r/amateurradio

A few months of updates on AntennaSim, our free and open source browser antenna simulator

Hey there. A while back I shared AntennaSim here, the free and open source NEC2 antenna simulator that runs in your browser. The response was way more than I expected and a load of you sent feedback and ideas, so I've been chipping away at them ever since. Here's what's new if you fancy another go.

What's landed since launch:

  • Multi band sweeps in one run, so instead of checking 20m, then 15m, then 10m one at a time you simulate them all together and see how the antenna does across every band at once. There's a per band breakdown of SWR, gain and bandwidth too.
  • Catenary sag for hung wires, so you can model how a wire actually droops between supports.
  • Bend a wire to whatever angle you want.
  • Axis locking while you drag, plus moving several wires at once, which makes laying out real antennas a lot less fiddly.
  • An impedance matching calculator for L, Pi and T networks.
  • More band presets, now with ITU region support.
  • Save and load your projects.
  • A validation pass that warns you about common mistakes before you hit run.
  • And a good pile of bug fixes.

Still completely free, still GPL-3.0, still a real nec2c engine running right in the browser, or self hosted with Docker if that's more your thing.

Thanks again to everyone for the kind words last time, honestly meant a lot. If you tried it at launch it's worth another look, and if there's an antenna you've been meaning to model just give it a go. It's everyone's project at this point really, so don't be shy about opening an issue or a PR, and tell me what would make it more useful for you. We keep making it better together.

Browser version: https://ea1fuo.github.io/AntennaSim/

Code: https://github.com/EA1FUO/AntennaSim

73 de EA1FUO

u/GoVlad314 — 10 hours ago

Handheld that is somewhat water resistant and also has a decent front end, without breaking the bank

I got an FT-65R hoping it would fulfill the requirement and it sorta does but it's completely unusable at 70cm in town. Granted it's probably *fine* since almost everything is on 2m and the few times we use a 70cm repeater for public service events it's in the middle of nowhere. And I don't really *need* one.

But hypothetically if I were to get one or try to drop hints for holidays in the future, what should I be looking at?

There's also a part of me that's tempted just to save money and buy a nice HT at some point but I don't use them that often.

Maybe a VX-6R or D890UV? Or something of that nature. Or are those Wouxuns with the superheterodyne receivers decent?

Edit: weirdly enough for most of the people recommending the VX-6R, https://qrpblog.com/vhf-uhf-handheld-performance-comparison/amp/ seems to imply it has worse 3rd order wide dynamic range than the FT65 at least on 70cm.

u/thesoulless78 — 13 hours ago

FT60 vs Anytone D890

I recently aquired FT60 so called holy grail of analog HT (plus pretty hard to get here in europe for decent price)

Unfortunately to my shock, the receiver is much worse than my Anytone D890.

Same conditions, basically the same antenna.

Anyone has any experience with this?

reddit.com
u/johnysed — 14 hours ago
▲ 7 r/amateurradio+1 crossposts

POCSAG/FLEX Pager Monitor Web App

Hey everyone,

I’ve been working on a small project and finally cleaned it up enough to share.

I built a web-based POCSAG/FLEX pager monitor that lets you decode and view pager traffic in real time using an SDR + multimon-ng pipeline with lot of functions.

👉 GitHub: https://github.com/Dj3ky/PagerMonitor

u/Dj3ky — 13 hours ago
▲ 7 r/amateurradio+3 crossposts

In my recording room I have this noise/interference sound. I recorded this using my U87 clone into my Allen & Heath CQ18T mixer, and I can hear it as well on my Rode NT1, but I can’t hear it at all with my Shure SM81. My best guess is that my xlr cable is picking up noise/interference somewhere, since it is a cheap Amazon basics xlr cable, and the problem gets worse/gets better when I touch the cable and move it around. I have tried multiple other Amazon basics xlr cables I have, same issue. I have ordered a WBC Pro star quad xlr cable with Neutrik connectors hoping to fix the noise, it’s not here yet, but I’m wondering what could be causing this noise in the first place, and why the SM81 was not affected at all it seems? I have made sure that the xlr cable from the mic to the interface isn’t touching anything, or any other cables. I have dimmer light switches in the recording room and around the building, but the noise does not improve with turning them off/down. Any advice is much appreciated.

u/spraypaintyourass — 20 hours ago

Anyone else get major "mic fright" after getting licensed? Love the tinkering, nervous about the talking

I got into amateur radio because I love the science, the tinkering, and the technical side of the hobby. But now that I’m licensed, I’ve run into an unexpected wall. I find myself nervous to actually chat with strangers. As someone who is used to only talking to established friend groups online, staring at the mic feels a bit daunting.

I know it’ll get better with practice, but right now I find myself freezing up, not knowing what to say other than my call sign and a few remarks after lol.

I know local clubs exist, but I kinda want ham radio to be a hobby I can enjoy comfortably from home. Also I'm generally a shy person, which I guess doesn't help? Does anyone else struggle with wanting to make contacts but being too anxious to key the mic? How did you break through it?

Edit: I wanted to thank everyone for giving their advice and thoughts! It's reassuring that many feel the same way and that many are encouraging to keep trying. I will try some POTA stuff for practice as some people suggested and I'm more curious to learn more about CW,FT8, etc as some have mentioned. I'll send out my call sign to the airwaves some more and see what happens. Thank you again everyone! 73 :)

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u/onebaddude14 — 1 day ago

grandad’s old stuff

Im 23 and know nothing about radio stuff. My grandma told me to get rid of my grandads old set up. Was wondering if you guys could tell me s bit about what i have, if its rare and worth keeping or if its all common stuff. I also dont wanna get scammed if i end up selling it.

u/No_Fan_4197 — 24 hours ago
▲ 184 r/amateurradio+2 crossposts

Band pass filter

Created an airband bpf in kicad. Not finished. I knew next to nothing going into this. But with the help of some great books and weeks of research I will have revision 1 completed. Not expecting it to be perfect and I am fully aware that one can be purchased for a very low price. But I did this as a learning experience. I will post the results once the components are populated. All smd except for L1 and L2. Some of these photos are just me learning the nanovna and inductance meter. I also tried to prototype this design originally in Manhattan style but quickly learned that was near impossible at this frequency. Thanks for checking it out.

u/SearchPlane561 — 1 day ago

Transistor tester necessary if one has an LCR meter?

Hello everyone

I have a Fnirsi LCR meter, the LC1020E, which I'm happy with but I'm wondering if there'd be a benefit of also having a transistor tester.

I'm very much an amateur trying to learn as much as possible so I'm not an advanced user. But I enjoy trying to salvage components from old kit sometimes and therefore wonder if a dedicated transistor tester would offer much I won't be able to do with the LCR meter?

Thank you very much in advance
Philip

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u/_philipus — 19 hours ago
▲ 202 r/amateurradio+1 crossposts

Can we please make this constant stream of vibe-coded software just stop?

Like, furrealz, I don't care about every new app that comes out that has some vague connection to ham radio. Maybe we need a hamradiosoftware sub. What do my fellow nerds think?

reddit.com
u/CW3_OR_BUST — 1 day ago

Did I make a mistake with this radio?

I got it for $300. Came with service manual, mic, speaker, and tuner. Yaesu FT901DM

u/ActualPrune9799 — 1 day ago
▲ 10 r/amateurradio+1 crossposts

How narrow can I make an inverted V dipole for 20m? First antenna build, open to suggestions

Hey everyone, I'm a rising college freshman on the east coast getting into HF with a Hermes Lite 2. I don't have my license yet so this is receive-only for now, but I'm building with transmitting in mind for when I do get licensed.

I'm planning to build a half-wave dipole for the 20m band as my first antenna and set it up as an inverted V in my backyard. Problem is my yard is small and sloped. I know the general advice is to keep the angle at 90 degrees or wider, but realistically how narrow can I go before performance falls off noticeably? What's the minimum horizontal spread between the two ends that you'd consider usable?

Planning to run FT8 at 5 watts once I'm licensed. For now just want to listen and learn.

This is my first antenna build so if there's something simpler or better suited for a small sloped yard on 20m I'm totally open to suggestions. Thanks!

reddit.com

New 30ft tower with no antenna

I have put up a used great condition 30ft tower that I got for $300 but really have no clue what kind of antenna I would like to put on it.

Current rigs:

● Icom IC-7300 for HF

● Icom ID-5100 for VHF/UHF

Current antennas:

● DIY 20m/40m fan dipole about 20ft up in some trees nearly horizontal

● DIY 2m j-pole about 25ft up

About the area:

● No HOA (somewhat obvious) lol

● Almost 1/2 acre

● 4 or 5 good sized trees (40ft or so) around the perimeter of the property

I usually stay on 20m but would like something I could play on other bands with also. I would like to spend no more than $500 on the antenna itself. If the suggested antenna is directional, I don't mind having to buy a rotator separate from the $500 budget from the antenna. I really enjoy DIY-ing things so let's hear it.

reddit.com
u/Own_Rush_2206 — 22 hours ago

Wtf is this?!

This was on 2204.407 MHz, kept going on and off for a while, never faded so maybe its a geostationary satellite? sounds like some sort of data. Im in Aurora, CO.

73 DE KF0WOL

u/Educational_Hold1453 — 24 hours ago

I found a bunch of these old Motorolas on marketplace, is this an okay place to start? I’d like to get my ham license soon, but I’m not sure if that this is where I should start?

Sorry if it’s a dumb post, I don’t have any radio friends so I’m coming to the internet for advice. I found a bunch of these cheap nearby and was thinking about getting one to play with. I was reading the spec sheet and it looks like it would be an alright starter, as it handles a lot. I’m just not sure if interfacing is easy for a newbie, or if I should just stay away in general. Thanks

u/Doorknob77 — 1 day ago

My Icom HT fell 150ft on granite and still works fine

My buddy dropped it rock climbing. I think lanyards are in order for the next climb!

u/DauphDaddy — 1 day ago

IF Output question

Not sure if this is a good place for this question (I don’t post on Reddit much, but read here often). In the process of getting my general again.

I have an old SDR receiver that was given to me by an RF engineer at a previous job. It’s an AOR SR2200. It doesn’t have an I/Q output but does have an IF Out at 10.7MHz. I recently picked up a tinySA ultra and connected the IF Out to it. I tuned into local broadcast FM stations to see if I could make sense of it. I was surprised to find that the displayed spectrum was reversed. Meaning the high frequency stations (106.5) showed up on the low end of the displayed spectrum and low frequency stations showed up on the high end of the spectrum. When I tune the receiver to, say 106.5, it shows up on the TinySA at the IF frequency of 10.7 which makes sense to me.

My question is why is the spectrum reversed? I expected to tune up and listen to a higher frequency station, but that was not the case.

reddit.com
u/ajwhlr04 — 22 hours ago

Alpha Delta switch question re: SWR

I have been planning to order an Alpha Delta Switch to put outside where the coax enters my house. I was looking at images online and there is a warning sticker on the back of the switch about not using if the SWR exceeds 2-1 at the antenna feedpoint.

I'm planning to experiment with random wire's, rybakov's, etc... and will require a tuner. Are there any switches that can easily handle these antennas and not have an issue? I don't want to have to go outside and unscrew the arc protector or replace the switch, because I wanted to use a random length of wire.

I'm only planning to run 100watts, but might as well purchase the best product for my usage.

Here is a link - not my site - that shows the picture. https://www.radioworld.co.uk/second-hand-alpha-delta-4b-4-way-coax-switch

reddit.com
u/LaMarr-Bruister — 23 hours ago

Looking for an enthusiast who knows more than I do

Hey folks! I have a strange request. I'm currently outlining a short story about an alien species using radio frequencies to communicate, and I wanted to know if there was anyone I could ask about the basic science/components of radio in a speculative sense. I've done a bit of research about how radios in general work, but I have a number of specific questions and think it's best I talk to someone who has a background in it.

reddit.com
u/oxymonty — 1 day ago

Home antenna question

Hello everyone,

I am wanting a good antenna to work some dx/hunt some pota from my house. I currently have an Inv-L efhw cut for 40m with the horizontal about 25-30’ up and it works fine, but I can tell where it has nulls sometimes compared to a vertical when I put one up. So my question is this- are there any antennas out there that anyone has experience with that are 1:not insanely expensive (like under $500) 2: not on a tower 3:multibanded and finally would anything even be worth doing over my current setup?

I am thinking something like a 4/6btv or dx commander?

I mostly work 20 and 40m, but sometimes hunt on 30 for cw and 15/10 for the openings nowadays.

Please no arguments in the comments let’s be civil, and yes I understand every antenna is a compromise.

Thanks and 73!

reddit.com
u/Top_Performer1634 — 1 day ago