/hamradio/ - Electronics

I've heard mediocre things about the pixie and good things about the rock mite. That pixie looks really simple to build though.

For learning CW, I recommend turning up the character speed so it's at 23+WPM and then turning down the effective word speed to 5-10WPM. This forces you to learn the sound of the letter instead of counting the dits and dahs.

Learning the dits and dahs is the fastest way to learn, but you will probably get speed capped at 10WPM, and it will be hard to overcome.

I'm still halfway through the alphabet at 25WPM/ 10WPM effective speed. So take what I say with a grain of salt.

I forgot to mention, QRP kits can be great fun.

But maximum funs if you have a good antenna. At a minimum have a quarter wave dipole.

If you have limited space try a magnetic loop antenna.

I have had not so great results with a loaded dipole indoors (20Meters QRP power). Then again 20 meters has been kind of poor lately.

>>567

The Pixie, honestly, was a kind of a "Fuck it" moment. Newegg sent an email offer of $10 credit to come back. Seen a 40m Pixie was under that, even picked up some solder as well for under it. I've been interested in kits, so, yeah…

Also, you're not the first I've some across with a similar tip for learning Morse by letter identification. I guess I should look into that a bit more. Any good sites or tools to use?

>>568

I'd also mainly be using an outside antenna. I have about 200' of copper stranded wire that I think might work. worth trying at least. As for a mag loop, I've been thinking about it. I've been trying to see if I can scrounge up some solid copper core wire. I might have some luck, a nearby building is about to undergo renovations, so they may be tossing some electrical wire, just need to get to it before the junk drivers or garbage men.

>>569

lcwo.net is a good resource. If you're using linux get "aldo" (if it segfaults, get the latest version and compile, if it fails to compile, you will need to install a newer version of aolib or something).

Any software that uses the "koch method". Make sure to put in two 15 minute sessions a day. Relax and don't think too hard.

With any antenna I haven't found the diameter super critical.

Magloops like a larger diameter.

Best of luck!

>>570

Thanks for the tips.

>>566

I recently assembled a chinese pixie kit. Worked on the first try .)

But the pixie receiver is mediocre at best, and well, it's quite shit due to the simplicity. so t's not the best transceiver for one's first CW qso's. But it's a simple and fun kit to build and use.

Especially when it's under 5eur on ebay and banggood these days.

For learning CW I have been using lcwo.net.

I've been interested in using a 40 meter Pixie CW kit in a survival kit for a family member, so he can contact home using everything in the kit, as means of "last resort" communications.

My idea is to make a .50cal ammo can complete with a 12V power source, (8x1,5v AA), a half or quarter wave wire dipole, and an Arduino to key up different messages on the Pixie, repeating it until it's turned off. I gonna use an Arduino because my family isn't going to learn morse, and I think I'd only need like 4 or 5 different messages to choose from. Like SOS, come get me, stay put, etc.

On my receiving end, I could just verify the messages by ear or have a smartphone with CW decoding do it for me, if that works reliably.

I guess I'd be fine with one-way transmissions, and as stated above, if it's reliable enough I might make it semi-duplex, with an app on my family members smartphone for transmitting to him as well.

The distance I'm trying to cover is about 30 miles.

I know HF is best for long distances, and HF equipment is very expensive and hard to operate for people that don't know anything about it. This pixie kit is cheap and tiny, so that would be perfect. I've seen you can mod them for a couple different frequencies in the 40m band.

I know VHF might cover 30 miles as well, but that would require height, a large yagi antenna and a bit more than 5 watts output power. A ((Baofeng(Please see sticky for more information on this radio))(Please see sticky for more information on this radio)) doesn't provide that easily. A yagi antenna is also significantly larger than the Comms-in-a-can kit I've got in mind.

I've got 4 question about this plan

-Is an SWR meter critical for making a working antenna?

-Is the whole plan by any means even feasible?

-how "reliable" is the 40 meters band for this distance (30miles)

-Do you think the smartphone+app could work with the pixie?

Thank you guys _so_ much for any input!

>>573

I forgot to ask what would be the best antenna configuration would be…

Inverted Vee? NVIS?

The family member does live at a hight, at the top of a >20 story apartment complex. There is no way he can get on the roof, but he could throw a single wire antenna out of his window and have it hang down the building.

Keep in mind I'd like to keep everything in that ammo can, so my first thought was an Inverted Vee, which in essention is just a bit of coax feedline, a dipole center, some insulators and rope and a bit of wire….

Throw a rope over a high tree branch, use that to pull up the dipole center with the attached antenna wires, and use some plastic tent pegs to position the dipole wires in the inverted V position.

I also thought about having the transceiver+Arduino right at the center dipole, to eliminate the coax loss, and that way I don't even have to put a feedline in the ammo can. The pixie just shy of a single Watt if I recall correctly, and I don't intend to lose a milliWatt of QRP.

I don't know a whole lot about antenna's so I don't even know what an NVIS is but I read it in the USMC Radio Operators manual. I know some radio basics, but it's still a lot of voodoo for me.

>>573

I would suggest something better than pixie. Even the other chinese kits are superior. More power and most importantly:

Far better receiver.

Also, don't discount a boafeng with a battery case that takes AA batteries (some long storage life alkalines, LSD nimh's or lithium) along with a roll up J-Pole or NA-771.

Even if pixie in skilled hands and with NVIS antenna will do hundreds of km, it does not matter if it's hard to use.

OP here.

Well, I got the Pixie, built it and attempted to listen. I hear the occasional signal, not too loud but it's there. Problem is, even so often, I get this loud and continuous screech that pops in randomly and goes away for a short time after I pull the plug. Gone for a while after restoring power, but picks up again.

I've double checked all my solder connections, however, troubleshooting is tricky since I haven't found any reports of this problem. Any ideas?

>>586

Use a good power supply for it. The LM386 audio amplifier might be oscillating. A weak power supply can do it.

I bought a couple Chinese kits last month, a Pixie and a Frog Sounds (both on 40m). I can say that the Pixie works fine for such a simple rig, and receives plenty with just my 2.5m magloop, but my 20m Rockmite wipes the floor with it. The Frog Sounds receiver seems to perform about as well as my Rockmite (though they're on different bands, so I can't do an A/B comparison). Also the Frog Sounds puts out 3 watts to the Rockmite's 0.5 and Pixie's 0.1, so there's that.

If you like building cheapo kits and want something beyond babby's first cw trx, go grab a Frog Sounds. Fun little radio. (Side note, the winding numbers for the toroids are wrong in the manual - look at the reviews on Banggood for the correct ones)

>>567

Second this. Go get a 8AA battery holder and power it from that.

>>575

True. I might just invest in an SWR meter and go build my own backpacking-style yagi antenna instead of going HF.

Would you recommend UHF or VHF for those distances?

I think I'd still prefer HF though. It might be a bit harder to operate but with detailed instructions and practicing the deployment a couple times I think I'd achieve better results than a ((Baofeng(Please see sticky for more information on this radio))(Please see sticky for more information on this radio)).

>>596

Yeah I found out about those 40m Rockmite clones just today. 5-8 watts at 12V, that's pretty nice!

If I build the transmitter + keyer in an enclosure and have it a the center of the dipole, would I still need a balun? Or is that only when you have a feedline?

>>598

A balun isn't necessary at power levels like these, feedline or not, as long as it's close to resonant in the first place. It's not strictly "best practice", but you'll be absolutely fine. It'd be a different story if you were running 100W into it, though.

I mentioned magloop antennas earlier; you may want to look into building one of those. I built one recently, and for about $40 worth of parts you can make a really nice portable antenna. (3.8m DRF-400, 2x SO-239 and 2x PL-259 from Universal Radio, a 566pF capacitor from Mike's Electronic Parts, a project box from eBay, and some wire and RG-58 to feed it, plus $5 of PVC parts for the stand)

"Making the Pixie QRP transceiver kit slightly less appalling"

https://www.youtube.com/watch?v=roAc4c1a-a0

VK3YE Really knows his shit and is a qrp operator, so hes words are worth something on the subject.

One of my pixies has those switches for two crystals.

In my case it's the stock 7.023MHz and 7.040MHz. But yet to add an VXO.

When (if) I stuff it in a proper case I'll take some pix for you folks.