Search found 55 matches

by franko
Thu Jan 31, 2019 8:05 pm
Forum: SDR Antennas
Topic: Antenna for LW
Replies: 13
Views: 9053

Re: Antenna for LW

Anytime thunderstorm activity is low. late summer, autumn and winter seem to be the best here in the eastern US. The QRN from lightning activity can travel great distances at longwave frequencies. You mentioned WSPR in your last post. I tried it out last light, heard several hams in Arizona and New...
by franko
Tue Jan 29, 2019 5:24 pm
Forum: SDR Antennas
Topic: Antenna for LW
Replies: 13
Views: 9053

Re: Antenna for LW

Overwhelmingly NDB's (Non directional beacons). You can investigate for yourself with the Maritime Radio Historical Society's low band KIwi SDR at http://198.40.45.23:8072/ It is connected to a Marconit T antenna. I could only find 4 active NDB's in California in the ClassAxe database. Thanks, I'll...
by franko
Tue Jan 29, 2019 6:51 am
Forum: SDR Antennas
Topic: Antenna for LW
Replies: 13
Views: 9053

Re: Antenna for LW

Better hurry, long wave season will end soon. Can you say anything more about what you hear, and when during the year you hear it? I'm unable to hear anything on LW due to very strong local MW broadcast interference, but am in the process of obtaining a low-pass filter. Interested in what might be ...
by franko
Sun Jan 20, 2019 5:28 pm
Forum: SDR Antennas
Topic: 60v p-p rf
Replies: 11
Views: 5847

Re: 60v p-p rf

I used the scope input and the antenna is a 900 ft wire grounded far end at lake, between 5 and 20 feet high, running approximately northwest. Like any loop its directional. About 3k ohm at MF/LF. DC loop resistance s about 50 ohm, mostly from wire, .03 aluminum welding wire. I have ground stakes a...
by franko
Sat Jan 19, 2019 8:17 pm
Forum: SDR Antennas
Topic: 60v p-p rf
Replies: 11
Views: 5847

Re: 60v p-p rf

I put a scope on my long antenna and it reads 60 volts peak to peak RF from local AM stations. As a new oscilloscope owner, I'm curious about the details of how you hooked this up. I know my scope has 1-megohm inputs, so for most RF devices including my antennas it's necessary to add a 50-ohm feed-...
by franko
Mon Jan 14, 2019 8:44 pm
Forum: General
Topic: Transmit-receive switches
Replies: 1
Views: 1452

Transmit-receive switches

The adjacent thread "MFJ-1708B-T/R Switch Experiences" reminded me of a question I wanted to ask, but I thought it might be clearest to post a new thread rather than tag on to that one. Currently I have two SDRplay RSPduo units running continuously, each attached to its own magnetic loop antenna. I'...
by franko
Sat Jan 12, 2019 7:53 pm
Forum: SDR Antennas
Topic: Loop antenna for SDR question
Replies: 5
Views: 4900

Re: Loop antenna for SDR question

Sorry for chiming in on the late side, but I have a Wellbrook ALA1530LNP loop antenna as well as a W6LVP loop. I've done a fair amount of side-by-side comparison with each connected to a separate SDRplay RSPduo, with them running simultaneously and monitoring the same HF FT8 band. Because of a stron...
by franko
Sun Nov 18, 2018 8:05 pm
Forum: SDRplay related
Topic: Safe distance between RSPduos and a low-power WSPR transmitter?
Replies: 2
Views: 2216

Re: Safe distance between RSPduos and a low-power WSPR transmitter?

Thanks, Roger. From the documentation it appears that the WSPR transmitter's power output can be set at custom levels using the configuration software -- I'll check that out further. Regarding RF limiters, I saw the following item mentioned here or in one of the other SDRplay discussion sites a few ...
by franko
Sat Nov 17, 2018 8:36 pm
Forum: SDRplay related
Topic: Safe distance between RSPduos and a low-power WSPR transmitter?
Replies: 2
Views: 2216

Safe distance between RSPduos and a low-power WSPR transmitter?

I have two RSPduo's with several virtual receivers each running 24/7 to monitor a number of HF FT8 bands. One is connected to a Wellbrook ALA1530LNP magnetic loop antenna, the other to a W6LVP magnetic loop antenna. Later today I'll be receiving one of these WSPR transmitters: https://www.zachtek.co...
by franko
Tue Oct 23, 2018 4:59 pm
Forum: SDRuno
Topic: Why are these SDRUno instances performing so differently?
Replies: 9
Views: 4411

Re: Why are these SDRUno instances performing so differently?

Hi Roger, this sounds a little like the diversity mode offered in some transceivers, where the radio makes use of two separate antennas to increase its ability to pull weak signals out of noise. I wonder if there is (or will ever be) a way to do that in SDRUno or other software making use of more th...