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1500 questions
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2 answers

Measuring actual feedpoint impedance for a given frequency

Background I'm attempting to tune an antenna with my NanoVNAv2. I calibrated it using the included open/short/(50-ohm)load standards by screwing them directly onto the NanoVNA one by one and running its calibration function. The antenna itself is a…
Bitbang3r
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Building Antenna Trap: Highest impedance/lowest capacitance/greatest # of turns?

I made my first multi band antenna this weekend for 20 and 15 meters for an EFHW wire with a 49:1 unun, to be used with 5 W rig. I used a toroid I had on hand, T80-2. I hang this antenna in my living room as an inverted L. It's far from an ideal…
wbg
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How can I decode an AFSK 1200 baud audio clip? (ISS)

I'm a new ham. The past few days, I've had a few nearby passes of the International Space Station. As it was going overhead, I managed to record what I believe to be 1200 baud AFSK transmissions from it (AX.25) - from it's 145.825MHz Packet Radio…
Brad
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Parameters needed to calculate inductor value to achieve proper phase delay?

I'm thinking about trying a coil in my collinear 5/8λ antenna, instead of the 3/8λ phasing delay line between the lower and upper elements pictured below. I figure that a coil with a certain inductance could give me a current delay of nearly 90° and…
Louis Seaman
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Why am I hearing FM radio show content on 1.355 MHz? (Using CubicSDR and SDR kit)

I am just beginning to learn about SDR. I purchased a "NooElec NESDR Mini 2 SDR & DVB-T USB Stick (RTL2832 + R820T2) with Antenna and Remote Control" I plugged it into my Mac, downloaded CubicSDR, and was quickly able to listen to local FM radio…
Jack Amoratis
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Antenna grounding / bonding in relation to my AC service (with pictures)

I'm trying to figure out how to properly connect new ground rods for an antenna to my main panel. Any advice from those who have done this + have great electrical knowledge would be greatly appreciated. I plan on hanging a dipole from a tree near…
kr4sh
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How do businesses develop and test amateur radio products in the US if you cannot be paid for amateur radio use?

Certainly there are companies in the US (like Kenwood) that develop HAM products that transmit. For development and QA they would likely need to test the product outside of a Faraday cage. How can companies test those products in the HAM bands if…
KJ7LNW
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Can I use my CB mobile antenna with a 10 meter radio also?

I have a mobile mounted CB antenna that has an SWR of 1.5 on channel 20. Is it possible to use it with a 10 meter radio? I do not have enough room on my car for an additional antenna, so if it is possible to use my CB antenna for 10 meters, that…
diodes123
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Can a regen receiver be used as a CW transceiver?

I've looked for a while, but I've never found a design like what I imagine: a single-tube (valve) regen CW transceiver (no cheating with a tube/valve that has two or more triodes/tetrodes/pentodes in a single envelope). The way I imagine this…
Zeiss Ikon
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Can I ignore the radial elements of a 2m/70cm antenna if it's on a metal roof?

I'm looking for a dual band base station antenna, and find that many of them have short radials around the base. Due to the specifics of my installation, I need to remove them. However, it is being mounted in a way that the antenna penetrates the…
Adam Davis
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How to correctly model a small helix antenna

I am getting weird results trying to model a small 433 MHz helix antenna similar to this one with 4nec2: In particular I am not able to obtain a resonable SWR value. This is the antenna an example of the nec file. CE SY L=0.0205 'Length of helix SY…
stenio
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How do you log (or not) "busted" FT8 QSOs?

When do you decide (when NOT in a contest) to log an "incomplete" FT8 QSO? For example, something like this: CQ HIMHIM EM00 HIMHIM MEMEME FN00 MEMEME HIMHIM -07 HIMHIM MEMEME R-09 HIMHIM MEMEME R-09 HIMHIM MEMEME R-09 (and then both sides…
QuantumMechanic
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How to apply for the ARRL WAC award?

I've managed (thank you FT8!) to have LOTW-confirmed contacts with the 6 applicable continents. However, on reading the ARRL page for the WAC award it says that you have to apply on paper and that LOTW contacts do not count but contacts in your DXCC…
QuantumMechanic
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SSB Single Conversion Superhet 2nd Mixer IF Termination on Transmit

I have a question about "best practice" in regards to how the 2nd mixer IF port is coupled to (in my case) a 20m double tuned filter on transmit. I'm currently building out the transmit chain for a 20m single band SSB transceiver and I've got as far…
Buck8pe
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Mounting a hex beam on top of a high urban building

I am moving into a new apartment in the city soon which is on the 24th and last floor of an apartment building. I will have access to the roof of the building also. I'm still trying to understand antenna theory fully. I am very tempted to buy one of…
Engineer999
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