Search found 238 matches

by g1hbe
Tue Oct 24, 2017 11:31 am
Forum: General
Topic: Another odd signal (or signal-like phenomenon)
Replies: 4
Views: 484

Re: Another odd signal (or signal-like phenomenon)

The magic of SDR that you can see these things as well as hear them. Indeed. On a conventional receiver, you'd just hear a 'blip' as the signal passed through the passband, but on a waterfall you can see what it really happening. You can also see all the image responses and other spurii of your rec...
by g1hbe
Sat Oct 21, 2017 11:47 am
Forum: General
Topic: Odd signals and other unusual patterns
Replies: 9
Views: 662

Re: Odd signals and other unusual patterns

That pattern of spikes looks like the type of buzz I get from a nearby plasma TV. If you listen in AM you may hear a sharp buzzing sound.
by g1hbe
Wed Oct 18, 2017 3:01 pm
Forum: General
Topic: SAM mode
Replies: 3
Views: 476

Re: SAM mode

It works reliably here. One mistake people make is to have the tuned frequency and the LO frequency the same, which corrupts the signal. The other possibility is that the signal is fading in and out and the sync is lost.
by g1hbe
Tue Oct 17, 2017 8:46 am
Forum: SDRuno
Topic: SDRuno RSP2pro Frequency entry problem
Replies: 2
Views: 244

Re: SDRuno RSP2pro Frequency entry problem

Surely there can be only one decimal point? For instance 150.123456 MHz doesn't need any more points , it is correct as it stands. Sorry if I am misunderstanding.
by g1hbe
Mon Oct 16, 2017 8:28 am
Forum: SDRuno
Topic: Excessive CPU usage
Replies: 4
Views: 694

Re: Excessive CPU usage

A couple of years ago my Win7 laptop started doing this. It would start up fine but within a few moments everything was running slowly and it was also running hot. To cut a very long story short, it turned out to be a well-known W7 bug which caused the PC to constantly search for updates. The cure w...
by g1hbe
Sat Oct 07, 2017 10:40 am
Forum: General
Topic: RSP2 Band Pass not working?
Replies: 5
Views: 667

Re: RSP2 Band Pass not working?

It's also worth bearing in mind that the noise floor of the 8 bit dongles is much higher than the 12-bit SDRPlay. The dynamic range of a cheap dongle will be around 48 dB, whereas the SDRPlay will manage 72 dB. The ghost signals may well be there on your RTL dongle, but the poor dynamic range is hid...
by g1hbe
Fri Oct 06, 2017 6:04 pm
Forum: SDR Antennas
Topic: Antenna's
Replies: 4
Views: 1050

Re: Antenna's

There's no DC present on the output of the interface boxes that come with active antennas. There's a DC blocking capacitor that stops any voltage appearing there.
by g1hbe
Thu Oct 05, 2017 4:12 pm
Forum: SDRuno
Topic: Antenna Length.
Replies: 2
Views: 491

Re: Antenna Length.

The wavelength at 1000 MHz (near enough) is 30 cm. For a quarter-wave groundplane, the length of the vertical element would be 30/4 = 7.5 cm. For a dipole, each leg would be 7.5 cm.
by g1hbe
Tue Sep 26, 2017 9:14 pm
Forum: New Users' experiences
Topic: RSP-2 with TS590SG
Replies: 7
Views: 793

Re: RSP-2 with TS590SG

I would say it's normal to see a strong signal on your TX frequency. If you have 100 watts going out and a sensitive receiver at the same location (even without an antenna connected), I'd say it was inevitable. I can't explain why you saw no signal before though.
by g1hbe
Mon Sep 25, 2017 11:14 pm
Forum: SDRplay related
Topic: RSP-1 as a bat receiver?
Replies: 3
Views: 697

Re: RSP-1 as a bat receiver?

I've built a few bat detectors and the difficulty is always the transducer. Some electret mics will reach up to about 20+KHz but most bats operate above this. Then there are the cheap 40KHz transducers that work well but their response is quite narrowband and they only pick up in the range of maybe ...

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