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I built a really simple modulating circuit, but it only modulates the upper envelope while keeping the lower envelope unchanged. This doesn't seem like normal Class C behaviour. NOTE: The original ...
Smaran Suthar's user avatar
  • 13
4 votes
1 answer
248 views

I'd like to build an RF-frontend for an AM-radio using discrete components for educational purposes. The schematic below looks interesting. It was posted by @Ryuji AB1WX in an older related question. ...
Christoph Tack's user avatar
  • 43
1 vote
1 answer
127 views

I'm super new to the hobby and I know next to nothing. I would like to start listening to HF while I figure out licensing to broadcast. I read that I could make my own antenna using a run of Ethernet ...
xXx_Sephiroth_xXx's user avatar
  • 11
-1 votes
0 answers
67 views

I know flag semaphore is a bit off-topic for this stack exchange site, but it seemed to be the most relevant and I suspect there's a bit of overlap between HAM radio operators and people who know flag ...
Huckle's user avatar
  • 107
2 votes
1 answer
103 views

I had my first ham license when I was 18 and have an engineering degree but then left it in the background for the next few decades and my neuron connections deteriorated. I want to get back into the ...
A. R's user avatar
  • 23
0 votes
1 answer
70 views

Trying to get my RP-70 10,11,12 meter (Aquario) to transmit through the PC. So I got a USB → 6-pin converter module called the FT232RL. But its DTR pin (which sends the PTT signal to the radio) is ...
G Bisconcini's user avatar
  • 101
3 votes
1 answer
198 views

I spend a lot of time as an amateur radio public service volunteer, which means I often find myself wearing an earpiece for several hours. I've noticed that just about all cheap (and even some not-so-...
larsks's user avatar
  • 688
0 votes
1 answer
197 views

I'm trying to create my own 432/433 MHz power amplifier for FM and SSB operations using RA60H4047M1 MOSFET module. Relays like Omron G2RL and Relpol RM81 had too low isolation and made my RA60 self-...
LaCrimen's user avatar
  • 25
1 vote
4 answers
126 views

Assume that I have a dipole antenna. Its radiation pattern is "well known" if it is fed with a frequency f0 such that length(dipole) = lambda/2 However, what would the radiation pattern be ...
Gospadi's user avatar
  • 13
5 votes
2 answers
642 views

I'm an engineering student studying RF direction finding techniques and trying to understand the practical challenges of locating a transmitter in forested environments. In theory, many DF methods ...
Cookie Pookie's user avatar
  • 51
1 vote
1 answer
73 views

I have a Wolf River Coils Silver Bullet antenna that I use both for portable and at home. At home I put the antenna on my balcony and use Faraday cloth instead of the supplied radials. My issue: ...
Dan - K9DGB's user avatar
  • 11
3 votes
2 answers
199 views

Measuring antenna radiation patterns usually requires access to an anechoic chamber or a dedicated antenna test range. However many amateur radio operators build their own antennas and do not have ...
Umut Bulus's user avatar
  • 31
2 votes
1 answer
134 views

Article Advancements in Antenna and Rectifier Systems for RF Energy Harvesting (fig. 18) has six different rf rectifying schemas. In them you can see ground connection after source and stab to the ...
Pavel Andreev's user avatar
  • 23
0 votes
1 answer
81 views

I am very new to the art of amateur radio, and just got myself an antenna. I don't intend to use it in a permanent location (for example fixed to my house), rather I plan to be using it at parks and ...
Code penguin's user avatar
  • 3
4 votes
3 answers
475 views

I keep hearing the recommendation to make your SWR as low as possible and that would imply good tuning. I'm a new HAM and made a centre-fed half wave fan, 40m, 20, 15m. It works, and pretty well. I ...
lornop's user avatar
  • 43

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