Newest Questions
4,998 questions
1
vote
1
answer
88
views
How to match 5w radio output to 0.005 watt input on amplifier
Found a 50-ish watt amplifier kit online that looked like a good challenging build.
It says it provides 40dB of gain, and specifies maximum input power of 0.005 watts.
The candidate radio I'd like to ...
- 111
0
votes
0
answers
31
views
Hopelessly Lost on BFO Island
I am picking up some low ssb somewhere I think on the 160meter band (1800 -2000 khz) on one of my homebrews. I can also pick up much higher ssb bands, but this low stuff I was concerned because I ...
0
votes
2
answers
52
views
Capacitance between two parallel wires with a cylinder of a dielectric added
A open twin feeder or a Lecher line is two parallel wires, both the inductance per meter and the capacitance per meter affect the impedance and the velocity factor of the line. While the polythene of ...
- 151
1
vote
1
answer
73
views
Reverse protection for PA
I am designing an RF transceiver for TX RX at 435MHz. I have the module working fine without any issues with PA TX at 2W.
The only issue is the reverse power from the antenna if both units are placed ...
- 69
3
votes
2
answers
433
views
Is this an unintended short circuit in my Moonraker GPA-80F vertical HF antenna?
I'm a newly licensed ham and purchased this Moonraker antenna from DX Engineering as my first HF antenna.
I noticed that there is continuity between the inside and outside of the SO-239 connector at ...
- 133
3
votes
4
answers
185
views
dBi gain of random wire antennas
All antennas are a compromise. Are there any antennas that in free space perform strictly worse than an isotropic antenna would? Or a simple flat ground model?
This is what has been bugging me. I am a ...
- 131
1
vote
0
answers
77
views
Help Identifying RF Data Protocol
I hope this is the correct place to ask. At my university, we've been picking up some strange transmissions on 146.66625 MHz in the engineering buildings. The noise persists at nearly full strength ...
- 11
1
vote
1
answer
89
views
Dual-watch implementation
I would like to know if there is an implementation of dual-watch (AKA split mode?, tri-watch in some brands) more extended than others, for both station equipment and ht, in case they differ. I'm ...
- 133
2
votes
1
answer
57
views
What is the authentication response algorithm in Winlink protocol?
I am writing a program that should integrate a Winlink client. All elements of the protocol used in Winlink network seem to be described well, but I cannot find the algorithm to calculate ...
0
votes
1
answer
63
views
Receiving P25 on a Ham Rig
I found this question: Receiving commercial / public-safety on a general-coverage HAM transceiver that has the same topic, but it's from 9 years ago and doesn't answer my question. I have an Icom IC-...
- 949
0
votes
2
answers
89
views
Converting mobile radio to portable use -- Will any whip antenna work?
I'm still a newbie amateur radio licencee (but slightly less newbie than before).
I have the AnyTone 578UVIII PLUS Tri-Band Mobile Radio
I'm seeking to make it into a portable use-out-of-a-bag radio ...
- 105
0
votes
1
answer
77
views
Yagi antenna design fails with short dipole elements – why?
I am trying to design a directional antenna with compact dimensions and considered using a Yagi antenna with a short length ($l < λ/4$). I ran an optimization algorithm in Matlab, where I maximized ...
- 11
0
votes
1
answer
52
views
Is my backup battery charged? Using my battery meter, how can I know?
I'm still a newbie amateur radio licencee (but slightly less newbie than before).
I have the AnyTone 578UVIII PLUS Tri-Band Mobile Radio and I use the DuraComm power supply unit from an accessory ...
- 105
0
votes
1
answer
77
views
Antenna matching for a dipole
I am working on a research project involving antenna design for a HAM payload on a deployable drone. The drone includes a deployable dipole antenna. After antenna deployment, the dipole antenna spans ...
- 69
4
votes
3
answers
163
views
Does a transceiver radio have a "receiving range"?
I'm familiar with the fact that a transceiver radio has an effective transmission range that is affected by several factors, such as the antenna, transmit power, obstacles, etc. I'm wondering if a ...
