Unanswered Questions
14
votes
4answers
3k views
What is the cause of this unusually long period of terrible HF band conditions?
I've been a ham for over 40 years, but never has there been such a prolonged period of such poor propagation. This has been especially the case over the past six months or so, and they continue to ...
11
votes
2answers
688 views
How do I receive ATV with GNU Radio?
How do I receive Amateur television (ATV) — e.g., NTSC in the U.S. — with GNU Radio so I can play the A/V in, e.g., the VLC video player? Are there any example GNU Radio block diagrams to accomplish ...
8
votes
0answers
132 views
How can I do direct digital synthesis of a 630m WSPR signal?
I want to do direct digital synthesis of a 630m band WSPR signal.
Specifically I'd like to use an Atmega 328 chip running at 20 MHz to produce such a signal.
I will use standard phase accumulator ...
6
votes
0answers
104 views
Rolling QRM from 3000-10000 kHz - What Is It?
Video
I was lucky to catch the QRM start this morning @ approximately 10 AM Pacific Standard time. It was wide, starting around 3000 kHz up to 10000 kHz.
It starts fast then slows to a crawl. The ...
6
votes
1answer
144 views
How terminate RG8 coaxial cable using PL259 (UHF) - screw - gasket - solder type?
Today I came across a problem in terminating RG8 cable using this PL259 plug.
I have never had this type and it arrived in a pile of parts; I have tried to puzzle it together but without positive ...
5
votes
0answers
153 views
ISS APRS Digipeater with Kam XL and ICOM IC-910H
I am trying to use the ISS APRS digipeater which transmits at 437.55MHz.
Hardware setup consists of the following
ICOM IC-910H.
The transceiver has been connected to a Windows PC running a HAM ...
5
votes
1answer
529 views
Doppler Shift Compensation in Inter Satellite Communication
I am currently doing a project in the area of optical inter-satellite communication (GEO-LEO).
I am using a optical carrier of 281 THz, and the Doppler shift corresponding to it is ±7 GHz. I ...
3
votes
1answer
34 views
FM spectral amplitudes during silence
General setting
I'm playing around with an RTL-SDR and recently captured some FM spectrum in Hannover, Germany. I want to undersand what's going on, so I've read a lot about FM and its spectra, but I ...
3
votes
0answers
471 views
OFDM spectrum, HACKRF, and GNUradio companion
I am trying to analyze the spectrum of wifi spectrum.
I getting a good OFDM spectrum with my HackRF at 2.412 GHz (from my first QTGUI Sink).
But I get nothing out of OFDM Receiver. I was wondering ...
3
votes
1answer
188 views
Warbler vs SoundModem
I'm trying to decode a BPSK 1200 (with no success). In this endeavor I tried both SoundModem and Warbler.
The scenario here is the following: Ettus receiver + HDSDR with speaker plugged into mic via ...
3
votes
0answers
71 views
Calculating effective SSN (sunspot number)?
I am doing research on how SSN-like parameters affect HF radio signals. As I can see, effective SSN is a parameter that is derived from SSN or using other parameters. Does anyone know how to calculate ...
3
votes
0answers
815 views
TS-590 Antenna Tuner Protocol
I'm looking for the protocol used by Kenwood's TS-590S antenna tuner port. I've worked as far as I can with Kenwood's tech support. They know what the pins are labeled, but don't have any information ...
3
votes
0answers
61 views
CML FX919B Forward Error Correcting
I would like to decode de-interleaved demodulated 4FSK symbols that were transmitted using the CML FX919B chip.
The datasheet only gives the following information:
Forward Error Correction In ...
2
votes
0answers
33 views
SNR measurement for a BPSK/QPSK signal
I have created a software (gnuradio) that performs modulation/demodulation and supports a number of modulation schemes and error correcting codes. I'm in the process of evaluating the BER vs SNR for ...
2
votes
0answers
67 views
Restoring full output power to rig with tube finals
I have a TS-830S that was initially doing about 60W in CW at 10m and 70W at 40m. I've heard these things are capable of at least 100W.
Determined, I started doing research on what components to look ...
