hybridfree/eevblog-posts huggingface dataset:
AM Modulation Drops - Page 1
Forum section: electronics / rf-microwave

author: Chrisku
author_rank: Newbie
timestamp: November 18, 2022, 02:49:46 am
content: Put my radio in AM mode and get about 100 watts with carrier only, Upon modulating (talking) the power output drops?? Shouldn't the power increase?useful links for leisure time:https://africanporn.tvhttps://blackporn.funhttps://ebonyporn.ooo

author: radiolistener
author_rank: Super Contributor
timestamp: November 19, 2022, 01:03:40 am
content: It depends on how modulation is implemented. When there is a carrier with fixed power which is mixed with DSB modulated signal, then the power sum will be increased. But if it uses fixed power which is shared between carrier and DSB signal, then the power sum will be fixed and carrier power will be decreased for the amount of power which is transmitted with DSB signal, but this is not classic AM.Since you have the power sum drop, maybe your power meter is not able to measure power properly when waveform is not pure sine (which happens when you put modulation signal).

author: Wallace Gasiewicz
author_rank: Super Contributor
timestamp: November 27, 2022, 01:42:42 pm
content: I do not know what radio you are using.Usually the carrier should be 10-20 watts in a 100 watt transmitter.Can you turn it down?
Return Loss of GNSS Antenna - Page 1
Forum section: electronics / rf-microwave

author: Sbilf
author_rank: Newbie
timestamp: November 15, 2022, 04:31:52 pm
content: Hi guys,I need help on a GNSS antenna. My board is a lap timer whit ceramic antenna GPS/BEIDOU/GLONASS. The datasheet explain best layout for to have best performance but I can't respect them.In the frequency 1561 / 1575 / 1602 MHz I should have low return loss. If I don't follow the suggestions of datasheet I think Frequency Range of antenna and curve of Return loss change. How can I measure these curves in my situation and understood how worsened have I gotten?I' m thinking by vector network analyzer for example "NanoVNA". But I don't sure is correct.Thanks a lot.

author: WPXS472
author_rank: Regular Contributor
timestamp: November 27, 2022, 04:17:36 pm
content: I am a bit puzzled as to why return loss is important with a GNSS antenna. They are receive antennas. If the specs for the antenna say it is for a given frequency, or range of frequencies, I think you would assume it works for those frequencies. Since most GNSS antennas have a built in preamplifier, it would be difficult to measure the return loss of the antenna from the end of the coax feed line anyway. Placement of the antenna is important because of the effects of nearby objects. They can cause reflections and multipath, reducing the accuracy of the GPS.

author: uski
author_rank: Frequent Contributor
timestamp: December 24, 2022, 08:24:33 am
content: I see the value of checking the antenna. A lot of sellers have no clue about what they are selling and I bet that single frequency, L1 GPS antennas, can very quickly be relabeled, by mistake or intentionally, as GNSS multi-band antennas.Similarly, some antennas will be better than others...I do agree that because of the LNA, it will be hard ot measure. But it makes sense to discuss how one could compare there antennas, so they can be compared, and their specs verified.Sbilf, the issue you are going to face if you do not respect the specifications of the antenna is that you might shift the antenna out of frequency. I would suggest working with the antenna manufacturer, I have been in similar situations before, and often they have useful guidelines for these situations (from "do this XXX and it will fix everything" to "we have no idea" with "if you do what you want to do it will not work" in between)
Is this Starlink transmission technology presentation sound? - Page 1
Forum section: electronics / rf-microwave

author: nixxon
author_rank: Frequent Contributor
timestamp: November 19, 2022, 05:45:21 pm
content: This YouTube presentation of "How does Starlink Satellite Internet Work?" is nicely made and impressive. And pretty interesting. But what do the electromagnetic RF signal path guys think?How does Starlink Satellite Internet Work?:https://youtu.be/qs2QcycggWU

author: radiolistener
author_rank: Super Contributor
timestamp: November 19, 2022, 06:11:17 pm
content: Phased antenna array is very old technology, it is widely used for radars.The incredible thing of starlink is how it tracks satellite position and move beams in order to keep the link. This is very complicated task.

author: 9aplus
author_rank: Regular Contributor
timestamp: November 19, 2022, 09:22:07 pm
content: Few words of first hand experience wisdom.Here using Starlink together with 4G and ADSL wired on multiport wan router, near one full year.Personally working on line, not just me but also significant number of our visitors.The system consist of 7 Wi-fi AP 2,4 GHz and number of upload streams like FR24 and AISStarlink works well 99% of time with exception of more dense rain showers.Word of warning: the electric meters of old electro-mechanic construction with rotating disccan pick up some microwave energy and go mad on numbers.For two of ours, both three phase positioned approx 1 m bellow Starlink antenna - that was the case.Now we have new modern electronic ones and still in discussion with distribution for real bill for spent energy.
AD CN0511 Signal Gen - Page 1
Forum section: electronics / rf-microwave

author: mawyatt
author_rank: Super Contributor
timestamp: November 16, 2022, 03:41:24 pm
content: https://www.digikey.com/en/product-highlight/a/analog-devices/cn0511-dc-to-5-5-ghz-signal-generator?utm_medium=email&utm_source=npa&utm_campaign=127492_NPA2211B&utm_content=mainproductlearnmore_US_505-Analog_Devices&utm_cid=11664090&mkt_tok=MTQ0LU5DQi0wMzAAAAGIH_lxMgomk0FnqW_J00irTsKH9aTZxm-uwOa9lT_mMbEPqAhkS_-6wTd1IWcXdZJQBX1EcPJVlSQXI12QWBtg5dxR0I78lYwQ46rLy1fNJXMUgqfWBest,
Coefficients for Anritsu 22N50 and 22NF50 open/short - Page 1
Forum section: electronics / rf-microwave

author: wilhe_jo
author_rank: Regular Contributor
timestamp: November 18, 2022, 11:53:10 am
content: Hi!Anritsu has nice Open/Short standards which are available on ebay for a reasonable price.However, there's no official data on them... It seems the data is shown in their VNAs, only.This is indicated here:https://groups.io/g/nanovna-users/topic/anritsu_22n50_open_short/76761196So could somebody with an Anritsu VNA possibly get me the call parameters for the 2 (22N50 and 22NF50) open/shorts?Regards,Johann

author: TheSteve
author_rank: Unknown
timestamp: November 18, 2022, 04:35:37 pm
content: I had one years ago but have since sold it. If I still had it I'd measure it as I have the gear to do it now. In the past I used it for scalar measurements only with an Agilent N1996A.I see the values from the thread you linked may be:Open: offset 17.83mm, C0=4e-15 F, C1=200e-27 F/Hz, C2=0 F/Hz^2, C3=1.1e-45 F/Hz^3Short: offset 17.83mm, L0=0, L1=0, L2=0, L3=0But someone really needs to verify.

author: wilhe_jo
author_rank: Regular Contributor
timestamp: November 18, 2022, 05:46:34 pm
content: Well, yes there is 1 set of parameters in this thread...However, I'd love to have the other set (for the female version of the kit) as wellHopefully, someone would also reply if the parameters are correct.Regards

author: switchabl
author_rank: Frequent Contributor
timestamp: November 18, 2022, 07:21:50 pm
content: Unfortunately, I don't remember which model those values came from. 22N50 and 22NF50 are still listed as accesories for most/all Anritsu handheld VNAs but at least on the newer ones, they don't actually seem to appear in the cal kit menu.In case it wasn't clear from the original post, I don't really trust those coefficients. They happen to match those from the OSLN50A-8 datasheet whichmayindicate that they are similar internally or simply that they are wrong.The 17.83mm offset should be good though, that seems to be the common across Anritsu male type N standards and matches well with the mechanical dimensions.

author: metrologist
author_rank: Super Contributor
timestamp: November 18, 2022, 10:49:23 pm
content: You need to use the specs in the components catalog, just the electrical length and propagation time is shown. They are NOT the same as the OSL series as suggested above.https://dl.cdn-anritsu.com/en-us/test-measurement/files/Brochures-Datasheets-Catalogs/Catalog/11410-00235AD.pdf

author: wilhe_jo
author_rank: Regular Contributor
timestamp: November 19, 2022, 12:32:28 pm
content: But the electrical length would be a first order approximation, only, right?Any idea to what frequency that could be adequate?In my applications, I tend to measure maybe around 50-60R (maybe 40-70 at most) up to 6GHz (3GHz is "critical"; >5GHz would be nice).So I'd guess these open/shorts with this minimal known parameters should outperform similarly priced Chinese standard.I mean, at least there are some known parasitics...Regards
Can we extend range for remote RF 2.4Ghz like wifi range extender? - Page 1
Forum section: electronics / rf-microwave

author: sairfan1
author_rank: Frequent Contributor
timestamp: November 09, 2022, 05:41:01 pm
content: More than a week ago I asked this question in the beginner section but did not get any response, asking here so that I could get some attention.I have a remote button it works on 2.4ghz I want to build a range extender for it just like the idea wifi range extender works.I want to receive the signal when button pressed, then transmit the signal through NRF24L with extended range module.I do not know how button is transmitting its key or code to turn on the switch, but I'm sure its one way.Is it something possible?what things should i take care of?

author: GromBeestje
author_rank: Frequent Contributor
timestamp: November 09, 2022, 05:53:53 pm
content: I have only worked with nRF24LU1+ based USB dongles, receiving data from an nRF51.But as you are mentioning something nRF24, I assume it uses Enhanced ShockBurst.In Enhanced ShockBurst, you have multiple communication pipes.Pipe 0 has one network address going with it, it would usually be used for stuff like pairing.The other pipes share a network address. These are usually for data communicationTherefore, in my example I will use pipe 1 and 2I suggest using pipe 1 to communicate from the transmitter (TX) to the Repeater.The Repeater starts in Receiver mode, listening on pipe 1. The Receiver only listens on Pipe 2.When the repeater receives a packet, it switches to Transmission mode, and forwards the packet on Pipe 2.Code:TX -- pipe 1 --> Repeater --> pipe 2 --> RX
RSP1A not calibrated below 1 MHz, 37 db wrong at 1 kHz - Page 1
Forum section: electronics / rf-microwave

author: bb1
author_rank: Regular Contributor
timestamp: November 08, 2022, 08:49:52 pm
content: SDRplay claims that RSP1A is calibrated and shows correct signal amplitude measured in dBm.They also claim valid frequency range for RSP1A to be from 1 kHz to 2 GHz.I applied -30 dBm CW signals of different frequencies from DG1022z to the input of RSP1A.At 10 MHz the screenshot SDRuno_10MHz_-30 dbm_dec1.png of SDRuno indeed shows signal level of -30 dBm and SNR ratio of about 80 db.When the frequency is decreased, SDRuno still shows correct signal level down to 1 MHz.However, below 1 MHz the signal level shown by SRDuno starts to decrease. At 100 kHz it becomes about -38 dBm, at 10 kHz -41 dBm.At the lowest end of the frequency range claimed by SDRplay, 1kHz, the signal level shown by SDRuno is very low 67 dBm, as can be seen on the attached sdrUno_1kHz_-30dbm_dec32.png.The SNR is also decreased to 60 db.SDRplay support admitted absence of calibration below 1 MHz, while SDRuno does use lower frequency ranges Broadcast LW and part of MW, and Ham Lower 2200 and 630.

author: ejeffrey
author_rank: Super Contributor
timestamp: November 08, 2022, 09:09:12 pm
content: I would normally expect "not calibrated" to mean that the signal can have an error of a couple dB. 37 dB too low isn't a missing calibration, it sounds more like an AC coupled signal path with a significantly higher cutoff frequency.
General Dynamics R2670B Any good for Ham Radio? - Page 1
Forum section: electronics / rf-microwave

author: Crambone
author_rank: Frequent Contributor
timestamp: November 07, 2022, 11:04:08 pm
content: I am wondering if the General Dynamics R2670B is a good Communications Analyzer for Ham Radio troubleshooting and alignments? I’m using a Marconi 2955 now but it’s just not good for SSB and I have an opportunity for a good priced General Dynamics R2670B.I value the groups input.

author: Wallace Gasiewicz
author_rank: Super Contributor
timestamp: November 08, 2022, 12:38:27 pm
content: Same as the MotorolaI have not used it. Looks good for up to one GHzhttp://repeater-builder.com/test-equipment/motorola/pdf/r2670-description.pdf
Isolation of Digital and RF Sections - Page 1
Forum section: electronics / rf-microwave

author: kml183
author_rank: Contributor
timestamp: November 14, 2022, 02:44:45 am
content: I am working on a RF attenuator that has a switchable pass-through. The stackup is from top to bottom rf - gnd - gnd - signal. The RF switches are controlled by a DC switch powered from a USB connector. Right now I don't think I would have to many issues with inter modulation between the RF to the DC side because it will only be driven with less then 10 mW.If I was to use a similar design with a higher power RF signal how would I create better isolation between the RF and and DC signals?

author: M0HZH
author_rank: Regular Contributor
timestamp: November 14, 2022, 10:16:08 am
content: What is the application?Common practice for attenuators is to use complete metal shielding around the switches / RF patch and decouple DC / control signals correctly with capacitors, maybe even using ferrite beads.

author: kml183
author_rank: Contributor
timestamp: November 14, 2022, 04:52:53 pm
content: Quote from: M0HZH on November 14, 2022, 10:16:08 amThis was just for fun and to test out the AS183-73 RF switch. I think that is what I was missing; its good enough to add some proper DC decoupling with caps and a ferrite bead.
Is there an adapter for RFM95/69 RF module generally available for purchase? - Page 1
Forum section: electronics / rf-microwave

author: nbolton
author_rank: Newbie
timestamp: October 27, 2022, 10:36:31 pm
content: The RFM95/69 RF module has a 1.5mm pitch spacing. Adafruit came up with abreakout boardto adapt this to 2.54mm pitch (as well as adding a regulator and level shifter for 5V MCUs, which I don't actually need). I managed to snag a couple of the Adafruit breakouts, but they seem to have become quite rare in the UK. Though, the actual RF modules (with 1.5mm) are fairly easy to find and I have a few of those. I'm aware that these 1.5mm pitch modules are meant to be mounted on another PCB, but I'd like to use them on a perfboard prototype.The module dimensions appear to be identical to the ESP* modules, so I wonder if the module type has a specific name that I can search for... I tried scanning theRFM95 datasheet, but didn't spot anything (it's a very long datasheet, so I probably just missed it if it's there). Anyway, before I go ahead and order a batch of my own breakouts from a PCB fab, is there anywhere that sells a generic breakout board for these modules? Either my Google Fu is weak, or they don't exist.p.s. My first post! I read theread before posting post, and looks like there are no anti-product-recommendation rules... hope I didn't make any faux pas! I normally post onEE SE, but product recommendations are against their rules, so here I am!p.p.s. For now, I soldered them dead bug style (with a bit of heat resist tape underneath the module to prevent shorting pins).

author: nbolton
author_rank: Newbie
timestamp: October 31, 2022, 04:47:17 pm
content: Update, IthinkI found the magic Google words to find an RFM95 adapter..."esp adapter plate" or "esp breakout board"Seems that the RFM95 module is exactly the same size and pin arrangement (on 2 sides) as the ESP module. The pinout labels won't be right, and it won't have the resistors and caps that the Adafruit adapter has... and there's a few ESP-specific resistors on there, but I'll give it a try.I also found "RFM95 Shield" for Wemos, but that's not quite what I'm looking for.Ordering now to double check.

author: Upballoon
author_rank: Contributor
timestamp: November 02, 2022, 03:20:02 pm
content: Will this work? :https://www.sparkfun.com/products/12775
Easy ground plane antenna - Page 1
Forum section: electronics / rf-microwave

author: Salmon_Sll
author_rank: Newbie
timestamp: October 28, 2022, 01:12:31 am
content: Any idea for simple ground plane antenna at around 2 MHz and any advice?

author: TheMG
author_rank: Frequent Contributor
timestamp: October 28, 2022, 01:53:10 pm
content: Easy? Not at that frequency. A ground plane antenna typically has a vertical radiating element that is 1/4 wavelength long. For 2MHz that would be 37.5 meters tall!Of course, you could go shorter than 1/4 wavelength with inductive loading, trading off bandwidth and efficiency for smaller size, but it's still not going to be "easy" (ie you can't make the antenna 1 meter long and expect good results, there are limitations).I would consider other types of antennas. A mag loop for example, or a beverage antenna if you have the horizontal real estate.

author: hagster
author_rank: Frequent Contributor
timestamp: October 29, 2022, 07:14:43 am
content: What do you mean by ground plane antenna?2MHz is naturally very large for any antenna.As always the choice is small, efficient or wideband. You can be anywhere within that triangle, but you can't have all three.E.g. Small. Use tuning components such as inductors and capacitors to make it efficient. Makes it narrowband. HAM antenna tuners are good for this. You can also add resistors to make it inefficient and wideband.'Small' for antennas is always compared to wavelength.

author: Wallace Gasiewicz
author_rank: Super Contributor
timestamp: October 29, 2022, 11:04:34 pm
content: A Mag Loop for 2 MHz transmit would be quite large to be of any practical use.Maybe just a large loop antenna with a tuner.

author: coppercone2
author_rank: Super Contributor
timestamp: October 30, 2022, 03:52:07 pm
content: jlc pcb must love youask to buy about 20 blank original size unprocessed fr4 copper clads to get started

author: A.Z.
author_rank: Super Contributor
timestamp: October 31, 2022, 06:12:33 pm
content: Quote from: Wallace Gasiewicz on October 29, 2022, 11:04:34 pmwhat about a classic "Marconi" T antenna?

author: A.Z.
author_rank: Super Contributor
timestamp: November 01, 2022, 07:07:39 am
content: GROANhttps://hfdxarc.com/aerials/t-antenna-with-matching-network/I wrote "T ANTENNA"
Need help identifying YIG oscillators - Page 1
Forum section: electronics / rf-microwave

author: EggertEnjoyer123
author_rank: Frequent Contributor
timestamp: October 30, 2022, 09:32:30 am
content: I bought some unknown YIG oscillators for $5 each at a ham swap meet, and I am wondering how to identify the pinout as I can't find any information on the internet.There are 6 pins on both of them.The model numbers are SDYX-3017 and SDYX-3018. They are made by a company called Systron-Donner, and they are L band and S band.It seems like pin 5 and 6 are the main power input, as there is an 18V zener diode (1N967). Resistance between these two pins is 3.3k on the L band one and 4.5k on the S band one. Pin 1-2 might be the main tuning coil, as the resistance on both is around 10-11 ohms. I am unsure what pins 3 and 4 do, as the L band one shows 2.5k ohms between them and the S band one shows 300 ohms. The DC resistance between any other pair of terminals is too high to measure with my multimeter. Any idea on how to operate these devices?

author: coppercone2
author_rank: Super Contributor
timestamp: October 30, 2022, 03:50:53 pm
content: look at impedance between center pin of coaxial and the outer pins, it might be of value

author: EggertEnjoyer123
author_rank: Frequent Contributor
timestamp: October 30, 2022, 08:27:11 pm
content: I think I have identified the pins with the help of this website:http://www.vhfcomm.co.uk/A%20Simple%20Approach%20tyo%20YIG%20Oscil.pdfIt seems like pins 1 and 2 are the coil, pins 3 and 4 are the heater element, and pins 5 and 6 are GND and +15VI don't have a spectrum analyzer with me so I can't operate it right now. I did hook up a power supply to pins 3 and 4. The current started out at 120mA with 15V applied and quickly dropped to 55mA. This is consistent with there being a PTC thermistor between pins 3 and 4.

author: EggertEnjoyer123
author_rank: Frequent Contributor
timestamp: November 01, 2022, 04:10:33 am
content: Looks like I was right. I put 15V into the power pins, 24V on the heater, and 60mA on the coil and I seem to be getting +18dBm out (there is a 10dB attenuator).
vintage 70's nixie frequency counter diagnostics - Page 1
Forum section: electronics / rf-microwave

author: sae-7125
author_rank: Newbie
timestamp: October 27, 2022, 05:50:38 pm
content: trying to figure out if the rf fed (fm bandwidth) freq counter has issues of if the output signal from a fet buffer and tuning gang needs a significant boost.input chip on the counter is fairchild 9528 dual "d" flip-flop ECL with positive vcc circuit design. no known schematic in existence for the board. the nixie counter is part of an SAE Mark 6 "a" fm tuner. there is a "b" version schematic widely circulated, i have yet to hear about an "a" version and yes there are noteworthy circuit differences. even though one would assume the first design/production documents and schematics would be of version 1.0 vs higher rev levels.it is a double sided pcb with a few traces on top and under a few chip sockets. overall relatively simple layout except humans do not perceive the invisible energy very well making diagnostics problematic. limited tools/meters/tech to do things right is an all to common obstacle as well. there is a 5 megahertz crystal/clock on one end and i get the basic bcd chip math/conversion that is transpiring but there remains a gremlin somewhere in the circuit equation.my other threads have more links and schematic info about this current migraine. fresh chips were installed, 5v supply was rebuilt and is stable. other than the assortment of ic's there is an se4021 ufo package transistor and an mps6507. i tried updating the ufo with a bc550c, still evaluating the results.anyone with related experience have thoughts or ideas? i have checked some component with a 100khz LCR meter even though it is several orders of magnitude below 100mhz.a few photos attached.

author: sae-7125
author_rank: Newbie
timestamp: October 27, 2022, 05:51:26 pm
content: more photos
Why doesn't CDM324 work as a FMCW radar when a fluctuating voltage is applied - Page 1
Forum section: electronics / rf-microwave

author: madladlabs
author_rank: Newbie
timestamp: October 26, 2022, 06:03:21 pm
content: Yes, I know CDM324 is a doppler radar module, however, Signal Path did a nice videotaking a deep dive into this module and observed that when the VCC applied is varied between 4 and 5 volts there is a swing in the oscillation frequency of about 6MHz (going from 23.901GHz to 23.907GHz). For those unfamiliar with CDM324, it's a very basic RF module that has a Colpitts(?) oscillator feeding an antenna, and then the transmitted and reflected signals are mixed using a rat-race coupler.My hypothesis was that if I apply a relatively low-frequency triangle wave modulation to VCC, I may be able to observe some distance-sensing component coming out of the mixer on CDM324.So, I set up a quick test. I had a 10-100kHz sawtooth wave generated on AWG of my oscilloscope, that was fed into an opamp to add a DC bias via a pot on the non-inverting input (CDM324 consumes about 30 mA at 5V, so it's within the opamp output spec). The result was a sawtooth waveform fluctuating from 4V to 5V (ballpark, voltages changed and I had to tune the circuit once the load was included). The IF output was fed into an active bandpass with gain of 100 and high cutoff of about 10kHz.Given the modulation of VCC at 10kHz and the oscillator swing of about 6MHz per 1V between 4V and 5V at VCC, I was expecting to see some component in the IF output giving me 800Hz per meter distance to target. That assumption is based on that for every meter distance to target, the reflection should be delayed by about 6.67 ns. With 10kHz sawtooth waveform going from Vmin to Vmax in 50 us, I would estimate the frequency shift of the reflected wave to be about (6.67 ns / 50 us) * 6MHz, or 800 Hz. I was expecting 10kHz to be a low enough of a frequency to not get filtered out by any RC elements in the circuit and be slow enough for the 24GHz oscillator to adjust to.I ran the experiment and saw nothing at all. The radar still responded to moving objects as expected but there was nothing but noise showing up on the FFT in the 400-1600 Hz range. Any thoughts from RF engineers as to why this doesn't work?

author: Georgy.Moshkin
author_rank: Frequent Contributor
timestamp: October 28, 2022, 02:58:29 am
content: There would be only 1/25-th of full 800hz sine period per 0.05ms modulation period. We will only see 4% of a sine and it will restart each modulation period from the same phase (almost DC?). Try to connect earphones to amplifier output through a capacitor, or use an FFT spectrum viewer. I've tried similar experiment with a different 24ghz CW sensor and different distances was audible but undistinguishable on the scope. Attachment shows comparison with 250 MHz bandwidth which gives more than one sine period during modulation period.
G3E Phase modulation - Page 1
Forum section: electronics / rf-microwave

author: JoeyG
author_rank: Regular Contributor
timestamp: October 24, 2022, 11:53:56 am
content: Can some elaborate on G3E modulation (legacy modulation label)... I think it is Phase modulation.Does any one have any technical details on how G3E can be modulated on a carrier and demodulated.I'm familiar with FSK but not G3E phase modulationSome info herehttps://fccid.io/Emissions-Designator/G3Ehttps://www.etsi.org/deliver/etsi_en/301900_301999/30192901/01.01.01_30/en_30192901v010101v.pdf

author: mag_therm
author_rank: Frequent Contributor
timestamp: October 24, 2022, 02:29:20 pm
content: G3E was Phase modulated phone, still listed as ham mode in USA.FM mode Modulation Index is limited to 1.0 for 10 metre and below.I seem to remember this book : Tucker D.G. "Modulators..." published 1954Not showing online as free, but still held in some of the libraries around here, maybe you can try a local uni.Here is a description which may be of use:https://www.eeeguide.com/theory-of-frequency-modulation-and-phase-modulation/

author: MartinL
author_rank: Regular Contributor
timestamp: October 24, 2022, 02:50:04 pm
content: Think of it in terms of an I/Q constellation diagram. In all constant-envelope modulations, the signal moves around the unit circle.- In analogue frequency modulation, an analogue signal is encoded as thecontinuous angular velocityat which the signal moves around the circle. Position on the circle doesn't matter.- In digital phase modulation, data is encoded asdiscrete angular positionson the circle - 2 fixed positions for BPSK, 4 for QPSK, etc.- In analogue phase modulation, an analogue signal would be encoded ascontinuous angular positionon the circle.
Testing Ericsson Telecom Radios - Page 1
Forum section: electronics / rf-microwave

author: Syllith
author_rank: Regular Contributor
timestamp: October 12, 2022, 10:44:19 am
content: Does anybody here happen to have any experience with telecom equipment? More specifically, Ericsson RRH's. I need to find a way to enable the RF output of these radios so that we can test them before shipping out to our customer. Before I go into a lot of detail about what we've tried / are doing, I'd like to see if there's anybody here who even has any experience in that field. Not sure if this is the right place to ask. Alternatively, if anybody knows of another place I might be able to go that could help, I'd appreciate you letting me know. Thanks

author: geggi1
author_rank: Frequent Contributor
timestamp: October 12, 2022, 06:27:41 pm
content: https://www.winncom.com/docs/ericsson/Ericsson_Radio_4408_Datasheet.pdf

author: rplabs
author_rank: Contributor
timestamp: October 20, 2022, 06:51:04 pm
content: You cannot just enable the RF. New generations are like an SDR, they need configuration to know exactly which frequency/channel/power to use. They are configured as a cell so you need from the core side to unblock the cell and put it on air for the GSM/WCDMA. For LTE you can block/unblock the cell from the eNodeB.If you have the complete eNodeB for example for LTE there are some opensource implementations for the core network side and you can try to configure the interfaces and bring the site/cells up. Use some attenuator (30-50dB@100W) and connect the RF output to a frequency counter. If the RF unit has multiple outputs configure it without MIMO as 1:1.It will not be easy to test them if you don't have the complete setup.
Testing HCS301 - Beninca Key Fob not working - Page 1
Forum section: electronics / rf-microwave

author: MarkH522
author_rank: Newbie
timestamp: October 04, 2022, 11:46:48 am
content: Hi everyone,Im looking some help with my Beninca TO.GO-WV garage door opener. The keyfob stopped working for some reason and I'm trying to figure out why.I have been looking at the HCS301 datasheet and can see that the PWM pin is TX out. I have been trying to power the keyfob and measure the output of this pin but it seems to constant around 9v regardless if I push the buttons or not.Any Ideas how I would test if the HCS301 is working and sending the correct signal?Thank youMark

author: MathWizard
author_rank: Super Contributor
timestamp: October 12, 2022, 02:44:45 am
content: So is it just a just a micro-controller w/ some RF output, and it runs off what ?, 1.5-3VWhat sort of frequencies do they TX at ?

author: geggi1
author_rank: Frequent Contributor
timestamp: October 12, 2022, 06:20:35 pm
content: First of all check that you got the correct voltage on the micro controller.If the voltages are correct.Try to jump over the buttons one by one to se if jou manage to activate the garage door.If this is not working look for things like water damage, bad solders and broken traces.
Si570 - 570CAC000141DG - Needed  - Page 1
Forum section: electronics / rf-microwave

author: AJ3G
author_rank: Regular Contributor
timestamp: October 11, 2022, 05:34:02 pm
content: All:I am wondering if anyone has the CMOS Variant of the Si570 they are willing to part with? The part number would be a 570CAC00014DG.I am able to secure the LVDS variant of this chip, but the CMOS Variant has been on back order for over a year, with no word on when they may be available again. The PCB I have is designed for Single Ended, so I am hoping I can secure the CMOS variant.If not, I can go to the LVDS output but I would have to bodge a SOT-23 package FIN1002 High Speed LVDS Differential Receiver. This will take the LVDS and covert it to single ended CMOS at 2.8 - 3.0V output. Not really wanting to do this, but it may be the only choice I have in the short term.Rich
What component is this? - Page 1
Forum section: electronics / rf-microwave

author: Ben321
author_rank: Frequent Contributor
timestamp: October 11, 2022, 03:24:47 am
content: I found it after taking apart a wireless cellphone charger. The charger's PCB has a flat coil on one side, and surface mount components (including ICs) for the RF coil driver on the other side. I'm not sure what this specific component is though. I'm thinking it's either a capacitor, used in conjunction with the coil to set a resonant frequency, or it's a crystal that forms part of an oscillator that is used to forcibly drive the coil at a specific frequency. I don't know what all the numbers and letters on it mean. They appear to be maybe some model number, or a specification of the properties of the component. Also the first marking on the second line appears to be a triangular shape, not a letter or number, and I'm guessing it's the logo of the company that made the component. Does anybody here recognize the logo?

author: srb1954
author_rank: Super Contributor
timestamp: October 11, 2022, 03:33:16 am
content: Quote from: Ben321 on October 11, 2022, 03:24:47 amEPCOS.It looks like it is a 330nF 10% 63V capacitor.

author: Ben321
author_rank: Frequent Contributor
timestamp: October 11, 2022, 05:00:03 am
content: Quote from: srb1954 on October 11, 2022, 03:33:16 amThanks. By the way, what is epcos?

author: picburner
author_rank: Frequent Contributor
timestamp: October 11, 2022, 07:11:03 am
content: QuoteIt's abrand

author: radiolistener
author_rank: Super Contributor
timestamp: October 11, 2022, 04:15:33 pm
content: looks like capacitor 0.33 uF
Catching spurius on an embedded Modem - Page 1
Forum section: electronics / rf-microwave

author: trp806mo
author_rank: Regular Contributor
timestamp: October 10, 2022, 05:54:06 pm
content: I'm integrating an IC modem on en embedded product and I have some TIS issue. As I have few knowledge in RF (outside tuning an antenna with a VNA) do you know if I can use a CMU or CMW500 (for example as I never seen one kind of device in my life) to inject a LTE signal into the modem and be able to check the noise of the RF signal ?
How to solve this logarithm expression? (SOLVED) - Page 1
Forum section: electronics / rf-microwave

author: knight
author_rank: Regular Contributor
timestamp: October 24, 2022, 04:14:39 am
content: Can anyone help me to find Pr(dBm) using this expression? Pr(dBm) = Pt(dBm) + Gt(dBi) + Gr(dBi) + PL(dB).Given: Pt = 37dBm, Gt = 1.8dBi, Gr = 1.85dBi and PL = -38.4dB.The answer given is Pr = -29.75dBm but I'm getting +32.25dBm. Thanks.

author: radiolistener
author_rank: Super Contributor
timestamp: October 24, 2022, 09:14:34 am
content: sorry, but this is bullshit. There is no logarithm expression, just a school arithmetic...Pr = 37 dBm + 1.5 dBi + 1.85 dBi - 38.4 dBi = 1.95 dBm

author: knight
author_rank: Regular Contributor
timestamp: October 24, 2022, 09:35:50 am
content: Quote from: radiolistener on October 24, 2022, 09:14:34 amPlay it nicely bro. It is indeed a logarithm expression. According to your logic, 1dBm + 1dBm = 2dBm but that's incorrect.

author: radiolistener
author_rank: Super Contributor
timestamp: October 24, 2022, 10:50:05 am
content: Quote from: knight on October 24, 2022, 09:35:50 amNo, your expression describes power of a single source with several gain described in dB or dBi units. dBi means signal gain relative to isotropic radiator.If you want to sum two power sources the result depends on the source properties and measurement point.For example, when sources are coherent and anti-phase, they cancel each other, so the sum of their power will be zero, in your case:1 dBm + 1 dBm = -infinity dBmWhen sources are coherent and in-phase the sum will be 20 * log10( 10^(P1/20) + 10^(P2/20), in your case:1 dBm + 1 dBm = 7.02 dBmWhen sources are incoherent the sum will be 10 * log10( 10^(P1/10) + 10^(P2/10) ), in your case:1 dBm + 1 dBm = 3.51 dBmSo, there is no way to say what is the sum of two power sources when you don't know what is phase relation between these sources.
Which material is the best for VHF (2m)?  - Page 1
Forum section: electronics / rf-microwave

author: szoftveres
author_rank: Regular Contributor
timestamp: September 03, 2022, 05:08:48 pm
content: I'm looking for a low loss material for building a receiver balun (hence power handling requirement is zero), with the lowest possible loss.43 and 61 seem to be the closest but these are still start rolling off at around 2.5MHz. Is there anything better out there?

author: A.Z.
author_rank: Super Contributor
timestamp: September 03, 2022, 05:39:20 pm
content: you may want to read thishttps://owenduffy.net/balun/G1-1-FT140-61/index.htmfor a start

author: szoftveres
author_rank: Regular Contributor
timestamp: September 03, 2022, 10:16:46 pm
content: Thanks, this tells me that the 61 material is perfectly fine for this.

author: Warpspeed
author_rank: Contributor
timestamp: September 09, 2022, 01:35:36 am
content: It depends on the type of Balun.If its the transmission line transfomer type, which is most likely at VHF, you might be surprised to discover that higher permeability low frequency material is actually better.

author: Kahooli
author_rank: Contributor
timestamp: October 08, 2022, 02:21:35 am
content: both 61 and 43 are perfectly acceptable for a 2M balun. Though I wonder - why not just buy the mini circuits component? or Macom ones? They are <$1

author: Hamelec
author_rank: Regular Contributor
timestamp: October 08, 2022, 08:19:22 am
content: Its a question of the power level..
Si4332 packet only contains last byte repeated for the entire length - Page 1
Forum section: electronics / rf-microwave

author: GromBeestje
author_rank: Frequent Contributor
timestamp: October 04, 2022, 07:10:44 pm
content: Hello. I am attempting to send a packet using the Silicon Labs Si4332.While the receiver appears to receive the packet, and gives me the correct packet length,the content of the packet is wrong. It consist of the last byte of the packet, repeated for the entire length.On both the transmitter and receiver I set the following registersCode:Reg 0x71 = 0x23; // GFSK modulation, FIFO as data sourceReg 0x05 = 0x06; // Packet sent, packet received interruptReg 0x75 = 0x53; // 434 MHzReg 0x76 = 0x64; // 434 MHzReg 0x77 = 0x00; // 434 MHzOn the transmitter I do:Code:Reg 0x08 = 0x01; // Clear TX FifoReg 0x08 = 0x00; // Clear TX FifoReg 0x3e = 0x04; // Data LengthReg 0x7F = 0x31 0x32 0x33 0x34 // DataReg 0x07 = 0x08; // Start TXOn the receiver I do:Code:Reg 0x08 = 0x02; // Clear RX FifoReg 0x08 = 0x00; // Clear RX FifoReg 0x07 = 0x04; // Start RXWait for packet received bit (0x02) in Reg 0x03Received size = Reg 0x48Receive data from Fifo 0x7FResult: Received data is 0x34 0x34 0x34 0x34These examples in codehttps://github.com/a-v-s/ucdev/blob/master/demos/radio/si433x/radio_test.cDoes anyone have any idea what I am doing wrong?
What F-conns to use with Belden 1694a RG6 coax? - Page 1
Forum section: electronics / rf-microwave

author: iXod
author_rank: Frequent Contributor
timestamp: September 24, 2022, 01:10:20 am
content: Doing an install this weekend of a broadcast TV antenna on my roof. Have Belden 1694a RG6 coax. I also bought PPC-Belden EX6PLUS compression F-connectors. These seem very hard to slip onto the stripped & prep’d coax. VERY hard.What compression F-connectors are recommended for this coax?Should I be concerned about changing the impedance when forcing the connector (which must be modifying the shield diameter)?Thanks,iX

author: ConKbot
author_rank: Super Contributor
timestamp: September 29, 2022, 05:50:57 pm
content: It's normal for compression fittings to be tight. Not a lot movement to be had by pushing in the plastic collar, so it has to be tight to start with. Is it "hard to slip on" by hand ? Or "hard to slip on" with a tool? My crimp tool comes with a hex shaped cutout on the base of it to sit the connector in while you push the coax in. It takes a lot of force, but it does slide into place, and I couldnt imagine trying with just bare hands.

author: Geoff-AU
author_rank: Frequent Contributor
timestamp: September 30, 2022, 02:17:10 am
content: Are you prepping the coax properly?I was doing some quad-shield recently under the influence of the Dunning-Kruger effect, and the connector really didn't want to go. Turns out, with quad-shield, you're supposed to fold back the outer braid, nick the foil layer with a knife and remove it, and then fold back the inner braid. Leave the innermost foil wrapped around the dielectric, and the connector slides on easily.I wasn't removing the middle foil layer, I was folding it back. No dice, couldn't even force the connector on.

author: jonpaul
author_rank: Super Contributor
timestamp: September 30, 2022, 09:31:34 pm
content: Bonjour we used that Belden 1694A SDI 6 ghz cable in TX research 2014.https://catalog.belden.com/index.cfm?event=pd&p=PF_1694A&tab=downloadsSee the Belden specs, application notes, and forum, especially by our old friend Steve Lampen6 ghz cable bandwidth requires genuine Belden crimp connectors, tools and dies.Belden provides a kit with everything needed.Bon courageJon
IC 746 no output on HF - Page 1
Forum section: electronics / rf-microwave

author: Xavierno
author_rank: Newbie
timestamp: September 29, 2022, 02:31:29 am
content: Hello,I have a buddy who owns an IC 746 that puts out full power on 2 meters but has no output on HF. It receives fine on HF but no transmit. Any ideas?thanks everyone for the helpuseful links for leisure time:https://forcedporn.funhttps://forcedporn.clubhttps://forcedporn.site

author: rainbow
author_rank: Contributor
timestamp: September 29, 2022, 05:00:54 pm
content: First download the service manualhttp://www.radiomanual.info/schemi/ICOM_HF/IC-746_serv.pdfand read the transmission chapter. If the problem arise also disabling the tuner you should start checking the voltage/faulty of the final HF mosfet (Q5 and Q6 on PA unit via RL2).

author: msuthar
author_rank: Contributor
timestamp: September 29, 2022, 06:30:20 pm
content: Hi,Check the IC-151 at the Main Unit Board.It is a known symptom of Missing HF power and full power on VHF Tx ok.Just change the IC 151.You will find many videos on youtube for reference.Best regards.73DE VU2EHY.

author: geggi1
author_rank: Frequent Contributor
timestamp: September 29, 2022, 07:17:51 pm
content: As far as i remember from many years ago this radio had some issues with the pre-driver for the PA.It was something with overheating on the transistors.

author: rainbow
author_rank: Contributor
timestamp: September 29, 2022, 07:25:12 pm
content: From the service manual:Quote
kenwood ts-770e faults - Page 1
Forum section: electronics / rf-microwave

author: tekguy
author_rank: Contributor
timestamp: September 26, 2022, 03:06:27 pm
content: Hi folks,i have a sick 770e i have just brought,here are the symptoms,on power on i get just one random didgit show on the display,if it appearts on the r/h side of the display it will change when the vfo is rotated,the rig hears static,it has no tx output,the band buttons beep when pressed but i cant tell if it does anything,the serial number is :1010099,the radio looks clean and unmolested inside,i cant see any bad caps or anything but havent tested anything yet for esr etc,any ideas where to start?,also the tx relay clicks as it should and the volume and squelch work ok also on turn off all the display digits flash briefly,TIA.,service manual attatched
Old RF semiconductors  (repost from ...techniques) - Page 1
Forum section: electronics / rf-microwave

author: mr ed
author_rank: Regular Contributor
timestamp: November 05, 2022, 07:45:23 am
content: I am beginning to think that some rf semiconductor devices get weak as they age. I'm talking about 100k hours of service old. Supplies are right on and match a DC ref chip) The reason is, as I try to repair a rohde and schwarz SMIQ, I see some mmics with lower gain than expected. I have found dead rf devices (a fet and 2 mmics so far) but I seem to have low gains in some related circuits. I don't know what's going on here? Replacing one mmic amp, I get a bit more db of rf (only running at 300Mhz). This repair has been a real grind.
Pluto SDR not working (RX/TX), what am I doing wrong ? - Page 1
Forum section: electronics / rf-microwave

author: cgroen
author_rank: Unknown
timestamp: September 20, 2022, 08:11:34 am
content: I just got a ADALM-PLUTO (from Mouser). I have installed drivers from Analog and also SDR Console.I have a RTL-SDR that just works perfectly. When I switch to the Pluto in SDR Console, I get the same data no matter what frequency I select. If I remove the antenna from the Pluto, the noise floor gets lower as expected. But no matter what I try to inject, I see no change in the signal(s) shown. I have a spectrum analyzer with a tracking generator set to zero span, not visible on the Pluto, but shows fine on the RTL-SDR.I have also tried activating "TX" on the Pluto from within SDR console, nothing gets transmitter (check on spectrum analyzer)I have a feeling that there is something completely obvious that I have missed, but what ?

author: cgroen
author_rank: Unknown
timestamp: September 20, 2022, 08:26:59 am
content: Bonus info, it seems that if I inject a large signal (-16 dBm) directly into the RX port, I can see the signal !This seems like an incredible low sensitivity? If I select "duplex" on the SDR Console so that I can TX while RX, I can also see a tone (with two antennas on the RX and TX ports).Is the Pluto deaf ??

author: cgroen
author_rank: Unknown
timestamp: September 20, 2022, 10:16:00 am
content: Ahh, it was a user mistake! I had not (properly) enabled the low frequency support on, after that, I can now receive....If anyone else stumbles on this thread, the info is here:https://wiki.analog.com/university/tools/pluto/users/customizing
Radio with Si4703 - improve reception - Page 1
Forum section: electronics / rf-microwave

author: panoss
author_rank: Frequent Contributor
timestamp: September 17, 2022, 09:55:47 am
content: I 've built an FM radio receiver around Sillicon Lab's Si4703.It has very good reception.BUT not as good as an old phone I 'm using as a radio receiver (a Samsung g-ts5260).It 's using the headphones' cable as antenna. Sonothing fancy used for antenna, just a cable.I want to 'replicate' this very good reception of this old phone to my radio.Using no fancy antenna, just a cable, like g-ts5260 does.I tried to find the schematics of g-ts5260 but didn't find anything.If you have any schematics of this phone (or can help me (in any way) in achieving a very good reception using just a cable as antenna) please do.

author: PA0PBZ
author_rank: Super Contributor
timestamp: September 17, 2022, 01:12:56 pm
content: One of the reasons that the reception seems not very good could be that the phone has a mono FM receiver but the Si4703 is stereo. Try to switch it to mono (some bit in the powercfg register).

author: panoss
author_rank: Frequent Contributor
timestamp: September 17, 2022, 02:02:46 pm
content: I have it in mono mode.

author: Rapto
author_rank: Newbie
timestamp: September 19, 2022, 10:58:40 am
content: I have a similar experience, used FM radio module based on Si4703 and it was reasonably good but not excellent.It might have been due to the PCB layout (just a Sparkfun module, not a dedicated, shielded PCB) but maybe it's about chip's sensitivity/selectivity.I've read (but not confirmed it myself) that very good reception quality can be obtained using NXP chips TEF6686, but they are usually used in car audio systems, probably not phones since it's a dedicated chip. Modules with TEF6686 can be easily bought on one of the Chinese auction portals.Unfortunately, I couldn't find any information about fm tuner in G-TS5260 either.What I plan on experimenting with is to add a simple antenna amplifier stage before Si4703, maybe it will help...

author: panoss
author_rank: Frequent Contributor
timestamp: September 19, 2022, 02:31:23 pm
content: Quote from: Rapto on September 19, 2022, 10:58:40 amVery interesting, maybe I will try this TEF6686. (car radios really have excellent reception).Quote from: Rapto on September 19, 2022, 10:58:40 amPlease let me know of the result.(I found modules (on the internet) with the TEF6686 around 25$. The IC alone, around 9$. Can't call it cheap)