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Topics - joczo

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Equipment / Beacon with a Raspberry Pi (rpitx)
« on: December 09, 2022, 1508 UTC »
Hi guys,I have a Pi 4 laying around,and I'm thinking about putting out a beacon with it.
Anyone did it before?
I've read it can do a couple 10mWs,with a nice antenna it should be an interesting thing to hunt in openings,maybe in the ISM bands,or somewhere on HF.

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Equipment / 9:1 or 49:1 unun for end-fed long/random wire?
« on: October 15, 2019, 1315 UTC »
Hi guys,not really hfu related,but I tought I might ask here as I have my account.
Before my house was built next to the older one and moved in,I used to have a 30m long long/random wire antenna.It was fed pretty "ghetto" way,with a simple speaker wire as a twinlead,and the house's metal gutter as the counterpoise.
Now in the new place,I can stretch out the old 30m wire to about 40m,and I would like to feed it with something better.The old twinlead was a bit too hard to match(tho I could do it more or less 80-10meters,with a beefy tuner),so I would like to add an unun.The radiating part would be the 40m long wire,the counterpoise could be the new and bigger gutter,or I can throw down another wire from the roof.
The question is:which unun would be more ideal?a 49 to 1,or a 9 to 1?The goal would be to have a not efficient but usable antenna 80m to 10m,until I can put up other and better antennas for the lower and higher bands.
Sorry for this short "novel" I wrote,I hope everything is understandable  ;D
Thanks in advance,73!

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Equipment / QRP Pixie rig as CW beacon
« on: November 06, 2017, 0827 UTC »
Hi guys,in the last couple of days I was thinking about setting up and HF beacon,but I couldn't really find anything useful on google about them.And then the qrp pixie cw transceiver came to my mind,as they are dirt cheap and simple,and with the couple hundred mW's is perfect for this purpose.
But my problem is,as a beginner in electronics,how could I key it automatically?Is it possible to do it from a pc without complicating it too much,or should I get something like an arduino nano?
Also on the pixie,how far can I go from the original 7023kHz by changing the crystal?
Thanks in advance! :)

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Equipment / Antenna tuner for random wire/longwire
« on: May 20, 2017, 1333 UTC »
Hi guys,I'm coming with a pretty noob question.Sorry asking it here,but you are nice guys,maybe you could help  ;D
I messed up my antenna tuner which I had until a couple weeks ago.So I started to make another one,with bigger coil and variable capacitor,because the other one didn't really handle 100W.
I tried out a couple schematics,but it didn't work very well,it couldn't handle my 30meter long random/longwire antenna.
First I tried this one,but it only worked for longer wavelenghts than the antenna(40 and 80m): http://homebrewradio.tripod.com/sitebuildercontent/sitebuilderpictures/tuner001.jpg
After I tried this,but also didn't work really well.It did something on the upper bands,but couldn't get the SWR down to 1.0 on none of the bands.
So finally,my question is,can you suggest an antenna tuner schematic that works from 10 thru 80meters?I don't need nothing fancy,just to do it's job.
One more thing,I only have 1 variable capacitor right now,and my coil has about 22 turns,it would be great to make one with these components.
Thank you very much!  :D

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The RF Workbench / Stealth parrot repeater
« on: April 01, 2017, 1431 UTC »
Hi guys!Sorry if I write to wrong topic(or forum),but maybe you could help :)
We would like to make a stealth parrot repeater hidden in an abandoned place with my friend.Our story is short:we have a freaking mountain(okay just joking,but a pretty big hill) between us,and it makes communication impossible.
So we were thinking about putting a repeater to that place,what all of us can reach.
I made some research:powering it is easy with some solar panels from ebay,and a 12V motorbike battery.I have several radios which we can try(old AM cb,PMR),so that's not a problem also.I got stuck with the repeater controller.On ebay,there are some simplex controllers which would be good,but they are too expensive.$60 for a box that does nothing else but recording and playing back...and also,as the repeater will be hidden,anything can happen with it,so we don't want to loose too much money if it happens.
Do you guys have any idea what could we use?I only have a very little knowledge about building electronics,so keep it simple please ;D For example,some kind of easy schematic,or something with an aurdino nano..you get the point.As this will be a low budget project,we don't want anything fancy.
Thank you very much,waiting for your ideas :) 73!

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