Amateur Radio Stack Exchange
Amateur Radio Stack Exchange

Questions tagged [qrp]

Low power operation, Typically 5 watts or less

28 questions
11
votes
6 answers

Practical limits to maintaining coherence in an HF channel

Lately I've been thinking about weak signal communication on HF. Very weak, like weaker than even WSPR could achieve. It would be nice if one could simply take any existing modulation and slow it down to achieve an arbitrarily high Eb/N0 and thus,…
Phil Frost - W8II
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1 answer

Is there anything special about 4.9152 MHz intermediate frequency?

I noticed that there are several QRP transceivers that use 4.9152 MHz intermediate frequency. For instance, John Dillon, WA3RNC uses it in Penntek TR-25, TR-35 and TR-45 transceivers. Also a very close frequency (4.914 MHz) is used in Elecraft…
Aleksander Alekseev - R2AUK
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8
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2 answers

New operator struggling to make a contact

I got licensed a couple of weeks ago and after making 4 attempts on different days, I have made no contacts on SSB, only FT8. What I have (done): Xiegu x6100; tried 5W and 10W Par EndFedz® EFT-10/20/40 Trail Friendly antenna Antenna deployed as a…
Amanda Helgström
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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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6
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5 answers

Are QRP transceivers only meant for CW communication?

I was just thinking about making a QRP transceiver, but are they only used for CW (Morse code) communication? If it is so, can I modify a QRP for two way audio communication?
Sumithran
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4
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1 answer

Really a Class C design?

In the March 2000 QST there was an article on the Tuna Tin QRP transmitter, which I thought I might build: The text describes Q2 as a C Class amplifier, but I just can't see how that can be true. "It's ouput (of Q1) tickles the base of Q2 (lightly)…
Ian_B
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4
votes
1 answer

no contacts with Rockmite

I finished building my Rockmite ][. It's running off of 3x 18650s, or 12v. I connected it to a MFJ-1840T and held the antenna horizontally in the air (also tried vertically) with my hand. I tried calling clean CQ on 7.030 mHz and get no response. I…
mh00h
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4
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2 answers

What is the minimum equipment necessary to get on the air with FT8?

To the extent that FT8 is a way to bring people into the hobby or re-ignite passion among those who haven't been on the air in a while, what's the easiest way to get someone on the air with this new mode? Cost is a factor, but simplicity of…
bcattle
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4
votes
6 answers

Tune a very short 3-5m random wire for 40m (around 7.030 MHz) for listening or occasional QRP CW sending

I would like to use a small trx first for listening CW on 7030 kHz and then for transmitting, locally, among friends. My conditions are "prohibitive" as for antennas: a block of flats, 4th floor in 8 floor building. Among other blocks of flats.…
Jacek Kotowski
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3
votes
1 answer

Using crocodile clips to make modular QRP antennas? Are there downsides?

I'm trying to get into backpacking QRP, which has lead me to read up on various ways to construct very portable wire antennas. I would ideally like to have a single antenna for the CW parts of the 40, 30 and 20 m bands, while avoiding having to…
EdvinW
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3
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1 answer

Output impedance of TAPR QRPi?

I'm a newly licensed amateur and have decided to start out by trying WSPR on a Raspberry Pi equipped with TAPR's 20m QRPi. The QRPi write-ups I've read always talk about long wire antennas but I'd like to try to connect it to my Elecraft AX1. But I…
Bezewy
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3
votes
4 answers

How do homebuilders find an audience to distribute kits to?

Many (QRP) homebuilders offer their projects as kits. A popular series nowadays is the BITX. There are often mailing lists connected to those projects; I am a member of several. I'm wondering how these communities come into being. Should I have an…
user885
2
votes
1 answer

How does this Pixie circuit produce a beat frequency?

I have two Chinese Pixie kits that I've assembled. I think they are pretty interesting, from a QRP / tinkering stand-point. Looking at the schematic below, where is the beat frequency coming from? I know Q1 is part of the crystal oscillator and Q2…
Will B - AF7EC
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2 answers

Can I convert an inline 1:1 CMC into a balun feed for a dipole?

I built my first 1:1 CMC transformer recently using 100 ohm CAT5e pairs in parallel. I used an FT-114-43 with 9 turns on each side and squeezed it into a small box with female coax connectors. I plan to use this only with 5 W QRP radio. The SWR with…
wbg
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1 answer

Will using a loaded coil antennas have detrimental effects on QRP operations?

I was looking for a 40 m antenna for QRP CW operation at 3 W. I looked at the Wolf river coil which is a nice portable antenna. From speaking with other hams they mentioned loaded coils are poor for QRP operations and told me to DIY a quarter wave…
rsn
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