Most Popular
1500 questions
9
votes
4 answers
Why are there differences in antennas that depend on electrical component and magnetic component of a radio wave?
I understand the idea that when we are targeting the electrical component of the radio waves we need to have some form of a linear conductor that receives the electrical component, this creates a current in the circuit and thus induces a signal.…
Bartha
- 169
- 1
- 8
9
votes
3 answers
Why does "Ethics and Operating Procedures" suggest tuning on a dummy load?
The seminal work "Ethics and Operating Procedures for the Radio Amateur" suggests in subsection II.8.1 to perform tuning only on a dummy load.
Sometimes before transmitting it is necessary to tune (adjust) the transmitter (or
antenna tuner).…
xmjx
- 203
- 1
- 6
9
votes
1 answer
What does CQ NM mean in FT8?
I saw someone on 20m FT8 this morning calling "CQ NM". What does NM mean in this context? They followed the NM with their call and grid as usual.
xxpor
- 331
- 1
- 7
9
votes
2 answers
How to clean up profanity on airwaves
We have a repeater here in Southern California (Sylmar K6GE 147.435), and no matter what time of day or night there are a great many operators spewing tremendous profanity, disrespect and meanness toward one another. This is embarrassing and makes…
ChiliYago
- 235
- 1
- 3
9
votes
2 answers
What is the purpose of the German CW exam if it is not required to use CW?
To receive the amateur radio license Klasse A (HAREC) in Germany it is since 2005 not required anymore to pass a CW exam, due to a corresponding change in the Radio Regulations. However, the exam is still available as a voluntary addition to Klasse…
DK2AX
- 624
- 5
- 13
9
votes
2 answers
What are some ways to ground a transmitter+antenna in an enclosed attic?
If I want to minimize "RF in the shack" and lightning hazard, what some good ways to ground a transmitter and indoor antenna in a top floor room or attic with no exterior access? (say a multi-story wood-framed building with large non-opening glass…
hotpaw2
- 13,316
- 6
- 45
- 76
9
votes
1 answer
What are the general effects of a geomagnetic storm on propagation?
Per NOAA/NWS Space Weather Prediction Center, "SWPC Forecasters are anticipating G3 (Strong) Geomagnetic Storm conditions to occur January 9 and 10."
What does that mean, very generally, for amateur radio communications? Does it depend on the type…
Adam Davis
- 12,125
- 2
- 47
- 107
9
votes
0 answers
Beyond Maximum Stable Gain of a transistor
I was plotting constant-gain circles on the Smith chart the other day for a potentially unstable RF transistor.
I recently read on-line that for a potentially unstable transistor the maximum gain that can achieved is the MSG or maximum stable gain.…
Thomas L
- 193
- 6
9
votes
3 answers
Is it legal to transmit with HackRF one?
Is it legal to transmit using HackRF one (in Germany), the purpose is to do some Lab research and Academic experiments.
for example i want to broadcast an FM signal using HackRF one and try to receive it using another hardware (RTL-SDR).
If no is…
A.SDR
- 93
- 1
- 4
9
votes
3 answers
What should I put on a QSL card for a repeater contact?
From time to time I'm a new ham's first contact - usually on a repeater. If I want to send the new ham a QSL card, how should I distinguish a repeater contact from a non-repeater contact? Is there a standard?
user3486184
- 1,902
- 13
- 27
9
votes
2 answers
What is the purpose of the transformer at the input (and output) of this RF push-pull amplifier
Firstly, feel free to move this to Electronics SE if it's not on-topic, but it's strongly related to ham radio and RF circuitry.
Reading Hayward's classic "Solid State Design for the Radio Amateur" and looking for inspiration, I came across the…
Buck8pe
- 989
- 5
- 14
9
votes
1 answer
Why are radio frequency ranges aligned on multiples of 3?
Why are the radio bands organized by multiples of three?
For example the HF band is from 3–30MHz and UHF is from 300–3000MHz. Why not multiples of 2? Or plain powers of ten?
natevw - AF7TB
- 7,411
- 2
- 28
- 60
9
votes
5 answers
Wire antenna slightly too long
Say I have a wire antenna that is slightly (a few percent) too long for the desired frequency (of resonance or lowest SWR). What are the options, other than cutting the wire(s) and very likely ending up with an antenna wire that is now too short…
hotpaw2
- 13,316
- 6
- 45
- 76
9
votes
2 answers
Why do the ham radio bands get broader with increasing frequency?
The ham radio frequency allocations tend to comprise a larger frequency range for increasing frequency (also see this plot). For example, the 40 meters band is from 7,0 to 7,2 MHz, thus 200 kHz, while 23 centimeters is from 1240 to 1300 MHz, thus 60…
koalo
- 399
- 1
- 10
9
votes
4 answers
Were there any 6m handhelds produced ever?
Just of curiosity...
Outside of kits/ham produced prototypes, Do you know about any commercially produced 6m handhelds?
Should be technically feasible despite the fact that it would be more cumbersome than VHF / UHF radios, But I recall that CB…
rodv92
- 173
- 1
- 7