:42:48 am
content: You need to start by reading this:Experimental Methods in RF Design. Also available at Amazon and many other outlets.

author: Rerouter
author_rank: Super Contributor
timestamp: August 31, 2013, 09:49:36 am
content: for terminations an oscilloscope is handy, but good design practices can nearly omit the need for one, also the golden rule is termination is only needed for distances larger than inches = wavelength / 10for filters and attenuators a spectrum analyser / vna can significantly speed up verification but in many cases simulation and calculation can get you close herepower and swf can generally be calculated with a spectrum analyser or vna,i would probably say an oscilloscope with fft would be a starting point if you want to get into it without throwing out too much $$$,

author: Psi
author_rank: Super Contributor
timestamp: August 31, 2013, 10:38:45 am
content: It entirely depends on the frequency you intend to work at.5800MHz is a completely different world to 433MHz for example

author: rozeh
author_rank: Regular Contributor
timestamp: September 01, 2013, 07:45:19 am
content: Thanks guys for reply,well, i want to work on 1mhz-2.5ghzi need to a complete list of hardware and software.any suggestion?

author: IanB
author_rank: Super Contributor
timestamp: September 01, 2013, 08:05:53 am
content: Quote from: rozeh on September 01, 2013, 07:45:19 amI think your list begins like this:1. Learning about RF design2. Knowledge of RF design3. Understanding of RF designWith knowledge and understanding you will recognize what equipment you need and when you need it.Without knowledge and understanding all the equipment in the world will be useless to you.

author: PA4TIM
author_rank: Super Contributor
timestamp: September 01, 2013, 08:58:20 am
content: I agree with IanB. First learn about RF.1 mHz = 1 milliHerz, You prabably mean 1 MHz (MegaHerz)1 MHz is almost audio. You need big coils and capacitors, for 2.5 GHz (not ghz) you use microstrip or stripline or other plumbing like constructions.Because you talk about swr meter you probably thinking about transmitters. For transmitters you need other gear as for receivers.I do a lot of RF.You need:- A very good knowledge about basic electronics and components.- a good knowledge about wave theory (things like reflections, propagation, delay, phase, transmissionlines etc)- Good books about RF like the book from Hayward as mentioned befor, RF circuit design of Bowick, And handbook of microwave component measurements from Dunsmore, AC theory from Knight (free to download pdf)Gear I use most:- Spectrum analyser,- Vector Network analyser with the right fixtures (this also gives you swr, but in RF design we most times talk about rho or return loss), a VNA can be replaced with a spectrum analyser with tracking generator and directional couplers and bridges for most things)- directinal couplers for high frequencys and a directional bridge for a few hundered MHz.- good calibration kit.- Fixed inline Attenuators and switchable ones in 1 dB and 10 dB steps- inline probeadapter- probeadapters to solder to the pcb- something like a sniffer antenna for the SA and H-field probes to couple the signal to the SA when using higher power- trimmerset- shielding material if you want to build stuff, and lots of sma, bnc and N chassismount connector. A crimper for coannectors to cable.- for transmitters a good dummyload- a high bandwidt scope (My DSO is 350 MHz but I have sample scopes upto 5 GHz and often use a max 3000 MHz scope downconverter.- good high bandwidt 10X, 50 Ohm Zo, and active probes- inline terminators- A lot of good RF coax cables (not the chinese ext ethernet bnc stuff but stick to amphenol or radial with something like belden cable- Good quality adapters from bnc to sma, N, PL, smb etc end the otherway around- A good LCR meterI probably forget some stuff. But most important for me are a VNA, SA, LCR (meter and bridge) and scopeBut all depends on what you want to build .

author: M0BSW
author_rank: Frequent Contributor
timestamp: September 01, 2013, 10:42:50 am
content: That sounds like a lifetimes learning, I've been a Radio amateur since 1997, I'm just really getting into the building side now, mine you I could be a slow starter

author: komet
author_rank: Unknown
timestamp: September 01, 2013, 11:13:38 am
content: Quote from: PA4TIM on September 01, 2013, 08:58:20 amIf you're going to correct other people then I recommend getting it right yourself. The guy's name is "Hertz", and one does not put a capital letter in the middle of SI units.

author: PA4TIM
author_rank: Super Contributor
timestamp: September 01, 2013, 12:33:19 pm
content: About the name, Sorry I normally only use it as Hz and never write it full. So yes , you are right abour that, it was Heinrich Hertz.But before you correct someone the way you did, better look it up first yourself.The SI unit it is hertz, not Hertz, and that is abriviated as Hz, with a capital and when used in the middle of a SI unit like MHz you use a capital !http://en.wikipedia.org/wiki/HertzBut that is not realy important and I corrected because of an other reason as you.The point is mHz and MHz both exist and are not the same and that can be important. Like in the sentence "I have a 100 MHz frequency standard that is 1 mHz off" In this case it is important to know the difference between mHz and MHz.

author: komet
author_rank: Unknown
timestamp: September 01, 2013, 12:59:22 pm
content: Quote from: PA4TIM on September 01, 2013, 12:33:19 pmI meant to say that spelt out, it is "Megahertz", not "MegaHertz". The abbreviation is of course "MHz".

author: c4757p
author_rank: Super Contributor
timestamp: September 01, 2013, 01:04:26 pm
content: Agreed, PA4, it is very good to get in the habit of care with unit prefixes. mHz/MHz is important. And it's not the same as spelling pedantry, it actually makes a difference.

author: jamesb
author_rank: Regular Contributor
timestamp: September 01, 2013, 02:08:31 pm
content: Quote from: rozeh on August 31, 2013, 09:02:44 amDepending on your jurisdiction, you may require a license / certification to operate in the appropriate band(s) for which you intend to build your RF circuits.

author: PA4TIM
author_rank: Super Contributor
timestamp: September 01, 2013, 02:23:47 pm
content: If the TS wants to build transmitters he may need a licence (depending the country he lives maybe), that is very good to mention. Not everybody knows and it can cost you a lot of money, or more, if the catch you.But RF is more as building transmitters only. You can also build receivers or measurement gear.I have build a spectrum analyser, a VNA, a satfinder and I'm now allmost finnished building a 25-2000 MHz (sweep)generator (in 10 ranges, with digital readout for frequency and power, AGC with pindiodes, FM and AM modulation , very steep LPF's and everything by my own designhttp://www.pa4tim.nl/?p=2662the blog from that project)

author: KJDS
author_rank: Super Contributor
timestamp: September 01, 2013, 02:37:35 pm
content: RFsim99 is a usedul freebie for analyzing RF design.What you really need for understanding most RF is a qualitative and quantitative understanding of effect of pcb traces and ground length on circuit performance and how components can interact inadvertantly.There's also the need to realize that all components have significant stray elements within them, so a capacitor will rarely have an impedance below an ohm for any significant frequency range and an inductor will rarely be quite as high an impedance as you'd like before it becomes self resonant and then a capacitor.

author: WarSim
author_rank: Frequent Contributor
timestamp: September 01, 2013, 02:44:45 pm
content: Quote from: jamesb on September 01, 2013, 02:08:31 pmVery good point. Every country I have worked with publishes a Frequency Band chart. Unless you are working in a Faraday cage, stay out of the restricted bands. Especially the ones that are not shared and not explained. If one of the sensors pick up your emissions the default action is take the lab. RF equipment is not cheep and loosing everything is not a good experience. Even worse consequences if you disrupt something important.Not trying to scare you just urging you to not get into trouble.

author: PA4TIM
author_rank: Super Contributor
timestamp: September 01, 2013, 03:18:09 pm
content: RFsim99 is indeed very handy. For RF Qucs (open source) is a good simulator. I use simetrix very much. Often measurements and simulation are very close (if you model it right including strays)I just started using spice because the free version of simetrixs is limmited to the number of components. Most times is this more then enough but sometimes not.But now it is up to the TS to tell what he wants more exact and what his knowledge / experience upto now is. Maybe he is already an analog guru

author: rozeh
author_rank: Regular Contributor
timestamp: September 01, 2013, 05:22:00 pm
content: O! thanks guys,actually, i'm a newbie in electronic.please more suggest software and device.hey PA4TIM,i saw your blog. i just can say, Excellent!i am eager to hear your suggestions, still, guys!

author: KJDS
author_rank: Super Contributor
timestamp: September 01, 2013, 05:29:51 pm
content: Quote from: rozeh on September 01, 2013, 05:22:00 pmWhat do you want to achieve?The requirements for a 35GHz radar are somewhat different from a medium wave AM receiver which is different to interfacing a zigbee chip to a processor and an antenna

author: rozeh
author_rank: Regular Contributor
timestamp: September 02, 2013, 06:17:56 am
content: Quote from: KJDS on September 01, 2013, 05:29:51 pmAnything for making a transceiver! and especially a program for easy make filter, amplifir and etc.

author: PA4TIM
author_rank: Super Contributor
timestamp: September 02, 2013, 07:53:42 am
content: Desinging your own tranceiver as a newby in electronics ? I do not think you will succeed.http://www.pa4tim.nl/?p=1337this is a schematic from one of the simpelest tranceivers I know. The bitx20, a simple 5W ssb HAM transceiver. But building this has no use, You can not use it whitout a license. Other HAM on the 20 m band will not come back to you because e it is not allowed to make a QSO with a non-HAM.Look at that schematic and if you say, " hey, that is easy, I know all components and why they used them here"then grab a paper and design your own. Use Qucs and RFsim99 as simulators. But if you look and think, "Oh my god, what is this, I do not think I'm even able to build that" Then start with some good books, study them and in a year or 4 you will be able to design one if you study hard enough.In the meanwhile build some receivers from existing schematics and maybe a FM-bug. Then find some RF test equipement.If you now build for instance a 3 meter FM transmitter and it looks like it does not work it can be on the half frequency or double the frequency or somewhere in between. OK, you will now because if you are on half the frequency the army rings your doorbell and if it was double the frequency the radio control agency (I do not know how they name that in your country) In both cases you got a hell of a problem. The first probably jail, the others take a way all your gear and ask a lot of money. Be very carefull while playing with transmitters. Their range can, under the right conditions, be much further as you think. I once made a connection on 70 cm with two farmers who used lpd's on 433 MHz. They were very supprised I heard them because these things normally go only about 1 km in open field and I was about 200 km away from them. A fm-bug has much more power as a LPD.Or become a HAM (radio amateur). you first must learn, then do an exam and if you pass you are alllowed to build transmitters. Probably there is some HAM club that give courses or some HAM nearby that will help and teach you. There probably are exams on internet that you can make to test if you are ready for the real test (that is, in my country they are there to practice)Fred PA4TIM (my HAM call sign)Two links about HAM radio in Iran.http://www.qsl.net/oh2mcn/ep.htmhttp://www.qsl.net/ep2fm/AmateurRadioInIran.htm

author: KJDS
author_rank: Super Contributor
timestamp: September 02, 2013, 09:25:12 pm
content: A good filter design exercise is to create a spreadsheet to calculate element values for lowpass, highpass and bandpass filters using the equations in the link below,http://www.rfcafe.com/references/electrical/filter-denorm.htmAnd some prototype values from this link.http://www.rfcafe.com/references/electrical/cheby-proto-values.htmIf you're feeling a little masochistic, then find the equations to calculate the element values yourself.Verify that they work by putting the calculated values into RFSim99 and check that they do what is intended.There's a lot of work there, but it's a tiny part of designing a tranceiver and will help you understand a basic part of RF design.Once you've got something sensible in RFSim99, it's time to build a prototype and test it,.

author: KJDS
author_rank: Super Contributor
timestamp: September 02, 2013, 11:01:48 pm
content: Quote from: AcHmed99 on September 02, 2013, 10:39:12 pmThere's plenty of design tools about, but working through the maths at least once helps so much to understand what's happening, When the affects of component strays and pcb traces are added in, then unless you understand their influence getting good performance is far more difficult.

author: olsenn
author_rank: Frequent Contributor
timestamp: September 02, 2013, 11:07:56 pm
content: QuoteA cauldron, finely powdered unicorn horn, a dash of root bark from the tree of life, and a spectrum analyzer.

author: PA4TIM
author_rank: Super Contributor
timestamp: September 02, 2013, 11:14:33 pm
content: You forget the most important part. You need to sacrifice virgins under a full moon (we use deep-frozen versions if we can not find fresh ones)

author: free_electron
author_rank: Super Contributor
timestamp: September 03, 2013, 01:07:15 am
content: silver plated wire, copper foil board, rf transistors, non-inductive resistors and lots of small value caps... and a good soldering iron..that'll get you started. oh, and excercise your dead-bug construction skills...

author: edavid
author_rank: Super Contributor
timestamp: September 03, 2013, 03:45:08 am
content: You live in Iran, and you post in a public forum about your desire to build radio transceivers? Wow.

author: BravoV
author_rank: Super Contributor
timestamp: September 03, 2013, 04:04:47 am
content: rozeh, please answer this question honestly, do you know how to bias a transistor properly ?Once you've answered that, I believe many generous members here will able to give you the correct answer to your question depending on the answer of my question, trust me.

author: rozeh
author_rank: Regular Contributor
timestamp: September 05, 2013, 10:33:49 am
content: @PA4TIMThanks friend for sharing your knowledge. So, i'm at the first of the way.yes, i know i should exercise sooooooo much untill succeed make a transceiver. now, i just want to find some primary thing about RF.@KJDSThanks for replythen for software, first i should to learn RFSim99.@AcHmed99thanks for software.@olsenn@free_electroninteresting this part of your remark!Quotecan you more explain about this part of your statement?also, i think it's correct completely!@edavidunfortunately many friend from USA think that the iran is like north korea or afghanistan!@BravoVQuotethis is the funniest thing that i heard at recent month!well, as i already said, i'm a nwebie.the answer of this question is this;no totally!ok, i trust you!i hope to get the best suggestions!------------------------------------------------------------guys,what's the best program for design the PCB for RF circuit?

author: w2aew
author_rank: Super Contributor
timestamp: September 05, 2013, 03:34:08 pm
content: Quote from: rozeh on September 05, 2013, 10:33:49 amPlease don't take this the wrong way, but asking for advice for designing RF circuits when you are unsure how to bias a transistor is similar to asking how to write a book when you don't know the language. There really isn't a substitute for learning the basics first - no shortcuts to designing successful and effective RF circuits until you understand the basics of components, circuit design, layout, parasitics, etc.Simulation tools do NOT teach you how to design. When used properly, they can be effective to help in the design process. When used improperly, they'll often lie to you. YOU have to be smart enough to recognize the lie.Simple example: A simulator will have no problem putting 1000 amps through a 1N914A diode. It does not know, and won't tell you, that you'd vaporize the diode if you tried this same thing in real life.My best advice - learn the basics of analog components and design first. Only after you've mastered the basics will you begin to have the ability to understand the nuances of RF design.

author: PA4TIM
author_rank: Super Contributor
timestamp: September 05, 2013, 04:34:28 pm
content: I worked with sonnet one time. I could get the result I wanted but it was very much work befor I found out how and what. And I know a little about (uWave) RF so I mostly had to learn to operate the software and used some books to calculate the filter first. If you have no clue about the simple electronics basics, transmission lines, wave theory you will have no clue what to do in such a simulator. Even something like qucs will be to difficult.To make an other compare, you now want to design and build a formula 1 car but you can not drive, do not know how a wrench looks, or how to operate a lath or a drill. You do not know how a normal car is build, how a piston looks and never have seen a formula car other then in a flash passing by on TV in a race.Do I need to say more ;-)pJust start with blinking a led by a wienbridge or a 555. Build a simple one transistor headphone amplifier. Then Build a audion receiver or a crystal radio if you want some RF exerience and connect your little amp to it etc.But please, forget the RF desiging stuff for the first couple of years (and study on it a few hours a day)

author: w2aew
author_rank: Super Contributor
timestamp: September 05, 2013, 04:56:02 pm
content: Quote from: PA4TIM on September 05, 2013, 04:34:28 pmsage advice.

author: IanB
author_rank: Super Contributor
timestamp: September 05, 2013, 05:19:01 pm
content: Perhaps there is a language problem here...?Let's suppose you are just starting out with electronics, and maybe you would like to build a simple AM or FM receiver as a educational project. That's not so hard to do given suitable instructions, yet technically it counts as an "RF" application. We wouldn't call it RF design in English since we think RF design means something more complicated than building simple radios, but that nuance may not be apparent to a non-native speaker.So if you wanted to build a radio from a kit or set of instructions, and you wanted to set it up and tune it correctly for optimum operation, what would you need apart from a basic meter? What are the hobby tools that would help?

author: ElectroIrradiator
author_rank: Frequent Contributor
timestamp: September 05, 2013, 05:52:51 pm
content: The most useful piece of gear for a beginner starting out working with radio, would be a calibrated FET dipper covering at least 1-30MHz. Doubly so, if it is coupled to a simple frequency counter, good for 3 or 4 digits of precision. A buffered 50 ohm output may also come in handy.A calibrated FET ('grid') dipper can act as a LC resonance checker, a power meter for low power signals, as a simple signal generator (usually not very stable, but...) and it can evaluate unknown capacitors and inductors when combined with components of known value. If it is very sensitive, then it may also act a bit like a simple spectrum analyzer, allowing you to hunt for parasitics and harmonics.That, a solid DMM plus a few good books to give the basics on components and proper RF construction techniques (no prototype boards!), will get you pretty far. A scope is not likely to be too useful for more than audio work, unless you happen to have deep pockets for active probes. Without those it will be difficult to directly inspect signals, without disturbing the circuit due to excessive capacitive loading.

author: PA4TIM
author_rank: Super Contributor
timestamp: September 05, 2013, 06:22:16 pm
content: Yep, one pof my first instruments was a heathkit griddipper.http://www.pa4tim.nl/?p=804My most beautifull griddipper.

author: M0BSW
author_rank: Frequent Contributor
timestamp: September 06, 2013, 11:29:55 am
content: And if it's for amateur Radio get licensed what ever rules yo have in your country, here in the UK If caught transmitting they would search you out, bust you , fine you , and if bad enough throw you in jail plus take all your equipment.

author: PA4TIM
author_rank: Super Contributor
timestamp: September 06, 2013, 11:57:21 am
content: Yeah, that is in Europe, we have very strickt rules and are not allowed to do anything. They trow you dead with stones if you only think of douing something wrong. But not in those regions where the TS lives, they have total freedom of speaking and writing, everybody is equal and the authorities are very gentle and forgiving. No risk at all ( I hope)

author: M0BSW
author_rank: Frequent Contributor
timestamp: September 06, 2013, 12:19:32 pm
content: Quote from: PA4TIM on September 06, 2013, 11:57:21 amYour right, I know a Ofcom officer and although we a fellow Radio amateurs, if my station was out of the band limits he'd bust me that's for sure, I got the 5Mhz variation and theirs another one I think it's 430Mhz's, despite the fact I may not use them I got they just to make sure I'm covered, so I'm OK for everything my HF licence covers me for. Is it strict over your side to.

author: PA4TIM
author_rank: Super Contributor
timestamp: September 06, 2013, 01:31:34 pm
content: In my country it is not very strickt anymore. Pirate stations are mostly located in the northern counties overhere and work the 3 meter band with many kW . There has been a time they stopped looking and only took action if to many people complained. The next step was only a warning , later they allowed them to even keep the transmitters.HAM radio is almost left to self/social-control over here.There are some SW and AM pirates but those bands are allmost empty and QRM is so high they do not cause troubles so they leave them. But 3 meter became a problem so at last they sharpened control and raised the fines a lo, but many pirate stations collect a lot of advertisement money and use that to buy gear and pay the fine, some even had/have spare transmitters hidden somewhere so they could be back on air the same day.

author: M0BSW
author_rank: Frequent Contributor
timestamp: September 06, 2013, 02:06:06 pm
content: Quote from: PA4TIM on September 06, 2013, 01:31:34 pmOh Dear that doesn't sound so good, I pleased they are strict over here, and have a grip on the pirates, Ofcom and us amateurs do have a good relationship , long as you stay within the law, the morse code test to gain the full licence is not so strict now, when I took mine back in 97 it was 10 wpm, I don't think it's anything like that now, I think its 5 wpm or an understanding of morse what ever that means. I have noticed looking though my computer logging, I've only spoken with 5 different PA stations in 3 Years.

author: edavid
author_rank: Super Contributor
timestamp: September 06, 2013, 03:27:21 pm
content: Quote from: M0BSW on September 06, 2013, 11:29:55 amOP is in Iran, which does not issue amateur radio licenses.

author: M0BSW
author_rank: Frequent Contributor
timestamp: September 06, 2013, 03:53:56 pm
content: Quote from: edavid on September 06, 2013, 03:27:21 pmSo does this mean you can operate, or do you have to risk get caught.

author: G7PSK
author_rank: Super Contributor
timestamp: September 06, 2013, 04:23:50 pm
content: The first prosecution for illegal possession of radio equipment in the UK was during WW1. a scout master was convicted of being in possession of 2 tent poles and a piece of wire which might be used for communicating with the enemy he was jailed.

author: PA4TIM
author_rank: Super Contributor
timestamp: September 06, 2013, 04:34:29 pm
content: http://www.qsl.net/ep2fm/AmateurRadioInIran.htmThey have a HAM organisation and callsigns (EP ) and must do exams.QuoteSounds like it is not easy but maybe there is no control. We will hear what our future Iran Ham member will have to say about this. It's seems to be very hard to log EP calls so maybe he can change that ;-)

author: marshallh
author_rank: Unknown
timestamp: September 06, 2013, 05:31:20 pm
content: Quote from: ElectroIrradiator on August 31, 2013, 09:42:48 amThanks for that tip. I picked up the book.

author: rozeh
author_rank: Regular Contributor
timestamp: September 08, 2013, 05:57:29 pm
content: Sorry for delay@AcHmed99Thanks again!@w2aewGreat!Ok! then, first i start to learn basic.Thanks for good advice.indeed, your YouTube channel is good. i think it's good that i see your clips.@PA4TIMThanks for interesting advice.Ok!Blink! oh god! for learn MCU first blink program, for analog first blink circuit for....why don't you use of MCUs(like AVR) for making measurment tools?@IanBQuoteNo, i don't think, i want to learn making RF transceiver(professional).@ElectroIrradiatorThanks, good point.@M0BSWi always say, the all britains are very cool.(like jeremy clarkson)then i will be careful.-------------------------------Quoteit's incorrect! we have an organisation for controlling.i uploaded the rules of radio(a pdf file):http://www.mediafire.com/download/esa003wsokikjky/radC2601.pdfenjoy of it!

author: KJDS
author_rank: Super Contributor
timestamp: September 08, 2013, 06:13:21 pm
content: There's some interesting looking starter projects here that could be worth putting together.http://www.electroschematics.com/radio/

author: rozeh
author_rank: Regular Contributor
timestamp: September 10, 2013, 11:17:47 am
content: Thanks KJDS