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Unanswered Questions

42 questions with no upvoted or accepted answers
14
votes
4answers
5k 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 ...
13
votes
2answers
767 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
148 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 ...
5
votes
0answers
162 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
539 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
0answers
68 views

What is the external mic/speaker pinout for the Yaesu FT-4XR / FT-65R / FT-25R / SSM-16B?

These newer HTs seem to have a different pinout than the older Yaesu HTs. The older HTs used a single 3.5mm TRRS plug - these use a two-plug connector, with a 2.5mm jack and a 3.5mm jack, similar to ...
3
votes
2answers
167 views

LoRa radio transceiver for PtP mesh?

I am very new to general RF/radio in general other than basic WiFi, but I'm looking at the feasibility and cost of a long range (>200M between nodes, sometimes probably 500+M) in flat terrain, ...
3
votes
0answers
513 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
0answers
849 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
63 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
1answer
63 views

How to scan while avoiding digital/noise frequencies?

Is there an established way of scanning frequencies, while avoiding listening to digital signals or static? For example, is there a scanner on the market which will allow you to blacklist a specific ...
2
votes
0answers
29 views

Using an OPC-478 programming cable for CI-V

I have an [clone of] an Icom OPC-478 programming cable for my IC-208H. I thought I read that I can use that same cable to do CI-V with my IC-706 if I can find an 1/8" mono (male) to 1/8" stereo (...
2
votes
0answers
39 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
46 views

UK Foundation Licence holder use of kits

The terms of the foundation licence allow for use of Commercial radios and kits that conform to IR2028. IR2028 basically says that the kits must operate within amateur bands . I cannot find any kit ...
2
votes
0answers
71 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 ...

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