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What is the socket for on this Baofeng BL-5L battery?

I have a Baofeng BL-5L battery for my Baofeng UV-5R transceiver, and I notice that it has a socket on the side: Please, what is this socket for?
Harry Weston
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Running ladder line through window from inside shack to outside dipole antenna - what to watch out for?

For HF operating, I am considering running a ladder line from the ATU just inside a window, through the window (squeezing it between the window and the window frame; not actually through the glass), and out to a dipole suspended outside. I am…
user
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HackRF One — Expected 'hackrf_transfer -t' file format and its creation?

What file format does the HackRF One expect on the command line, using the -t option with hackrf_transfer? Also, how would I create or convert that format from a standard WAV file? I was expecting the following to transmit a 36 second wav…
M6JNY
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How to produce a NEC antenna file (and what software to use it with)?

So I'm really trying to get to grips with antenna radiation patterns, and more importantly things that are to close to the antenna that might interfere. I've downloaded Qantenna and 4NEC2 to try and model my antenna and see what I can do, however…
FraserOfSmeg
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Minimum thickness of whip antenna

I'm looking at designing a communication system using very low power transmitter (0.1 W) and operating in the 400 Mhz range. For my uses I think a quarter wave whip antenna would work well, so I've calculated the length of the antenna to be 187.5…
FraserOfSmeg
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How far the near-field reactive region extends from the transmitting antenna?

I am doing research on near-field harvesting. In my situation the transmitting antenna is a dipole antenna operating at 2.45 GHz and its length is 14 cm long. I am trying to find how far near-field reactive region extends from the antenna. I…
Shiva Mudide
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Can PIM occur with one carrier?

the literature talks about PIM occuring with two or more carriers: can it not happen in a single carrier antenna? e.g. creating second harmonic (2*f)?
user5448
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Is string trimmer line suitable for supporting antennas?

In searching for suitable materials for a wire antenna, I found a few mentions of using string trimmer line to hold up each end of the antenna. This would be a nice option as it is readily available locally. For a long-term installation, I've seen…
W5VO
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What do hams mean when they refer to "higher bands"

For example, the Ultimate3S kit info page says: Produces 250mW RF output on 30m (lower output on higher bands) Would bands "higher" than 30m mean: bands with higher frequency e.g. 20m/17m/15m? bands with higher wavelength e.g. 40m/80m/160m? It…
natevw - AF7TB
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Is there good antenna for 160m Band?

I live in Japan. Japanese houses are very narrow, but I want to try 160 m band. Is there good antenna for 160 m band? I want to operate HF (160m～10m) bands. Now I use vertical antenna (40, 30,20,15,10m). I want a low band (under 40m) antenna. Low…
Akira Hamada
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What are the rules for proper use of the 5.8G (5cm) band?

I see several products that operate in the 5.8 GHz range that specifically mention a Ham license is required for their use. For example, the page for this video transmitter specifically mentions The use and operation of this type of product in the…
Mark Harrison
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What's the unlicensed power limit for 5.8 GHz (5 cm) transmissions?

5.8 GHz NTSC video transmitters are popular for FPV (first person view) model aircraft flying. However, because the 5.8 GHz band (5725 to 5875 MHz) is also available for ISM (unlicensed) use, it's not clear to me at what point I need a license to…
Nick T
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Does a low amount of atmospheric noise reliably indicate a lack of propagation?

We know that the primary source of interference at HF is atmospheric noise. Thus, all else being equal, the strength of heard noise is a fair indicator of RX system performance (such as in adjusting an antenna tuner for maximum noise while…
Kevin Reid AG6YO
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Dipole versus ungrounded end fed for HF RX

I've built a 2 meter ground plane antenna that works pretty well for RX and has a decent SWR on 2 meters with my Alinco. However, I'm experimenting with SDR quite a bit and would really like to build something for weak signals, especially CW and…
David Hoelzer
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Decoding weak APRS signals

I've recently started looking into APRS, and can easily receive some APRS signals from my station - however, I can't seem to decode them using QTMM or any similar software. Is this because they're too weak / noisy, or am I doing something else…
berry120
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