/hamradio/ - Electronics

Currently using dump1090 with web-based front end for air traffic ads-b watching.

>little aerial I made works

Full of win!

>>370

Awesome!

dump1090 also worked for me.

I fucking fucked up my RTLSDR. It fell down and one of the inductors fell of the PCB.

Im about to buy a HackRF now. I'm also already bonered for the HackRF blue amplifier.

>>577

Please let me know how those perform if you get one. I got a FUNcube Pro+ before realizing that the updated HackRF can also see into the HF band. The FCP's main issues are the low sample rate making it tedious to scan with. It also seems to be totally blind around the 3-4MHz area.

>>356

Also yeah, even screwing a telescopic antenna into the base will improve reception dramatically. I've yet to try a real one.

just what I was looking for

Thanks!

Contributing:

CW (Continuous Wave)

Also known as On Off Shift Keying.

The most common form of O.O.S.K is Morse

code. It's known for being the absolute simplest and most efficient way to send and receive messages across the ether.

It is possible to construct a working HF CW set for only a few tens of dollars and use it to contact stations thousands of miles away. The efficiency of CW is of particular benefit to operators who use simple low-powered stations.

CW has superior bandwidth efficiency, using only a few hertz of the spectrum.

In 1966 when prisoner of war Jeremiah Denton, brought on television by his North Vietnamese captors, Morse-blinked the word TORTURE. You never know when it will come in handy strelok!

Keep It Simple Stupid seems to be the best way for me to describe Morse code.

PSK31

Or Phase Shift Keying (At 31 baud)

Think of it as CW's fast and cool brother. It's a digital mode that most people send it using soundcard on their PC (audio out) to their radio (audio in).

It has built in error correction, so if the person receiving is plagued with interference or fading, they’ll still be able to make out most of the transmission.

How does it work? With phase shift keying, When the signal is present and "normal" we call it a 1. However, when we FLIP the signal wave upside down (so the peaks are valleys and the valleys are now peaks), We call that a zero.

Side note!

Why do we change the amplitude and make it sound warbly? Believe it or not but a carrier by itself does not take any bandwidth! It's the change in carrier!

So if we "SLAM" a signal 180degrees out of phase, it will have infinite bandwidth and interfere with other people. If we do it over time, it takes far less bandwidth.

The same applies to CW. If we turned our transmitters instant on and instant off, it would splatter everywhere. By giving it some "shape" and slowly rising and falling to zero. It takes far less bandwidth. For example 5Hz. And in the case of PSK-31 >100Hz.

HELLSCHREIBER

One of my favorites, because it reminds me of an Enigma machine for some reason. While mostly novelty, think of it as RTTY but with ticker tape instead.

Encoding and decoding of this mode can be done with a PC and a sound card. This simple mode is easy to use and tune! It is suited to HF since it does not use 'sync' and you can pick out the text by eye, even in high levels of background noise!

A quick addendium to the CB section.

While CB radio can talk around the world, It is usually during years with high sunspot activity (Yes strelok, the sun does charge up our atmosphere). Most people who using CB and 11 meters to talk around the world use "SSB" or Single Side Band.

>>514

They probably do.

If >>495 is just scanning, a scanner might be a better choice.

>>515

I would do more than scan but the state requires i get a licence from offcom

Build a 2m quarter wave ground plane out of some #8 copper wire. Super simple, almost nothing can be made better for cheaper. Put that shit on your roof and you're golden.

The problem is with making your own antenna is that you _need_ a SWR meter or else it destroys your radio or it just doesn't work

I made a coax dipole antenna for PMR446. Works okay for listening but I haven't transmitted with it yet.

Someone from a ham club would probably let you use their SWR meter. Maybe not on the first day (they are expensive).

I don't use echolink at all.

>>544

I prefer IRLP.

so what is the difference between IRLP and echolink, besides (i think) echolink requiring you register before you can use it.

>>554

They are both VOIP services somewhat.

If I remember correctly. Echolink doesn't require a radio.

IRLP requires a radio to get in to/ use the network.

K1MAN :^)

>>532

looks like you're in trouble with the FCC

K9PEE :)

>>419

Art Bell has his own show now. . .

not coast 2 coast. .

>>409

that one is made with RG213 and the impedance is 50Ω

well, i nigger-rigged a SWL antenna by stripping the copper out of old electronics cords once

Yes, my homebrew is based on the thousands of years of conflict for the holy lands in the Middle East. It encompasses all the cultures and their respective mythologies of the peoples that had a hand in the conflict.

>>509

also on a different topic from that article, he says antenna grounding can be successfully accomplished by grounding the coax at the loightning arrestor point. is this true or will it get me fucked?

Unplug your kit. Hope your antenna in grounded. Wait for storm to pass.

>>510

This should not fuck you. The arrestor should have a good low impedance path to ground.

>>505

If the radio is unplugged it might survive a hit to the antenna. With the arrestor it likely won't. But stuff downstream of the rig might. and the rig likely won't catch fire.

The amount of energy in a lighting strike is quite insane. Good protection is hard.

>>512

I meant keeping the radio unplugged from the antenna, not unplugging the power.

>>510

>is this true or will it get me fucked?

as this anon says

>>512

>This should not fuck you.

in fact if your lightning arrestor does not have a good path to ground it is useless or worse by giving you a false sense of security.

>>512

>The amount of energy in a lighting strike is quite insane.

is so true it hurts.

I can tell you what I've seen from my work in cell phone base stations.

1. well grounded arrestor

2. arrestor is placed at lowest point on coax either on tower or building.

3. equipment inside is not connected to power mains grounding system.

#3 can be accomplished like the cell tower does by running all equipment from 48v battery bank that floats on a constant charge system.

or

using a good UPS for your equipment to provide ground isolation.

In short the antenna needs to be well grounded not your radio. You want the ONLY path to ground to be through the arrestor and not your costly equipment inside the shack.

If you just plug your equipment straight into the wall outlet there will exist a low impedance pathway from the transmission line's coax shield thru the chasis of the radio to the power mains grounding system that a lightning strike will follow.

I cannot say it enough times, the only thing in the system that should be well grounded is the antenna, and the shield on the coax.

they go to great lengths to ground the cell tower and shack. Post too long. Click here to view the full text.

You did good. The yaesu handhelds _all_ have better front ends. So you can attach whatever matching antenna to it.

Also, I've yet to see one that doesn't put out it's specified power.

VX-8/-8R/-8DR are solid little radios, especially for the price you can get them at now. My only compliant is that they're too damn small and the interface is awfully damn cramped.

I keep waiting for the big three to realize that there's a market for a high-end commercial-grade amateur handheld, but it's just not happening at this rate.

looking for a wire stripper, crimper, and cutter for working with coax. what are some good places to buy from? from all i've seen, the tools aren't suitable for coax.

>>517

You will need a proper crimper, and a box cutter for working with coax.

Depends on the coax you plan to work with. Most people use RG-58. But there are other sizes depending on your application (some underground cables are larger etc. etc.).

>>516

That noise floor is way too high! -88dB across the board? Try disconnecting the antenna. If it stays the same, their may be a problem with the Rx'er. Also, that noise looks like a comb generator, maybe the front end is getting overloaded?

>>519

Even for one of those $20 TV tuners? I do intend to pick up something better but wanted to evaluate if I want to get into this proper first. Also all the spikes can be put down to all the electronics and wireless things that are here. The same happens if I move the antenna close to the laptop I run from.

>>518

I was planning on using RG-8 for less loss

anyway, just recommend me some brands that manufacture coax tools?

G5RV and off-center-fed dipole (OCFD) are popular multiband wire antennas.

You just need two trees to hang it between.

Both are also simple to build yourself.

a quick question

on the 7410, it says the radio comes with a built in tuner. does that mean i don't need to buy a separate tuner? i'm asking because i don't know if internal tuners are as good as externals.

>>492

The built in tuner usually works acrossa a limited range, like 3:1 or 5:1 SWR at maximum. A dedicated tuner is usually much more versatile.

And can include various other goodies, like built in 1:9 balun for using wire antennas and so on.

That's my experience with built in tuners. But I mostly use my MFJ–945E and LDG AT-200ProII.

But in general, I rarely needed tuners when using my OCF-D.

All the bands I used it on it was under 2:1 SWR, and in my books that's perfectly fine.

>>483

Why the IC-7410? Why not get the IC-7200, then spend the extra $600 on a power supply, stand-alone tuner, antenna(s) and coax?

You could make ghetto soldering iron tips from nails, just use the one's that are not zinc plated.

But if you want better ghetto soldering iron tips, use thick solid copper wire from scrap powercables. Like the stuff used to feed houses.

Copper is superior for soldering. Also, many sotres actually have replacement tips for even the cheapest <10usd irons.

But I'd really suggest getting a better iron.

And for antenna work, 60W minimum.

If you are thinking about soldering UHF connector (PL259? type for USA?) and using the cheap shiny stuff.

Then you will be much happier if you file away the crome/nickel stuff around the soldering holes. and preferably inside them too. I bought a cheap (<20eur) needle file kit for that. It might solder without, but it is much easier when it's cleaned.

Also more on the connectors them selves.

Get Teflon (PTFE) insulated connectors!

Your life will be so much better when soldering them. Saving a few bucks on the connector is simply not worth the headache and bullshit of a failed connector with a bent pin as the cheap plastic insulation melted while soldering.

As for "how to wire and antenna"? most ham guides tons of info as is and internet is filled with guides and pictures.

One place to start your journey.

http://www.dxzone.com/catalog/Antennas/

>>463

What band is this intended for?

>>464

40 through 15, ideally, but all I really need is 30 and 20.

>>463

Only the outer diameter matters, as in, more surface area = better. People have used aluminium and copper tape on PVC pipe to make magloops.

>>432

It's a passive reflector for fucks sake!

There is no power at all on it. It Is used to reflect microwaves from some some site miles away ffs.

Your phone dumps literally thousands of times more power in to your body than any position on it or near it.

>>438

Well it was just the 4th time it was stated that it was safe and not dangerous. Maybe now people will get it.

Misinformation should be combated at every turn :)

>>439

"Well it was just the 4th time it was stated that it was" … "dangerous. Maybe now people will get it."

-Anonymous

OP here weeks later, I should have clarified that I was joking when I said cancer. I know that RF is non-ionizing and that all the recent freaking out about RF emissions giving you cancer is overblown. I was just wondering if there are any ill effects, like cataracts or other shit if I stand infront of it too long.

I hate all this digital voice shit.

First off, its all proprietary, which is shit in and of itself, but that also puts its use in a legal grey area regarding part 97 use.

But most of all. I love ham radio because its such a simple hobby. You can make a perfectly good rig out of simple parts if you want to do cw or phone. I have nothing against digital shit in and of itself, but its adding a layer of complexity that I don't want to become the norm.

>>452

freeDV is 100% opensource from codec up :)

It uses codec2 at 1400baud.

I made an SSTV board if anyone wants to post SSTV. :^)

>>>/sstv/

>>203

The tapes aren't missing, they were recorded over most likely with Skylab data. Tapes are expensive, even for NASA (speaking of people that love proprietary formats…).