hybridfree/eevblog-posts huggingface dataset:
Unknown RF connector - Page 1
Forum section: electronics / rf-microwave

author: Zenwizard
author_rank: Regular Contributor
timestamp: January 14, 2023, 11:14:39 pm
content: Wondering if anyone knows what this connector is. It is a GR-874 to "unknown" the barrel is stamped UM. I am going to be attempting a calibration on a Tektronix 284 so I need to get GR-874 to something that can handle a 70ps rise time. Which will ultimately need to go in to 3.5mm RF on an SD-24 for doing the adjustments.

author: Kosmic
author_rank: Super Contributor
timestamp: January 14, 2023, 11:17:48 pm
content: Look like a standard male 3.5mm connector. They are compatible with SMA.

author: Co6aka
author_rank: Unknown
timestamp: January 16, 2023, 04:28:17 am
content: Quote from: Kosmic on January 14, 2023, 11:17:48 pmMechanically they will "connect" but then RFiles will beat you with wet Radio Shack "RG-58" coaxial cable that's been terminated with a wire nut.

author: CaptDon
author_rank: Super Contributor
timestamp: January 20, 2023, 01:28:09 pm
content: I thought maybe SMA. I guess it is to small to be TNC?

author: David Hess
author_rank: Super Contributor
timestamp: January 20, 2023, 07:00:18 pm
content: GR-874 to SMA was a pretty common adapter since they coexisted, but I have never seen GR-874 to 3.5mm.

author: xmo
author_rank: Regular Contributor
timestamp: January 21, 2023, 01:41:09 am
content: It does look like 3.5 mmKeysight says: "It is easy to see which type a connector is by looking at the material surrounding the center pin. SMA type will have a foam bead, while 3.5mm uses an air interface."

author: radiolistener
author_rank: Super Contributor
timestamp: January 22, 2023, 12:49:04 am
content: Quote from: xmo on January 21, 2023, 01:41:09 amI have Chinese 10W dummy load with SMA male connector and it uses air insulator around center pin

author: Tony_G
author_rank: Super Contributor
timestamp: January 22, 2023, 01:29:25 am
content: Difference between a properly engineered SMA connector and a Chinese one?

author: Bud
author_rank: Super Contributor
timestamp: January 22, 2023, 01:39:06 am
content: Quote from: Tony_G on January 22, 2023, 01:29:25 amCrapy plating, turns dark with time.Pin diameter too large or two small, resulting in damaging the mating connector or unreliable connection.Pin sitting loose in the insulator, resulting in wobbling or being pulled out or pushed deep in and breaking the soldered coax.The insulator piece not sitting tight in the shell, resulting in being pulled out of the shell as you disengage the mating connector.

author: Tony_G
author_rank: Super Contributor
timestamp: January 22, 2023, 01:50:18 am
content: Sorry I was making a snarky response about the "Chinese 10W dummy load" - Should have been clearer.Though your points are very, very valid...
See exactly how and why a Microwave Tube Klystron amplifier works. - Page 1
Forum section: electronics / rf-microwave

author: BrianHG
author_rank: Super Contributor
timestamp: January 11, 2023, 11:25:45 am
content: Thanks to these, high broadcast power UHF TV was possible.The way the oscillation chambers are illustrated rotated in 3D really clarifies the high frequency and high power capable design. Also, how mind blowingly stupid simple the design is...

author: BrianHG
author_rank: Super Contributor
timestamp: January 11, 2023, 11:32:42 am
content: See an actual power Klystron for broadcast.This one runs on 230,000vThat's like feeding it HV power tension lines directly.

author: CaptDon
author_rank: Super Contributor
timestamp: January 13, 2023, 02:55:03 pm
content: 230Kv? That seems unusually high. The old klystrons and the newer klystrodes used in television broadcast were in the 10Kv to 15Kv range. They can be easily damaged with flashovers requiring H.V. to be removed in the 10's of nanosecond range, done by firing thyratrons to dead short the H.V. Many of those older models had 'Ion pumps' which helped trap ions. Body Current was also a big no-no and was reduced by the focusing coils. The original klystrons used at WSBA-TV 43 in York were an all in one housed unit and looked like a filing cabinet on wheels. I think they were around $80,000 each with about a 1 year lifespan. The military electronics guys instantly destroyed a lot of very very expensive Klystrons, Klystrodes and Crossed Field Amplifiers by treating them like a 'Plug-n-play' device and not following the lengthy installation and tuning procedures. $150K and up each!! Your tax dollars at play! I also witnessed one idiot smashing them up for the copper!! Can you say Beryllium Oxide dust which can be deadly!

author: coppercone2
author_rank: Super Contributor
timestamp: January 13, 2023, 03:21:46 pm
content: they accelerate electronics training through an ion gun at the military

author: BrianHG
author_rank: Super Contributor
timestamp: January 21, 2023, 10:46:30 am
content: You think my post above of a power Klystron for broadcast was big?Here is a Giant 1.2 Megawatt Radar Klystron Tube for US 1500 miles Early detection and tracking of Ballistic Missiles.This one might operate in the megavolt range.It looks like the mother of all fire hydrants...
RF SELECTOR logic using one pin  - Page 1
Forum section: electronics / rf-microwave

author: 24602
author_rank: Contributor
timestamp: January 20, 2023, 03:46:37 am
content: Hey AllWant to control the two RF Select pins of a RF switch (schematic attached) using only one logic line, What's the simplest way of achieving this?Ie LOW selects RF 1 HIGH selects RF 2Thanks!

author: edavid
author_rank: Super Contributor
timestamp: January 20, 2023, 06:02:26 am
content: It looks like you just need an inverter (74LVC1G04?) between the two control pins of the IC.

author: 24602
author_rank: Contributor
timestamp: January 20, 2023, 09:09:03 am
content: Thanks edavidI have updated the schematic (attached), do you see any issues?

author: edavid
author_rank: Super Contributor
timestamp: January 20, 2023, 03:27:45 pm
content: It looks good to me.
Waveguide H-plane step modal analysis question - Page 1
Forum section: electronics / rf-microwave

author: szoftveres
author_rank: Regular Contributor
timestamp: January 19, 2023, 01:52:22 am
content: Hi All,I'd like to calculate the reactance of an H-plane step, according toPozar 4.6, Modal Analysis of an H-Plane Step in Rectangular WaveguideWhat is unclear to me is theImnintegral - For TE10 mode primary excitation, for whichmandnvalues does this integral need to be evaluated? Also how doesNrelate tomandn?If there was a Matlab code example implementation somewhere, that would also help a lot.

author: yl3akb
author_rank: Regular Contributor
timestamp: January 19, 2023, 10:17:36 am
content: Imn is so called coupling integral and in this case 'mn' are not indexes seen in usual mode numbering convention such as TEmn (if that confuses You), but instead m is index of all possible modes in waveguide with dimension 'a' and n is index of modes in waveguide with dimension 'c'.In case of H plane step and TE10 excitation only modes TEx0 = TE10, TE20, TE30,... are excited, so 'm' indexes modes TEx0 in waveguide a and 'n' indexes modes TEx0 in waveguide c. The Imn theoretically has to be evaluated for all possible mode couplings, but truncated to N terms in practice like this (prefix '_a' and '_c' identifies waveguide with dimension a or c):I(TE10_a, TE10_c) I(TE20_a, TE10_c) I(TE30_a, TE10_c) ... I(TEN0_a, TE10_c)I(TE10_a, TE20_c) I(TE20_a, TE20_c) I(TE30_a, TE20_c) ... I(TEN0_a, TE20_c)I(TE10_a, TE30_c) I(TE20_a, TE30_c) I(TE30_a, TE30_c) ... I(TEN0_a, TE30_c)...I(TE10_a, TEN0_c) I(TE20_a, TEN0_c) I(TE30_a, TEN0_c) ... I(TEN0_a, TEN0_c)Term I11 here is first term (or N = 1) in the coupling matrix or coupling between the TE10 in waveguide 'a' and TE10 in waveguide 'c'. Of course, You should use N >> 1 to for solution to converge.
Going down a regenerative rabbit hole in search of a Quiet circuit - Page 1
Forum section: electronics / rf-microwave

author: jonovid
author_rank: Super Contributor
timestamp: January 24, 2023, 09:54:40 am
content: moved from beginnersbefore starting something that maybe a pointless exercise? do you know the answer to this? as I do not.for most of us that can still remember, and are somewhat familiar with the single transistor 27MHz regenerative receivers used in toy walkie talkies of the 1980sand the extremely loud hissing when no in-coming signal was been received.the question I have for the forum is this. can the current draw of a single transistor regenerative receiver determine its received signal strength?assuming the regenerative circuit is stable. if so a squelch type of noise gate can be added to the regenerative circuit audio output by monitoring the regenerative supply voltage.the particular regenerative circuit schematic I had in mind was the VHF regenerative receiver in this video.its simple to make and get going. as the base of any regenerative experiment.and if by adding a experimental DIY squelch circuit it?its not so Mach finding or designing a squelch noise gate design. but determining if a single transistor regenerative receiver changes its current draw based on received signal strength?if yes , I am looking at a 2 or more transistor or op-amp Schmitt trigger with a voltage reference circuit. I can figure it out my myself.and yes going down a regenerative rabbit hole in search of a quiet circuit that also adds to the component count.if no! I have saved myself a pointless exercise and also by posting here others also.update-perhaps a completed circuit is needed before posting hypothetical questions.... get back in 2 to 3 weeks time.

author: MathWizard
author_rank: Super Contributor
timestamp: January 26, 2023, 12:51:38 am
content: I remember some 1980's walkie-talkie's. I wish I never took them apart as a kid, I wish they weren't thrown out.
Data Box Question - Page 1
Forum section: electronics / rf-microwave

author: ko4nrbs
author_rank: Regular Contributor
timestamp: January 18, 2023, 05:38:32 pm
content: Can I use this Data Box to connect a Ham Radio to two different devices, i.e. computer and a relay box. In other words are the connectors wired in parallel? Needed a 8 Pin Mini Din Y-splitter cable with one male and two female connectors but can’t find one.https://vi.raptor.ebaydesc.com/ws/eBayISAPI.dll?ViewItemDescV4&item=254429339342&category=162&pm=1&ds=0&t=1616632704000&ver=0&cspheader=1Bill
Identify an amplifier - Page 1
Forum section: electronics / rf-microwave

author: igor78
author_rank: Contributor
timestamp: January 15, 2023, 08:23:56 pm
content: Please help identify this device.I bought a lot of old RF equipment, and among other things, there is a device that looks like an RF power amplifier. It saysMSH-4532201FSCM: 65151It does not say what voltage it needs, or what RF bandwidth it has, or any specs at all.I was not able to find a datasheet here. Perhaps it's obsolete.https://www.microwavesolutions.com/categories/power-amplifiersI emailed the manufacturer, but they are ignoring me.Does anyone recognize it? I suspect it must work in at least one WIFI band because the other equipment came from the wifi business.

author: Co6aka
author_rank: Unknown
timestamp: January 16, 2023, 04:20:02 am
content: Quote from: igor78 on January 15, 2023, 08:23:56 pmWrite that you have a potential customer for 200,000 units of an equivalent amplifier, so would they please provide an equivalent model and datasheet, and detail any differences between them. Probably you'll receive a phone call 20 seconds later.

author: max-bit
author_rank: Frequent Contributor
timestamp: January 17, 2023, 09:59:27 pm
content: Most likely, the amplifier was built "turnkey", i.e. for some dedicated device (maybe military), so they probably can't or don't want to reveal the secret, so no wonder.

author: Co6aka
author_rank: Unknown
timestamp: January 19, 2023, 02:36:00 am
content: FWIW, the "FSCM" ("Federal Supply Code for Manufacturer") number is the identifier of the manufacturer. The numbering scheme was replaced by "CAGE" ("Commercial and Government Entity") quite a few years back. I don't recall exactly when.Manufacturers will tweak "stock" products to meet required specs and then assign a new part number. Sometimes the product isn't tweaked because it already meets/exceeds the required spec, so actually it's the stock product with a different part number. Sometimes manufacturers will tell you which stock part is the base part. Sometimes they won't, but will suggest a stock part that should be equivalent for you to try.Anyway, "MSH-4532201" is most likely the part number because there is this listing of current products...https://www.microwavesolutions.com/categories/power-amplifiersYou may be able to work out the base part via testing, but asking them to suggest an equivalent current part might be easier.
DC-DC step-up converter for PIN diode - Page 1
Forum section: electronics / rf-microwave

author: srce
author_rank: Regular Contributor
timestamp: January 14, 2023, 08:57:24 pm
content: Any recommendations for anything better than a boost converter (say LT8336) to step-up 5V to 28V for biasing a PIN diode used as an RF switch? (Better meaning less noise / harmonics etc).Some boost converters support spread-spectrum and programmable switching frequencies. Anything else that might be beneficial? Or that should be avoided?
Hacking USB Wi-Fi dongle firmware for SDR use - Page 1
Forum section: electronics / rf-microwave

author: Scratch.HTF
author_rank: Regular Contributor
timestamp: January 13, 2023, 03:08:45 am
content: Do you know of any projects where USB Wi-Fi dongle firmware (particularly Ralink) has been hacked to convert the dongle into a software defined radio?

author: Hamelec
author_rank: Regular Contributor
timestamp: January 13, 2023, 11:00:06 am
content: normaly a USB-DVBT dongle is used for SDR..

author: AndyBeez
author_rank: Frequent Contributor
timestamp: January 13, 2023, 11:47:12 am
content: None that I know of.I doubt there is much demand for using 2.4Ghz hardware as SDRs due to the narrow bandwidth and, because the band is mainly used for short range WiFi, Bluetooth and HID devices. Plus emissions on the band are limited by output power. Okay, there are high gain point to point links, but otherwise there is no interesting LoRa or DX traffic for thediscone dudes.Furthermore, if you want to go 'hacking' the band, there are plenty of wireless tools such as Wireshark and Aircrack. Not forgetting the wifi toolset in Kali Linux.

author: wraper
author_rank: Unknown
timestamp: January 13, 2023, 12:01:42 pm
content: They don't have a HW capable to be used as SDR. Also they have a band pass filter in antenna path.

author: NiHaoMike
author_rank: Super Contributor
timestamp: January 14, 2023, 02:23:37 pm
content: https://github.com/seemoo-lab/nexmon
Looking for datasheet MN6520 CTCSS IC  - Page 1
Forum section: electronics / rf-microwave

author: BartV
author_rank: Newbie
timestamp: December 19, 2022, 10:35:27 pm
content: Hello,I am looking for the datasheet of the Panasonic MN6520. This is a CTCSS tone squeals IC used in vintage HAM equipment. I found some schematics online, but didn't succeed to find the datasheet.Does anyone have a datasheet of the MN6520 laying around and is willing to scan it and share it with me. This would be very helpful in recreating a tone squeals PCB for my Vintage Yaesu FT-727R with the vintage MN6520 I have acquired.Thanks in advance, Bart

author: geggi1
author_rank: Frequent Contributor
timestamp: December 20, 2022, 10:54:44 am
content: Check out these two links. You might get a bit further.https://www.circuitsonline.net/forum/view/154853https://www.zl2pd.com/CML_PW_50tone_CTCSS_Encoder.html

author: BartV
author_rank: Newbie
timestamp: December 20, 2022, 03:46:04 pm
content: Thanks for the links, much appreciated. These pages, unfortunately only give limited information. What I am hope fr finding is the a complete scan of the original datasheet, with description of all functions (with e.g. the tone lock)and specifications of the MN6520Thanks again and have a great day.

author: iz1fks
author_rank: Newbie
timestamp: January 12, 2023, 07:36:51 pm
content: never been able to find it out, I think that is was never scanned to pdf...the ic mn6520 have been available until a few years ago from specialised distibutor of hard to find parts, but now all sources seem not been able to sell them anymore. If you know where those are available, please let me know.best regards

author: BartV
author_rank: Newbie
timestamp: January 12, 2023, 08:22:44 pm
content: Thanks, for the reply.I am still hoping someone has a hardcopy of the datasheet and is willing to scan and mailt it.You can still find them in a limited quantitie on aliexpress.

author: iz1fks
author_rank: Newbie
timestamp: January 13, 2023, 05:28:45 pm
content: I cannot find them anymore on aliexpress and also specialised distrbutors like utsource or new strenght answer zero available

author: BartV
author_rank: Newbie
timestamp: January 13, 2023, 05:40:34 pm
content: https://nl.aliexpress.com/item/4001244215487.html9 in stock

author: iz1fks
author_rank: Newbie
timestamp: January 22, 2023, 03:00:27 pm
content: already asked to the seller, but it's out of stock (i don't understand why they don't remove the adv accordingly...)

author: BartV
author_rank: Newbie
timestamp: January 22, 2023, 03:40:19 pm
content: Thanks, said that they are out of stock now.
reading and processing hantek 6022be data on python - Page 1
Forum section: electronics / rf-microwave

author: sadia02
author_rank: Newbie
timestamp: January 10, 2023, 07:46:24 am
content: I need help in understanding the code of reading and processing pulse data on python using dll file. I have used march.dll file for hantek 6022be. I do not understand why the samples read from channel 1 are divided by 12 and then the how the trigger value is set to determine if a pulse is found or not.The code is pasted below. Your help will be appreciated.Code:def read_hantek():dll.dsoReadHardData(m_nDevIndex, # indexpCH1Data, # ch1 datapCH2Data, # ch2 datanReadLen, # read lenm_nCalData, # cal datam_nCH1VoltDIV, # ch1 volt divm_nCH2VoltDIV, # ch2 volt div0, # trig mode0, # trig source20, # trig level0, # trig slopem_nTimeDIV, # time div0, # horizontal trig posnReadLen, # draw lenctypes.byref(nTrigPoint), # trig index0 # insert mode)data = [] #data arraysample1=[] #sample1 arrayfor sample in pCH1Data:data.append((sample/12.0))#print("Data: ", data, "\nLength: ", len(data))print("\nLengthdata: ", len(data))#"Data: ", data ,print("Sample: ",sample)return datadef process_pulse_data(data):avg = sum(data) / len(data) # get the averge of data samples from scopemaxv = max(data) # get the maximum peak of datatrig = maxv / 1.5 # set trigger value to be max/1.5pfound = 0pidx = round(len(data)/2) # if len of data = 600, then pidx = 300for idx, sample in enumerate(data): # idx = index, sample is the array value at the indexif sample > trig: # if sample is greater than the set triggerpavg = sum(data[idx+4:idx+8]) / 4 #1 calculate pavg for 4 points. These will be calculated 4 points after#2 the current index to avoid glitches. e.g if index (idx) value is at 4#3 then pavg will be calculated for samples from indices 8 till 12.if pavg > trig: # if pavg is greater than triggerprint (pavg) # print pavgpfound = 1 # pulse foundpidx = idx #1 set pidx (pulse index) to current idex value e.g if current index (idx) value isprint("pidx: ",pidx) #2 at 4 then pidx will be 4break # break the loopx1 = 0 if pidx - 200 < 0 else pidx - 200 # x1 is zero if pidx -200 is less than 0 otherwise it will be pidx-200 //why 200 ??x2 = len(data) - 1 if pidx + 200 > len(data) - 1 else pidx + 200 # x2 is len(data) -1 if pidx +200 is greater than the length of data else it will be pidx + 200 // why 200 ??print("x1: ",x1)print("x2: ",x2)pdata = data[x1:x2] # length of data from valid pulse till the endprint("\nlength: ",len(pdata))#"pdata",pdata,"pavg = pavg if pfound else 0 # pavg is pavg if pulse was found otherwise it will be zeroreturn pfound, pdata, pavg
Regenerative feedback for sensor coil - Page 1
Forum section: electronics / rf-microwave

author: petergriffin56
author_rank: Contributor
timestamp: January 04, 2023, 10:05:06 pm
content: Hi all,I'm looking for some advice regarding implementation of some kind of regenerative feedback in an existing circuit to increase the Q factor of the sensor. This sensor is a center tapped coil with parallel capacitance for resonance, the differential output from that goes to a high impedance preamplifier stage made of two JFET instrumentation amplifiers, and I would like to feed part of this amplified signal back into the sensor coil using another coupled loop (called a tickler coil in old regenerative circuit schematics). There are a few extra things on this circuit that are also not relevant to the question, please ignore them. One thing of note is that the preamplifier output is also differential.I have tried getting this to work in LTspice for a while now but nothing seems to work, although in theory it should be doable and not too difficult. So far I've tried simulating a the feedback coil using a high coupling coefficient between the sensor and the tickler, and using a resistor to limit the current and with it the amount of regeneration / feedback / Q factor. I think it is the differential output sensor / differential output preamplifier that is causing the confusion, since regenerative feedback should be in phase with the sensor signal, I find it hard to understand how to apply this concept to this specific circuit.I'm hoping the more experienced HAM enthusiasts / analog engineers can weight in on this, I'm not very well versed in analog electronics and most schematics online are quite ancient and hard to understand.

author: RoV
author_rank: Regular Contributor
timestamp: January 04, 2023, 10:53:48 pm
content: The circuit around the AD8224s seems wrong, with IN+ and IN- attached together. Apart from this, I would use a very small coupling coefficient between the regenerative coil and the others and I would drive it in low impedance, to avoid that itself impairs the Q.You haven't set a Q for the base circuit (without regeneration), you should add some parasitic resistance.

author: petergriffin56
author_rank: Contributor
timestamp: January 04, 2023, 11:16:44 pm
content: The instrumentation amplifier configuration is functional, both in spice and on my bench, it is based on an ADI app note attached to this post.As for the coupling coefficient, the tickler coil has to share the ferrite core with the main coil sensor, anything else would be very impractical, so the coupling coefficient will inevitably be quite high.The inductors have ESR modeled in spice based on real world measurements of AC and DC losses.I have tried changing feedback series resistor value, but nothing seems to give good results. I think the issue might be due to phase delay between the feedback signal and the coil signal, as can be seen in the screenshot below, but I'm not sure how to correct that.
Robot Research 1200C SSTV converter schematic + teardown - Page 1
Forum section: electronics / rf-microwave

author: Scratch.HTF
author_rank: Regular Contributor
timestamp: January 01, 2023, 03:41:08 am
content: Summary of internals:All ICs were available off the shelf (no custom ICs/PLDs/BPROMs despite considering video processing) and can be second source.CPU is a 12 MHz 8031 (I once thought it had something more powerful such as a 68000 or an 8086/8088 or even an 80286 considering video processing).64K x 6 DRAM for each R/G/B plane.Do you know where I can find a schematic for the Robot Research 1200C?
OSC5A2B02 OCXO has massive spurs? EDIT: Probably not. - Page 1
Forum section: electronics / rf-microwave

author: bayjelly
author_rank: Regular Contributor
timestamp: December 31, 2022, 08:24:22 pm
content: Yes, I was missing something fundamental: My scope was aliasing, those spurs don't exist if I measure with the SA, or choose a higher sample rate. Truly a trap for young players. I somehow thought the scope would apply a proper lowpass filter before FFT'ing, but of course it does not.Anyway, using the signal as reference to my SA still actually does make spurs appear in signals very clearly (easily verified by yanking out the reference cable and watching those spurs disappear), but before jumping to conclusions I will make a proper adapter board instead of the breadboard jankiness I was using, which I already knew was unsuitable for 10MHz, especially square waves.I bought two OSC5A2B02 10MHz 5V OCXOs from eBay, and they seem to work great, except for the massive spurs 3.7MHz apart from the fundamental and the harmonics? There are smaller spurs as well, as can be seen in the screenshot. Overall they are bad enough that if I try to use the signal as a reference on my spectrum analyzer, it begins showing spurs in strong enough signals, too.It does not seem to matter whether I terminate into 50ohm or apply a control voltage or not. The power supply for both Vcc and control voltage comes from a linear lab supply, so I'd be very surprised if that causesthis.Am I being dumb and missing something fundamental (no pun intended)? Are they just broken?
How to calculate audio Polyphase networks? - Page 1
Forum section: electronics / rf-microwave

author: LM21
author_rank: Regular Contributor
timestamp: December 28, 2022, 07:46:39 pm
content: I want to build a Tayloe detector and Polyphase network for audio for SSB.Is there a good online calculator or easy formula to get the values. I wonder if people have have checked what is available today. There are precision resistors and capacitors available. Digikey has resistors with 0.1% tolerance or better, and capacitors with 1% tolerance.PTH valueshttps://www.digikey.com/en/products/filter/through-hole-resistors/53?s=N4IgjCBcoMxaBjKAzAhgGwM4FMA0IB7KAbRAHYYJ8A2AFgCYQaBWKka6sp9gTmpAC6%2BAA4AXKCADKogE4BLAHYBzEAF98YMrXggkkNFjyESIGPQAcZCtxhaeYRvlu17zG3bD98tMJobcfTQ5BEXFIKVlFFXUQAFpGaF0oWQBXIyJIUjcBVVygAAnd SMDhttps://www.digikey.com/en/products/filter/chip-resistor-surface-mount/52?s=N4IgjCBcoMxaBjKAzAhgGwM4FMA0IB7KAbXDBgnwDYBWSkKqgdhGoE4rWQmKuAOMJ3x8ALHy5smnALr4ADgBcoIAMoKATgEsAdgHMQAX3wBaAEzwQSSBoCueQiRA0Q0g26AAnd capacitors with 1% tolerance.https://www.digikey.com/en/products/filter/film-capacitors/62?s=N4IgjCBcoMxaBjKAzAhgGwM4FMA0IB7KAbXDBggF18AHAFyhAGU6AnASwDsBzEAX3wBaAEzwQSSGwCueQiRABWEJT6qgAI think it is time for new networks

author: kleiner Rainer
author_rank: Regular Contributor
timestamp: December 31, 2022, 01:51:25 pm
content: Tonne Software QuadNet:http://www.tonnesoftware.com/quad.htmlGreetings,Rainer
Strategy to assign initial node number on packet ism radio  - Page 1
Forum section: electronics / rf-microwave

author: MadScientist
author_rank: Frequent Contributor
timestamp: January 01, 2023, 11:47:52 am
content: I was wondering if a nice number assignment strategy could be devised that allowed a master slave system using master pooling to assign initial node numbers to the shave units. Clearly there’s an issue as several non node slaves power up and try and resolve a node number from the master. I don’t have any user interface , but I could use a “ learn button “ approach but this rely on user sequencingAny strategies people think might work

author: LaserSteve
author_rank: Super Contributor
timestamp: January 03, 2023, 09:02:48 am
content: Let the system sort itself out once. Read the self assigned numbers back snd store them?Steve
PLL Generator WILTRON 6747A-20 - Page 1
Forum section: electronics / rf-microwave

author: Nahim
author_rank: Contributor
timestamp: December 19, 2022, 01:19:52 pm
content: Comrades help with the circuit schematic for the device WILTRON 6747A-20It has been in the office for several years, faulty, it’s a pity to throw it away. I want to repair it, but I can’t find a circuit schematic.You need a circuit schematic, not a manual.Ready to buy!

author: geggi1
author_rank: Frequent Contributor
timestamp: December 19, 2022, 05:45:03 pm
content: Here is a link for some documentation.https://www.opweb.de/english/company/Wiltron/6700A_SeriesThis is a older equipment so I would start looking into the power supply for faults first.Check if you got all voltages. There are probably a few electrolytes that is getting dry and can be changed.At these frequencies its most likely YIG oscillator. If so try to find some data for the one installed in your instrument and check the voltages.
Attenuators and noise - Page 1
Forum section: electronics / rf-microwave

author: xmo
author_rank: Regular Contributor
timestamp: January 17, 2023, 01:28:17 am
content: Assuming a matched situation with lossless interconnections and all at ‘room’ temperature such that kTB = -174 dBm/Hz, there are a few accepted facts.▪ The noise figure of an attenuator is the same as the attenuation, thus for an example 10 dB attenuator, NF = 10 dB, loss L = 10 dB, and “gain” G = 0.1 (linear factor)Considering signal output from the attenuator vs. signal input: SO = SI – L or SO = G * SI▪ Attenuators attenuate noise as well as signals. For the 10 dB attenuator example:If SI = -100 dBm, then SO = -110 dBm and If NI = -120 dBm/Hz, then NO = -130 dBm/Hz▪ Attenuators do not attenuate noise to below kTB. Therefore, if the input to an attenuator is at -174 dBm/Hz, the output is also at -174 dBm/HzNow for the question and the reason for this topic: Again, for the 10 dB attenuator example, if NI = -164 dBm/Hz, what is NO =

author: ejeffrey
author_rank: Super Contributor
timestamp: January 17, 2023, 05:17:04 am
content: The output noise of an attenuator just is:NO = G * NI + (1-G) * kTBYou can think of an attenuator as a directional coupler (itself lossless and noiseless) with both the the through and isolated ports terminated into matched loads The coupled port sees a small copy of the input + almost all of the of the thermal noise from the termination at the isolated port.So the answer to your example is: ~-171.2 dBm/Hz.

author: xmo
author_rank: Regular Contributor
timestamp: January 17, 2023, 04:07:46 pm
content: ejeffrey,Thanks. I did some internet research and did find one reference to the solution you posted but most noise tutorials don't explain it. I was sure that smart people on this discussion board would confirm.I created a drawing to show the attenuator noise contribution symbolically.
Attaching SMA male to end of UT141 semi-rigid coax - center pin preparation? - Page 1
Forum section: electronics / rf-microwave

author: wb0gaz
author_rank: Frequent Contributor
timestamp: December 17, 2022, 03:00:46 am
content: I have some UT141 semi-rigid coax (silver plated steel solid center conductor, I believe) and some SMA male connectors which are little more than the threaded shell and a soldered-on back retainer component. I believe the idea is to solder the retainer component onto the end of the UT141 coax shield, stack on the threaded shell, and let the center conductor of the UT-141 semi-rigid coax serve as the center conductor of the connector.Here's my question - when I look at commercially fabricated UT-141 jumpers (from inside RF/microwave test/telecom equipment, for example), the end of the center conductor seems cleanly formed (rounded end tip, consistent length, free of burrs, defects, etc.)I don't see how to prepare the end of the UT-141 coax so that it is similarly "clean" and SMA-compliant from a mechanical perspective. I don't want the end of the coax to damage the mating female SMA connector, which seems likely would happen if there are sharp edges or burrs at the end of the UT-141 coax, such as would likely be the case if I cut the end of the coax center conductor with diagonal cutters or the like. Getting correct length seems not too far out of the question, but getting a properly prepared end is puzzling.Is there a recommended procedure for properly (manually) preparing the male end center conductor? Can this be done without specialized tooling?Thanks very much any advice.

author: radar_macgyver
author_rank: Frequent Contributor
timestamp: December 17, 2022, 02:02:42 pm
content: Could you post a picture of the connector body? The RG-402 connectors I've come across all have a center pin that's soldered on to the center conductor, and then pushed through a PTFE bushing.

author: khach
author_rank: Contributor
timestamp: December 17, 2022, 02:18:28 pm
content: Such type toolhttps://www.digikey.com/Site/Global/Layouts/DownloadPdf.ashx?pdfUrl=DD7132D2717240F9ABF57802EC93A889
Transformer Amplifier - Page 1
Forum section: electronics / rf-microwave

author: dmowziz
author_rank: Contributor
timestamp: January 29, 2023, 04:02:29 am
content: Hi.I am trying to learn how to measure the Noise figure of an amplifierThe amplifier (AC) is the first imageAnother problem, is that the response from prototype is not as simulated : 2nd image. Green : S21. Orange : S11(About modelling the coupling, decoupling caps and inductor (not the core) to see)The core is a BN-61-202Maybe there's another problem from the board?And the core, it has 2 holes. I used only 1 hole. 1 turn is passing the wire through the hole just onceIs this ok?Thanks in advance for your help

author: szoftveres
author_rank: Regular Contributor
timestamp: January 29, 2023, 07:08:37 am
content: Is this a class-C amplifier?

author: jonpaul
author_rank: Super Contributor
timestamp: January 29, 2023, 11:57:14 am
content: poorly built prototypeBalun has wrong windingWhat exactly do you want to measure?frequency min, max, power output of amp?j

author: szoftveres
author_rank: Regular Contributor
timestamp: January 29, 2023, 10:09:56 pm
content: He wants to measure the noise figure, but an unbiased (i.e. transistor not conducting) class-C amp will have no noise to measure.
Polyphase receiver kits anywhere? - Page 1
Forum section: electronics / rf-microwave

author: LM21
author_rank: Regular Contributor
timestamp: December 15, 2022, 07:14:12 pm
content: I saw a polyphase receiver kit somewhere, but I can't find it now. I could buy one. Can some one point me to it, thanks. I think the name had something to do with NorCal Qrp kits, but that wep site does not have any Tayloe or polyphase receivers, and very little else too.

author: Kalvin
author_rank: Super Contributor
timestamp: December 16, 2022, 09:22:32 am
content: Do you mean something like these:http://qrp-labs.com/polyphasehttp://qrp-labs.com/receiver

author: rmozel
author_rank: Newbie
timestamp: December 16, 2022, 01:17:45 pm
content: You may also like to check JUMA kits page:http://www.jumaradio.com/juma-trx2/http://www.saunalahti.fi/hohtola/ham/DC-TRCVR/DCradio.htm

author: LM21
author_rank: Regular Contributor
timestamp: December 17, 2022, 08:21:40 am
content: Thank you. Jumaradio is new to me. I have to check it
How do we connect/use our Keysight N2751A (3.5 GHz) Differential Active probe to - Page 1
Forum section: electronics / rf-microwave

author: hilper
author_rank: Contributor
timestamp: December 16, 2022, 02:33:22 pm
content: HiHow do we connect/use our Keysight N2751A (3.5 GHz) Differential Active probe to/with a Spectrum Analyzer ?(e.g. by doing some kind of “breakout board” + external power supply exist ?)The user guide (p44) states: “Noise Referred to Input”: 2.5 mVrms (at 2:1).How shall this be understood ?Do Keysight (or other) literature exist, which explain the parameter “Noise Referred to Input”, in conjunction with Active probes ?BR
New Apple patent - Page 1
Forum section: electronics / rf-microwave

author: motionthings
author_rank: Newbie
timestamp: December 15, 2022, 11:01:04 am
content: First time poster. Long time reader and watcher.Apple Inc. got a new patent yesterday, and I'm not smart enough to understand it.The patent is here:https://ppubs.uspto.gov/pubwebapp/external.html?q=(11528076).pn.&db=USPAT&type=idsI also attached the PDFUS-11528076-B1_I.pdfSome are saying that this transceiver is going into an iPhone. Is that even possible?The patent says "communication terminal" and is classified under the following CPC's:H04B 7/18513 {Transmission in a satellite or space-based system}H04B 7/18515 {Transmission equipment in satellites or space-based relays}Doing a bit more research this looks like a version of a 'Luneburg lens'?https://en.wikipedia.org/wiki/Luneburg_lensAnd I have found a couple of papers that have made a '2D flat Luneburg lens antenna'1.https://ietresearch.onlinelibrary.wiley.com/doi/full/10.1049/el.2019.29012.https://ieeexplore.ieee.org/abstract/document/8416712To me this looks like either a ground station or inside a satellite 'communication terminal'Has anyone here looked at this yet?Any thoughts?Simon
How to solder/crimp this SMA connector - Page 1
Forum section: electronics / rf-microwave

author: igor78
author_rank: Contributor
timestamp: December 11, 2022, 05:35:57 pm
content: I foolishly bought a bunch of these male SMA connectors.Though they are crimped on RG316. Turns out they are solder (?) only. The pin's hole is too narrow for the RG316 center conductor (stranded) to fit in. The solder barrel (second from the bottom) has a mysterious purpose. And the pack is missing anything that would solder/crimp the outer braid.I'm confused about how one is supposed to use it. I searched youtube, but nothing; people use the other kind where the outer braid is pulled back and crimped with a cylindrical sleeve.https://www.digikey.com/en/products/detail/amphenol-rf/132249/2627844https://s3-us-west-2.amazonaws.com/catsy.582/132249.pdf

author: mzzj
author_rank: Super Contributor
timestamp: December 11, 2022, 06:09:29 pm
content: Datasheet says that it is for .047 semi-rigid cable.Semi-rigid doesn't have outer braiding, it has solid "pipe" as outer shield. Cant crimp so it is connected with sort of butt-joint solder joint.More like plumbing parts than cable!Useless connector for RG316 as you already found out.

author: coppercone2
author_rank: Super Contributor
timestamp: December 13, 2022, 01:17:30 pm
content: the dimensions are incorrect for your application.You can try to bodge it for low frequency use but... just buy the right stuff

author: 2N3055
author_rank: Super Contributor
timestamp: December 13, 2022, 03:57:54 pm
content: Not trying to be smart ass but...I tend to buy these connectors from decent brands (like Amphenol and such) exactly because they have detailed datasheets, with installation instructions and such.Unfortunately you bought wrong type for your application, like mzzj said.When doing something, I spend huge amount of time reading documentation and datasheets during design and before ordering. It saves a lot of frustration later on...But it happens to all of us, so take this as a learning experience..

author: igor78
author_rank: Contributor
timestamp: December 15, 2022, 08:29:40 am
content: In my defense, itwasan Amphenol connector

author: 2N3055
author_rank: Super Contributor
timestamp: December 15, 2022, 08:36:11 am
content: Quote from: igor78 on December 15, 2022, 08:29:40 amThe point is that they have good documentation..So next time also go with Amphenol and do better homework.Not that I never make a mistake... You cannot do exactly right all the things, all the time.It happens. Point is to make it happen less, that's all.Best,
DIY 4x4 MIMO antenna design for 4G LTE - Page 1
Forum section: electronics / rf-microwave

author: AntiProtonBoy
author_rank: Frequent Contributor
timestamp: December 07, 2022, 03:25:06 am
content: I'm thinking of building a 4x4 MIMO antenna for aQuectel EM160R-GLmodem, for fun and experimentation. Can anyone suggest me a good resource on designing 4x4 MIMO antennas? One approach I had in mind is usingBatwing antennasin 4x4 arrangement, basically a two pairs of Batwing antennas mounted 45 degrees and mirroring each other. Would this be a sensible start?
32.768kHz RTC - Ultra Sonic Welding (USW) - how to verify "Phase Noise"/jitter ? - Page 1
Forum section: electronics / rf-microwave

author: hilper
author_rank: Contributor
timestamp: November 30, 2022, 03:33:46 pm
content: HiWe are using a 32.768 kHz Real Time Clock (RTC), in an electronic product, we have under development.The dimensions of our PCBA are approximately 30x25 mm.The assembly method used to join the top & bottom plastic shells (enclosures), is Ultra Sonic Welding (USW).The parameters for the USW process are (pls see the picture below):Welding energy: 38.1 WsMax. power: 452 WPower loss: 30 WFrequency: 34953 HzWelding time: 142 msWelding travel: 0.24 mmDo you see any problems in using the USW process ?If yes, do you have any suggestions to how to verify that the RTC/"CRYSTAL UNIT" has been affected by the USW process ?We are concerned about that the USW could harm/"degrade the performance (in terms of "phase noise"/jitter) of" the RTC.Do you have any suggestions to how to verify the "phase noise"/jitter performance of the RTC ?BR

author: RoGeorge
author_rank: Super Contributor
timestamp: November 30, 2022, 03:54:29 pm
content: Compare the phase noise of the same unit before and after the ultrasonic welding.Phase noise accumulates as time jitter. Therefore, if you count many oscillations with a counter, then overflow edge will not fell always at the same moment, it will wiggle around the expected overflow moment, or else said it will show time jitter. By looking at how widespread the jitter is around the expected counter overflow moment, before and after USW, one can tell if there was any performance degradation.This is an unrelated example based on the same principle (phase noise accumulated as jitter in time), where the oscilloscope is triggered at t0, then the counter overflow pulse (the one jumping back and forth on the oscilloscope's screen) is observed million counts later from t0(here is one second later).
Regarding BJT in parallel as Power Output - Page 1
Forum section: electronics / rf-microwave

author: JhonStan
author_rank: Contributor
timestamp: November 25, 2022, 10:42:09 am
content: What do you think of the possibility of putting several BJTs in parallel, each of which has its own independent circuit? I know that it could be done with higher power components but I would like to know if one could work or not once built. Input and output of all BJTs are in parallel. What problems could there be and how to solve them?I attach schematic image and .asc file for LTspice (right click and save).Thank you!Quote

author: Tangent_Tracker
author_rank: Regular Contributor
timestamp: November 25, 2022, 01:32:28 pm
content: Your biggest problem is going to be input impeadence... You need some sort of buffer or matching stage with a very high impeadence.

author: T3sl4co1l
author_rank: Super Contributor
timestamp: November 25, 2022, 03:05:30 pm
content: Considering you chose a 8GHz transistor, you will quickly find problems in layout as the reactance / transmission line length between ostensibly-parallel units is not negligible but indeed makes the whole thing scream at undetectable frequencies (unless you have adequate equipment to probe it).More common is to build a distributed amplifier, which also acts to extend bandwidth, but BJTs are not good at this, for the same (above) reason. Most often they are built with FET cascodes (or vacuum tubes if you're feeling particularly old school). (Monolithic dist. amps, using FETs or PHEMTs, push into the 100s of GHz!)Tim

author: JhonStan
author_rank: Contributor
timestamp: November 25, 2022, 04:05:08 pm
content: Ok thanks to both of you for the answer, I just point out that in simulation with this component, also given the low capacitance, it allows you to have an almost flat phase up to 100Mhz. I attach screenshots of the plot.That said can I get the same result with dej JFet?. Maybe someone would be kind enough to make me a schematic with the same structure with some JFets if suitable? I just need a msolo scheme then I'll take care of putting it in parallel. With this simulator and very simple.

author: Wallace Gasiewicz
author_rank: Super Contributor
timestamp: November 28, 2022, 12:20:05 pm
content: There are plenty of MOSFET linear power amps that are used by CB people. I believe they are mostly illegal. 27 MHz stuff.Having said that, there are lots of diagrams of these "Boxes" available. Look around for a few. Mostly they use IRF 520s and I do not know if those meet your needs for the frequency you desire.Usually these things use maybe one MOSFET to drive 4-5 MOSFETS. They use RF transformers on input and outputs. Pretty simple designs.Perhaps you could also look into HAM 144 MHz amplifiers for the 2 meter band. The designs in that range might be closer to your needs.I would think that using MOSFETs would be cheaper than BJTs, I could be wrong of course.
"The Titanic and Technology of Early Radio" - Page 1
Forum section: electronics / rf-microwave

author: MathWizard
author_rank: Super Contributor
timestamp: November 27, 2022, 08:05:28 pm
content: Good overview of some early radio technology, like on the Titanic. I'm very surprised that it's radio ran off about 110V DC and up to 60 Amps. I knew some navy ships ran off 125VDC, but I'm not used to how much power a transmitter uses. Just one of the motors was 10HP.The audio is not the greatest at times, but there's a slide show too.

author: james_s
author_rank: Super Contributor
timestamp: November 27, 2022, 08:37:05 pm
content: IIRC the entire electrical system on Titanic was DC. It was built the early days of electricity, there were still a lot of proponents of DC around.
Looking for information on Q-Bit QBH-9008, 9009 - Page 1
Forum section: electronics / rf-microwave

author: WPXS472
author_rank: Regular Contributor
timestamp: November 27, 2022, 08:47:49 pm
content: I recently came across these, and so far, have not been able to find any information on them at all. They are mounted on a small heatsink tab, and have 2 amplifying stages. I am looking for operating voltage, and current, as well as frequency range, gain, and P1dB.
50R conductor impedance - Page 1
Forum section: electronics / rf-microwave

author: chipeater
author_rank: Contributor
timestamp: November 15, 2022, 05:14:19 pm
content: Hello,I need to layout a 4 layers board with a 868Mhz RF module and a SMA connector for the antenna.I will use JLCPCB service and their JLC7628 stackup.To compute the trace width between the RF module and the SMA connector, I used online calculator and Saturn PCB design software.With a dielectric constant of 4.6 and a 7.1th prepreg thickness, the calculator gives me a conductor width around 12th.But I was told it was wrong without further explanation, the trace must be much larger.Does anyone have any experience in this ?Thank you very much

author: TheUnnamedNewbie
author_rank: Super Contributor
timestamp: November 16, 2022, 08:25:27 am
content: The thickness all depends on the type of transmission line (CPW? GCPW? Microstrip? Stripline? Slotline? ...) you want. Without stating that we cannot help you.

author: chipeater
author_rank: Contributor
timestamp: November 16, 2022, 09:31:27 am
content: I don't know what I want/need. I don't have the skills to make that choice.The layout is super simple so I have some flexibility.I have a full ground plane on inner 1, the RF module and the SMA connector are on top layer.I tried with a microstrip configuration and JLCPCB gives me a 11.55th trace width for JLC7628 stackup.Saturn PCB gives me 12.45th with no plating thickness ( there is soldermask on this trace ).Then I tried with coplanar ware configuration and with 55th of conductor gap between top layer ground plane and the RF trace, Saturn PCB gives me 14.95thI find that both results are in the same order of magnitude but I was told that the trace must be much larger.I'm looking for information so I don't look too stupidThank you for your time

author: NickZA
author_rank: Newbie
timestamp: November 16, 2022, 10:47:23 am
content: According to JLC, their 7628 stack-up has a prepreg thickness of 0.21mm, so in AppCad I came up with the following:0.4mm trace with 0.4mm clearance gives you close to 50ohm impedance.

author: M0HZH
author_rank: Regular Contributor
timestamp: November 16, 2022, 04:58:51 pm
content: What are you designing?I did some 868Mhz modules on 4-layer JLC7628 stack as well, used their calculator for impedance (11.55mil for 50ohm) and PCB traces weren't matched properly, luckily the traces were short and didn't matter much.

author: Miek
author_rank: Regular Contributor
timestamp: November 27, 2022, 02:44:33 pm
content: fwiw, the JLCPCB calculator for their 7628 stackup has been pretty much spot on in my experience. I did some TDR tests a while back and posted them here:https://github.com/miek/usb3-fixtures/tree/main/microstrip-test#microstrip-test