Programming the Retevis RA-25, a bildungsroman – part I

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I recently got a Retevis RA-25, a nifty and resourceful little analog rig from Retevis. I won’t discuss the GMRS version (I nearly don’t know what GMRS is) but the HAM version. The hardware may probably be the same. Also, there are some other models that are said to be the same hardware, marketed under … Leggi tutto

A bandstop filter for dirty VHF-UHF ham radio

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I have a few baofengs I don’t use, as I prefer going around with my Yaesu. My QRP rig set is centered on my Yaesu, in fact. But there are times when I am not very confortable with losing or damaging the Yaesu, and being able to carry a Baofeng would be nice. But the harmonics! Aw!

Now, once I got my SDR radio I had the chance to look in a very non-scientific way to the harmonics of those Fengs and decided that I would be funny to have a few filter and try to clear up those emissions and learn something (I am no filter expert whatsoever)

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Categorie ham

APRS packet interface with Baofeng and Pine A64

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Since I was a boy I was intrigued a lot by TNC and packet Radio. In these days a TNC was a serious investment and soundcard weren”t as capable as now, plus we didn’t have (or at least I didn’t) access to programs like Direwolf and the lot. Moreover, I didn’t have access to a serious radio or receiver. Cheap SSB receivers like SDRs and XHDATA D808 were a mere dream. You would have to get a serious radio receiver with BFO and the price tag.
Now everything is simpler, and at arm reach (information and hardware). What you need is: time to fiddle with them.

My adventure with packet radio started with a very simple audio interface.§ This is more a diary for work in progress than a tutorial (there are many, and well made on the tube).
Let’s also state up front that by doing an interface like this you risk a lot damaging your valuable radio and PC. Not by chance I used an old UV3R and let my trusty Yaesu in its bag. As this is not a tutorial, I suggest you don’t follow the advice below and document yourself elsewhere very well before risking damages to your gear.

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YADL, a dummy load for VHF/HF

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I recently change my antenna cable and noticed I didn’t have a dummy load (“carico fittizio”) rated for VHF/UHF, so instead of buying or borrowing I decided to make one. I mostly do QRP: power rating isn’t really an issue, but I didn’t want to risk the RFP. I just bought a 50 ohm RFP … Leggi tutto

Categorie ham