Search found 207 matches

by alanzfq
Wed Jul 28, 2021 7:06 am
Forum: RTL-SDR Discussion
Topic: Weird Direct Sampling VHF Signals
Replies: 1
Views: 62

Re: Weird Direct Sampling VHF Signals

Direct sampling is only for LOW frequencies. Below say 24MHz.
Anything can happen if you tune higher. Do not do it.
Alan
by alanzfq
Thu Jul 01, 2021 7:10 am
Forum: RTL-SDR Discussion
Topic: RF Input DC isolation
Replies: 3
Views: 3559

Re: RF Input DC isolation

As the V3 has a bias T it would be a good idea for you to isolate it yourself.
Alan
by alanzfq
Thu Jun 17, 2021 7:26 am
Forum: RTL-SDR Discussion
Topic: How hot is hot?
Replies: 9
Views: 5486

Re: How hot is hot?

I hope you have now covered the joints in your fan power leads with hot-melt?
When I do something like that they quickly twist together and short:-)
Alan
by alanzfq
Thu Jun 17, 2021 7:21 am
Forum: RTL-SDR Discussion
Topic: Regarding extension cables
Replies: 4
Views: 4004

Re: Regarding extension cables

If you want to use HF and VHF then really you need two antennas, the little whip will work on VHF but will give very little on HF. For HF a long wire or active antenna will be needed. I assume that outside antennas are not possible? Indoor antennas can be a problem with electrical noise from just ab...
by alanzfq
Wed Jun 16, 2021 5:09 am
Forum: RTL-SDR Discussion
Topic: Regarding extension cables
Replies: 4
Views: 4004

Re: Regarding extension cables

For a start tell us what you have. Presumably a RTL dongle? v3?
What do you want to do with it? HF/VHF?
The little antenna supplied is generally of little use but that depends..
Alan
by alanzfq
Sat Apr 24, 2021 7:39 am
Forum: RTL-SDR Discussion
Topic: Calibrating RTL-SDR
Replies: 3
Views: 1756

Re: Calibrating RTL-SDR

All I have ever done is calibrate on a known frequency. IF I was certain 120.9 was truly accurate I'd use that. I am lucky to have 2 accurate ham beacons close enough. The need for calibration depends on how accurate you need to be. The V3 might be good enough for you but would need calibrating if y...
by alanzfq
Mon Apr 12, 2021 6:47 am
Forum: RTL-SDR Discussion
Topic: SDR-RTL for longwave and mediumwave
Replies: 3
Views: 1055

Re: SDR-RTL for longwave and mediumwave

For local stations a v3 will probably suit you.
If you get a little critical then an upconverter will be better.
By the time you've bought those then you are not far away from the cost of an Airspy which, providing 700Khz bandwidth is acceptable, is about as good you'll get for the price.
Alan
by alanzfq
Wed Mar 24, 2021 6:30 am
Forum: RTL-SDR Discussion
Topic: GEOS Software Question?
Replies: 3
Views: 994

Re: GEOS Software Question?

A simple Google for "Nooelec GOES Weather Satellite RTL-SDR Bundle" brings me quickly back to this site where there is a good tutorial.
by alanzfq
Thu Mar 18, 2021 11:40 am
Forum: RTL-SDR Discussion
Topic: Stability Issue using Nooelec Up Converter ?.
Replies: 1
Views: 720

Re: Stability Issue using Nooelec Up Converter ?.

All radios/converters will have at least one oscillator that may drift. So you have two. How much does it drift? How much stability do you want? The RTL is more likely to drift the most although the converter will as well. A temperature controlled oscillator (TCXO) will usually satisfy most. The V3 ...