hybridfree/eevblog-posts huggingface dataset:
anybody go to Dayton this year? - Page 1
Forum section: electronics / rf-microwave

author: djacobow
author_rank: Super Contributor
timestamp: May 24, 2016, 08:24:29 pm
content: If so, were there any cool, new toys to see?I've heard about the KX2. It looks really cool, and the pricing is tractable, too. I really fancy the idea of putting on of these, a wire, and not much else in my backpack to take into the backcountry.

author: neonhomer
author_rank: Contributor
timestamp: May 25, 2016, 07:25:26 pm
content: Didn't really see too many new things. Icom is still touting the IC-7300, Kenwood is still pushing the 990s, and Yaesu is always late to the party. People out in the flea market area were wanting serious gold for a bunch of crap!KK4BFN

author: djacobow
author_rank: Super Contributor
timestamp: May 25, 2016, 09:53:18 pm
content: Quote from: neonhomer on May 25, 2016, 07:25:26 pmThat's a bummer, but thanks for the report!I think I also heard about a new Kenwood HT with DSTAR.

author: GreyWoolfe
author_rank: Unknown
timestamp: May 29, 2016, 04:22:53 pm
content: Quote from: neonhomer on May 25, 2016, 07:25:26 pmKevin, the flea markets there are any different from here?? At least you got to go. Maybe someday I will. Every time I go to Melbourne or Orlando, I remember what I like about Hamfests and conversely, why I didn't go to one for 10 years.Wolfie
Radiometrix MURS RF Modules - Experiences? - Page 1
Forum section: electronics / rf-microwave

author: LabSpokane
author_rank: Super Contributor
timestamp: May 28, 2016, 08:05:02 pm
content: http://www.radiometrix.com/files/additional/nim1b.pdfHas anyone played with these RF modules from Radiometrix? They are low-power to be sure, but the 150MHz band sure would be nice. In the US, we can go up to 2W in MURS, so maybe there are higher power options to consider?

author: uncle_bob
author_rank: Unknown
timestamp: May 29, 2016, 01:14:00 am
content: HiA < $30 Chinese VHF handheld would be another option. Getting them at 2W is not a problem.Bob
UWB transceiver mounted near metal - Page 1
Forum section: electronics / rf-microwave

author: AndrewDojo
author_rank: Contributor
timestamp: May 18, 2016, 09:43:01 pm
content: Considering using the decawave DW1000 radio system for a M2M application but there is a need to mount the device on a metal chassis - a problem that has to be dealt with.The radio chip covers frequencies between 3GHz and 7GHz.1. In designing the housing for the system, what would be the minimum acceptable distance to put between the antenna and the chassis?2. Is there any type of material that could be placed between the antenna and the chassis that might reduce the effect of the metalwork near the antenna?

author: AF6LJ
author_rank: Unknown
timestamp: May 18, 2016, 09:46:57 pm
content: I would think that if you had the antenna a couple of wavelenghts above the metal surface you should be fine. Lets Three GHZ that is 30 CM.If it is a horizontally polarized yagi I would think even 30cm would be fine.

author: AndrewDojo
author_rank: Contributor
timestamp: May 18, 2016, 11:44:10 pm
content: Thanks.The board uses a chip antenna. Spacing of 30cm is not a practical option. More likely to be 30mm.This is why I was looking for options on intervening materials to minimise the problem. I am familiar with such materials used for 13.56MHz RFID, but that is a very long way from 3GHz+.Someone suggested teflon sheet/board.

author: AF6LJ
author_rank: Unknown
timestamp: May 19, 2016, 02:36:02 am
content: Does the chip antenna have a ground plane under it?Have a photo?

author: AndrewDojo
author_rank: Contributor
timestamp: May 19, 2016, 01:56:56 pm
content: Details from the product datasheet attached.

author: Georgi
author_rank: Contributor
timestamp: May 19, 2016, 05:02:42 pm
content: Why don't you use the dipole Antenna from the Evaluation Board ? I suggest also contacting Decawave and asking about this. I also worked with the DW1000 and asked them tons of questions and they answered them all. Also there is a Decawave forum on Google+, maybe it will be a good idea to look there too.Georgi

author: AF6LJ
author_rank: Unknown
timestamp: May 19, 2016, 06:41:17 pm
content: It seems to me they are fairly clear about keeping the antenna clear of metal objects.Because the antenna isn't in free space to begin with it is compromised from the get-go. This is true with many RF products these days. Even the antenna in your smart phone is compromised to a significant degree simply because the people want the antenna out of sight.You may have to work a degree of signal degradation into your project.
Need info about this FM transmitter (1 of 2) - Page 1
Forum section: electronics / rf-microwave

author: Merlysys
author_rank: Regular Contributor
timestamp: May 03, 2016, 06:24:16 pm
content: I want an FM transmitter to do some experiments with (using load)http://www.ebay.ca/itm/222099498416Specs are given as- Output power: 3 DBM - 15 DBM- Working frequency: 85 MHZ--115 MHZIs this really an FM transmitter? If so what would the max power output be? Is it possible to convert dbm to watts?

author: xrunner
author_rank: Super Contributor
timestamp: May 03, 2016, 06:34:37 pm
content: Quote from: Merlysys on May 03, 2016, 06:24:16 pmWell, that's what they claim. Buy one and see.QuotedBm is power relative to 1.0 mW. 0.0 dBm is 1.0 mW of power, so (+) 3 dBm would be twice that or 2.0 mW. (+) 15.0 dBm is 31.6 mW output power.

author: Ammar
author_rank: Regular Contributor
timestamp: May 19, 2016, 12:40:33 am
content: It very much could be. I assume those SOT-23 packages are discrete transistors. I don't know why they have bothered when there are many integrated solutions. Looks like a cheapy. Expect the frequency to drift if you do get it.

author: mos6502
author_rank: Frequent Contributor
timestamp: May 19, 2016, 08:01:06 am
content: It's just your standard 3 transistor FM bug. Dozens of circuits out there. Transistors used:J6 - probably MMS9014J8 - MMS9018
200Mhz in a 14 pin DIP??? - Page 1
Forum section: electronics / rf-microwave

author: oilburner
author_rank: Contributor
timestamp: May 18, 2016, 05:39:04 pm
content: 200Mhz in a 14 pin DIP???I thought my "google-ing" was strong, but I can't find out what chip this is, any ideas?We know we can't make this for $25 shipped, so I don't why the sandpaper was used...It uses 12V for power and the voltage to tune, if that helps.Thanks!ghttp://www.ebay.com/itm/131700683861?rmvSB=true

author: ataradov
author_rank: Super Contributor
timestamp: May 18, 2016, 05:59:08 pm
content: MC1648

author: chris_leyson
author_rank: Super Contributor
timestamp: May 18, 2016, 08:27:03 pm
content: That's a blast from the past, last time I used an MC1648 it was 35 years ago, they've got to be new old stock unless ON Semi still make them.

author: mos6502
author_rank: Frequent Contributor
timestamp: May 18, 2016, 08:39:25 pm
content: Oooh, all of 200MHz. How about 2.4 GHz?

author: edavid
author_rank: Super Contributor
timestamp: May 18, 2016, 09:31:07 pm
content: Quote from: ataradov on May 18, 2016, 05:59:08 pmYou would think that if they were using the MC1648, they would have made the board run on 5V instead of 12V.

author: oilburner
author_rank: Contributor
timestamp: May 18, 2016, 09:32:15 pm
content: Wow, you guys are quick, thanks! Looking at data sheets, and learning : )g

author: ataradov
author_rank: Super Contributor
timestamp: May 18, 2016, 09:33:51 pm
content: Quote from: edavid on May 18, 2016, 09:31:07 pmIt might be designed to work from an unstable power supply or just for 12V system. You can clearly see a voltage regulator there.Pinout matches MC1648, so I'm pretty sure it is the IC used here.
Schlumberger 4017 Stabilock from 1986 - Page 1
Forum section: electronics / rf-microwave

author: MT
author_rank: Super Contributor
timestamp: May 10, 2016, 07:51:22 pm
content: Found this Schlumberger 4017 Stabilock in a local junk yard. Have not turn it on yet, will open it up to make a inspection first, is it wort spendingtime on this boat anchor?

author: wkb
author_rank: Super Contributor
timestamp: May 10, 2016, 08:59:25 pm
content: I for one would try to get working...

author: MT
author_rank: Super Contributor
timestamp: May 12, 2016, 05:38:51 pm
content: Clean inside, staggering amount of trimmers, counted to 46-47 powers up, beeps, crackles and burps a bit, but after settling down some signals.Edit: found schemo for 4010, 4020 4021 4022 quite straight forward machine, i save the 10Mhz ovenized crystal reference and junk the rest.

author: SeanB
author_rank: Super Contributor
timestamp: May 15, 2016, 06:53:17 pm
content: Keep those decade switches, they are quite useful at times, especially make sure to use a wire to keep the whole assembly with the end pieces and spacers together. They can be BCD, reverse BCD or even 1 of 10 selection depending on the model. Quite useful at times to do selection of data or for selecting data that can change occasionally.

author: MT
author_rank: Super Contributor
timestamp: May 16, 2016, 03:02:21 am
content: yes, thanks for the reminder!

author: nanofrog
author_rank: Super Contributor
timestamp: May 16, 2016, 03:11:20 pm
content: The rotary switches and pots on the front may be worth keeping as well.

author: German_EE
author_rank: Super Contributor
timestamp: May 16, 2016, 03:54:11 pm
content: I'd try to get it working as well, you could build a complete radio service bench around an instrument like that and it seems a shame to scrap it.

author: CJay
author_rank: Super Contributor
timestamp: May 16, 2016, 05:04:25 pm
content: Quote from: MT on May 12, 2016, 05:38:51 pmOh that's a real shame, it'd be a great piece of kit if you were into radio repair, servicing or homebrew.I'd have been very interested in buying it as faulty if you were in the UK

author: MT
author_rank: Super Contributor
timestamp: May 16, 2016, 07:47:55 pm
content: Alright, its a shame, so i keep it as is....... for now......It do work, i just dont have time for it right now so i put into storage.
LimeSDR: Flexible, Next-generation, Open Source Software Defined Radio  - Page 1
Forum section: electronics / rf-microwave

author: Abdu
author_rank: Newbie
timestamp: May 15, 2016, 05:14:21 pm
content: Hello,Open Hardware LimeSDR: Flexible, Next-generation, Open Source Software Defined RadioFunding ends on Jun 21, 2016 at 04:59 PM PDT (11:59 PM UTC)Features & SpecificationsRF Transceiver:Lime Microsystems LMS7002M MIMO FPRFFPGA:Altera Cyclone IV EP4CE40F23 - also compatible with EP4CE30F23Memory:256 MBytes DDR2 SDRAMUSB 3.0 controller:Cypress USB 3.0 CYUSB3014-BZXCOscillator:Rakon RPT7050A @30.72MHzContinuous frequency range:100 kHz – 3.8 GHzBandwidth:61.44 MHzRF connection:10 U.FL connectors (6 RX, 4 TX)Power Output (CW):up to 10 dBmMultiplexing:2x2 MIMOPower:micro USB connector or optional external power supplyStatus indicators:programmable LEDsDimensions:100 mm x 60 mmhttps://www.crowdsupply.com/lime-micro/limesdrEarly Bird (Second Flock) - LimeSDRSave $50 off the $299 retail. This second flock of early bird LimeSDRs is made possible by further support from our manufacturing partners. The LimeSDR is based on Lime Microsystem’s latest generation of field programmable RF transceiver technology, combined with FPGA and microcontroller chipsets. These connect to a computer via USB3. LimeSDR then delivers the wireless data and the CPU provides the computing power required to process the incoming signals, and to generate the data to be transmitted by the LimeSDR to all other devices.Free US Shipping / $15 Worldwide 202 claimed, 298 left (at this time)From Radio Astronomy to Personal TelcosHere are just some of the applications that are possible with the LimeSDR:Radio astronomyRADAR2G to 4G cellular basestationMedia streamingIoT gatewayHAM radioWireless keyboard and mice emulation and detectionTire pressure monitoring systemsAviation transpondersUtility metersDrone command and controlTest and measurementMany more…With state-of-the-art technical specs, fully open hardware and toolchain, and integration with Snappy Ubuntu Core’s app distribution platform, LimeSDR is limited only by our collective imagination.Hackaday"What makes LimeSDR interesting is that it is using Snappy Ubuntu Core as a sort of app store. Developers can make code available, and end-users can easily download and install that code."Electronics Weekly"Crowd-funding changing the game for chip firms"Microwave Journal"Learn and test new communications techniques, unleash new applications and open up new markets using the powerful LimeSDR platform"Electronic Engineering Journal"...a low cost, app-enabled software defined radio (SDR) base station that can be programmed to support any type of wireless standard – putting significant power at the disposal of anyone who wants to innovate in the world of wireless"EE Times - Europe"Lime Microsystems have built a wide range of open source support tools and resources...from the outset"Wireless - Electronic Specifier"Create and deploy wireless network infrastructure almost anywhere at a fraction of today’s costs"Regards
Pixel Receiving Loop Project - Page 1
Forum section: electronics / rf-microwave

author: AF6LJ
author_rank: Unknown
timestamp: May 14, 2016, 04:54:07 pm
content: WARNING THIS LINK CONTAINS TEAR-DOWN PORNThis is a thread I started over on QRZ.com (Yes I was invited back there by popular demand.)The posting is complete with pictures and such along with my review of the product.So check it out and we can discuss it here or over there if you wish.http://forums.qrz.com/index.php?threads/pixel-receiving-antenna-project-part-one.523271/

author: tantulatum
author_rank: Newbie
timestamp: May 16, 2016, 05:09:09 am
content: Why is your antenna right next to a power line?

author: borjam
author_rank: Unknown
timestamp: May 16, 2016, 06:40:53 am
content: Quote from: tantulatum on May 16, 2016, 05:09:09 amIt's not so close. Look at the perspective, long telephoto lens

author: chris_leyson
author_rank: Super Contributor
timestamp: May 16, 2016, 07:37:57 am
content: Nice, I once used a marine crossed loop DF antenna for picking up ELF/VLF signals, mainly Alpha and Omega navigation signals. It was nice how you could null out any interference by rotating the antanna, wish I had kept it.

author: borjam
author_rank: Unknown
timestamp: May 16, 2016, 07:50:54 am
content: I have three loop antennas (Sony AN-LP1, Wellbrook ALA-1530+ and MFJ 1788) and it's amazing what you can achieve with so unobtrusive antennas.

author: AF6LJ
author_rank: Unknown
timestamp: May 17, 2016, 02:54:03 pm
content: Quote from: tantulatum on May 16, 2016, 05:09:09 amThat is not a power line, one end of my doublet. The nearest power line is fifteen feet away.

author: AF6LJ
author_rank: Unknown
timestamp: May 17, 2016, 02:55:29 pm
content: Quote from: chris_leyson on May 16, 2016, 07:37:57 amThat brings back memories of my old Navy regenerative receiver (14-600KHZ)

author: AF6LJ
author_rank: Unknown
timestamp: May 17, 2016, 02:57:08 pm
content: Quote from: borjam on May 16, 2016, 07:50:54 amThey work really well, this one has minimized my noise situation.Now if I could knock it down a few more DB.....
Tx-2B Rx-2B ! How Could we Reach their Maximum Power Capabilities ??? - Page 1
Forum section: electronics / rf-microwave

author: battery13v
author_rank: Contributor
timestamp: May 15, 2016, 12:19:45 am
content: Hi everyone ! Learning is by Doing !so i have this Broken RC car ... i took the circuit and i want to make another project ... i want to make a small boat, however i want to reach the maximum limits of this chips to increase my range !! by tweaking antennas or circuit ...and if their is tutorials on the internet post their links here ...Please do not tell me go and buy from ebay etc.... :p I'm a prepper and i'm training my self to deal with all situation that could happen to me in the apocalypse :cool:--------------------------------------------------------------------
email issue with the WINC1500 module - Page 1
Forum section: electronics / rf-microwave

author: aliyesami
author_rank: Newbie
timestamp: May 10, 2016, 09:07:30 pm
content: iam not sure if this post belong to this group or microcontroller so please move it accordingly.iam using the SAMW25 module that has winc1500 wifi module. I use it to send email and is working for me but if I try to send it again it doesn't. which steps I m missing ? I tried to initialize everything to send the email but it doesn't work.after sending the first email the code hangs at system_init() and if I comment it out , I get bus initialization error on nsm_bsp_init().basically for the second email I have included everything that the email example comes with in the ASF library .
SM?RF RF Vector Power Meter - Page 1
Forum section: electronics / rf-microwave

author: Electro Fan
author_rank: Super Contributor
timestamp: May 08, 2016, 03:47:25 pm
content: This looks very cool.http://microham-usa.com/store/product-info.php?pid115.htmlMaybe Dave could do a review

author: Electro Fan
author_rank: Super Contributor
timestamp: May 08, 2016, 04:24:34 pm
content: Curious to see how hams might consider using the features in this product in conjunction with or possibly as an alternative to antenna analyzers (MFJ 259/269, RigExpert 600, Saark 110, etc) for various purposes including antenna design and rig operation? At first look the Smorf* seems to be an operational tool more than an analysis tool; it looks like it would compliment an antenna analyzer but there is some overlap. The device looks to have a lot of features and functionality both in the box and available via computer, smartphone, and tablet. It looks like a rare product where the engineering dept talked to the marketing dept and the users; I have a hunch this might have been inspired by one person wearing all 3 hats. If the actual product is half as good as the video it could be a great product if the price doesn't take it too far out of reach for most hams.*kind of unlikely that people will figure out how to type the Omega symbol - but so far the hard to type name and the fact that you have to specify the complimentary display color at time of order (and the impending price increase) are the only glitches I see - very curious to see how this product does with hams - so far it looks positioned for the ham who has everything else and doesn't want to buy another transceiver or put up another tower. (If you put the hard to type symbol embedded in the product name, the lack of user changeable color, and the price on the marketing dept the engineering dept is still 100%.) (The color change item was done by the marketing dept to keep the price from going higherno doubt.). Seriously, the product looks like something hams would enjoy using.
3G embedded module recomendation - Page 1
Forum section: electronics / rf-microwave

author: msr
author_rank: Regular Contributor
timestamp: January 29, 2016, 04:26:17 pm
content: Hey everyone,I never used a cellular embedded module but at the moment I have a project which requires one. The whole design needs to obtain FCC/PTCRB certification so a pre-certified module would come in handy. However I would prefer to pay a bigger price tag in order to reduce the hassle of certification as much as possible so I'm not looking only for a pre-certified module but a board that contains everything's RF related (the antenna tuning layout) and that is pre-certified as well. Good support and documentation is also a must have.Do you have any suggestions on such board?So far I came up with NimbleLink which uses a Telit module:http://nimbelink.com/skywire-evdo/

author: Lord of nothing
author_rank: Super Contributor
timestamp: March 28, 2016, 08:27:40 pm
content: why not an normal 3G Module?https://forum.sierrawireless.com

author: Apollyon25_
author_rank: Regular Contributor
timestamp: May 02, 2016, 10:57:52 pm
content: You'll have to certify regardless of how pre-certified modules are.The process may simplify slightly...

author: steve_w
author_rank: Regular Contributor
timestamp: May 03, 2016, 02:08:26 am
content: Try thesehttp://www.telit.com/cellular/
fascinating eBay find: R&S Goniometer - Page 1
Forum section: electronics / rf-microwave

author: wkb
author_rank: Super Contributor
timestamp: March 30, 2016, 09:11:10 pm
content: Fascinating piece of kit, looks like something miliary?http://www.ebay.nl/itm/Rohde-and-Schwarz-Goniometer-Type-NA501-3-11-T-/131708794946?hash=item1eaa74b842:g:i2kAAOSwCypWo3T0

author: mmagin
author_rank: Frequent Contributor
timestamp: March 30, 2016, 09:19:28 pm
content: Looks like a gigantic antenna relay.Maybe some kind of thing related to radionavigation (aviation)?

author: wkb
author_rank: Super Contributor
timestamp: March 30, 2016, 09:25:54 pm
content: Definitely military, according to this one (Bundeswehr == German army):http://www.ebay.nl/itm/Bundeswehr-BW-R-S-Na-501-3-11-Goniometer-29x-R-S-Anschlus-/180476898355

author: wkb
author_rank: Super Contributor
timestamp: March 30, 2016, 09:30:08 pm
content: Hmm..... radio direction finding maybe?http://www.armyradio.ch/radio-d/p-730.htm

author: 1design
author_rank: Regular Contributor
timestamp: March 31, 2016, 12:07:20 pm
content: There you go:http://www.virhistory.com/navy/manuals/10232a/ctm-10232a-18.pdfBR

author: GEuser
author_rank: Frequent Contributor
timestamp: March 31, 2016, 02:59:14 pm
content: Quote from: 1design on March 31, 2016, 12:07:20 pmThat was a interesting read , tnks for the link ..

author: mmagin
author_rank: Frequent Contributor
timestamp: March 31, 2016, 05:49:52 pm
content: BTW, for anyone interested, amateur radio folks do this recreationally in a number of places:http://www.homingin.com/

author: German_EE
author_rank: Super Contributor
timestamp: March 31, 2016, 07:44:30 pm
content: Well, now you have something to measure your gonios with.

author: Apollyon25_
author_rank: Regular Contributor
timestamp: May 02, 2016, 10:56:11 pm
content: Thats a cool bit of kit.
Differential Coplanar Waveguide Impedance ? - Page 1
Forum section: electronics / rf-microwave

author: chris_leyson
author_rank: Super Contributor
timestamp: June 13, 2016, 10:19:13 am
content: HiI'm using a short length of 0.5mm pitch flat flex as differential coplanar waveguide for routing 1000Base-T ethernet, and I'm using a single ground trace between the differential pairs, sketch attached. I haven't found any online calculators that cover this particular arrangement. The flat flex material is PET so the relative permittivity is around 3.0, does anybody have a calculator or field solver that will give me a ballpark estimate for differential impedance ?Many thanks Chris.

author: bktemp
author_rank: Super Contributor
timestamp: June 13, 2016, 10:30:37 am
content: 0.5mm FFC should have an impedance of around 100ohms for differential pairs. Here is an appnote about using FFC for USB:http://ww1.microchip.com/downloads/en/AppNotes/00001579A.pdf

author: chris_leyson
author_rank: Super Contributor
timestamp: June 13, 2016, 10:51:33 am
content: Thanks bktempI guessed it wouldn't be to far from 100 Ohms.

author: chris_leyson
author_rank: Super Contributor
timestamp: June 13, 2016, 12:24:20 pm
content: I just found this paper if anyone is interested,http://meritec.com/wp-content/uploads/2014/03/FFC-Impedance-Tests.pdf
Reflective PIN Switch - Page 1
Forum section: electronics / rf-microwave

author: EVlab
author_rank: Contributor
timestamp: May 01, 2016, 08:32:54 am
content: I want to connect a YIG-oscillator to a reflective PIN switch.Can someone give a hint (pros/cons) of either using an isolator or a 0dB attenuator to protect the YIG if the switch is turned off e.g. open position?Best, Simon

author: KE5FX
author_rank: Super Contributor
timestamp: May 01, 2016, 10:15:06 am
content: The 0 dB attenuator (whatever that is) won't do much of anything.The isolator will present a load near Zo (usually 50 ohms) no matter what's connected to its output port. They're not usually used to protect the YTO, though, but to improve output level flatness (and sometimes frequency stability) and provide a better port match for a subsequent stage (typically a mixer.) The output amplitude of a typical YIG oscillator isn't high enough to be a threat to the output device when unterminated.

author: uncle_bob
author_rank: Unknown
timestamp: May 01, 2016, 02:16:38 pm
content: Quote from: EVlab on May 01, 2016, 08:32:54 amHiWhat are you trying to do? Put another way, what does your system design look like?Are you trying to keep the YIG from "chirping" when the switch is thrown?Are you trying to improve the isolation of the switch?There are lots of possible things you may be worried about. A bit more information might allow us to give better advice.Bob

author: EVlab
author_rank: Contributor
timestamp: May 01, 2016, 05:29:43 pm
content: I want to combine two YIG oscillators to one common output. Only one single YIG should operate at a given time. The YIG's cover two different frequency ranges. Thus I will use a two port PIN switch to select between the two YIG's and have one single output port providing frequency coverage over both YIG's.The PIN switch is reflective and I'm not sure if one YIG will get damaged, if the PIN switch is in open position.One can disable the not used YIG, but there will be some overlapping during transition when switching from one to the other.Best, Simon

author: uncle_bob
author_rank: Unknown
timestamp: May 01, 2016, 09:29:44 pm
content: Quote from: EVlab on May 01, 2016, 05:29:43 pmHiSimple answer - no you do not need to worry about the YIG going up in smoke with the designs I have seen. Is there one out there that could have a problem? Who knows. A 3 db pad between the switch and YIG will likely take care of any weird part that does have a problem.Shutting off the un-used YIG does have the benefit of getting rid of a spurious signal in your system. No switch is ever ideal. Isolation will be "interesting" with a YIG driving a reflective switch ( = you don't know the voltage at the switch). Will this be a problem in your system? Again, a "that depends" sort of thing.Bob

author: eb4fbz
author_rank: Regular Contributor
timestamp: May 02, 2016, 03:28:36 pm
content: It depends on the application but you usually want to put one isolator at each YIG oscillator output to reduce frequency pulling due to load impedance variations, even when using an absorptive switch.
#48 UHF homebrew duplexer cavity build and testing.*Heavily Caffeinated* - Page 1
Forum section: electronics / rf-microwave

author: Radio Tech
author_rank: Frequent Contributor
timestamp: April 30, 2016, 03:29:58 am
content: #48 UHF homebrew duplexer cavity build and testing.*Heavily Caffeinated*In this video I spent a week building and testing one cavity for our homebrew UHF duplexer project. I show where thedesign originated from and how to build the second cavity. In the next video we build the other two cavities, check outVSWR and do a full tune up of the duplexer. By this time I plan on having the UHF repeater running.N4GUS repeater Geezer linkhttp://www.arrg.us/pages/WB3AYW/UHF-duplexer.htm
Upgraded Spec. of a 40 year old Tek SG 504 - Page 1
Forum section: electronics / rf-microwave

author: Mosaic
author_rank: Regular Contributor
timestamp: April 09, 2016, 09:39:42 pm
content: Hi all:As an exercise in RF detection I refined the TEK SG 504 leveled sig gen leveling head to give the instrument around +/- 0.05dB flatness across the Ghz range at the 4Vpp (16dBm) level.http://www.nscainc.com/uploads_2014/product_guides/TEK_SG504.pdfThe new head used new detectors and a custom PCB on 0.8mm FR4 with BNC connectors (optional SMA).The measurement was done (after warmup) via a broadband 10dBm attenuator into a Boonton 4210-4b micro watt meter to mitigate any VSWR errors.Thus actual delta p-p measurement levels (less adapter losses) => 5.88 dBm - 5.78dBm (0.1dB pp) = .005Vrms, or +/- .0025Vrms for a +/- 0.05dBm swing.As 5.78dBm = 0.425 Vrms => the % precision deviation is +/- .0025/0.425 x 100 =+/- 0.588%versus4% OEM.This makes it more useful as a reference tool for measuring 'scope bandwidth or determining RF amp/mixer IP3 etc.Most of the improvement was obtained from PCB size reduction, improved ground plane coverage, a modified BNC (m) launcher, and using parasitic stub trace 'tuning' to improve return loss leveling across the band.I hope to do a Hackaday page for DIY and offer a kit for convenience. I put up a few excess calibrated units from my development on Ebay as well.Another persons 'substitute' head I tested had a 0.5dBm dip @ 800Mhz or so on the same test jig. Basically 5 x 0.588% = 2.94%.Thus that is within the 4% level OEM spec, but I needed a better result.Here are a few pics:https://www.dropbox.com/sh/xmf4hgaxvpjyc2j/AAAuzDz2vfhjWrACqvMcXT8Ea?dl=0

author: AF6LJ
author_rank: Unknown
timestamp: April 11, 2016, 02:18:27 pm
content: Nicely Done.

author: Earendil
author_rank: Regular Contributor
timestamp: April 11, 2016, 08:04:18 pm
content: Hmm. Looks interesting.And what about the harmonic content of the signal generator? Have you factored those into your calculation too?Also the Tektronix claims 4% on the full temperature range (-15degC to 55degC). Have you tried varying the temperature of your circuit and see if your measurement results change?

author: Mosaic
author_rank: Regular Contributor
timestamp: April 29, 2016, 01:47:39 am
content: There's internal temp compensation via a matched detector diode which is also built into the OEM Tek unit. Temp shifting is not an issue. Also the housing is fairly isothermal with a very small air volume and insulating material compared to the OEM product.What makes the new unit better is it contains stub TX line tuning to knock out resonances in the band.Typical flatness is +/- .05dB as I noted. I have built units down to +/- .025dB!As to the harmonics or new out of band resonances....no noticeable difference using my calibrated Spectrum Analyzer and S12 testing with a 3GHZ VNA.
Component identification - Page 1
Forum section: electronics / rf-microwave

author: kazam
author_rank: Regular Contributor
timestamp: April 21, 2016, 01:06:39 pm
content: Hi,I'm looking at a 1GHz receiver and want to know how the RX chain is built up. I come up empty on these two components though! The LNA and the VGA.Any thoughts?/K

author: elecman14
author_rank: Unknown
timestamp: April 21, 2016, 02:10:11 pm
content: The second one may be a clone of a Mini-Circuits ERA-3SM.https://www.minicircuits.com/pdfs/ERA-3+.pdf

author: kazam
author_rank: Regular Contributor
timestamp: April 21, 2016, 02:35:53 pm
content: Thanks,I think you're right.The LNA looks like a Mini-Circuits PSA4-5043+/K

author: kazam
author_rank: Regular Contributor
timestamp: April 24, 2016, 09:53:01 am
content: There's something fishy about that LNA... I can't find any LNAs with that case style, what Mini-Circuits call MMM1362, that match.In my picture it's clearly mounted with gate at top left while all the Mini-Circuit ones have drain there. So it must be another brand.
How to "copy" signal for digital VU meters? - Page 1
Forum section: electronics / rf-microwave

author: algorhythm
author_rank: Contributor
timestamp: April 24, 2016, 01:46:16 am
content: Hello EEVBlog.I'm putting together a relatively simple audio system for my workshop:raspberry pi + hifidac -> lm2b unbalanced-balanced conv. -> dbx231s eq -> dbx 233xs xover -> art sla-4 ampIt sounds great so far. I bought a couple of the cheapo Banggood AS30 VU Meter kits to fill the extra rack space with blinky goodness (see pics).When I split signal from the raspberry pi into the meters, they severely distort the signal. When playing a 440Hz sine wave through the system and looking at it on the scope, I notice that approximately the top 1/3 of the waveform is "rounded" flat (i.e. soft-clipped). It's really strange. I like these meters since they're simple looking and fit well in the extra rack space, but they murder the signal. It looks like there's no input stage. The audio signal goes straight into the uc.Is there a good way to "copy" a signal for the meters without affecting the signal going into the audio system? What's the best way of doing it?I've tried feeding the meters from the balanced outputs of the eq, using various combinations of +/-/g, but the problem persists. I've got an audio isolation transformer coming in the mail for a different project, and will probably try it here to see if anything changes, but I have no idea if it will make a difference.Can anyone point me in the right direction with this?

author: algorhythm
author_rank: Contributor
timestamp: April 24, 2016, 03:04:39 am
content: Isolation transformers just arrived.Each meter is being used as a 'mono' meter since I have two, so I'm just putting left channel into one meter and right into the other.Attached is a schematic of the left channel and what I tried with a transformer, and it actually seems to work, with only minor attenuation of the signal and no distortion. Please see the picture.What are the problems with this?

author: algorhythm
author_rank: Contributor
timestamp: April 24, 2016, 04:04:23 am
content: Ok great. The solution is easier than I had hoped. $2.52 is no problem.Can I get away with a circuit as simple as the one in the picture here? Are caps a good idea, or unnecessary?

author: algorhythm
author_rank: Contributor
timestamp: April 24, 2016, 04:16:00 am
content: Ok excellent.Something like 1k resistor between buffer output and vu input?I actually have a TL072 in my drawer and am going to mess around with it right now. 5v is the minimum supply voltage, so hopefully it works, otherwise I'll order a couple OPA2365s.
Carlson Wireless I-WLL teardown - Page 1
Forum section: electronics / rf-microwave

author: mojoe
author_rank: Frequent Contributor
timestamp: April 24, 2016, 02:07:29 am
content: I wasn't sure which section of the forum to post this in, but since it uses 2.4 GHz, I'll post it here.Months ago, I acquired two weatherproof boxes with mast mounting hardware. I thought they might be of some use, so I set them aside. Just a few days ago, I opened one up and realized that these boxes weren't empty.I'm not sure how to do in-line pictures, so I'll attach them at the end and list a brief description here.1 - The nice weatherproof box and mounting hardware.2 - View of the inside, after taking off the cover, we see the antenna (circuit boards mounted behind).3 - With the antenna/circuit board sandwich flipped down (I already removed the screws holding it to the hinges)More in the next post.

author: mojoe
author_rank: Frequent Contributor
timestamp: April 24, 2016, 02:10:00 am
content: 4 - View of the circuit board sandwich, showing the top circuit board.5 - A side view of the sandwich.6 - The other side view of the sandwich.Still more below.

author: mojoe
author_rank: Frequent Contributor
timestamp: April 24, 2016, 02:27:23 am
content: 7 - With the top circuit board removed.8 - Closeup of the bottom circuit board.I did find some information at this site:https://fccid.io/OPA-I-WLL-TIt seems that this FXO unit and the matching FXS unit that I also have were used to extend up to two phone lines wirelessly. The FXS unit looks idential to this one. I suspect only the firmware is different.There is an Atmel uC and what looks like a JTAG on the top board. I also see an AM79C02 Dual Subscriber Line Audio Processing Circuit and a Xilink Spartan. The bottom board looks to be just some power supply circuitry and mostly some phone line interface stuff. According to the docs, the internal antenna is rated 14 dB.I see that Carlson Wireless also sold/sell similar units for wireless Ethernet. I'd guess that there is some similarity between products. The interesting thing is that they used a standard PCMCIA wireless card on these. I wonder which other cards are supported.Very interesting looking devices. I'm not sure what I'm going to do with them. I don't need them and have too many projects already to fool with these things.
Oxidation on Mag Loop Antenna - Page 1
Forum section: electronics / rf-microwave

author: ronsch
author_rank: Newbie
timestamp: April 10, 2016, 12:31:57 am
content: Does anyone know whether oxidation on an aluminum mag loop surface reduces performance over time? I have a Pixel Pro-1B receive-only non-resonant amplified loop antenna that has been in the weather for several years.Thanks, RonK2RAS

author: T3sl4co1l
author_rank: Super Contributor
timestamp: April 10, 2016, 04:54:40 am
content: As long as it's solid I doubt you'll notice a difference. Mind possible corrosion of internal surfaces / structures / connections.Tim

author: AF6LJ
author_rank: Unknown
timestamp: April 10, 2016, 09:38:53 pm
content: Since Aluminum oxide is an insulator I suspect there won't be a problem.

author: borjam
author_rank: Unknown
timestamp: April 11, 2016, 02:29:56 pm
content: Quote from: ronsch on April 10, 2016, 12:31:57 amBeing non resonant it shouldn't be a problem. It might be for a resonant, transmitting loop which requires a very high Q to be efficient. But for a receiving antenna I don't think it will be a problem at all. Moreover, aluminum tends to form a passive oxide layer, it doesn't get deeper as far as I know (unlike other metals like iron).(Wellbrook ALA-1530+ and MFJ1788 user here)

author: donmr
author_rank: Regular Contributor
timestamp: April 11, 2016, 06:43:31 pm
content: In normal air aluminum always has an oxide on its surface but its pretty clear.Are you seeing corrosion?

author: ronsch
author_rank: Newbie
timestamp: April 11, 2016, 06:45:05 pm
content: No corrosion is seen. Just the normal concern is the antenna working as well as it can...RonK2RAS
[Aust] LF navigation beacons closing down - Page 1
Forum section: electronics / rf-microwave

author: vk3yedotcom
author_rank: Frequent Contributor
timestamp: May 23, 2016, 11:12:24 am
content: A whole heap of LF navigation beacons are planned to close down in a few days.If you've got a 200 - 500kHz receiver it could be worth tuning around while you still can.This video is a band scan done at night near Melbourne. Speed it up and/or do something else as it's a long one!The receiving setup was a home made upconverter with ferrite rod antenna feeding an HF transceiver. The description has links to lists of beacons.
RF transformer confused schematic - Page 1
Forum section: electronics / rf-microwave

author: kendalll
author_rank: Contributor
timestamp: March 24, 2016, 11:50:40 pm
content: I'm confused by the schematic symbol for this RF transformer drawn as a choke. But if you look at the pin names, and the location of the dots, it looks like it's actually a 'standard' configuration transformer. Anyone know why this is? I posted in the RF section figuring maybe you guys might have run into this before.Does anyone know why it's shown this way in the schematic for the ETC1-1-13?http://cdn.macom.com/datasheets/ETC1-1-13.pdf

author: rfeecs
author_rank: Frequent Contributor
timestamp: March 25, 2016, 12:39:00 am
content: It's a transmission line transformer balun they are spec'ing like a power splitter. Pin 1 is the input. Pins 3 and 5 are the outputs.Refer to figure 3a:https://www.minicircuits.com/pages/BalunApplicationNote.htm

author: G0HZU
author_rank: Super Contributor
timestamp: March 25, 2016, 02:01:47 am
content: Google for 1:1 "current balun"

author: German_EE
author_rank: Super Contributor
timestamp: March 25, 2016, 04:25:40 pm
content: The schematic is incorrect anyway because a dot is normally used to indicate the start of a winding. One coil has two starts and the other coil never starts at all.

author: rfeecs
author_rank: Frequent Contributor
timestamp: March 25, 2016, 04:47:33 pm
content: In this case, the dot indicates the polarity. They are calling pins 1 and 2 the primary and pins 3 and 5 the secondary. Secondary dot pin 5 is in phase with primary dot pin 1. Pin 3 is 180 degrees out of phase.

author: Richard Head
author_rank: Frequent Contributor
timestamp: March 29, 2016, 06:36:12 am
content: The drawings a cock-up. No wonder you are having a problem understanding it!The dots indicate the relative phasing of the windings and there should be a single dot on each winding, not two on one winding.
Rohde & Schwarz CMD or CMU  - Page 1
Forum section: electronics / rf-microwave

author: Nuno_pt
author_rank: Frequent Contributor
timestamp: March 14, 2016, 03:34:31 pm
content: Hi,Can any of you guys share if the CMD or CMU units are suitable to work with radios, I've seen videos of guys working on radios with the CMT, CMTA, CMS units.I know that CMU has SA, Signal Generator, Power meter, SINAD, etc, but I can't see nothing from the CMD unit.Its worth to get one or should I pass the CMD and get one CMU, since I don't see any CMT or CMTA for sale and the IFR, HP, Motorola service monitors are expensive.

author: Nuno_pt
author_rank: Frequent Contributor
timestamp: March 16, 2016, 04:54:24 pm
content: No thoughts on this?

author: Wuerstchenhund
author_rank: Super Contributor
timestamp: March 18, 2016, 06:08:02 am
content: Quote from: Nuno_pt on March 16, 2016, 04:54:24 pmSince this is a Test Equipment related question you might get more replies by asking in the right subforum

author: Nuno_pt
author_rank: Frequent Contributor
timestamp: March 18, 2016, 10:13:43 am
content: Quote from: Wuerstchenhund on March 18, 2016, 06:08:02 amSince my objective is to repair and tune ham radios, I suppose this is an appropriate forum.

author: Wuerstchenhund
author_rank: Super Contributor
timestamp: March 18, 2016, 02:59:34 pm
content: Quote from: Nuno_pt on March 18, 2016, 10:13:43 amSure, and it's easy to see that it does work really wellAnyways, good luck!
Connect to Samsung Gear BLE profile? - Page 1
Forum section: electronics / rf-microwave

author: farsi
author_rank: Regular Contributor
timestamp: March 17, 2016, 11:34:20 pm
content: Hi,I got this Gear Fit watch from a local electronics store.Unfortunately, it seems not to work with my smartphone Motorola Moto G.Before returning the watch, I wanted to see if it could be an option to connect to the watch with my PC?A simple dump of the services UUID gives:Found device with local name: Gear Fit (A3CD){ localName: 'Gear Fit (A3CD)',txPowerLevel: undefined,manufacturerData: <Buffer 00 75 01 00 02 00 02 01 03 77 6d 73 00>,serviceData: [],serviceUuids: [] }advertising the following service uuid's:advertising the following service uuid's: {"id":"080775cfd4eb41cf8f1990673dd37b40","address":"08:ec:a9:c4:a3:cd","addressType":"unknown","advertisement":{"localName":"Gear Fit (A3CD)","manufacturerData":{"type":"Buffer","data":[0,117,1,0,2,0,2,1,3,119,109,115,0]},"serviceData":[],"serviceUuids":[]},"rssi":-38,"state":"disconnected"}How could I explore/claim/connect to that device? Any chance of reverse engineering the protocol to create some kind of open-source connection manager?Thanks a lot!
Distributed element filters/RF stuff solder mask - Page 1
Forum section: electronics / rf-microwave

author: darthtony
author_rank: Contributor
timestamp: March 12, 2016, 12:40:10 pm
content: Why do distributed element filters, and generallly RF stuff on a PCB have some sort of gold plating and no solder mask on them?https://en.wikipedia.org/wiki/Distributed_element_filter

author: jeremy
author_rank: Super Contributor
timestamp: March 12, 2016, 01:19:26 pm
content: I can only guess, but the soldermask will change the average dielectric constant of the region, and thus will affect the trace characteristic impedance at high frequencies.From my quick googling, see:http://www.icd.com.au/articles/Stackup_Planning_AN2011_2.pdfhttp://www.sigcon.com/Pubs/edn/PassivationandSolderMask.htmPerhaps it is more difficult to control the thickness of the soldermask layer than it is the shape of the traces.

author: darthtony
author_rank: Contributor
timestamp: March 12, 2016, 03:29:28 pm
content: That sounds reasonable, thanks!

author: tggzzz
author_rank: Super Contributor
timestamp: March 12, 2016, 05:30:57 pm
content: Firstly it will be lossy, which also translates into reduced Q in filters.Secondly the material will be variable, and the thickness will be variable, which translates in to frequency deviations.

author: nctnico
author_rank: Super Contributor
timestamp: March 12, 2016, 07:16:28 pm
content: The soldermask isn't always left off. IMHO there is not much use in not having a solder mask because the etching tolerance will be as worse as the variation in the solder mask layer.

author: KJDS
author_rank: Super Contributor
timestamp: March 12, 2016, 08:13:23 pm
content: The only reason to lose it is loss. I've never measured any other difference.

author: Dago
author_rank: Frequent Contributor
timestamp: March 15, 2016, 06:15:28 am
content: It increases loss and is not as controllable thus affecting the characteristics of the filter in a hard to predict way. At high GHz stuff it can also act as a waveguide and cause rather interesting problems.

author: LukeW
author_rank: Frequent Contributor
timestamp: March 17, 2016, 06:12:10 am
content: In addition to the facts posted above, it looks cool
#32 Random ham radio repair Kenwood TM-621A no 220 MHz RX - Page 1
Forum section: electronics / rf-microwave

author: Radio Tech
author_rank: Frequent Contributor
timestamp: March 02, 2016, 11:27:37 am
content: In this video we take a look at another 621 with no 220 MHz receive all the way from Manchester Maryland. We do not haveany service info for the 220 band board so we go to the white board and draw it out. Links belowKenwood TM-721 service manual:http://www.repeater-builder.com/kenwood/pdfs/tm-721-svc-man.pdfFor more ham radio and tech tips please visit my friends:Mr. Carlsons Labhttps://www.youtube.com/channel/UCU9SoQxJewrWb_3GxeteQPATRXBenchhttps://www.youtube.com/channel/UClqWe58x9q6jx61gB16731A

author: voltz
author_rank: Frequent Contributor
timestamp: March 02, 2016, 12:21:34 pm
content: I do like your videosAnother good job. Hope you got your IFR y offset sorted too, looked ok in the video.

author: Radio Tech
author_rank: Frequent Contributor
timestamp: March 02, 2016, 01:19:13 pm
content: Quote from: voltz on March 02, 2016, 12:21:34 pmThanks for your comment.I fixed the issue with the IFR in video #31 incase you missed that one.https://www.eevblog.com/forum/other-blog-specific/31-ifr-1200-service-monitor-problems-and-fixes/

author: AF6LJ
author_rank: Unknown
timestamp: March 02, 2016, 11:00:41 pm
content: Good Deal.

author: Radio Tech
author_rank: Frequent Contributor
timestamp: March 02, 2016, 11:22:10 pm
content: Quote from: AF6LJ on March 02, 2016, 11:00:41 pmThanks Sue

author: RobertoLG
author_rank: Frequent Contributor
timestamp: March 03, 2016, 10:33:17 pm
content: this one was kinda simple, but keep going

author: Radio Tech
author_rank: Frequent Contributor
timestamp: March 03, 2016, 10:56:10 pm
content: Quote from: RobertoLG on March 03, 2016, 10:33:17 pmYep, I do these in my sleepWill get some tough ones real soon...

author: RobertoLG
author_rank: Frequent Contributor
timestamp: March 03, 2016, 11:18:46 pm
content: Quote from: Radio Tech on March 03, 2016, 10:56:10 pmhehe, but it's cool to see how it's done in such detail, people that are learning how to solder can get a huge benefit from that, as the troubleshooting itself, and as reference, soon you will have a crowded channel, you will see

author: Radio Tech
author_rank: Frequent Contributor
timestamp: March 04, 2016, 12:24:04 am
content: Quote from: RobertoLG on March 03, 2016, 11:18:46 pmFor me that is what it is all about. helping folks that are just starting out. One reason why I try and keep things simple without throwing out all the technical stuff. When I first started out many years ago there was no internet, heck not even computers for the public lol. I had to learn from thrown out magazines and what ever books I could find.Thanks for the support Roberto