hybridfree/eevblog-posts huggingface dataset:
User Manual for Solver64 - Page 1
Forum section: electronics / rf-microwave

author: dieciduej
author_rank: Newbie
timestamp: March 11, 2024, 12:40:21 pm
content: I was just introduced to Joe Smith's Solver64 software for the LiteVNA and I am trying to find a user manual for Solver64. I didn't not see anything at the Dropbox location for the software. Can someone point me in the right direction, please.Thanks4JoeD

author: joeqsmith
author_rank: Super Contributor
timestamp: March 11, 2024, 12:57:37 pm
content: The last manual is stored with the older software. It is out of date. Out side of that, you have various videos showing how to use the new features.

author: dieciduej
author_rank: Newbie
timestamp: March 11, 2024, 01:19:09 pm
content: Thanks. One other question, I know it is using NI LabView as the backer, but is there a way to make it go full screen? My eyes ain't what they use to be.JoeD
What happened to all the Low Power Sub 200MHz FM ICs? - Page 1
Forum section: electronics / rf-microwave

author: labnet
author_rank: Contributor
timestamp: March 07, 2024, 11:55:53 pm
content: I have a commercial product currently using the now obsolete Melexsis TH7122.1 for a 13.5MHz receiver.My requirements are 100kbit BW(2FSK with +-30kHz deviation), <150uS from sleep to RX RSSI out, operate from 2.7v to 3.3v @ < 10mA, -100dBm sensitivity.It seems all the semi integrated FM receiver chips that can work sub 180MHz are now gone.I've cheked outChipMakerIssueSA615NXPDiscontinuedTH7122MelexisDiscontinuedSi407xSkyworksCommercial FM Only. Only 15kHz BW OutSi48xxSkyworksCommercial FM Only. Only 15kHz BW OutTEF665XNXP$$ and >100mASAF3600NXP$$ and > 500mACC seriesTIOnly >180MHzAX5043OnSemiDiscontinuedI know I can build a receiver discretely, but its a lot more work, expense and board real estate. Any suggestions?

author: rsjsouza
author_rank: Super Contributor
timestamp: March 08, 2024, 12:57:46 am
content: You can find several 13MHz receivers in the product lineup below. Although most are NFC or RFID, you may be able to tweak them to do what you want.https://www.ti.com/wireless-connectivity/other-wireless-technologies/products.html

author: labnet
author_rank: Contributor
timestamp: March 08, 2024, 05:30:26 am
content: I've looked at most the RFID chips and they are mainly tailored to OOK/ASK operation.

author: vk4ffab
author_rank: Frequent Contributor
timestamp: March 08, 2024, 06:00:29 am
content: Quote from: labnet on March 08, 2024, 05:30:26 amTake a look on LCSC, they have the Chinese version of the FM telephone IC's. I got a 100 of them here like 12 cents a pop, I use them for the Gilbert Cell mixer rather than a NE612.EDIT, Ok they are still there, they have 1400 in stock, 22 cents in 150 lots, MC3361 copy by UTC. Even if that part if not useful, dig though their china parts you might find exactly what you are looking for.

author: labnet
author_rank: Contributor
timestamp: March 09, 2024, 07:10:11 am
content: Thanks VK4FFAB. That's leading me down a few rabbit holes.For examplehttp://www.lansdale.comspecialize in buying old semiconductor lines to keep making old IC'shttp://www.utc-ic.com/en/products/categories/special/RadioandCassetteRecorderCircui/have some old FM IC's

author: vk4ffab
author_rank: Frequent Contributor
timestamp: March 09, 2024, 09:12:10 pm
content: Quote from: labnet on March 09, 2024, 07:10:11 amYou're welcome. I hope it proves fruitful.
Identify RF 16pin IC from Garmin DC40 collar - Page 1
Forum section: electronics / rf-microwave

author: pallsveen
author_rank: Newbie
timestamp: March 16, 2024, 10:44:30 am
content: I am currently trying to repair a Garmin DC40 GPS collar, and have found one chip that is faulty. (IC is shorted)The chip is next to the antenna, so I belive it is a RF transciever, but i can not find a match online.Can someone please help me identify this IC?The markings are: RF 10G HD7Z

author: PA0PBZ
author_rank: Super Contributor
timestamp: March 16, 2024, 11:42:08 am
content: RF5110G

author: pallsveen
author_rank: Newbie
timestamp: March 16, 2024, 12:04:05 pm
content: Thank you!😃
Duty cycle and pulse width for high power power amplifier - Page 1
Forum section: electronics / rf-microwave

author: enemra
author_rank: Contributor
timestamp: March 08, 2024, 09:10:21 am
content: Hello,I was looking at a datasheet of a general purpose high watt (100W) Broadband High Power Amplifier Module (SSPA), supporting 2GHz - 6GHz. The specifications list says Duty cycle is 10% typical and pulse width of min 2us, and max 200uS.My question is, why do you specify a restriction on duty cycle and pulse width for RF in power amplifiers? How does switching RF ON/OFF affects the PA?Spec in the attachment.RegardsEnemra

author: CaptDon
author_rank: Super Contributor
timestamp: March 08, 2024, 02:21:22 pm
content: Because the amplifier can only sustain an AVERAGE POWER OUTPUT of 10% of the rated maximum power output. So it comes down to duty cycle, however they have also given you a minimum and maximum PULSE WIDTH which apparently you must obey. Normally you could run that amplifier in continuous wave fashion at 10% of the rated maximum output power but the amplifier you specified may only be rated for pulse duty such as radar. A best example is a small boat radar. 4 Kilowatts pulse power but with a duty cycle of .001 percent the average output power is 4 watts. If you need an amplifier of that power level in your daily work you should have a fundamental understanding of how duty cycle directly effects power dissipation within typical amplifiers with efficiencies of 60 to 75%??? Longer pulse width = more heat. Duty cycle and pulse width also effect repetition rate. Small radars typically have repetition rates from 400 to 1000 p.p.s.

author: enemra
author_rank: Contributor
timestamp: March 08, 2024, 02:45:59 pm
content: Understood. Thanks for the response. So, if the issue bottom down to "heating", then I can duty cycle a continuous rated power amplifier to any extent isn't it? For instance, if the spec says 100W continuous, I can duty cycle it to 0.01%?

author: CaptDon
author_rank: Super Contributor
timestamp: March 08, 2024, 03:04:07 pm
content: Yes indeed!! If the amplifiers rise and fall times are fast enough (which they probably are) you can use less than 100% duty cycle with no harm. In fact the average heat and average power dissipation will fall directly as a function of duty cycle. With extremely narrow pulse widths down in the tens of nanoseconds or less you may need an amplifier with a bandwidth of double or more of your maximum R.F. operating frequency to preserve the shape of your R.F. pulse if that is an important factor such as in the old LORAN-C systems or perhaps the new E-LORAN if they ever get around to building it. Preserving pulse envelope shape and phase is also important in pulsed doppler systems. Cheers!!
Active vs passive gain of a Symmetricom 58532A GPS antenna - Page 1
Forum section: electronics / rf-microwave

author: tverbeure
author_rank: Regular Contributor
timestamp: March 23, 2024, 11:03:34 pm
content: I have a Symmetricom 58532A GPS antenna. The data sheet says the following:Total gain: >30 dBi (38 dBi typical @ elevation angle 90°)dBi is the gain compared to an isotropic passive antenna that radiates or received uniform from all directions. Since the 58532A is a disc shaped, active antenna, I assume that the 30 dBi has an active and a passive component?There are multiple PCB variants of this antenna. One of them has an NE3508, an LNA with a gain of 14dB. There are also two 2SC5508 LNAs with a typical gain of 16dB each. When I add up everything, I get a total of 46dB, but since there's a narrow pass band filter, I assume that the passive components around these LNAs reduces the total gain? Any idea by how much?I'm also trying to figure out the typical gain of a flat disc shaped antenna (the PCB), but I can't find any pointers for that either.PCB image source:https://febo.com/pipermail/time-nuts_lists.febo.com/attachments/20190314/7d9a0aa1/attachment.pdf
How to connect Resonators to VNA - Page 1
Forum section: electronics / rf-microwave

author: Julian.Berk
author_rank: Newbie
timestamp: March 05, 2024, 04:10:36 pm
content: Find attached the image of a Resonator my colleague would like to measure the S11 parameter off. Now how would i go about attaching this bare copper to the vna. Not very familiar with VNA Measurements.

author: Roger Need
author_rank: Regular Contributor
timestamp: March 06, 2024, 12:47:26 am
content: Quote from: Julian.Berk on March 05, 2024, 04:10:36 pmYou need to use a test jig in order to make the measurement. The type of test jig will depend on the physical size of your resonator and the frequency of resonance under investigation. The higher the frequency the more critical the construction of the test jig due to stray capacitance and inductance.If you provide some more info on your resonator (size, frequency) and what type of VNA you plan to use I will provide more details.Roger

author: Julian.Berk
author_rank: Newbie
timestamp: March 07, 2024, 06:38:18 pm
content: Hello, Thanks for the response!it is 1 cm wide and designed for 100-300 Mhzwe are going to use the siglent sva1032x VNA for the measurementHope to hear back
variable cap options - Page 1
Forum section: electronics / rf-microwave

author: p.larner
author_rank: Frequent Contributor
timestamp: March 05, 2024, 08:57:13 pm
content: my main vc in my atu is large with plates about 3inches x 1.5 inches,the max pf was 1000pf but its min was to high for higher bands,i removed about 2/3 of the plates so now its 300pf ish max but the min c is still to high,I have another cap i can build up with plates roughly half the size,would that have a lower min c if i built it for the same say 300pf max c?

author: vk4ffab
author_rank: Frequent Contributor
timestamp: March 06, 2024, 06:12:39 am
content: Quote from: p.larner on March 05, 2024, 08:57:13 pmIts not the plate size that is critical for minimum capacitance, its the amount of overlap that remains when the plates are in the fully disengaged state and the number of plates in the stack.QUESTION. What is the minimum capacitance you require for tuning on higher bands?

author: p.larner
author_rank: Frequent Contributor
timestamp: March 06, 2024, 10:56:02 am
content: Tbh i dont know the min c needed,its min now is about 30pf 10 would be ok by the feel of it i guess,i may remove another plate and test,73.

author: p.larner
author_rank: Frequent Contributor
timestamp: March 06, 2024, 10:59:10 am
content: so would a smaller number of large plates be better than the same area divided by a larger number of smaller plates for the same surface area provided they are not in mesh?for lower min c?.

author: vk4ffab
author_rank: Frequent Contributor
timestamp: March 06, 2024, 08:47:56 pm
content: Quote from: p.larner on March 06, 2024, 10:59:10 amI honestly do not know. But, also check the minimum inductance from the inductor as well. Remember that an antenna tuner it a relationship between L and C. Bust out your LCR meter and measure it as well. Cap might be borderline fine if the L goes low enough.As to your above question, give this calculator a try, you can get a rough idea of the minimum and maximum cap before you pull things to bits.https://www.66pacific.com/calculators/capacitor-calculator.aspx

author: A.Z.
author_rank: Super Contributor
timestamp: March 06, 2024, 10:14:22 pm
content: and thenhttps://www.utmel.com/tools/series-and-parallel-capacitor-calculator?id=25try a 30pF fixed cap (switched) in series to the VC
Antenna type identification - Page 1
Forum section: electronics / rf-microwave

author: sadboi
author_rank: Newbie
timestamp: March 06, 2024, 06:20:11 am
content: Does anyone know what this type of antenna (attached) is called? It is used for multiband GNSS. Thanks.

author: miniant
author_rank: Newbie
timestamp: March 06, 2024, 08:07:05 am
content: I think it's about a crossed dipole antenna

author: sadboi
author_rank: Newbie
timestamp: March 06, 2024, 08:53:24 am
content: Interesting, I didn't realise you could combine 2 dipoles perpendicularly like this. Thanks a lot!

author: shadow.dark
author_rank: Contributor
timestamp: March 06, 2024, 09:18:51 am
content: Is this a serious product or just made in China? Because based on the pictures，it doesn't look well built，like something crudely made. The input feed appears to be some sort of balun. But I still don't understand the purpose of those wide copper foils around the perimeter.Crossed dipole antennas are generally used to receive circularly polarized waves, or linearly polarized waves of unknown direction. This is in line with the GNSS application scenario. The upward arching state may be to maximize the use of space inside the enclosure.

author: ch_scr
author_rank: Frequent Contributor
timestamp: March 06, 2024, 10:26:02 am
content: It seems to be fed by two coaxial cables. How they are combined is a different mystery. Maybe a transmission line quadrature hybrid?This type might be called "crossed dipole" or "turnstile antenna". The L-shaped areas along the side of the dipole elements remain mysterious.Maybe they optimize the radiation pattern or polarization (linear / other circular rejection?).
5G Signals? - Page 1
Forum section: electronics / rf-microwave

author: Grandchuck
author_rank: Super Contributor
timestamp: March 04, 2024, 06:17:45 pm
content: New toy: TinySA Ultra. Am I seeing 5G activity?

author: MartinL
author_rank: Regular Contributor
timestamp: March 04, 2024, 10:55:36 pm
content: Could well be.The lump with the marker spans about 3950-3965 MHz. That's within the 5G n77 band, which is in use in the US by both Verizon and AT&T. And 15MHz is a valid channel width in that band.

author: ejeffrey
author_rank: Super Contributor
timestamp: March 04, 2024, 11:04:25 pm
content: What antenna are you using? What are you measuring? Where? All we can see is that you are looking between 3.9 and 4.0 GHz which is part of the C band used by Verizon 5G. So maybe, but it could be anything or nothing.

author: Grandchuck
author_rank: Super Contributor
timestamp: March 05, 2024, 12:37:36 am
content: Quote from: MartinL on March 04, 2024, 10:55:36 pmThanks! Sounds as if they/some could be 5G signals.I am located in SW Florida and the SA was sitting on a desk in my lab. Just using the supplied whip for now (fully collapsed as shown)
[ADC] LTC2208 Price ? - Page 1
Forum section: electronics / rf-microwave

author: mr_byte31
author_rank: Regular Contributor
timestamp: March 01, 2024, 06:33:12 pm
content: Hi Folks,I was looking for fast ADC and I foundLTC2208(16-Bit, 130Msps ADC) to be a perfect match for my requirements.Its price on Mouser or DigiKey exceeds $90. I found it onAliexpressfor $15.any explanation for this huge price difference ?did anyone try the Aliexpress chip and find it working as expected?

author: radiolistener
author_rank: Super Contributor
timestamp: March 03, 2024, 12:27:33 am
content: it can be genuine chips but from long storage with incorrect conditions (temperature, humidity, for example with corrosion signs and can be problematic for soldering), also it can be factory reject, or just a fake chips. Who knows.If they sell genuine chips with bad storage conditions it don't means that it will be bad, its random, such chips just is not allowed to use for factory manufacture, so they selling it.

author: mr_byte31
author_rank: Regular Contributor
timestamp: March 04, 2024, 01:58:11 pm
content: I think your arguments make sense !I will try to avoid them.
How to fix a LDMOS MRFX1K80NR5 to copper heat spreader? - Page 1
Forum section: electronics / rf-microwave

author: g3vbv
author_rank: Newbie
timestamp: February 26, 2024, 11:13:21 pm
content: This amplifier does not have flanges for screwing to the copper heat spreader like others of the LDMOS family.It looks as if it has an adhesive back, not entirely sure.

author: langwadt
author_rank: Super Contributor
timestamp: February 26, 2024, 11:59:00 pm
content: you solder it, or clamp it with a strap over the top and deal with the problems of insuring a good connection to the tap

author: eb4fbz
author_rank: Regular Contributor
timestamp: February 28, 2024, 11:23:40 pm
content: https://www.nxp.com/docs/en/application-note/AN1907.pdf
Seeking info on Navicom OCXO - Page 1
Forum section: electronics / rf-microwave

author: AussieBruce
author_rank: Regular Contributor
timestamp: June 11, 2021, 05:23:41 am
content: Hello, I’ve acquired a Navicom OCXO, model NOX038663XS, and am in the process of setting it up as an accurate frequency reference. It seems to be a fairly common device, there are plenty available on Ebay. However, I’ve totally failed to come up with any data on the unit despite copious hunting. I’ve managed to get it going by ramping the supply voltage up, the output 10 MHz sinewave stabilizes when the supply reaches about 9 volts, so a 9v supply seems to be OK. However, I would like to know the specified supply voltage, can anyone assist?A pointer to a datasheet would be nice, but it seems that I can get away without it.TIA

author: ahbushnell
author_rank: Frequent Contributor
timestamp: June 11, 2021, 02:27:43 pm
content: This says 12Vhttps://www.agmexportv.com/index.php?main_page=product_info&products_id=159806

author: sorin
author_rank: Frequent Contributor
timestamp: February 27, 2024, 12:38:47 pm
content: I wanted to buy the same OCXO, but unfortunately there is no information on the Internet about it.What is your experience with it so far?How accurate is it? Did you had a chance (or capability) to measure its phase noise?Thank you!
Need help selecting subghz RF chip - Page 1
Forum section: electronics / rf-microwave

author: gru
author_rank: Newbie
timestamp: February 27, 2024, 03:26:44 am
content: I need to decode signals similar to how RTL_433 decodes things, only with very low power consumption. It has to be able to decode short bursts of OOK, FSK, PSK, all of different baud rates, encodings (Manchester for instance) carrier drifts, frequency deviations.So I figure I need something that has carrier sense, FIFO IQ sample queue (around 4-16 KB) and SDR front end. Upon sensing a carrier, it powers up the DAC and FIFO, starts recording IQ samples. Then when carrier sense goes low, it sends an interrupt signal so that a microcontroller can read the queue and decode. Also, I need a receiver each for 315 MHz and 433 MHz bands.I would imagine for even lower power consumption, the carrier sense could consist of a super regenerative receiver, so even the LNA can be unpowered until needed.What are the available options that come the closest to this functionality? I could probably implement this in discrete components, but I would like to avoid it if something similar is already in production.I know this could be done in GNU Radio and a RTL dongle, but the main issue is just sheer power consumption.At present, I simply have a lot of CC1101s out in the field programmed for a few the different types of modulation schemes individually. I want one sensor to rule them all. Or maybe just two (for each band)
EMI receiver - Page 1
Forum section: electronics / rf-microwave

author: Stancer
author_rank: Newbie
timestamp: February 25, 2024, 11:39:41 pm
content: I am looking for a USED 40GHz EMI receiver such as ESU40, ESW40 OR ESIB40 TO PURCHASE.

author: coppercone2
author_rank: Super Contributor
timestamp: February 26, 2024, 12:14:25 am
content: zero poster looking to buy some SERIOUS kit. maybe I am being cagey but after seeing 10? hacked accounts get banned on this subforum and then a mysterious 1 post, it looks like someone trying to get the big score (cost of new car)

author: floobydust
author_rank: Super Contributor
timestamp: February 26, 2024, 02:42:43 am
content: That A-50 getting smoked out of the sky last week... commies might need some new radar gear. 1PBTID probably pay in bitcoin.Keysightgot fined $6.6Mfor violating ITAR. Selling EW S/W and H/W for warfare and battlefield advanced radar etc. russia and china "EMI" lol.https://www.keysight.com/ca/en/industries/aerospace-defense/electromagnetic-spectrum-operations.html
Agilent 8714ET 50 ohm N center pin split apart? - Page 1
Forum section: electronics / rf-microwave

author: wd5jfr
author_rank: Regular Contributor
timestamp: February 25, 2024, 06:27:51 pm
content: I'd like to see if I can find a type N female bulkhead connector for my 8714 Port 2 directional bridge coupler but.... I don't want to take out all the screws to see what it looks so I can find a replacement since I can still use it. I'm assuming that the type N bulkhead connector is inserted in the directional bridge coupler. Does anyone have a picture that I can use to identify one or where to look? About 20 years ago I recall my Eagle RLB came with a tool so that you could replace just the center pin. I never had a broken one before and I don't know why it broke so I'm looking for advice. ThanksHankPS I just got this from HP groupshttps://www.keysight.com/us/en/ecom/parts/part-detail.html/08711-60038,Keysight price $1054.00 with over 20 different sets using this part. I'm not sure what the part is but at the price I assume it's the directional bridge coupler with type N female.

author: wd5jfr
author_rank: Regular Contributor
timestamp: February 25, 2024, 06:57:19 pm
content: I think I just found some on Groups. Here's what they look like in a screenshot from a Youtube 8711C video by IMSAI Guy.
mounting rf diodes in cavities etc? - Page 1
Forum section: electronics / rf-microwave

author: coppercone2
author_rank: Super Contributor
timestamp: February 23, 2024, 10:22:21 am
content: If you have those really low capacitance diodes (old) how do you go about mounting it in a cavity?Are these parts designed to be soldered in place with a oven with pastes and preforms, or do they require conductive epoxy? Or is it meant for spring contacts? perhaps a spring copper baffle that deforms with a screw?Like those high GHz diodes you can buy, look like MELF packages. Its tiny. its fast. Its possibly soviet and has no name or documentation.

author: CaptDon
author_rank: Super Contributor
timestamp: February 24, 2024, 01:34:49 am
content: My only experience is with the old 1N23E / 1N23ER and the similar 1N21 S band and X band mixers which use a mount with a form of spring finger contacts. Some of the diodes have a removable cap that fits over the nubs so you can reverse a 1N23 to replace a 1N23R. I have also used the little tiny X band Gunn diodes that look like a saccarin tablet. they fit into a sort of machined pit in the waveguide with a quarter wave resonator post that screws down against the diode to make D.C. and R.F. connection. I suspect you may be looking at something similar to the X and Ku Gunnplexer styles of mounting. Don't know if that helps?

author: coppercone2
author_rank: Super Contributor
timestamp: February 24, 2024, 03:50:02 am
content: hmm I think these are like 100GHz + though. I forgot but it was very high for spring fingers I thinkI thought of this.1) big shallow counterbore2) less shallow less wide counterbore3) threaded hole1) solder thin plate across big shallow counterbore, make flush2) insert screw into threaded hole. The screw should be able to deform the thin plate slightly so it squeezes the diode in placelike a burst disk almost. then its all smoothso it works like arteries

author: mr ed
author_rank: Regular Contributor
timestamp: February 25, 2024, 04:30:47 am
content: You can solder a modern SMD diode on to the end of some hard coax and place it in the cavity. Something like a BAT24 which are current parts and under 2 bucks. Some are good to over 60GHz.
How does the RF/Microwave sector in Europe compare to that in USA? - Page 1
Forum section: electronics / rf-microwave

author: jonsikul
author_rank: Contributor
timestamp: February 17, 2024, 04:35:23 pm
content: My question relates to both the quality (and maybe quantity) of the education in said fields between the two and the industry as well.Being a European myself, I would at least guess the defense industry and companies related to that in the US would account for a lot more of RF/Microwave jobs than in Europe./Jonsikul

author: jonpaul
author_rank: Super Contributor
timestamp: February 17, 2024, 11:43:05 pm
content: USA and UK are most active in wireless, microwave, mm wave for telecom, networks, defense.In EU France has strong defense industry (Airbus, Thales, Sagem, Safran)Jon

author: TheUnnamedNewbie
author_rank: Super Contributor
timestamp: February 24, 2024, 11:00:12 am
content: You have quite a few companies working on RF/Microwave stuff.- There are Ericson and Nokia doing everything RF under the sun.- IC design wise: You have Bosch and Infineon both making millimeter-wave radar chips (and associated packages, antennas, modules). There is a decent RF/mmwave community in the Leuven-Eindhoven-Delft region with lots of small companies, that partially flows out of the fact that the universities in those areas have some world-class Professors working on those fields. There are also still quite a few Huawei design groups (Milan, Leuven, Gent, Munich, Stockholm...). I believe Analog Devices had a millimeter-wave team in Ireland, but I don't know how much of that team still exists after the ADI radar team got bought by Bosch.- Infineon, ST and NXP all have a broad range of RF-related products in all frequency bands, many (most?) of which are designed in the EU.- Passives: You have Huber+Suhner in Switserland/Poland and Rosenberger in Germany doing a lot of antenna, cable and connector design.- You do have quite a bit of defense companies, like jonpaul mentioned.- Keysight has a few design centers in the EU, some working on very high speed stuff (afaik, their highest speed >100 GS/s AWGs are designed near Stuttgart). Almost every product Rohde & Schwarz has is designed near Munich.As to the quality:I'm biased, but you have some Professors and research groups in the EU that are amongst the top in (RF)IC design and antenna design - especialy around the Benelux area, with companies and heritage from NXP, ASML, imec, etc... This translates to some top-notch PhDs and companies.

author: radiolistener
author_rank: Super Contributor
timestamp: February 24, 2024, 12:25:16 pm
content: Jobs amount for RF/microwave and electronics is rapidly decreasing in EU and US for many years.If you want to work in that area, there is a strong sense to look for relocation to China, but don't expect that it will be easy, they have very hard competition in this area.
Does area inside a constant circle on smith chart represent constant refection ? - Page 1
Forum section: electronics / rf-microwave

author: electronic_guy
author_rank: Regular Contributor
timestamp: February 23, 2024, 06:59:22 am
content: Hi,Why does the area inside a constant circle on a smith chart represents loads with constant reflection coefficient of value equal to the circle's radius, no matter where they are inside that circle ? I just don't understand how. I mean if I take the reflection coefficient 1 circle and the area covered by it, wouldn't it make all the loads inside other constant reflection coefficient circles to have the same reflection coefficient of 1.Please look at the picture.Let's say we take the constant gamma circle of -20 dB. Then if all the load points inside the area covered by that circle give same reflection coefficient which is -20dB, If I consider the constant reflection coefficient circle of 0 dB and take a load inside the -20 dB circle, then it's confusing as to which reflection coefficient to choose. Is it 0 dB or -20 dB ? I'm sure there must be something I'm missing here. I'm very new to this, please explain with little bit of maths and physical meaning of this.Thank you.

author: RoV
author_rank: Regular Contributor
timestamp: February 23, 2024, 08:21:07 am
content: The magnitude of the reflection is the same for the points belonging to the circle (that must be centered on the chart), not for points inside it.Remember that the chart plots the reflection coefficient in cartesian coordinates, with superimposed curves for readout of impedance and/or admittance. A circle of radius r centered on the point with ro = 0+j0 (the center) is exactly the locus of constant magnitude abs(ro)=r.

author: pdenisowski
author_rank: Super Contributor
timestamp: February 23, 2024, 11:10:22 am
content: Quote from: RoV on February 23, 2024, 08:21:07 amAnother way of saying this is that all points lying along a circle centered around the origin* have the same VSWR (voltage standing wave ratio).The radius of the circle is the VSWR, so you can read off VSWR by looking at the point at which the circle crosses the resistive (real) axis on the right side of the axis. In the attached image, all points on the blue circle have a VSWR of 2 and all points on the red circle have a VSWR of 5.*or "prime center"

author: radiolistener
author_rank: Super Contributor
timestamp: February 23, 2024, 11:32:44 am
content: exactly the same reflection coefficient can be for different combination of active and reactive component of impedance. This is why you can draw circle for the same reflection coefficient.But note that area inside or outside circle is not the same reflection. The same reflection lays exactly on circle line.
Looking for help to build a replicable DIY small infrared deep tissue heater  - Page 1
Forum section: electronics / rf-microwave

author: MustardBoar
author_rank: Newbie
timestamp: March 26, 2024, 04:15:08 pm
content: Hello everyone!!I am Looking for help to build a :replicable,DIY,small sized,infrared deep tissue heaterit’s size should be a rectangle 4,5cm (width) x 15cm (length) x 1,5cm (or 2cm) (thickness)With a wired control deviceand above each “resistance”(heater vertical (parallel to the width) band) a button to shut it off individuallythe deep heat should reach 38,9C (102F) and 43,3C (110F)and reaches them in 2minutes max (or maybe add an Intensity button/roller)thx for reading!!!!
TinySA Ultra driver for Win XP SP2?? - Page 1
Forum section: electronics / rf-microwave

author: CaptDon
author_rank: Super Contributor
timestamp: February 19, 2024, 02:37:36 am
content: Has anyone else run into this and found a solution?? My TinySA Ultra shows up as an UnKnown Device in the SYSTEM / HARDWARE Control Panel group. It is supposed to show up as a Com Port sort of like how a USB to RS232 Serial cable shows up as a Com Port. I have tried several things including serial cable drivers but usually when I point to a driver and try to install it I get the message "File contains no information about your device". I believe my device to be genuine and not a fake ripoff. It meets all specs and works as advertised. I had heard others using VNA's and so forth had this driver problem. Anyone have a solution? The TinySA website hasn't helped. Thanks!!

author: selcuk
author_rank: Frequent Contributor
timestamp: February 19, 2024, 07:01:25 am
content: Did you try this one?https://www.st.com/en/development-tools/stsw-stm32102.htmlIt is detected as "USB ACM device" having idVendor=0483, idProduct=5740 on my Ubuntu System. You may search with these IDs for the driver.

author: CaptDon
author_rank: Super Contributor
timestamp: February 19, 2024, 02:39:51 pm
content: Thank you very much indeed. I saw that driver was listed for Win7 and I did not realize it could also be used for WinXP. I installed the Win7 32 bit driver package and it works perfectly now!! Indeed this is what I needed. I am impressed by what the TinySA Ultra can actually do. I may do the headphone mod for the 'Listen' mode. I am mostly using the TinySA to look at the spectral output of a specialized receiver which has a 4 MHz wide output centered at 21.4 MHz. I also need to document a 40 MHz comb generator up in the 1.4 GHz range. Thanks again for the help!!

author: selcuk
author_rank: Frequent Contributor
timestamp: February 19, 2024, 09:37:38 pm
content: You are welcome. I didn't hear about the audio modification. Good to know that as well.

author: Solder_Junkie
author_rank: Frequent Contributor
timestamp: February 20, 2024, 08:38:08 am
content: There is a dedicated TinySA support forum at:https://groups.io/g/tinysa/I also have a TinySA Ultra, really excellent kit.SJ
Starting with Simulink, how to simulate mixer - Page 1
Forum section: electronics / rf-microwave

author: prutser
author_rank: Regular Contributor
timestamp: February 18, 2024, 06:40:05 pm
content: I am just starting with Simulink with the intention to simulate some conversion chain. I thought let's start simple, take a mixer with 2 inputs and display the mixer output in the frequency domain. It seems not so trivial.SRC = 100MHz, LO = 2GHz but I also need to specify a frequency for the out port, why is this necessary (based on both frequencies the mixer output can be calculated) ? A mixer will produce many different output frequencies, so what to specify for the output port ?I was also looking for an option to select start/stop frequency or span in the analyzer, but couldn't find it. Should this be provided in another way ?Tried to find a simple example, but without success, so any pointers, suggestions are welcome.

author: Odysseus
author_rank: Regular Contributor
timestamp: February 18, 2024, 10:25:41 pm
content: https://www.mathworks.com/help/simrf/gs/model-an-rf-mixer.html

author: jjoonathan
author_rank: Frequent Contributor
timestamp: February 19, 2024, 02:24:12 am
content: QuoteThis seems pretty useless for modeling spurs or anything beyond "look ma, I did a radio!" Is there a different model that might be more suitable for engineering purposes?

author: prutser
author_rank: Regular Contributor
timestamp: February 19, 2024, 06:18:14 pm
content: This one I have seen as well. It seems indeed a rather simplistic model, since I would expect (to a certain extend) all mixer products including some harmonics. I tried this example and connected the spectrum analyzer in parallel with the scope, the screen remained black. I have seen many complex communication chains simulated, but something basic like this seems not that easy

author: rfdave#gmail.com
author_rank: Contributor
timestamp: February 20, 2024, 02:43:49 am
content: Do you understand the different data types used in your simulation? Simulink has tools to display what is flowing on each line, and the lines and arrows are color coded to represent the data types you're using. Simulink is not a circuit simulator, it's a math tool, and it's incumbent on you to make sure you set it up correctly.
Heathkit IM-4180 Deviation Meter is repaired!! - Page 1
Forum section: electronics / rf-microwave

author: CaptDon
author_rank: Super Contributor
timestamp: February 23, 2024, 02:56:55 pm
content: It lives!! I had to replace every resistor with green corrosion on the leads. They actually fell apart when desoldering!! The capacitors somehow were in good shape and not needing replacement. The circuit board is single sided with traces underneath only but I think somehow the drycell acid leakage found its way under the board because many traces were destroyed and many more got damaged when I replaced the I.C. sockets. The DIP-8 CA3130's work perfect as a replacement for the TO-5 can style!! The unit calibrates very well at 7.5, 20 and 75KHZ but it is a bit stingy on the 2KHz scale only showing 1.8KHz when 2KHz is being generated. I used the 'first missing carrier' method to prove my generator was producing the correct deviation output using the 2.405 modulation index. Here is a list of the tones to use, 832Hz for 2Kdev, 2079 for 5Kdev, 4158 for 10Kdev and 15593K for 37.5Kdev. Hope you folks find those numbers useful. If you have a spectrum analyzer those numbers can help you set deviation. Also, Carson's Rule for those unfamiliar, (Modulating tone + Deviation) X 2 will describe the carrier and sidebands totaling apprx 98% of the power.Cheers all!!
Boonton 102F AM FM RF Signal Generator Manual - Page 1
Forum section: electronics / rf-microwave

author: eminitellect
author_rank: Newbie
timestamp: February 23, 2024, 06:56:04 pm
content: Hello all , I purchased a Boonton 102F on FBMP and I chose to believe the seller that it worked. ( I know, I know) Does anyone here have a Manual/service manual/schematic they would copy or sell to me. I have not found one on the net for some time.

author: 807
author_rank: Frequent Contributor
timestamp: February 24, 2024, 12:50:24 pm
content: Artekmanuals have the operator/service manual with schematics for $12.50http://artekmanuals.com/manuals/other-manuals/

author: Solder_Junkie
author_rank: Frequent Contributor
timestamp: February 24, 2024, 02:18:21 pm
content: There is a 102d manual for free from the Boat Anchor Manual Archive:https://bama.edebris.com/manuals/boonton/102d/SJ
id a mystery board - Page 1
Forum section: electronics / rf-microwave

author: p.larner
author_rank: Frequent Contributor
timestamp: February 13, 2024, 02:00:31 am
content: I brought this at a rally for a pound,i wanted it for the diecast box it was in,the seller told me it was a filter,the pcb has on it pc magazine limmited 1385 WR202,any ideas what it may be?,the can has no markings that can be read but has 4 legs,it had a bnc connector a red+ black pair of wires and the coax to it,i think it maybe a preamp and the can a dual gate fet?,any ideas?.

author: Andy Chee
author_rank: Super Contributor
timestamp: February 13, 2024, 02:34:27 am
content: The chip appears to be an ECL divider. So I'm guessing the entire circuit might have intended to buffer and divide a clock down. It could also potentially function as a filter. Who knows.https://www.tautec-electronics.de/Datenblaetter/Schaltkreise/SP8680B.pdf

author: edpalmer42
author_rank: Super Contributor
timestamp: February 13, 2024, 03:40:50 am
content: Economy UHF Prescaler - Practical Wireless, Sept. 1985

author: MarkT
author_rank: Frequent Contributor
timestamp: February 15, 2024, 09:03:30 pm
content: Perhaps a pre-divider for frequency counter?
Heathkit IM-4180 Modulation Monitor I.C. question, - Page 1
Forum section: electronics / rf-microwave

author: CaptDon
author_rank: Super Contributor
timestamp: February 20, 2024, 01:55:40 pm
content: I have two IM-4180 units that came to me for repair from another ham operator. Both were devastated by dry cell leakage. I got the lesser damaged unit working and calibrated and it is a very useful piece of gear. I am now starting on the heavily damaged unit. The 8-pin I.C. sockets are bad and will be replaced. The CA3130's in the TO-5 cans have damage to their leads. Heathkit only shows the TO-5 style I.C.'s in the assembly instructions but the DIP version would be so much easier to deal with. Does anyone here have experience using the CA3130 DIP style as replacements? I don't think the metal can is returned to any ground / earth shield lead so it doesn't seem to be a matter of shielding causing Heathkit to prefer the TO-5 style. Any insight here?? I can buy either but would prefer the DIP package. The pinout is the same for both. Thanks!!!

author: Wallace Gasiewicz
author_rank: Super Contributor
timestamp: February 21, 2024, 12:11:36 am
content: CaptI have not had your exact problem with this particular unit.But I have replaced lots of can op amps with DIPs.I think some of those op amps were CA 3130.I did this for the reason you stated, easier to physically deal with using a socket. Otherwise I use a socket and put the can into another socket so it is easier to put in and take out. It is a lot easier to install the can into a socket when the socket is not on the board. Then you can also easily remove the op amp and change if needed.This is probably not optimal for very high freq stuff, but I have had no problems with the double socket.

author: CaptDon
author_rank: Super Contributor
timestamp: February 21, 2024, 01:57:19 pm
content: W.G., that is a good idea to put them into an 'auxilliary socket' so to speak. I think I will order up a bunch of the DIP style CA3130 devices and start to swap them in to the working unit one at a time to observe the effect. I could then also take the 'pullouts' and place them into their own carrier socket. The IM-4180 used 10 AA batteries internal to the unit and no leakage protection was provided. I suppose many of these units were simply too damaged to be worth repair? They are a very useful piece of gear when calibrated and working. I guess so many of these sat on a shelf, seldom used and battery leakage onto the PCB was the grim reaper. The upside is the tuner assembly is above where the damage occurs and seems to survive quite well.

author: Wallace Gasiewicz
author_rank: Super Contributor
timestamp: February 22, 2024, 12:40:14 am
content: the round leads stick much better in round machined sockets,rather than the other spring sockets.
IR-UWB Radar? - Page 1
Forum section: electronics / rf-microwave

author: LRJ
author_rank: Contributor
timestamp: February 12, 2024, 10:33:18 pm
content: Calling all RF / Radar experts –See video below of continuous 24/7 stream of 397-434 Mhz signals in my home (dBm between -67 and -73) measured with GQ EMF-390. Scanned everything in the house, basement & garage and nothing we have is emitting this.https://youtu.be/1kl9BqL91fwSuspect nearby neighbor may be running IR-UWB radar. Does this activity match what I would be likely to see if someone in a nearby home was using IR-UWB radar with ~400 MHz as the central frequency? May need RF engineer to come onsite for analysis. Any referrals / recommendations for someone in the Kansas City area who could take on this type of project?

author: coppercone2
author_rank: Super Contributor
timestamp: February 14, 2024, 12:15:21 am
content: UWB technology is used for precision distance measurement in the 3-12GHz band.There is nothing ultra wide about what you see. Ultra wide means octaves. the only thing you figured out that you have someone moderately technologically advanced nearby that is capable of using common gadgetsthe only thing UWB can do is precisely measure the distance between two devices i.e. covid exposure badges.

author: coppercone2
author_rank: Super Contributor
timestamp: February 14, 2024, 02:08:22 am
content: I am not gonna jump the gun and claim paranoia because people sometimes use this as a threat when they are pissed off ( i heard all types of threatening 'plots' ) but I do suggest trying to relax. Menacing related to computer/electronics has become more common with the youththere is no point in being mean because we don't have the detailsBTW teaching this guy how to find a signal in a calm civilized fashion is going to reduce anxiety way more then finger pointing at the psyche. There is a off chance that someone is crazy enough to plant a microphone or something like that. But usually that involves lawyers or politicians. It's not exactly hard to do because these devices only get smaller and cheaper but difficult to do anything with and there is a extreme risk of getting caught (as always, its trespassing or breaking and entry) and the punishment is severe (felony).

author: Bud
author_rank: Super Contributor
timestamp: February 14, 2024, 02:42:56 am
content: This is the case of a solution looking for a problem. OP lived a happy life until he bought that gadget. Now he is looking what problem to apply it to.

author: Halcyon
author_rank: Unknown
timestamp: February 14, 2024, 04:28:29 am
content: Duplicate post.
RTL-SDR's tuner E4000 Have 6 IF stage, why? - Page 1
Forum section: electronics / rf-microwave

author: Seyyed Mohammad
author_rank: Newbie
timestamp: February 08, 2024, 01:44:37 pm
content: I'm newbe in RF, Why E4000 tuner in RTL-SDR have 6 stage of gain?The only reason I can think about is that maybe The earlier stages consume more power, because thy have better noise figure. They've split gain to achieve balance between current consumption and noise. But it seems 6 stage is really overkill, doesn't it?And the image of stages has been attached.

author: radiolistener
author_rank: Super Contributor
timestamp: February 08, 2024, 05:35:14 pm
content: IFstg1 to compensate loss on RF filter, mixer and mixer filter.IFstg2, IFstg3, IFstg4 to compensate loss on IF RC filter.IFstg5, IFstg6 to compensate loss on IF filter.It combines several PGA in series in order to provide more possible gain levels.Quote from: Seyyed Mohammad on February 08, 2024, 01:44:37 pmif you remove IFstg6, it will allow max gain on IFstg5 as 15 dB. With IFstg5 and IFstg6 it provides gain setting up to 30 dB (15 dB + 15 dB).Using two 15 dB amplifiers in series instead of one for 30 dB allows to get more stable circuit, because amplifier with very high gain is more vulnerable to instability due to possible self-oscillations which may happens due to parasitic feedback.

author: MarkT
author_rank: Frequent Contributor
timestamp: February 09, 2024, 09:39:40 pm
content: I think the basic reason is linearity, this isn't an FM front end, its a realtively wide bandwidth amp to drive an ADC, everything needs to be as linear as possible, so feedback is used limiting each stage's gain (also keeps frequency response wide and flat).
swr directional coupler - Page 1
Forum section: electronics / rf-microwave

author: p.larner
author_rank: Frequent Contributor
timestamp: February 02, 2024, 12:10:07 pm
content: I see a few swr meter couplers for hf,most use two torroid coils,both of mine have more,my diamond hf unit has 4 just for hf,the uhf coupler is simmilat to a bird type asensor,why the different number of coils used,apart from cost?what is best 2 or 4?.

author: A.Z.
author_rank: Super Contributor
timestamp: February 02, 2024, 08:44:24 pm
content: did you ever stop for a split second, think, and try to understand HOW those couplers work ? Or are you just trying to raise waves around?

author: RFDx
author_rank: Regular Contributor
timestamp: February 02, 2024, 09:07:40 pm
content: Show a picture of the HF unit.

author: A.Z.
author_rank: Super Contributor
timestamp: February 03, 2024, 07:53:24 am
content: oh, he just refrains it over and overhttps://www.eevblog.com/forum/rf-microwave/swr-bridge-re-use-repair/msg5313140/#newhttps://www.eevblog.com/forum/rf-microwave/coil-winding/msg5300707/#newapparently w/o even reading the replies

author: p.larner
author_rank: Frequent Contributor
timestamp: February 03, 2024, 10:28:26 am
content: Quote from: A.Z. on February 03, 2024, 07:53:24 am

author: tggzzz
author_rank: Super Contributor
timestamp: February 03, 2024, 01:56:22 pm
content: Quote from: A.Z. on February 03, 2024, 07:53:24 amYes, and not just on this subject, e.g.https://www.vintage-radio.net/forum/showpost.php?p=1613791&postcount=4https://www.eevblog.com/forum/repair/solartron-dmm/msg5314369/#msg5314369https://www.eevblog.com/forum/metrology/solartron-7075-413074/msg5307547/#msg5307547He is beginning to remind me of f*/t*/o*

author: A.Z.
author_rank: Super Contributor
timestamp: February 03, 2024, 02:54:58 pm
content: *SIGH* (notice how he quoted my message)

author: p.larner
author_rank: Frequent Contributor
timestamp: February 08, 2024, 10:21:56 am
content: heres a pic of the hf coupler,as asked for.

author: Kean
author_rank: Unknown
timestamp: February 08, 2024, 10:52:46 am
content: Amazing... his soldering is consistent with his typing