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1500 questions
7
votes
3 answers
Passively reducing ground loss?
Would a disconnected wire or conductive mat below a low height antenna reduce ground losses?
A tuned length of wire under a wire antenna might be suitable for NVIS gain. But would a bunch of space blankets or unconnected random length wires or mesh…
hotpaw2
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7
votes
2 answers
Double power-handling ability of RF amplifier output transformer
I want to base the output network for a 500W push-pull HF amplifier on "A 250W Broadband Linear Amplifier" described in Chapter 17 of the 2014 ARRL Handbook. I need advice on whether and/or how the 1:4 impedance step-up transmission line transformer…
Brian K1LI
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7
votes
2 answers
Configuring an SDR for CW?
So I'm developing my own SDR software from scratch (I like to "own" the code). The channel between the RF-to-USB hardware and the software is 192kHz sample-rate IQ audio samples. The degrees of freedom seem to include at least 4 frequencies and a…
hotpaw2
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7
votes
7 answers
Is it practical to use a slug-tuned variable inductor in an antenna matcher (aka "antenna tuner")?
I will soon need an antenna impedance match (aka "antenna tuner"), because I'll initially only have a single antenna for my HF rig (needs to cover 80m, 40m, 20m, 15m, and 10m). Obviously, in order to manage SWR, I'll need a matching network, quite…
Zeiss Ikon
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7
votes
5 answers
Is a 5 watt UHF/VHF handheld considered QRP?
QRP doesn't have a strict definition, though 5W or less seems to be a common threshold. So would "QRP operation" usually be considered to include UHF/VHF handhelds?
Phil Frost - W8II
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7
votes
2 answers
distance between shack and antenna
I am putting a 40m antenna in my attic and I was wondering would it be safe to have a shack in the room right below the attic (10ft of coax or less) or should I have my shack in the basement/ground level (50ft coax).
Are there any health effects of…
Bogdan YU2DBC
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7
votes
4 answers
Antenna options for a 10x20m property with a large metal roof?
I live in a house that sits in the middle of the city, in a lot 10x20m in size.
The first 6x10m are covered by a metal roof with a rather low angle (IIRC only 50cm difference between the highest and lowest point). The rest is concrete roofing.
I…
hjf
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7
votes
2 answers
What are the official Baofeng websites in the USA?
Which Baofeng website(s) in the USA is (are) official (that is, selling genuine Baofeng radios, programming cables, and accessories)?
Which "Baofeng" websites are NOT, allegedly selling counterfeit radios and programming cables?
A Google search…
Mike Waters
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7
votes
1 answer
Signing of messages transmitted over ham radio
FCC Regulation 97.113 (a) 4 states that:
"messages encoded for the purpose of obscuring their meaning"
Are "Prohibited transmissions", I believe this is the clause that is used to prohibit encryption over ham radios.
Are there any other clauses that…
DavidT
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7
votes
1 answer
How does aluminum siding on a house affect an inverted-vee antenna next to it?
My two-storey house is wood with alumninum siding. I had wanted to install an inverted-vee antenna with its midpoint hanging from the eave, and endpoints near the ground, but this would place the wire of the antenna about a foot from the siding. …
Cyberherbalist
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7
votes
1 answer
What happens to your callsign if you migrate?
If, as an amateur radio operator, you're licensed in one country with a callsign, let's suppose, the US and you migrate to, say, Germany, will you have to reapply and obtain a new callsign?
What if your migration is temporary, and you're only…
Amin Shah Gilani
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7
votes
3 answers
Long range communication with just 1W of power?
Is it possible, and how can I setup communication between stations 1000km apart from each other by using just 1W of transmission power?
By communication, I mean:
It can be text based
It can be very slow. It's okay if I receive a small message in…
Akshit Mehra
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7
votes
2 answers
Water cooling a GS-35B in lieu of air cooling?
Does anyone know how to --or have any experience with-- water or oil-cooling the anode? Since forced-air cooling is required, the sound from the blower and the exhaust air would be too noisy for my ears.
They look similar to an 8877, but have…
Mike Waters
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7
votes
1 answer
How to determine number of turns for a 1:1 balun?
I would like to make a 1:1 balun with М1000НМ ferrite core (magnetic permeability - 1000) and 1 mm thick copper wire using triple bifilar winding. Unfortunately I didn't manage to find a clear instruction on how to determine the required number of…
Aleksander Alekseev - R2AUK
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7
votes
8 answers
Does a 1/2 wavelength end-fed antenna need a good RF ground?
I was searching for DIY end-fed antenna.
Some of the articles I found say that for a 1/2 wavelength end-fed I need a "small to no counterpoise" (with a lambda*0.05 m counterpoise), but some other articles say that I need "a good RF ground in close…
Hose Dias
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