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9 votes

What is an undulator (as used for CW)?

Since I can't answer this authoratively myself, but Mike Waters' comments indicate that search engine results of other people might be sparser than mine: A link collection: Title/Link Short ...
Marcus Müller's user avatar
4 votes

Advice on keyer: two paddle on old Kenwood with 'straight key' only

In my experience radios are generally keyed by grounding the tip of the key jack. The tip will be pulled high by a resistor inside the radio, to 12 V or maybe 5 V. Other arrangements are possible; I'...
tomnexus's user avatar
  • 11.5k
4 votes

Will a LPF filter on the transmitter prevent CW key clicks?

No, the key clicks, just like any form of AM, are carried in sidebands that are close to the carrier frequency. The type of LPF you're talking about will have no effect on them. To eliminate key ...
Dave Tweed N3AOA's user avatar
4 votes

What are the electrical properties and connectors of a CW key?

Is a key simply a normally open SPST push button switch? Yes - if you're thinking of a simple hand-operated key. Does one end need to be connected to ground? (I believe that is the common usage - is ...
glen_geek's user avatar
  • 1,001
3 votes

What is an undulator (as used for CW)?

an "undulator" used for CW reception circa before and during WWII. WWII? My then employer still had a Marconi UG-6 undulator in our radio lab in the mid-1980s. While Marcus Müller has ...
Graham G8URP's user avatar
1 vote

Configuring an antenna for (short distance) ground wave propagation on 40 m?

A dipole is not very portable, nor "small", if by that you mean, small area needed for deployment. A vertical, would be the most space efficient, requiring only one anchor point, 20M or so, ...
Louis Seaman's user avatar
  • 1,127
1 vote
Accepted

Will a LPF filter on the transmitter prevent CW key clicks?

To extend on Dave's excellent point. Take this (simplified) block diagram of the minimum CW transmitter: I'll just give names like $m(t)$, $s(t)$ and $c(t)$ to signals in your CW transmitter, so that ...
Marcus Müller's user avatar
1 vote

Help implementing a custom signal source in GNURadio for FMCW

Don't reinvent the wheel – just use a "Signal Source" configured to emit a sawtooth wave, use a "Multiply" block to multiply it with itself and thus square it, and use that as ...
Marcus Müller's user avatar
1 vote

POTA and SOTA Spotting networks?

I've been a fairly active POTA hunter, though not yet an activator, and so I use the POTA.app spots page. This updated in two general ways. The first is by manual spots. A park activator can (and ...
Don Levey's user avatar

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