|
Just means 'less' ground. It'll work fairly well.
|
#
?
Jan 2, 2020 19:05
|
|
|
|
| # ? Apr 29, 2024 09:14 |
|
|
My 2020 resolution is to get better at CW, buy a key, and make some QSOs.
|
|
#
?
Jan 2, 2020 19:14
|
|
|
I have a 40m QCX coming soon!! I need to keep going on LCWO. I will do more portable qrp CW this spring/summer/fall.
manero fucked around with this message at 05:13 on Jan 3, 2020 |
|
#
?
Jan 3, 2020 04:58
|
|
|
lol that OwOComm is starting NanoVNA V2 project and the designer of NanoVNA wants them to call it NanoVNA-B to avoid confusion.
|
|
#
?
Jan 8, 2020 19:40
|
|
|
I understood maybe 1/10th of that sentence
|
|
#
?
Jan 8, 2020 19:47
|
|
|
Jim Silly-Balls posted:I understood maybe 1/10th of that sentence nanovna are a vector network analyzer. edit: also i am not good at posting.
|
|
#
?
Jan 8, 2020 19:53
|
|
|
Big Mackson posted:nanovna are a vector network analyzer. Specifically, a cheap VNA that is getting really popular but suffers from that thing where 80% of the manufacturers don't shield or build them properly, so you gotta buy the ~correct brand. it's like when the RTL SDR sticks showed up and you had to make sure to buy the exact right one even though they all had an rtl820 or whatever chip.
|
|
#
?
Jan 8, 2020 20:28
|
|
|
Actually the hardware designer is just being contracted to make a new version that is almost completely redesigned from scratch with the commonality being that it can run the same firmware and is about the same size. They're giving away the schematics and gerbers for free as soon as it is done. The original creator of the NanoVNA simply asked for a name change to differentiate it from his design, which seems fair enough, but they're not in charge of naming whatever product comes out because they're just designing the hardware. Seems fair enough.  For those that don't know, the NanoVNA is a $40 VNA with a (lovely) touchscreen and lipo battery that does S11 and S21 measurements from 50KHz - 300MHz and can measure up to 900MHz with reduced accuracy. It is pretty OK tool, but pretty amazing for its price point. You can't even get a low end VNA for 10x that price. The "V2" is redesigned to go up to 3GHz with increased accuracy across the board, targeting the same price, so I'd say hardly lol-worthy. Sure going to beat my setup with an RTLSDR, broadband noise source, RF bridge, and rtl_power doing sweeps to just get reflected power for the same price.
|
|
#
?
Jan 8, 2020 23:24
|
|
|
postin' cause this poo poo's sleepy picked up another white whale  icom r1. 100khz-1300mhz wideband receiver. love it to death already. been hunting for a good one for like 5 years and got this one at a great price (50 shipped) a little cleanup and screen polish and she'll be good as new. guts work perfect. vintage '92 vibes
|
|
#
?
Feb 21, 2020 06:46
|
|
|
Moved my Posting Station around in my office a bit, now I have my IC-735 on my desk with my computer, plugged into the PC's line in, so I can decode SSTV. The antenna tuner has a line running out into the other room, to the patio door so I can throw up my hamstick when I want to get on the air. And I have a J-38 key coming in the mail today from a generous fellow on Facebook! Looking forward to banging out some QSOs.  Now my wish list is an auto tuner, a better antenna (maybe a loop antenna would be best for receiving SSTV, but wouldn't be good for transmitting. Small footprint tho), and a better SWR meter than the one built into the IC-735. HF in an apartment with a small balcony is tough :\ Count Thrashula fucked around with this message at 15:21 on Feb 21, 2020 |
|
#
?
Feb 21, 2020 15:16
|
|
|
Any goons run HF mobile? What do you run? It's been on my wish list for some time now, especially since I don't know how much HF I will be able to do at home now. I really want to do it right, but I have a small SUV and just can't get away with putting a giant screwdriver on it. I know a couple of local guys who run the Yaesu ATAS antennas mobile, but it won't do 80m, and not sure about going the hamstick route, especially on the lower bands. I'm looking at the FT-891, or would wait if there was any news from Kenwood about a replacement for the TS-480 radios. I dont need VHF/UHF and/or digital, but wouldnt be opposed to it either.
|
|
#
?
Feb 21, 2020 19:13
|
|
|
Jonny 290 posted:Specifically, a cheap VNA that is getting really popular but suffers from that thing where 80% of the manufacturers don't shield or build them properly, so you gotta buy the ~correct brand. it's like when the RTL SDR sticks showed up and you had to make sure to buy the exact right one even though they all had an rtl820 or whatever chip. Any reccomendations on a good one to buy? I've been looking at them, but they all look nearly the same to me.
|
|
#
?
Feb 21, 2020 19:15
|
|
|
Might as well post about my new-years project now that the thread is alive again! I built a Mini-Whip antenna back in 2016 using an old Decca navigation antenna housing, and it's worked pretty well. Especially after I modified it to use differential transmission over twinax instead of coax. I figured I could do better now, so I've built this:  It's an old GPS timing antenna housing, with entirely new electronics. Inside it's a little messy, the brass plates form the antenna element.  Below the antenna is a stack of circuit boards:  This is (to my knowledge) the first time someone has built a Mini-Whip where the output is RF over Fiber. The reason I'd want to do this is my antenna location means that I have a real risk of forming ground loops and other nastiness with other radio equipment. Fiber is immune to this, and so the optical signal will be free of any common mode noise etc. The actual mini-whip portion is pretty solid IMO, it's ESD protected with an ultra-low capacitance varistor, 22µH series inductors + a 10k in series forms a RLC low pass with the FET gate capacitance, giving around 30-40 MHz cutoff right in the first stage. There's also active AGC since the laser diode has a limited dynamic range. Laser biasing and RF AGC is handled by a STM32F030 MCU, the solution including all the analog interface circuits takes up the middle board. Bottom board is the power regulators and the laser driver. Once inside, the fiber is currently split into 8 outputs using a super cheap 1:8 splitter off AliExpress. I can then use modified CATV passive fiber receiver modules to get a fully electrically isolated copy of the HF spectrum into whatever receiver I want:  It's extremely capable on the low end, picking up a bunch of NATO VLF transmitters with very strong signals. There's not a huge amount of higher frequency signals I can pick up here at the moment, but synthetic tests show good performance up to around 27 MHz and acceptable up to 30 MHz. Transmitting 145 MHz FM at 30W+ right nearby doesn't affect it much at all, so the filtering was definitely worth it. VLF spectrum a few days ago (those are real transmitters, not just spurs):  Might try to make a 50-500 MHz version for my next project, then I'll have continuous kind of crappy but good enough coverage for stuff like scanners and SDR receivers with no ground loop issues etc.
|
|
#
?
Feb 21, 2020 21:17
|
|
|
Wow that's a really neat project would definitely love to see future updates!
|
|
#
?
Feb 21, 2020 21:27
|
|
|
Yeah that's real cool and I need to reread it when I have more time to soak up details.
|
|
#
?
Feb 21, 2020 21:51
|
|
|
Totally forgot to mention that I also wrote a utility to calibrate and monitor the things on the bench using the UART on the MCU. (That's the startup view with dummy values, but it's close enough to real values) The calibration parameters are the optical output power, the monitor photodiode gain, and the RF AGC target. Since the RF AGC has a precision VGA I actually run it open loop, the power monitor (AD8307) monitors the input to the VGA (AD603), this means I can keep it extremely simple and I just filter the RF level and calculate the required gain to reach the target level. Laser power is a full PID regulator with a thermal derating function (since laser diodes work like poo poo at higher temperatures I reduce the target power linearly above 40 degrees C to avoid thermal runaway). The look is designed to piss of my web-designer friend. I mentioned I used a STM32F030 MCU... the thing with that bad boy is it's an extremely powerful Cortex M0, with an absolutely tiny flash:  Feature complete, because I can't fit any more 
|
|
#
?
Feb 21, 2020 22:09
|
|
|
My white whale, at least when I was a kid, was the TH-78a. That poo poo had DTMF paging  You could also slide a cover over the keypad. Other stuff I’ve got going on: I picked up an IC-7300 and did the IF tap mod and have an RSP1a attached to it for a pan adapter, so that’s pretty slick. Nice radio. Still working through LCWO lessons and I’m closing in on the end. I built a 40m QCX this winter and it worked right off the bat:  Very fun project and cool little radio
|
|
#
?
Feb 21, 2020 23:34
|
|
|
Oh gently caress where'd you get the case, I thought they stopped selling them
|
|
#
?
Feb 22, 2020 00:21
|
|
|
COOL CORN posted:Oh gently caress where'd you get the case, I thought they stopped selling them BaMaTech out of Germany: https://www.bamatech.net/geraetegehaeuse/qcx-gehaeusebausatz.html Took a few weeks but it was worth it!
|
|
#
?
Feb 22, 2020 14:29
|
|
|
longview posted:Mini-Whip where the output is RF over Fiber. god drat wizardry uli2000 posted:Any goons run HF mobile? What do you run? It's been on my wish list for some time now, especially since I don't know how much HF I will be able to do at home now. I really want to do it right, but I have a small SUV and just can't get away with putting a giant screwdriver on it. I know a couple of local guys who run the Yaesu ATAS antennas mobile, but it won't do 80m, and not sure about going the hamstick route, especially on the lower bands. I'm looking at the FT-891, or would wait if there was any news from Kenwood about a replacement for the TS-480 radios. I dont need VHF/UHF and/or digital, but wouldnt be opposed to it either. kenwood ts-50s with the matching auto tuner here. to hell with trying to work 80/75 mobile. you're just going to have a mildly leaky dummy load. Save it for home or the campsite imo. I put a ball mount on the Ford's fender, built a 3.5 foot mast using copper pipe and some 3/8x24 hardware, and screwed a spare hamstick whip into the top. the autotuner gets it anywhere 40 through 10m, works great. uli2000 posted:Any reccomendations on a good one to buy? I've been looking at them, but they all look nearly the same to me. I haven't kept up on the scene but i'll scan around and see what's out there right now.
|
|
#
?
Feb 22, 2020 17:58
|
|
|
longview posted:Might as well post about my new-years project now that the thread is alive again! Those passive RFoF converters are the same sort of thing that'd be used in a FiOS install to provide "basic cable" to TVs without boxes, right? How did you have to modify them for this use?
|
|
#
?
Feb 22, 2020 19:35
|
|
|
longview posted:Below the antenna is a stack of circuit boards:
|
|
#
?
Feb 22, 2020 20:58
|
|
|
wolrah posted:That is one of the coolest things I've seen in this thread, period. Thanks, I've literally spent a year trying to figure out a use for the laser diodes I got (for free!) and this one seemed to be a worthy use. I don't know the details of FiOS installations, but possibly yes. I got them off AliExpress for around $5 a piece. Mine are wide-band (~1100-1650 nm coverage), but I noticed some sellers make them with filtered diodes. Since a typical FTTH (both for xPON and Ethernet) application uses a dual wavelength system (AFAIK 1310 and 1550 nm for TX/RX), you could absolutely make a system with RF over Fiber where the RF is e.g. at 1650 nm with filtered converter boxes. They might also use the powered variant that's slightly more expensive, the advantage would be that they could use a less powerful laser at the transmitter end and still feed a lot of devices an acceptable signal. I'll repost my original picture, which is a modified one. The actual diode is the upper two leads, the lower one is the case and is isolated from the diode. The PIN diode is operated in "solar panel" mode where it's generating a current that corresponds to the light. The absolute most basic implementation is to put a 50 ohm resistor in parallel with the diode, that lets the current flow and the bandwidth is fairly large. Since the CATV devices are built to cover 47-860 MHz they can get a bit more efficiency out of them by using an inductor instead of a resistor, that way less RF energy is lost in the resistor and can instead go to the load. So my mod is just to replace the inductor with a 240 ohm resistor (bandwidth with 240 ohm is almost identical up to 1 GHz compared to 50 ohm, but the efficiency is higher). I also replace the series capacitors with 1µF ones to get better VLF performance. I'm also considering making one or two powered converters with a distribution amplifier, that way I could use a single splitter output to feed several devices e.g. inside a rack. Some receivers require a stronger signal than the passive converters provide, so it would help with that as well. For HF a wide-band opamp seems to work reasonably well, and Maxim makes an amplifier IC specifically for optical CATV that should work well for 50-500 MHz coverage. Incidentally, with the VLF coverage this antenna is very good at picking up lightning strikes.
|
|
#
?
Feb 22, 2020 20:59
|
|
|
Thinkin' about what a disaster AZ will be if ol' COVID comes around got me digging out my old Ham stuff. I only ever had an HT, an Icom IC-W32A, but I was delighted to see that replacement batteries are readily available, since the NiCd pack in this thing is dead as disco. Also, holy poo poo, batteries in the '90s suuuuuuuuuucked. The OEM battery for this radio was a 9.6v 650mah pack that weighs a lot. I bought a 7.4v 2000mah replacement for like $30. We'll see if I can find something cool and cheap to keep me on the air for a while this time. Or I'll go back to playing Frostpunk.
|
|
#
?
Mar 1, 2020 07:06
|
|
|
Picked up a dipole adapter mount so I could turn two hamsticks into a dipole, and it's more or less working on my little balcony. Horizontal ~works~, but it's hard to get it out over the sidewalk. Having it sort of sloped vertical works better for my space, but I'll have to test to see if that makes the gain much worse.  A guy in the SKCC sent me an old J-38 that works like a dream after wiring it up  Here's to beepin' and boopin'
|
|
#
?
Mar 2, 2020 18:58
|
|
|
Jedi425 posted:Thinkin' about what a disaster AZ will be if ol' COVID comes around got me digging out my old Ham stuff. I only ever had an HT, an Icom IC-W32A, but I was delighted to see that replacement batteries are readily available, since the NiCd pack in this thing is dead as disco. Nicads kinda suck now that we have cheap nimh cells that can be sorta-basically-trickle-charged the same, just for a longer time. my w32a is my favorite HT (and i have over a dozen) of all time. Mine came with a dead battery and i cracked the case and refilled with solder-tab nimh aa's and they still run great. You can even program it with chirp!
|
|
#
?
Mar 3, 2020 22:29
|
|
|
Has anyone built an antenna rotator for tracking satellites and talking to the ISS? I don't have any HF gear at the moment but I do have a few VHF and UHF radios and wanted to do something with them. I've looked at SatNOGS https://satnogs.org/ a few times and wondered if this would be the best way to build a antenna rotator that would work over RS232? I start to look at the build sheet and get overwhelmed and shelf the project for another year. I think if I had a rotator I could use it for sats, ISS and eventually a trackuino balloon launch that I've been working on for a few years as well. Or am I making this way too hard and I just need to get one of those arrow handheld antennas and point it by hand? johnnyonetime fucked around with this message at 17:46 on Mar 5, 2020 |
|
#
?
Mar 5, 2020 16:15
|
|
|
Yeah i built one. https://github.com/k3ng/k3ng_rotator_controller, a 24v AC transformer and some relays and switches. It runs pretty fine, though i used one of those accelerometer chips and a differential serial converter chip pair to fly the data down to the controller box itself via a 100ft cat6 cable, and it was a fair bit of work to try to get things running properly. It does line it up just right though now. satnogs is interesting but it feels very makerbot 3d printer fair-weather temporary-usage type of tier. Good for park afternoons, not something you'd want (or be able to without lots of re-engineering) to put up on a pole like my old Alliance rotators are. step 1 of all satellite builds should be the Arrow (or similar lightweight dual band antenna) in your hand, i will say for sure. Get used to the signal strengths and the beamwidths of the antenna, when you gain the satellite signal and when you lose it. that helps a lot when designing more advanced controllers.
|
|
#
?
Mar 5, 2020 19:52
|
|
|
Jonny 290 posted:Nicads kinda suck now that we have cheap nimh cells that can be sorta-basically-trickle-charged the same, just for a longer time. You know what's amazing? Not only is this Li-Ion pack half the weight and twice the talk time, but CHIRP makes about a million times more sense than I remember the goddamn ICOM software making. Luckily, I still have my serial cable! Popped my new battery in, and damned if everything doesn't work perfectly. I forgot how many bands this thing did too, especially after you opened up the expanded frequencies via that hack. I should think about doing that with my dead NiCad pack, I can always dispose of the old battery and keep the case for later.
|
|
#
?
Mar 6, 2020 02:05
|
|
|
Jonny 290 posted:Yeah i built one. https://github.com/k3ng/k3ng_rotator_controller, a 24v AC transformer and some relays and switches. Thanks for the info! Well in a strange turn of events I came across https://www.work-sat.com and K6LCS mentioned that the IC-W32a is a full duplex HT that is a good choice for working satellites. After reading the praise of the W32a up in the thread it was a no brainer. Coincidentally there was a cherry W32a that was just listed on ebay that I purchased for $144. So I'll pick up an arrow antenna at HMO this weekend and get chirp fired up and see if I can contact the ISS. So instead of agonizing over antenna rotator builds for hours then doing nothing I'll just get outside and actually use the radio, neat! Edit: She's a beaut, like opening a time capsule 
johnnyonetime fucked around with this message at 20:14 on Mar 10, 2020 |
|
#
?
Mar 6, 2020 17:25
|
|
|
I'm stuck at home all week due to Corona, so I figured I might as well talk a bit about an upcoming project, and a project I did in late 2018 that's related. I have this ITT Mackay 3021N communications receiver, it covers 15 kHz to 30 MHz.  Non-standard features shown include the LED lighting for the S-meter, and the golden tuning knob (I've since gone back to the original MS91528 series knob). There's some info here about the 3020 model: http://www.w7kf.com/Articles/Rigs/ITTMackay3020A.html And a service manual: http://bama.edebris.com/download/mackay/3020a/3020A.pdf The 3020A is functionally identical to the 3021N except the 3021 has the rotary frequency input instead of thumb-wheels, and IIRC the N model has a different Wide filter bandwidth. It's a glorious thing, made ca. 1975 it lends it self very well to tinkering. It uses plug-in cards for almost all functions, and most of the cards only perform a single high level function. Previously it had an issue with the frequency selector system (that drives the 7-segment display, and configures the synthesizer). The display uses HP5082-73xx digits, in case anyone was wondering. The issue was that to remember the frequency it was last set to, it uses 4000 series CMOS counters that are battery backed. The battery backup probably worked fine when the radio was left powered up for 8+ hours every day, but for occasional use it would run out all the time. When it ran out the display would initialize in weird random ways and I'd have to spin the knob around to reset each digit in turn to get back to a valid frequency. I later discovered that leaving the MHz/kHz selector in the Lock or MHz position would drain the battery like crazy, which frankly seems like a design error since Lock is the normal state for that switch. The rotary knob was a very early optical encoder system, using an extremely large open chopper with quadrature encoders. Long story short I re-did the entire card with a STM32F030 MCU to read the optical encoder (hardware timers in the MCU can be configured to read incremental encoders directly!). I used an I2C F-RAM IC to store the last frequency input, since they have very fast write cycles with no wear-out mechanism so this should be a forever-fix for that problem. I also replaced the original encoder with a super cheap modern one that had much higher resolution and wasn't horribly unbalanced like the old one. Anyway, in 2018 I got RNNoise working on a STM32F4 MCU (just barely), and after training my own network with SSB/broadcast AM audio it worked pretty well. I then figured that the easiest way to use this in a radio was to add it to the 3021N receiver. After looking around the block diagram I decided to replace the AF amplifier card with my new noise reduction card. The original card was a 22 pin plug-in card whose entire job was to drive a 3W loudspeaker and drive the S-meter when set to Audio Output monitoring.  Fun fact: the original functionality of the card I replaced is effectively handled by the two SO-8 ICs just right of bottom center. So this card ended up being pretty complicated (probably the most complicated PCA I'd built by then, outside of professional stuff). There's a STM32F103 management MCU that handles reading things like button and analog inputs (i.e. pot-meters to set volume etc). Initially I was going to do it using mostly analog processing, with analog switches to select the signal path, attenuator ICs for volume control, and the STM32F4 MCU could be switched in to handle the noise reduction. This seemed pretty complicated to design, and potentially very tedious to modify. I also wasn't super thrilled about squeezing extra features into the RNNoise MCU (since I'd still want to do some normal filtering etc.). Because of that I decided to add a ADAU1445 DSP chip, which is the heat-sinked IC in the middle of the board. This is as far as I can tell, an off-shoot of the SHARC line of DSPs. It can do a very impressive amount of 28-bit fixed point processing of audio signals. The DSP digitizes all the analog audio signals going in and out, and can route these wherever they need to go. It's set up with 4 in/4 out analog, where one set of analog lines goes to the RNNoise system (I couldn't get the I2S interface on the STM32 to work reliably so the analog I/O was a backup solution). Only one external AF input is used, and the outputs are Speaker, Line (transformer coupled in the back-plane), and Headset. There's also a fairly simple LM1884 style noise reduction system in the DSP, it uses a voice activity detector to control the cut-off frequency of a low-pass filter. This essentially acts as a noise gate, but it's much smoother in action (being essentially "analog" instead of just gating) and works really well for FM type noise (it does degrade the quality a bit if the incoming signal is good so not something you'd want to just leave enabled). It also works reasonably well for certain types of AM noise, but it's not super useful for a HF receiver. Following the "smoke 'em if you got 'em" line of thinking I also do speaker correction in the DSP for the audio output going to the speaker driver. On my to-do list is to actually measure the response in system and update that correction though. And yes, the S/PDIF I/O to the right is a single mode SFF module, the S/PDIF is routed to the rear I/O panel on the receiver. The DSP has it built in, and I expected to use it as part of a larger system later that's now on hold. I have actually tested the SPDIF output, and it does work flawlessly. This post is getting long, so I'll have to get back to the future project but here's a teaser:  This is the SigmaDSP "programming" environment for the audio DSP. This is actually running on my desk right now (using a breakout box for the card shown above). It's extremely easy to get up and running with this system, though it does have some limitations. Basically what I'm doing is downconverting the 8 MHz IF from the radio to 12 kHz, then doing the demodulation in the DSP. It's already working for SSB/CW (which is dead easy to implement), and I've got several solutions for AM demodulation. My goal is to add a proper synchronous AM demodulation feature to the receiver, since I like to DX MW/SW broadcast signals and carrier-fading is often an issue. A synchronous decoder (i.e. a DSB decoder) is much less sensitive to carrier levels. So this new card will replace the existing demodulation card in the radio, which is a basic design containing a product detector and an envelope detector. The hard part is actually doing the carrier tracking (PLL based) to compensate for frequency errors; there's some numerical accuracy limitation with the fixed point math in this DSP that makes it essentially impossible to do it exclusively in the DSP. I've got a solution for that, and it only involves an extra STM32F3 MCU/DSP, a 32-bit DDS synthesizer, and a CPLD. How hard can it be
|
|
#
?
Mar 17, 2020 10:05
|
|
|
Hello ham thread! Just got my tech license last week. Had one of the cheap Baofeng UV-5RTP radios just to play with. Took less than a week for me to upgrade and my Yaesu FT-65 came in today. It even works with the Nagoya antenna I bought with the Baofeng. I’m stuck home indefinitely because the PA governor shut down the entire state due to COVID-19, so I’m going to mount my copper cactus in my attic tomorrow. I can have 5w of fun until the FTM-100DR (that is currently sitting in LA customs) gets delivered. I was going to take my general on the 26th, but the virus screwed that up as well. Welp.
|
|
#
?
Mar 20, 2020 23:07
|
|
|
Good for you. Get your self operating. I just went back to the old house to take down the ZS6BKW. Got a rope up decently high in one tree, the one on the other side is going to go as high as I get get it with a ladder as soon as I find a pulley or eyelet to up up there (no branches down that low). I've got another tree that I can pretty much call the middle that has a branch up WAY further than I can throw, so I just ordered a $7 slingshot and some 1 oz fishing weights off of amazon. Not how or where I was planning on putting this thing, but I'd rather have it up for now.
|
|
#
?
Mar 20, 2020 23:26
|
|
|
Motronic posted:ZS6BKW latest experiment is that i laid a ground radial field under the point where the coax feeds the ladder line up to the feedpoint, and added a couple jumpers with spade terminals to feed both sides of the ladder line against ground. this adds 160 meters and a different 75 meter radiation pattern to the default setup that gives me 40, 20, 17, 12, 10 and 6m. takes a quick stroll outside and 10 seconds to change the config. the both-sides-against-radial-field setup is REALLY good on MW broadcast too. i can pull some 1kw little guys out from 2-3 states away.
|
|
#
?
Mar 22, 2020 08:14
|
|
|
Ohhh....I like that idea. Not very practical where I just threw this thing out in the woods but I'm gonna keep that in mind for it's more permanent location. I was also considering just throwing up enough wire through the trees to cover 160. I've got a mighty fine junk antenna tuner that will do random wire on "antenna a" and a button to swap to a second coax so it would be easy to switch. But your idea sounds better. I was doing okay-ish last night. Decent signal reports but nothing fantastic. Certainly a lot worse than when it was up higher (also flat top at that time). I'm looking forward to the sling shot arriving and trying it as an inverted Vee - I didn't have a sensible spot with center support to try that at the old place. Also, looks like I'll be picking up an SB-200 from an SK through a friend at work. As soon as we can both leave the house so I can get it.
|
|
#
?
Mar 22, 2020 17:19
|
|
|
Hey thread, newbie here. Looking to listen in on the local emergency management agencies and hospitals. I am in indiana and most of them use P25. It looks like the local ham radio shop recommended the uniden sds 100, but the price tag is around $650. I researched SDR’s a little. My question is, are these even an option as a scanner with a Mac? I don’t mind forking over for a copy of parallels and installing linux if needed, but I don’t want to boot linux as the main OS. My other question is range. Hospital A is 10 miles away, hospital B is 25. There are a couple more closer to 35-40 miles away. Most of the emergency management agencies are in the 25 mile range. Is that feasible with an SDR or the SDS100 or even 200? I live on a hill but its not really flat terrain. I can put up external antennas provided they can go on the same mast as my existing cell amplifier and TV antenna.
|
|
#
?
Mar 24, 2020 03:53
|
|
|
A $20 RTL-SDR will let you listen to that just as much as a $600 SDR will. The big things are going to be the software your computer is running and your antenna setup. Hopefully somebody else has some Mac software advice because I’m not aware of any. As for the distance, there’s a good chance they’re using repeaters to cover your city if they have to use these nets to communicate to first responders throughout the area.
|
|
#
?
Mar 24, 2020 04:49
|
|
|
could just get a raspberry pi and do radio stuff using that, I believe there are even prebuilt images for it a $600 sdr might be able to transmit and will surely have far more bandwidth (thus you could listen to more frequencies at once) ... but if you are only doing a bit of this and that, a simple sdr would surely be enough
|
|
#
?
Mar 24, 2020 09:39
|
|
|
Thanks. I ordered one from nooelec directly. Amazon went from 1 week delivery to over a month overnight despite the item being in stock. No luck getting a raspberry pi anytime soon either. I am going to go ahead and just put linux on a spare external ssd for my mac. Lets just hope it gets here before whatever is about to happen does happen.
|
|
#
?
Mar 24, 2020 12:43
|
|
|
|
| # ? Apr 29, 2024 09:14 |
|
|
There are a number of OS X radio packages that work with the rtl sdr. You don’t really need to switch to worrying about using linux or windows if you’re looking for more complex stuff like writing your own sdr in gnuradio. I’ve gotten P25 decoding working on OS X but it is easier under linux or windows. GQRX is a good starting point.
|
|
#
?
Mar 24, 2020 16:42
|
|
