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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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

Encryption on Asus Fonepad FE170CG, or how to transform your phablet in something slow as a dog

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I recently fixed a problem on an Asus Fonepad FE170CG. This tablet (or technically, more a phablet, since you can also make phone calls with it) is sold in Italy at the bargain price of 99€ and is quite popular in circles where people need a cheap appliance that can stand as access point, and make the occasional phone call.

Asus FE170CG fonepad
Asus  fonepad (courtesy asus.com)

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