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FPS_Sage
Oct 25, 2007

This was a triumph
Gun Saliva

Jonny 290 posted:

PICS INC.



Let's design an antenna. Since people are getting started here, we have decided to build a simple 2-meter (144 MHz band) vertical antenna that would be suitable for putting up on a pole, in your attic, whatever.

We'll do a simple focus on trying to optimize the Standing Wave Ratio (SWR) which indicates how tuned the antenna is to the feedline and radio. 50 ohms is a perfect 1:1 match. We'll shoot for 1.5 or lower across the band.

DANGER WILL ROBINSON, HAM RADIO SOFTWARE ON THE HORIZON. PREPARING FOR BAD USER INTERFACE.......

Welcome to MMANA-GAL, written by an insane japanese ham. It's one of my tools for basic design and optimization.



Let's add a wire. We'll start with a 1/4 wavelength wire and feed it at the bottom. The "w1b" signifies the feedpoint at bottom left.



Aww, it's so cute.



Let's click that "Calculate" tab. Only pay attention to the top line for now, I was playing with other antennas - MMANA fills this newest-at-top. Looks like our antenna, when placed on the ground and fed against it, has about 1.4 SWR. Hey, not bad! We wouldn't hear much on a VHF antenna sitting on the ground, though.




After we click "Plots", MMANA will show us the projected radiation patterns. Pretty much by the book so far.



The SWR tab shows that we have decent, but rising SWR, and our antenna is possibly too long (if it's too long it'll be a better match at lower freqs, opposite for too short)



Let's get this thing off the ground! Add 5 meters of height and OH GOD WHAT THE gently caress JUST HAPPEN



We lifted it off the ground, and MMANA keeps track of all the electrical connections. By raising the antenna, we disconnected it from its ground plane. See how important the ground plane is?

Let's add a ground plane. Remember that a decent ground plane can be made by four 1/4 wave wires sticking out horizontally.



More interesting looking now.



You might have seen that "Optimize" button. This is where the magic happens. Here you can enter parameters to wiggle, criteria to wiggle them by, and metrics to judge the performance of the antenna, which you can individually weight.

What i'm doing here is wiggling the length of the vertical element (wire 1). Then, because the radials should match the element at this point, we 'bind' the radial lengths to the element length (the 'Associated' column). Now the program will wiggle all five elements' lengths in 5mm increments, measuring the SWR at each iteration. If it lengthens and the SWR goes up, it goes back and shortens.





Hey, better match now! You see the bottom line (right after we added the wires) and the top line (after we optimized). That SWR is still a little high, though. What else can we do to tune this?

Bend those radials! As your ground radials get bent down, your impedance rises - and that's just what we need here.

Let's go back and work that Optimize tab some. We'll set it up to wiggle the vertical element length, as before, but this time we're going to change the zenith angle (vertical tilt) of the radials, pivoting them around their start point (the feedpoint) between 90 degrees and 180 - straight out to straight down. START!



Holy crap, that worked perfectly! Look at the SWR below. Almost a perfect 1:1 match.



What's it look like now?



Looks like MMANA bent them down right around 35 degrees to get that match. Easy to reproduce on the real antenna.

And here's the SWR curve if we go back to Plots, a very well-tuned antenna that will give us less than 1.5:1 SWR (this is our general benchmark for usability) across the entirety of the 2 meter band.




best Lets Play i've seen in a while

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atomicthumbs
Dec 26, 2010


We're in the business of extending man's senses.
and then you work on the antenna a bit more and



:catdrugs:

spankmeister
Jun 15, 2008






i ordered a bunch of stuff today, most notably the baofeng UV-5RE+, with a nagoya RH-771, UT-106, USB cable and also a pigtail for my RTLSDR dongle so i can connect SMA antennas to it.

Bloody
Mar 3, 2013

i dont understand the basic premise of wanting to talk to ham users

PuTTY riot
Nov 16, 2002

spankmeister posted:

i ordered a bunch of stuff today, most notably the baofeng UV-5RE+, with a nagoya RH-771, UT-106, USB cable and also a pigtail for my RTLSDR dongle so i can connect SMA antennas to it.

lemme know how you like that antenna. its fukken huge and would prob only be good for fukken around in the yard

PuTTY riot
Nov 16, 2002

Bloody posted:

i dont understand the basic premise of wanting to talk to ham users

same but yospos

spankmeister
Jun 15, 2008






PuTTY riot posted:

lemme know how you like that antenna. its fukken huge and would prob only be good for fukken around in the yard

i probably ordered a fake because it was like $6 but oh well.

Jonny 290
May 5, 2005



[ASK] me about OS/2 Warp

spankmeister posted:

i probably ordered a fake because it was like $6 but oh well.

No, that's the real one, hahah.

Nice haul! Should make for a bunch of fun


Bloody posted:

i dont understand the basic premise of wanting to talk to ham users

if nobody but old men get their ham license, nobody but old men will be on the air

I have been a big amateur radio community hater over the past several years but this thread has proven to me that young people still give a gently caress about this, i have changed my mind


thanks guys :shobon:

Bloody
Mar 3, 2013

yeah but fundamentally like who cares

idk my understanding of hammers is limited to the notion that they say hi to each other and then mail each other signal strength reports or w/e but like... so what?

PuTTY riot
Nov 16, 2002

Bloody posted:

yeah but fundamentally like who cares

idk my understanding of hammers is limited to the notion that they say hi to each other and then mail each other signal strength reports or w/e but like... so what?

my understanding of drag racers is that they drive 1/4 mile to see who goes faster then they go home.


my understanding of football is they run with a ball and see who runs faster but like...so what

PuTTY riot
Nov 16, 2002
i mean i get what ur saying and the new car smell hasn't worn off for me cause im not even licensed yet, but just like... idk its the equivalent of putting dd-wrt on ur home router and doing a bunch of sperg poo poo just to do it.

Bloody
Mar 3, 2013

PuTTY riot posted:

my understanding of drag racers is that they drive 1/4 mile to see who goes faster then they go home.


my understanding of football is they run with a ball and see who runs faster but like...so what

drag racing is p dumb

football pays really well

talking to greybeards is not interesting, if i wanted to talk to them i would just talk to them at work

PuTTY riot
Nov 16, 2002
https://www.youtube.com/watch?v=IWE7FrVY9T4

is this u irl bloody?

Jonny 290
May 5, 2005



[ASK] me about OS/2 Warp
you can talk about whatever you want as long as you're not committing crimes or uttering profanity.

talk about beer, talk about cars, talk about gardening. Make some friends that have shared interests, get some licenses, get on the radio and start runnin your mouth. it's easy


There are contexts in which yes, you're right, the entirety of communications is "Here's my call, I received your call, here's your signal report, next", but contest operators like that are only active now and then and easy to avoid

Bloody
Mar 3, 2013


basically yes

PuTTY riot
Nov 16, 2002

Jonny 290 posted:

you can talk about whatever you want as long as you're not committing crimes or uttering profanity.

talk about beer, talk about cars, talk about gardening. Make some friends that have shared interests, get some licenses, get on the radio and start runnin your mouth. it's easy


There are contexts in which yes, you're right, the entirety of communications is "Here's my call, I received your call, here's your signal report, next", but contest operators like that are only active now and then and easy to avoid

ya i listed to the local club's net on sunday and dude was like 'yep been layin on the couch all day watching the blow dryer race' (it was raining in daytona sunday)


the tech to me is cooler than the 'talkin to dude across town' stuff

maniacdevnull
Apr 18, 2007

FOUR CUBIC FRAMES
DISPROVES SOFT G GOD
YOU ARE EDUCATED STUPID

idk it would be neat to be licensed to buy cool radio gear and hook it up to cool rc planes and make a drone instead of relying on the government to kill foreigners for me

GameCube
Nov 21, 2006

can i listen to local atc on one of the cheapo radios

PuTTY riot
Nov 16, 2002

maniacdevnull posted:

idk it would be neat to be licensed to buy cool radio gear and hook it up to cool rc planes and make a drone instead of relying on the government to kill foreigners for me

theyre rly strict about how far u can go w/ rc planes

PuTTY riot
Nov 16, 2002

Werthog 95 posted:

can i listen to local atc on one of the cheapo radios

no, but u should be able to w/ one of those cheapo rtl-sdr dongles

Jonny 290
May 5, 2005



[ASK] me about OS/2 Warp
That's not a frequency limitation or anything by the way, it's just that air traffic still uses AM modulation and the little chinarigs only demodulate FM.

spankmeister
Jun 15, 2008






Jonny 290 posted:

That's not a frequency limitation or anything by the way, it's just that air traffic still uses AM modulation and the little chinarigs only demodulate FM.

what the baofengs do below 136 mhz? b/c air traffic control is like 118

Zap!
May 15, 2002

Nuts.

Werthog 95 posted:

can i listen to local atc on one of the cheapo radios

Even better is using LiveATC on your computer or phone to listen to ATC chatter.

Fax Sender
Aug 11, 2013

kiss my ass
I'm more into listening to things than talking

Jonny 290
May 5, 2005



[ASK] me about OS/2 Warp

Fax Sender posted:

I'm more into listening to things than talking

This is a big part of it too. You can have a shitload of fun listening and learning and building, and if you want to get into transmitting and actually getting your voice out there, you can compartmentalize that and do it on the side.

there are more engineering challenges with transmitting than receiving - power handling, interference to your neighbor's TV, power supply - so many times throughout the years I have been receive-only and been completely fulfilled in the hobby. And it's true that you don't need your license to listen, but it comes in as a huge advantage in two ways:

-Hams give other hams more respect than unlicensed people, so they will be more forthcoming with help and info
-Amateur radio licenses grant you waivers to operate otherwise prohibited radios in many states. If you have a ham license, it is completely normal that you have a scanner in your car. If you don't, they're going to crawl up your rear end WHY DO YOU HAVE THIS. My license rides in my wallet and I've never had anybody question my radio activities, but if they do I have the backing of state law

Bloody
Mar 3, 2013

can i listen to nasa satellites n poo poo

PuTTY riot
Nov 16, 2002

Bloody posted:

can i listen to nasa satellites n poo poo

http://www.belvoireagle.com/news/family_life/article_36718200-9fb5-11e3-95a8-0017a43b2370.html

Jonny 290
May 5, 2005



[ASK] me about OS/2 Warp
https://www.youtube.com/watch?v=0efTTWMl3v0

PuTTY riot
Nov 16, 2002

yes, you can get this from the internet, but isn't pulling it out of the air way cooler?

SO DEMANDING
Dec 27, 2003

PuTTY riot posted:

yes, you can get this from the internet, but isn't pulling it out of the air way cooler?

...

uh

YES???!??!?!?

SO DEMANDING
Dec 27, 2003

ok this thread has just been pushing me closer and closer to the edge here...ive been to a local ham radio festival a few times, there's a ham radio store not far from where i live...

j290 could you see about posting more of a beginners guide or something? i see lots of talk about pretty damned cheap radios and neat looking SDR stuff but its all still kind of a lot and a bit confusing. where do u start, what's some good beginner hardware (even if just for listening) and/or books/sites/other info?

PuTTY riot
Nov 16, 2002
im a beginner. i got a baofeng uv-5r(a) but any uv-5r is fine. as far as the test goes hamstudy.org is p neat. all of the questions for the test are available so its just finding something that meshes w/ how u study. im taking the test monday :ohdear:

Jonny 290
May 5, 2005



[ASK] me about OS/2 Warp
qrz.com is a valuable resource, they have practice tests there as well

let me see if i can find some guides and such.

For radios if you're in the US, start out with as much Baofeng on Amazon Prime as you can afford. The GT-3 is pretty popular right now, but it's like 65 or 70 bucks which approaches the price of an eBay I/Y/K* handheld and the UV-5RA+ seems popular so I say go for that instead. Get the USB cable, I hear they're a bitch to program through the keypad but I don't know personally.

For antennas I believe the Nagoya 770 or 771, also on Amazon, are really popular, and are super-recommended as the stock antenna is poo poo.

Wouxun handhelds are about in the middle of the price vs quality continuum versus the I/Y/K's and the Baofengs. Don't know much about them.

*Icom/Yaesu/Kenwood, the big three Japanese amateur radio manufacturers. Generally the benchmark for quality mass-produced radios. Most finicky hams pick high end radios of these brands. They're all roughly equal and pretty much a Chevy/Ford/Dodge thing. I'm an Icom guy.


E: as far as SDR goes, I just ordered one of these today. Order any dongle with a similar trip and i'll LP us through getting it set up.

Jonny 290 fucked around with this message at 03:34 on Feb 28, 2014

PuTTY riot
Nov 16, 2002
should i get the 8" or 16" nagoya? id imagine 16" is a little big but is it likely to work that much better that it's worth the extra length?


the lil ducky it came w/ can't even pick up broadcast FM inside this metal buidling

Bloody
Mar 3, 2013

https://www.ettus.com/product/details/X310-KIT rule 36

starsoldier
Jun 21, 2009

Your music's bad and you should feel bad!
i got a technician license in 2005 and upgraded to general in 2010. i found out later my deceased grandfather was really into amateur radio and i picked up one of his old heathkit receivers from the basement that i played with with a random wire antenna. i've basically only hosed around on 2m and 70cm. i got a raspberry pi over christmas so i made a little aprs digipeater/i-gate at my parents house which is in bumfuck nowhere so i only picked up packets from other digipeaters which was kinda boring. rpi aprs is pretty easy to set up though, you just need a usb sound card and interface to the radio and soundmodem plus some aprs software like aprx will do the rest. setting up something to do audio isolation and ptt was literally my first soldering experience and it worked out fine. i even used the interface to make a echolink node just to see if it worked. i really want get some hf going but i'm in college in a lovely apartment so i have limited financial means and space to set up a radio and antenna. so far i have an icom 2100 and a chinese baofeng uv-b5

starsoldier fucked around with this message at 06:22 on Feb 28, 2014

Jonny 290
May 5, 2005



[ASK] me about OS/2 Warp

starsoldier posted:

i got a technician license in 2005 and upgraded to general in 2010. i found out later my deceased grandfather was really into amateur radio and i picked up one of his old heathkit receivers from the basement that i played with with a random wire antenna. i've basically only hosed around on 2m and 70cm. i got a raspberry pi over christmas so i made a little aprs digipeater/i-gate at my parents house which is in bumfuck nowhere so i only picked up packets from other digipeaters which was kinda boring. rpi aprs is pretty easy to set up though, you just need a usb sound card and interface to the radio and soundmodem plus some aprs software like aprx will do the rest. setting up something to do audio isolation and ptt was literally my first soldering experience and it worked out fine. i even used the interface to make a echolink node just to see if it worked. i really want get some hf going but i'm in college in a lovely apartment so i have limited financial means and space to set up a radio and antenna. so far i have an icom 2100 and a chinese baofeng uv-b5

welcome and i hope you are enjoying the thread

I didn't have enough scratch to get an HF radio going for years and years, I definitely feel you. It stung so bad that the first purchase I made after my first real long adult relationship fell apart was my Icom 735. I've been thinking about taking my old Alinco 2m radio and putting APRS on it, i'd like to know more about the cheap and easy APRS setup for sure!

longview
Dec 25, 2006

heh.
IMO the HT antenna to get is the Comet SMA-24, it's basically the same as the nagoya but much thinner and lighter

also the SMA-209 for when you're in good coverage areas, Icom FA-S270C is pro as gently caress though

and the Diamond RH-770 if you want to show off, it's fragile as gently caress but it performs really well at both 2m and 70cm

Sniep
Mar 28, 2004

All I needed was that fatty blunt...



King of Breakfast
this is the HT antenna that i use on my FT-60R

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Wiggly Wayne DDS
Sep 11, 2010



i have a bunch of rtlsdr gear kicking around here from a project last year, think i'll get it set back up after this cool thread

there wasn't a whole lot to listen to last time i checked the uk airwaves. just air traffic control and watching plane transponders. ships never worked here for some reasons, i blame the terrible software

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