Search found 12 matches

by SDRguy22
Fri Jul 26, 2019 3:28 pm
Forum: New Users' experiences
Topic: Best antenna no good signals?
Replies: 21
Views: 9300

Re: Best antenna no good signals?

The G5RV has an interesting history and the theory behind it is explained in this article:

https://www.nonstopsystems.com/radio/pdf-ant/G5RV-1.pdf

Bill
by SDRguy22
Thu Jul 25, 2019 8:11 pm
Forum: SDR Antennas
Topic: "Low Noise" Vertical Antennas for Receiving
Replies: 12
Views: 7758

Re: "Low Noise" Vertical Antennas for Receiving

Hi Bill, I dare to say, ANY antenna with coax can be made immune to man made noise when the 3th current is removed. His approach isn't much different from a mini-whip but he uses twin-line so he hasn't have to deal with common-mode-problems, that is why his design has less issues as most mini-whip ...
by SDRguy22
Thu Jul 25, 2019 6:43 pm
Forum: SDR Antennas
Topic: Receive Antenna & Impedance "Matching"
Replies: 114
Views: 36046

Re: Receive Antenna & Impedance "Matching"

I have some links to reference material on the concept of Noise Figure (NF) and how atmospheric and man-made noise is measured. I hope readers find it useful for understanding some of the issues being discussed here. There are many tutorial articles and books that discuss the concept of Noise Figure...
by SDRguy22
Wed Jul 24, 2019 4:18 pm
Forum: General
Topic: RSP-2 HiZ Input Question: 1:9 Balun and Grounding ?
Replies: 7
Views: 3516

Re: RSP-2 HiZ Input Question: 1:9 Balun and Grounding ?

I have the two twisted wires from the NooElec output going to the P and N terminals of the HiZ input.(green connector on the RSP-2) Question: Should the Gnd connection on this green connector be grounded ? To what ? Or, just leave floating ? The sketches I've seen always seem to show it floating. T...
by SDRguy22
Sat Jul 20, 2019 11:04 pm
Forum: SDR Antennas
Topic: "Low Noise" Vertical Antennas for Receiving
Replies: 12
Views: 7758

Re: "Low Noise" Vertical Antennas for Receiving

The purpose of this post is to present my views on a "Low Noise Vertical Antenna" conceived by Dallas Lankford. An updated article describing this antenna can be found here: https://tinyurl.com/DallasLNV I have been a SWL and ham for a long time and have always been interested in antennas. About ten...
by SDRguy22
Sat Jul 20, 2019 8:12 pm
Forum: General
Topic: AM and FM Band Reject Filters
Replies: 5
Views: 2103

Re: AM and FM Band Reject Filters

Bas,

That is an interesting device. I see that it has a built in noise source. Have you used it to do any filter tests?
by SDRguy22
Sat Jul 20, 2019 8:00 pm
Forum: SDR Antennas
Topic: Receive Antenna & Impedance "Matching"
Replies: 114
Views: 36046

Re: Receive Antenna & Impedance "Matching"

WSPR will go down as low as -33db, the only thing matters is the quality of it's own noise-level, as the RSP1A does something like -140db there is absolutely no problem. Bas your comments on WSPR agree with my experience using this mode. I have tried it on 630M, 80M, 40M and 20M with good results u...
by SDRguy22
Sat Jul 20, 2019 4:31 pm
Forum: General
Topic: AM and FM Band Reject Filters
Replies: 5
Views: 2103

AM and FM Band Reject Filters

Many SDRplay users live near AM and FM stations and find that these strong signals have a detrimental effect on reception with their RSP. In some cases the built-in AM and FM filters are not sufficient. There have been numerous posts recently on how to build filters to reject unwanted signals. If on...
by SDRguy22
Sat Jul 20, 2019 12:49 am
Forum: SDR Antennas
Topic: DCF 77 77.5KHZ
Replies: 17
Views: 8782

Re: DCF 77 77.5KHZ

Mike,

I find it interesting to read that you can receive signals from so far away on LF, which is a fairly noisy band, on such a low cost antenna. From what I understand you have designed an active antenna and I hope you can post a little more about it (some pictures and/or a schematic).

Bill
by SDRguy22
Fri Jul 19, 2019 8:56 pm
Forum: SDRplay related
Topic: Front end protection during thunderstorm?
Replies: 7
Views: 4204

Re: Front end protection during thunderstorm?

An isolation transformer will not protect against lightning damage. However it will help drain static voltage that you get during rain or snow conditions. For nearby lightning protection you need surge protection devices that have a gas discharge tube and the device connected to a solid ground conne...