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1500 questions
9
votes
1 answer
Help understanding path taken by APRS packet
I'm looking at some raw APRS packets over APRS-IS. I'd like to determine which stations heard particular packets, but I'm having trouble understanding how TNC-2 paths work. Here are two examples:
2016-05-19 05:51:46 PDT:…
watkipet
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What is the largest gauge (thinnest diametre) wire I may use as an antenna?
A follow-up to Good wire for wire antenna?
I'm QRT at present - thanks to fooling around with just a couple of diodes and PVC capacitors instead of a well-regulated supply. The antenna I used earlier was a mono-bander inverted-vee for 20M. I may be…
VU2NHW
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9
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1 answer
What's this "crossover" toroid winding called and what is its purpose?
I am winding an EFHW matchbox and many of the designs I've found (including the diagram provided with the kit I bought) include a sort of "twist" when winding them:
(Image taken from this post and similar can be seen here and here and here.)
My…
natevw - AF7TB
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9
votes
1 answer
How do I know if my dummy load is working?
I understand why a dummy load is used, but (aside from it getting hot) how do I know if it's doing it's job and doing it's job well?
In my specific case, I'm using a Hack RF One SDR and a Souked SMA Dummy Load 50 Ohm.
M6JNY
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9
votes
1 answer
Digital-mode signal reports
When operating analog voice, we give a qualitative (or possibly just arbitrary) signal report, 'scoring' the signal either out of a maximum 'five by five', or a maximum '599'. How do you report the quality of the received signal when using digital…
Dan KD2EE
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9
votes
3 answers
Can cellular radio be used for communication with a balloon?
(Sorry, I don't know if this is the right forum for this question, but maybe someone will know the answer. If not, which StackExchange forum could be more suitable?)
Me and a few friends of mine are planning to build a remote controlled balloon…
ruthra
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9
votes
3 answers
Drones for lifting verticals?
I would like to lift a 5/8 wave wire vertical for 160m, using a drone, over my lovely saltwater swamp. The thing must be powered from the ground, capable of being left aloft for a couple of hours while I work DX, and capable of hovering in position…
VE6MRV
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9
votes
1 answer
Can two diodes be parallelled in RB to get double the capacitance?
It's a fact of life that air-gang capacitors, are increasingly more difficult to come by - having been superseded by the far more compact varactor diodes.
My part of the world components such as the venerable BB212, MPN3700, MV1662 are almost…
VU2NHW
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9
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1 answer
Why bother to have a high power base station when mobile units are generally low-power?
I want to find out why, say in a GSM/cellular system, a base station can be up to 50 watts however the mobile units can be only 100mw (for example).
Surely if the base station ever uses 50w to reach a mobile at long range, the mobile will have no…
code_fodder
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9
votes
1 answer
What is the correct procedure to beam long-path?
I'm new to directional beam antennas, and saw that K9W Wake Island DXpedition was working 10 meters "long-path" at 1230z, or 6:30a.m. in Texas. This was late enough for the sun to be coming up, but is it even possible to make the "long path"…
Bill - K5WL
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9
votes
2 answers
Marine VHF whip antennae - what are they?
For marine VHF (156~162 MHz), the most commonly used antenna is a 1/2-wave dipole or a collinear array in the form of a fibreglass rod. Collinear arrays are used to increase gain in some antennas. Dipoles/collinear arrays by their nature do not need…
user5314
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9
votes
3 answers
How would I modify a satellite dish to transmit and/or receive to a Baofeng UV-5r plus? ( A handheld transceiver) If it's possible
I have an old satellite dish just lying around and was wondering how to hook it up to my baofeng uv-5r plus.
Sudo_Cats
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9
votes
3 answers
Baofeng low power mod
I have a few baofeng UV5R handhelds sitting around that only transmit, the receiver is damaged.
What I would like to do with these is build a foxhunt transmitter. Sure, I could set it to low power (1 watt) and put it through a less efficient…
Skyler 440
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9
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1 answer
Is a modded Yaesu FT-270r acceptable to use on MURS frequencies?
I am a bit new to the radio scene, so excuse me for any ignorance that may follow.
I saw on a website that you could mod the Yaesu FT-270r so that you can increase its transmission range outside of 144 MHz. I have no plans on transmitting outside of…
RailfanCJ
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9
votes
4 answers
What does a SSB signal look like?
I don't really get it. How is it possible to just send upper or lower side of a band (SSB USB/LSB):
And how is it possible to send anything without the carrier wave!
If I have misunderstood anything I am sorry because I am new to this and would…
Axel
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