import 4.code.options;
import 4.code.about;

class Header{

public void title(){

String fullTitle = "/diy/ - Do-It-Yourself";
}

public void menu();

public void board();

public void goToBottom();

public void refresh(a);

}
class Thread extends Board{
public void /ham/-Ham/Amateurradiogenera(OP Anonymous){

String fullTitle = "/ham/ - Ham/Amateur radio genera";
int postNumber = "1517356";
String image = "1540155497488.jpg";
String date = "12/15/18(Sat)16:25:01";
String comment = "Last thread died for our sins edition.
FAQ:
ftp://50.31.112.231/pub/radio_FAQ_Preview8.htm"
;

}
public void comments(){
if(Anonymous && title=="" && postNumber==1517360 && dateTime=="12/15/18(Sat)16:30:46")

"So I need the help of you hams.
I'm new to the whole ham thing, but I want/need to build a telemetric system for a project. The first prototype uses an Adafruit Feather 32u4 RFM95 LoRa Radio and transmits/recieves at 868MHz.
To increase the range I wanted to use better antennas than the monopole antennas (a.k.a piece of wire) shipped with the module.
I thought about a dipole antenna on the radio (instead of a monopole - because the chip would be the ground plane and that seems wasteful) and a yagi uda antenna for the reciever. Everything I read about is a 600+ page overkill and it's honestly pretty overwhelming. If I build a yagi uda and a half wave dipole and connect them to the chip normally, would those work?
Or do I need to somehow control the signal phase, match impendances or some other stuff? It's all a bit complicated."
;


if(Anonymous && title=="" && postNumber==1517529 && dateTime=="12/15/18(Sat)20:13:30" && image=="hammer.gif")

if(Anonymous && title=="" && postNumber==1517533 && dateTime=="12/15/18(Sat)20:23:33")

">>1517356
wtf is wrong with his pants?
he literally wearing a giant diaper so he doesn't have to leave his chair for days?"
;


if(Anonymous && title=="" && postNumber==1517627 && dateTime=="12/15/18(Sat)23:06:24" && image=="QuickAndDirty.png")

"I have no idea what "connect it normally" means. I'll assume you meant solder.

The ground is the other part of the antenna, so all your "ground" wiring will affect it.

To improve the range I would try one of the following.

Add a metal disc for a ground plane underneath it. At least .6 wavelengths in diameter. If you use a non-stick cookie tin make sure to clean the area you solder too really well and use a fan! Teflon fumes are nobueno.

Another option is to have the wire sticking up with four 1/4wave wires hanging down at a 45 degree angles from each other. This will be closer to a 50ohm match I'm sure the chip is looking for.

A dipole. 1/4 wave wire attached to the ant and ground pins.

Feeling dangerous? Try a yagi. There are many calculators online, the provided dimensions should get you in the ballpark.
You can test if you did it right by making the TX signal weak enough that you can barely receive it, then rotate the antenna. It should be strongest when pointed at the tx and get weaker when pointed away (will only work when the signal is on the _fringe_ of reception).
Things to watch out for here are multipath, so uh.. do this in a field. You might be able to get the signal weak enough indoors with the TX, by soldering a ~50 ohm resistor across ant to ground,


Are you the anon putting this a rocket?"
;


if(Anonymous && title=="" && postNumber==1517658 && dateTime=="12/16/18(Sun)00:19:50")

">>1517627
>Are you the anon putting this a rocket?
I know I will be."
;


if(Anonymous && title=="" && postNumber==1517684 && dateTime=="12/16/18(Sun)01:31:18")

"I want to make world's smallest pirate radio station. So I'm wondering what the smallest distance I can transmit for it to still be considered radio. Could I do it in 1 mm or less?";


if(Anonymous && title=="" && postNumber==1517689 && dateTime=="12/16/18(Sun)01:45:07" && image=="fm transmitter.png")

">>1517684
It could be magnetic induction if you are too close.
If you are receiving it greater then one wavelength away at the frequency of interest it is radio. (This is my guess because radio is a magnetic wave collapsing into an electric field.)
I.E. 2meters at 144MHz
λν=c
300(speed of light)/144(Frequency in MHz)=2(Length in meters)

300/88=3.4meters

So for an FM station at the low end of the range, 3.4 meters.

I'm 86% sure about my reasoning on this, hopefully another anon can confirm.

You may also be interested in Lecher Lines.
https://www.youtube.com/watch?v=SbVbMR6jmSI
https://en.wikipedia.org/wiki/Lecher_line

Visualizing RF Standing Waves on Transmission Lines By w2aew
https://www.youtube.com/watch?v=M1PgCOTDjvI

http://www.electronics-lab.com/project/simple-fm-transmitter/"
;


if(Anonymous && title=="" && postNumber==1517714 && dateTime=="12/16/18(Sun)02:23:01")

">>1517533
hes probably trapped in all that shit"
;


if(Anonymous && title=="" && postNumber==1517777 && dateTime=="12/16/18(Sun)05:30:04")

">>1517620
Thanks for the detailed answer!
By using both antennas I meant one for the transmitter and the other for the reciever, the transmitter should have the more omnidirectional radiation pattern...

>I have no idea what "connect it normally" means. I'll assume you meant solder.

The chip has pads for a Umf connector, I wanted to connect the poles of the antenna to these pads.

>Another option is to have the wire sticking up with four 1/4wave wires hanging down at a 45 degree angles from each other.

Should those 45° wires connect to ground with less losses? If so does that still work if the chip is in free space? (A.k.a. 100+ m in the air)

And lastly:
>This will be closer to a 50ohm match I'm sure the chip is looking for.

Does that mean the impendance of my antenna (so the resistance of my wire/ resistance of my dipole) should have entirely real impendance of 50+0j ohms?
Impendance matching seems the most complicated part of this to me.

Again thanks a lot for such a detailed answer!"
;


if(Anonymous && title=="" && postNumber==1517779 && dateTime=="12/16/18(Sun)05:35:23")

">>1517627
I forgot answering:

>Are you the anon putting this a rocket?
yes. Again, this is only for the first and second prototype, likely the chipset will be a semi custom one by someone who knows their shit for the third prototype. That being said, optimising the antennas should work for another chipset as well (as long as the frequency stays the same).

If you are the anon answering all the time earlier, thanks a lot."
;


if(Anonymous && title=="" && postNumber==1517780 && dateTime=="12/16/18(Sun)05:36:38")

">>1517658
Honestly? Try it. You can get pretty damn high with (boring) solid fuel. If you have a big enough team you can even design a liquid fuel engine. It's a lot of fun."
;


if(Anonymous && title=="" && postNumber==1517782 && dateTime=="12/16/18(Sun)05:41:06")

">>1517777
was meant for >>1517689 before >>1517620 was deleted by the way."
;


if(Anonymous && title=="" && postNumber==1517974 && dateTime=="12/16/18(Sun)13:36:54" && image=="70MHz_Quarter_Wave_Antenna_Construction_7.jpg")

">>1517777
The previous comment was deleted because I didn't like the tone I used and also realized what you were trying to accomplish.

https://m0ukd.com/calculators/quarter-wave-ground-plane-antenna-calculator/
Connect to ground with less losses? I am lost as to what you mean.
The "ground" side of the antenna, is just that. A side of the antenna.
With these antennas there is always current leaving one side, while current comes in the other.
(This will cook your noodle! The rest of wires attached to ground (on the chip) will affect the radiation pattern I.E. battery leads etc.. )

In this case the ant. ground is going to be the ground on the circuit board. It will not need to be connected to the earth "ground".

If you mean, will it connect to the ground station RXing the signal better?
Maybe.
It will be more efficient, so it will radiate more power. However, the "radiation pattern" will change, so less power may make it to the ground.


Because it's so much easier to build and get going I recommend trying the dipole on the rocket.

Will it work in freespace?
It will work best in free space.
It will work about the same from ~10 meters to 100,000m in the air. However as distance increases, power received decreases.

Impedance matching.
You are _not_ using coax and coming directly off the chip with low power.
I wouldn't worry about impedance matching. That RF power _will_ be radiated or become heat. Have a resonant antenna to make sure the most signal gets radiated.

To have the absolute best efficiency you may need impedance matching.
You could test your TX/RX setup before launching by mounting the TX a few meters above the ground away from other objects. Then walk away and see how far you can RX.
The experiment with a different antennas and see what works best."
;


if(Anonymous && title=="" && postNumber==1518231 && dateTime=="12/16/18(Sun)20:21:14")

"how do I find a good frequency for listening to meteors?";


if(Anonymous && title=="" && postNumber==1518538 && dateTime=="12/17/18(Mon)09:05:45")

">>1518231
Directly listening to a meteor at RF frequencies may be possible. See:
http://www.vlf.it/F6AGR/meteorsignatures.html

Detecting the presence of meteors by listening to forward or back scattered signals from the meteor burning up in the atmosphere is a lot easier. It can be done with just an FM receiver.

So you want to hear meteors? A basic
how to guide:
https://www.rasc.ca/sites/default/files/RadioAstronomy_NovaNotes.pdf"
;


if(Anonymous && title=="" && postNumber==1518547 && dateTime=="12/17/18(Mon)09:25:51")

">>1518231
http://www.livemeteors.com/"
;


if(Anonymous && title=="" && postNumber==1518643 && dateTime=="12/17/18(Mon)13:04:29")

">>1517533
looks like cancery balls"
;


if(Anonymous && title=="" && postNumber==1519086 && dateTime=="12/18/18(Tue)07:39:57")

">>1517356
Will a coax notch filter work well as an FM trap? Trying to get some decent signals out of my chinkshit RTLSDR, and I've never built filters before, so I'd like to learn"
;


if(Anonymous && title=="" && postNumber==1519384 && dateTime=="12/18/18(Tue)17:41:31")

">>1519086
Type 'coax cable notch filter'
Visit http://www.hb9amo.net/fmcoaxialfilter.php"
;


if(Anonymous && title=="" && postNumber==1519477 && dateTime=="12/19/18(Wed)07:32:27")

">>1519384
thats what I meant. Will it work, to clear FM? Else, whats another good option? Eventually I'll build one with a PCB and a proper condenser network I suppose"
;


if(Anonymous && title=="" && postNumber==1519638 && dateTime=="12/19/18(Wed)14:32:47")

"Hello,
I live in East Armpit, Georgia, 150 miles from Atlanta, so rural that your cousin looks good.

I want to stream video from my tractor, to a video monitor headset receiver 200, no more than 300 yards away.

I would like to use a RC video transmitter 5.8GHz at 200mw.
However I'm told I need a HAM Technician license, with a test that doesn't address anything about video transmission.
It' a power thing, both the transmitter and government.
The closest HAM club that does testing is in Atlanta. No one around goes as far unless they need the medical college doctors.

How come drones like DJI can transmit long distances without the operator needing a license? I almost bought one to duct tape to the tractor hood!

Thanks for any answers.
Merry Christmas"
;


if(Anonymous && title=="" && postNumber==1520460 && dateTime=="12/20/18(Thu)20:19:16" && image=="Envío-Gratis-Tecsun-r-218-AM-FM-TV-bolsillo-sonido-Radios-receptor-con-altavoz-incorporado.jpg")

"Hey,

I live in Spain, and, while I know that there are no analog TV channels in most European countries anymore, I would like to try analog TV DXing. But I have no clue of how any of this works, and if I would receive anything in 2018.

I would like to buy one of these handheld radio/TV sets like the one in pic related. I would probably put a longwire antenna on it, or something more complex if that would make this work. But I know that I would probably receive absolutely nothing on the TV band.

I would like to know if someone is doing this in [current year] and if any of you knows if I could get any TV channels on Europe.

I posted this on /g/, but then I found this general, so I repost it here.

Thanks!"
;


if(Anonymous && title=="" && postNumber==1520515 && dateTime=="12/20/18(Thu)21:45:40" && image=="s-l1600.jpg")

"Would an antenna extension like this Tecsun AN07 make a difference on FM/SW reception? It doubles the length of the aerial.

I wouldn't mind using a random longwire to improve the signal instead of this, but this thing looks comfy as fuck."
;


if(Anonymous && title=="" && postNumber==1521706 && dateTime=="12/22/18(Sat)15:56:46")

"K9RSY is leading the usual shitshow on 7200 right now. There's a dozen different voices today.";


if(Anonymous && title=="" && postNumber==1521861 && dateTime=="12/22/18(Sat)18:39:31")

">>1520460
Analog TV is no longer a thing in Europe, it's become DVB-T/T2. You could try DVB or DAB DX. Some African countries probably still do broadcast analog, so those could be an option.
A portable setup is mostly a no-go, since you will be needing a directional TV antenna (yagi)."
;


if(Anonymous && title=="" && postNumber==1523284 && dateTime=="12/25/18(Tue)03:24:00")

">>1520460
Long wire is not really what you want for vhf. A phased array would be worth looking at.

I suspect there may still be analogue tv further east in places like Ukraine etc"
;


if(Anonymous && title=="" && postNumber==1523305 && dateTime=="12/25/18(Tue)05:16:08" && image=="1471457736112.jpg")

">>1517356
The fuck I am looking at."
;


if(Anonymous && title=="" && postNumber==1523750 && dateTime=="12/25/18(Tue)21:23:42" && image=="2528812_blue_dress_polka_new.jpg")

"Hey guys so a while back I asked about RF on arduino.

I am going to pick the project back up, basically I was able to successfully clone my doorbell RF signal that I bought from home depot.

I mainly did it manually. I recorded the signal in sdr# opened it in audacity, did the timings on the signal etc.. etc..

What I want to achieve now is using arduino to automatically capture, and time the signal..

So I noticed the "sync word" or "preamble"? is the same every time. Do I use that in my arduino code to listen for the signal, and capture it that way?"
;


if(Anonymous && title=="" && postNumber==1524183 && dateTime=="12/26/18(Wed)21:08:06")

">>1523305
https://translate.google.com/translate?sl=auto&tl=en&js=y&prev=_t&hl=en&ie=UTF-8&u=https%3A%2F%2Fhe.wikipedia.org%2Fwiki%2F%25D7%259E%25D7%2599%25D7%259B%25D7%2590%25D7%259C_%25D7%2592%25D7%2595%25D7%25A8%25D7%2593%25D7%2595%25D7%25A1&edit-text="
;


if(Anonymous && title=="" && postNumber==1524508 && dateTime=="12/27/18(Thu)13:46:11")

"Are the Bands shit for everyone else today or is it localized?";


if(Anonymous && title=="" && postNumber==1524512 && dateTime=="12/27/18(Thu)14:04:06")

">>1523750
We don't know where you are and what signals are available locally. Wwv and wwvh were set to close were they not."
;


if(Anonymous && title=="" && postNumber==1524591 && dateTime=="12/27/18(Thu)18:09:21")

">>1524512

Sorry, but I had no idea what those terms were until I googled it. But based on the locations, I am not near those signals? I am in the midwestern part of the US. Maybe the signal travels this far out, but I forgot to mention I was on 315mhz."
;


if(Anonymous && title=="" && postNumber==1524622 && dateTime=="12/27/18(Thu)19:24:08")

">>1524591
>I was on 315mhz
What kind of propagation are you expecting? What are you even listening to?"
;


if(Anonymous && title=="" && postNumber==1524679 && dateTime=="12/27/18(Thu)21:54:51")

">>1524622
Meh, Im going to go ask in /ohm/ or arduino Im just trying to automatically clone my doorbell signal instead of doing it manually through sdr# and audacity. btw this is my post. >>1523750

I still think you replied to the wrong person. I believe you probably meant this post. here >>1524508"
;


if(Anonymous && title=="" && postNumber==1524682 && dateTime=="12/27/18(Thu)22:00:38")

"Idk anything about Ham, but what's the deal with Channel 9 on CB? It's a bunch of old black guys yelling nonsense?";


if(Anonymous && title=="" && postNumber==1524684 && dateTime=="12/27/18(Thu)22:01:38")

">>1524682
I meant channel 6"
;


if(Anonymous && title=="" && postNumber==1525035 && dateTime=="12/28/18(Fri)16:31:32")

">>1524684
Its an RF pissing contest basically. I’m guessing you are a burgerlander."
;


if(Anonymous && title=="" && postNumber==1525432 && dateTime=="12/29/18(Sat)09:06:35")

"Is there a transceiver that just plugs into a pc and uses the pc as an interface to control the unit?";


if(Anonymous && title=="" && postNumber==1525436 && dateTime=="12/29/18(Sat)09:22:11")

">>1525432
Many modern ones will have a USB interface you can do that with but might need a panadapter."
;


if(Anonymous && title=="" && postNumber==1525443 && dateTime=="12/29/18(Sat)09:29:26")

">>1525436
i know most transceivers nowadays can connect to pc, but i'm looking for units specifically designed to be used with a pc (no display, minimal interface) and are cheap

after a bit of digging i found this which is basically what i'm talking about, are there any others like this?

https://www.tentec.com/?p=1449"
;


if(Anonymous && title=="" && postNumber==1525637 && dateTime=="12/29/18(Sat)14:12:18")

">>1525443
A lot of older SDR kits (TinySDR etc.) are plain demodulators meant to be connected to the sound card of a PC for processing."
;


if(Anonymous && title=="" && postNumber==1526268 && dateTime=="12/30/18(Sun)12:37:15" && image=="IMG_20181230_123641.jpg")

"copped this at a goodwill
I'm thinking I can take a peak at the circuit inside, maybe change a few resistors or caps around and change what frequency it amplifies"
;


if(Anonymous && title=="" && postNumber==1526763 && dateTime=="12/31/18(Mon)01:18:31")

"How hard would it be to build a mm wave telescope? You know like receiving 100 GHz from space. The best way of detecting planet nine may be in the mm wave band. I've also determined that there's nothing that prevents me from naming planet nine after that baka Cirno if I'm able to discover it.";


if(Anonymous && title=="" && postNumber==1526989 && dateTime=="12/31/18(Mon)11:45:25" && image=="1387025742072.jpg")

">>1526763
I bet those 79GHz automotive radar chips could be re purposed. (They work up to 81)

However, what's the atmospheric absorption of radio waves over 5GHz? Something to think about.

>>1525443
Even simpler Software Defined Radio (and thoughts on soundcards)
https://www.youtube.com/watch?v=A6r66Pc1MYk

Remember that it's homebrew. 5 years later I know why that project didn't work when I built it. There was some sort of coating on the inductor. Caveat emptor"
;


if(Anonymous && title=="" && postNumber==1527286 && dateTime=="12/31/18(Mon)19:53:32")

">>1526989
this is the bad boy we gotta beat here:
https://en.wikipedia.org/wiki/South_Pole_Telescope
10m dish, working at 95 GHz, 150 GHz, and 220 GHz with 960 detector elements at each frequency. Dish is like accurate to 25 microns and probably has a damn good pointing accuracy. Plus it's operating in the south fucking pole so there's less mm wave absorbing water vapor."
;


if(Anonymous && title=="" && postNumber==1527671 && dateTime=="01/01/19(Tue)12:33:35")

">>1527286
I guess cryogenic operations are simplified when outdoor temperatures are below the sublimation point of CO2."
;


if(Anonymous && title=="" && postNumber==1529476 && dateTime=="01/03/19(Thu)20:13:30")

"How much of the info in this general applies to television broadcasting? I have an old TV with no input besides the antenna. I would like to broadcast to it from my PC.";


if(Anonymous && title=="" && postNumber==1529697 && dateTime=="01/04/19(Fri)06:16:27")

"Would you send a reception report to an FM station?";


if(Anonymous && title=="" && postNumber==1531064 && dateTime=="01/05/19(Sat)21:36:57" && image=="1384762500899.jpg")

">>1529697
Did you hear them at a distance beyond what is normal for that station?

If no, you shouldn't do it. (But do it anyways, maybe they'll send you free shwag!!)

If yes, go for it. Include information like distance, receiver used, etc. etc."
;


if(Anonymous && title=="" && postNumber==1531417 && dateTime=="01/06/19(Sun)13:18:31")

">>1517356
While it isn't directly amateur radio related, is the ~10.8 dB gain of SSB over AM worth it for CB radios these days or do you need an amp to get over QRP levels of power to actually make it worth while to have? For those unaware, SSB usage on the CB band is restricted to 12 watts in the US so right at what's considered to be QRP levels for phone modes on the amateur radio bands. My main interest is mobile use.

I know the 10 meter band is basically closed these days outside of sporadic E and the very peek of the solar cycle so it doesn't seem like CB SSB would see too much use unless for skywave/skip. The only real use I can think of is if I'm in a wooded area or somewhere where you have to deal with high levels of attenuation and was trying to communicate with someone else who specifically bought a CB radio that offered SSB, since I should be able to get just under 3.5x the range without considering the radio horizon with that increase in power."
;


if(Anonymous && title=="" && postNumber==1531469 && dateTime=="01/06/19(Sun)14:24:03")

">>1517533
Right inguinal hernia most likely."
;


if(Anonymous && title=="" && postNumber==1532222 && dateTime=="01/07/19(Mon)16:04:23")

"We were discussing local monitoring of the ionosphere earlier, using phase differences of L1/L2/L5. Some interesting news:

>First GPS III satellite successfully launches
https://www.gpsworld.com/first-gps-iii-satellite-successfully-launches/
Civilian L2 (L2C) will now be available in addition to L5.

At teh same time:
>Allystar releases multi-band GNSS raw data chip and module
https://www.gpsworld.com/allystar-releases-multi-band-gnss-raw-data-chip-and-module/

Using all 3 bands it should be possible to do a tomographic cross section of the ionosphere using calculations that have been used for over 30 years.

It would be interesting then to correlate this with propagation data."
;


if(Anonymous && title=="" && postNumber==1534385 && dateTime=="01/10/19(Thu)17:54:56")

"What is there really to do on the amateur radio bands these days, or really just radio in general? I don't mean all the different ways you can use radio waves such as satellites, EME, and whatnot. I mean what is there to do with other people beyond exchanging signal reports?

It seems like most activity I've heard about that isn't just swapping signal reports either requires running a good deal of power into a decent size antenna for phone modes on HF which I don't have the means to do where I live and with lower power HF phone mode use being more restricted to just signal reports from what I've heard, requires you to actually have local people interested in using repeaters for something beyond saying they're present for a net which really only happens during severe weather where I live, requires nearby networked digital voice mode repeaters if you want to get involved in that without using an expensive HT as a fancy wireless speaker/microphone for your computer with a hotspot, or requires you to live near one of the few places where people are experimenting with digital modes for data purposes rather than just digital voice modes or keyboard to keyboard chatting. Besides those issues, the nets I have listened to via websdr that went beyond people announcing they were present have been rather boring vs what I can find on various internet boards pertaining to those topics and APRS traffic that I can pick up is really just location data rather than anything else that APRS can be used for.

cont."
;


if(Anonymous && title=="" && postNumber==1534386 && dateTime=="01/10/19(Thu)17:57:02")

">>1534385
I really want to have fun with this, but the activities you can actually do these days beyond swapping signal reports in interesting ways seem to either not be available or don't seem enjoyable. I'm really not interested for practical purposes, but the lack of enjoyable activities to actually do still discourages me from going any further into this hobby. Honestly, the most interesting things I can think of right now are messing around with receiving weather imagery from satellites and breaking the rules and building my own transceiver for the CB band since that's actually active around where I live unlike the VHF and up amateur bands."
;


if(Anonymous && title=="" && postNumber==1534473 && dateTime=="01/10/19(Thu)20:57:45")

">>1534386
BINGO
there's not much to do on anymore unless you want to listen to old guys give each other signal report hand jobs. ham is flatlining."
;


if(Anonymous && title=="" && postNumber==1534478 && dateTime=="01/10/19(Thu)21:10:51")

">>1524682
Last time I listened in on a CB it was a dick swinging contest involving a bunch of degens with linear amplifiers and echo mics"
;


if(Anonymous && title=="" && postNumber==1534632 && dateTime=="01/11/19(Fri)06:36:38")

">>1534385
There is the social aspect with competitions (how many can you reach, how fast Morse can you receive) but also technical challenges (improving radios, new antennas, improved digital modes and DSP).

These days DSP is in the reach of hams but the cultural gap between analogue radio and DSP is still there. If we should do a project here I would propose a better digital transmission than FT8 etc. Something what carries useful data payload would be useful. I have done some thinking, anyone interested to join? And no logos, please."
;


if(Anonymous && title=="" && postNumber==1534696 && dateTime=="01/11/19(Fri)09:07:43")

">>1534478
ditto"
;


if(Anonymous && title=="" && postNumber==1534763 && dateTime=="01/11/19(Fri)11:07:18")

">>1534632
>I would propose a better digital transmission than FT8 etc.
Go for it, it's not like there's a ton of other digital protocols already, or anything.
>What is Olivia, MT63, PSK, MFSK, RTTY, Thor, THROB, DominoEX, FeldHell, Contestia"
;


if(Anonymous && title=="" && postNumber==1534780 && dateTime=="01/11/19(Fri)11:48:10")

">>1534632
>competitions (how many can you reach
That really just ends up in the swapping signal reports category. Turning messing around with radios into a competition where I grind one task repeatedly seems like it would get old quickly. Also, turning the imprecise nature of amateur radio contacts into a contest really doesn't seem too interesting.

>technical challenges (improving radios, new antennas, improved digital modes and DSP)
That's really not what I'm asking about. Did you read my post past the first sentence? I already know what technical aspects interest me, my problem is that it doesn't seem like there's much to actually do with the knowledge/equipment once you have it and I don't want to have more stuff sitting around that I don't use.

>>1534763
You left out JT8 (formerly FT8 CALL) for people who want the low SNR operability of FT8 but don't want to be restricted to the short messages that FT8 and similar modes restrict you to."
;


if(Anonymous && title=="" && postNumber==1534799 && dateTime=="01/11/19(Fri)12:27:49")

">>1534763
Do any of the existing digital modes characterise the channel? Or do any use more tan one amplitude per bin?"
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if(Anonymous && title=="" && postNumber==1534826 && dateTime=="01/11/19(Fri)13:09:54")

">>1534799
I don't understand what your are asking."
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if(Anonymous && title=="" && postNumber==1534924 && dateTime=="01/11/19(Fri)15:49:58")

">>1534826
All the modes that I have seen analysed divide the signal bandwidth into bins of equal width. In each bin or subdivision of the signal bandwidth a carrier is present or not. This is done by modulating an audio signal onto the carrier but the effect is practically the same.

To improve data rate you can amplitude modulate each bin signal on a finer scale than on or off, for instance using 4 levels. You can only do this reliably if you already have characterised the channel and already know how resilient you have to make the signal to make it distinguishable at the receiver.

Old modems did a lot of characterisation of the channel which is something I have never seen done here. Models also did checks for echo cancellation but that we are unlikely to need here.

You will probably have to have a preamble for each subsequent transmission to further characterise or update the knowledge of the channel. The upside is that you could increase data rate by a factor of 4, perhaps more."
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if(Anonymous && title=="" && postNumber==1534979 && dateTime=="01/11/19(Fri)17:34:47")

">>1534924
If you're wondering about HF use, look up PACTOR IV and the quadrature amplitude modulation that the higher speeds use. No amateur radio specific modes bother using that modulation because the FCC restricts the baud rate for digital modes on HF to 300 baud and bandwidth isn't enough of an issue to justify a narrower band digital mode that doesn't work as well at lower SNR. IIRC, the FCC is considering eliminating the baud limit on HF and replacing it with a bandwidth limit."
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if(Anonymous && title=="" && postNumber==1534985 && dateTime=="01/11/19(Fri)17:50:46")

">>1534979
Baud is not bits per second, just transitions per second. So you can do this and still be within the regulations."
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if(Anonymous && title=="" && postNumber==1535174 && dateTime=="01/11/19(Fri)23:05:49")

">>1534924
you need to look at the Joe Taylor modes a little more closely. they're basically slow audio FSK. OOK would be just begging for dropouts
>characterised the channel
y tho, it'll change, due to atmospheric turbulence, overflying aircraft, meteors, and/or other factors
it seems more sensible to simply take advantage of the channel gain provided by FEC and maybe play some interleaving games to guard against fade"
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if(Anonymous && title=="" && postNumber==1535376 && dateTime=="01/12/19(Sat)09:11:03")

">>1535174
>y tho, it'll change, due to atmospheric turbulence, overflying aircraft, meteors, and/or other factors
I know. That is why I wrote it would have to update the characterisation.
>it seems more sensible to simply take advantage of the channel gain provided by FEC and maybe play some interleaving games to guard against fade
Mobile phone tech (which is where I come from here) has enormous incentives to squeeze the last drop of performance from the channel. That is why they do the characterisation and the error corrections and Trellis encoding and more.

And therein lies the whole point. Unlike cell phone channels the HF net is global in nature, so all stations that can receive two parties in communication can use that to pre-train their characterisations. Especially these days with poor conditions this would be an advantage."
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if(Anonymous && title=="" && postNumber==1535761 && dateTime=="01/12/19(Sat)20:32:54")

"What happens if I take 30 meters of copper cable and put it like this, as if it was a giant ferrite antenna, and I connect it to my shortwave radio? Would this improve reception?

Also, could I make something like this for a specific shortwave band? For example, using a length of wire of 1/2 of the wavelenght?"
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if(Anonymous && title=="" && postNumber==1535762 && dateTime=="01/12/19(Sat)20:33:57" && image=="w5altindoorvertant-1.jpg")

">>1535761
>What happens if I take 30 meters of copper cable and put it like this, as if it was a giant ferrite antenna, and I connect it to my shortwave radio? Would this improve reception?
>Also, could I make something like this for a specific shortwave band? For example, using a length of wire of 1/2 of the wavelenght?
Forgot pic"
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if(Anonymous && title=="" && postNumber==1535837 && dateTime=="01/12/19(Sat)22:38:05")

">>1535762
Make a loop
http://www.k5dkz.com/4loop1.html
or
http://makearadio.com/loops/"
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if(Anonymous && title=="" && postNumber==1535856 && dateTime=="01/12/19(Sat)23:28:05")

">>1535761
The longer and higher the better when it comes to reception only. 30 meter is almost 100 feet and I had a 100 "Randomwire" antenna on my roof as a kid that was shaped like a W and I could receive signals on an ancient Hellicrafters S-83 Tomsk, USSR on it easily at night.

Wavelength is really only important when transmitting."
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if(Anonymous && title=="" && postNumber==1535908 && dateTime=="01/13/19(Sun)00:32:46")

"Hey guys, my older neighbor who I'm really friendly with is really into ham radios. He has a ton of antique ones that have won awards or something at shows (?) and has a lot of new shit too. I'm kind of half interested in getting into the hobby, but to be honest, all he really does is talk to other old guys.
So I was wondering, what do you guys do on your radios? I'm sure you don't just talk to old guys, so what other things are there to do on radios?"
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if(Anonymous && title=="" && postNumber==1535923 && dateTime=="01/13/19(Sun)00:55:07")

"There is so much more to do than just exchange signal reports. Some of my favourites are;
- download pictures from the international space station with SSTV (surprisingly easy)
- climb a mountain and get points for summit activations (SOTA)
- build cheap kits from China and see how far the signal goes (got Calgary to Vancouver with a standard 9V battery into a $4 Pixie kit
- various contests & awards, but being selective picking the interesting ones like straight keys only (SKCC), antinue radios (BK is the ultimate challenge), etc.
- see if you can light up the neighbour’s neon tubes using only your VHF transmitter ;-)
- listen in on air traffic control and try to match the conversations with flightradar24..."
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if(Anonymous && title=="" && postNumber==1536435 && dateTime=="01/13/19(Sun)18:27:05")

">>1535923
>- climb a mountain and get points for summit activations (SOTA)
Exchanging signal reports from hard to reach locations.

>- build cheap kits from China and see how far the signal goes (got Calgary to Vancouver with a standard 9V battery into a $4 Pixie kit
Building new equipment to exchange signal reports.

>- various contests & awards, but being selective picking the interesting ones like straight keys only (SKCC), antinue radios (BK is the ultimate challenge), etc.
Get awards for exchanging so many signal reports, sometimes with specific hardware."
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if(Anonymous && title=="" && postNumber==1536451 && dateTime=="01/13/19(Sun)18:44:01" && image=="Coffee.gif")

">>1536435
Yes, confirming (via 2nd party) proof (signal report) that my equipment(radio and antenna) is performing satisfactorily, sometimes using self-built equipment in hard to reach locations with specific hardware. 99% of the time the other station would like to do this also."
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if(Anonymous && title=="" && postNumber==1536519 && dateTime=="01/13/19(Sun)20:39:51")

"When the amateur radio community offers suggestions for people who are interested in the hobby, are they actually trying to keep people away? It always seems like the suggestions people give are purposely kept unrelated to what the person wants.

>person asks what one can use their radios for because they think most ragchew would be boring or aren't interested in swapping signal reports
>most answers pertain to variations of what the person doesn't want if the person wanted more than just signal reports or are activities one can do that are unrelated to the direct act of actively using a radio

>person expresses interest in amateur radio because of what one can do without infrastructure/while being off the grid but is hung up because ragchewing with old guys doesn't appeal to them
>gets directed to contesting or working on their equipment rather other than interesting things that one can do while not relying as much on infrastructure/being off the grid that one normally wouldn't be able to do

>person expresses interest in amateur radio because they're interested in the tinkering aspect with working on radios/building their own radio/making their own antennas
>gets directed away from their interests because one should spend a ton of money on new equipment to get a feel for the hobby first rather than entering the hobby in an inexpensive way that actually matches with that person's interests"
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if(Anonymous && title=="" && postNumber==1536525 && dateTime=="01/13/19(Sun)20:50:54")

">>1536519
if you don't want to talk to people or swap signal reports, yet you still want to transmit and not be a mere listener, about the only things left to do are to work digipeaters or spot WSPRnet, which is basically having your computer swap signal reports automatically
>one should spend a ton of money on new equipment to get a feel for the hobby
I, for one, would like to spike those people's Geritol with beet juice. buyfagging is not my idea of a hobby"
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if(Anonymous && title=="" && postNumber==1536550 && dateTime=="01/13/19(Sun)21:32:00")

">>1536525
>yet you still want to transmit and not be a mere listener
While amateur radio normally involves actually transmitting, I don't see why people can't still be directed to interesting things one can receive as well. I was actually surprised about how much you can receive that doesn't fall under SWL or normal FM scanner use when I found rtl-sdr.com. Particularly the unencrypted satellite signals which are a lot more interesting to me than amateur satellite use which just amounts to sending signal reports with anything more than that being looked down on (though it's understandable why it's looked down on)."
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if(Anonymous && title=="" && postNumber==1536733 && dateTime=="01/14/19(Mon)08:08:08" && image=="satcom.jpg")

">>1536550
Which satellites, which antenna?"
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if(Anonymous && title=="" && postNumber==1537061 && dateTime=="01/14/19(Mon)20:47:55" && image=="desperation.jpg")

">>1535923
sounds exciting"
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if(Anonymous && title=="" && postNumber==1537092 && dateTime=="01/14/19(Mon)21:54:54")

">>1537061
He's having more fun than you."
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if(Anonymous && title=="" && postNumber==1537272 && dateTime=="01/15/19(Tue)06:17:06")

"The sdr.hu network of kiwi-sdr receivers now have upgraded the front end with a Morse decoder. Too bad far from all hams have a good fist - dare I say ham fisted?";


if(Anonymous && title=="" && postNumber==1537301 && dateTime=="01/15/19(Tue)07:24:04")

"This seems like the right place to ask, please excuse me if it isn't. Is galvanized steel a good-enough material for antenna elements? It'd be in the 2.4GHz range if it matters, me and some buddies wanna make a little mesh net but we're strapped as fuck for cash since lolturdworldcollegestudents. I'd be making a bunch of patch Yagi-Uda's (the commie guy's "wifi gun" except isolating the driven element unlike a retard), and would like to know if the diameters and spacing on all the elements are the same as your conventional n-element yagi antenna so I could make sufficiently high-gain antennas as needed. Threaded rod is cheap, nuts are cheap, smooth galvanized steel sheets are cheap (cheaper than aluminum), and I can salvage SMA connectors and wire from your usual 2 dollar generic omnidirectional antennas. I know this might be a little over my head, but it only really needs to get a few blocks with one of my janky antennas on each end and all of us live in pretty high apartment buildings within LOS of each other.

Thanks in advance for any help!"
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if(Anonymous && title=="" && postNumber==1537801 && dateTime=="01/16/19(Wed)04:01:53")

">>1537301
>within LOS of each other
In that case you can go with optical links. Those are license free and proven tech. Look up RONJA
https://en.wikipedia.org/wiki/RONJA"
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if(Anonymous && title=="" && postNumber==1537803 && dateTime=="01/16/19(Wed)04:11:57")

">>1537301
>and all of us live in pretty high apartment buildings

The problem here with 2.4ghz is that every man and his dog will also be on that band so the noise floor will be sky high."
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}
}