Search found 6 matches

by AcidJazz
Wed Nov 13, 2019 12:05 am
Forum: Troubleshooting Help
Topic: RTL-SDR Dongle V3: Frontend Effecting Filter Response, Manufacturing Fault?
Replies: 7
Views: 459

Re: RTL-SDR Dongle V3: Frontend Effecting Filter Response, Manufacturing Fault?

Add to your shopping list NanoVNA. Measuring filters with noice source was justified when VNAs were expensive, but not now.
by AcidJazz
Mon Jul 01, 2019 7:06 am
Forum: Off-Topic
Topic: More fake units sold on Ebay
Replies: 19
Views: 34315

Re: More fake units sold on Ebay

Many china FM reject filters has listing name "by RTL-SDR Blog" or uses grafiks of original filter, for example https://www.ebay.com/itm/Broadcast-FM-Band-Stop-Filter-88-108-MHz-FM-Trap-by-RTL-SDR-Blog-shortwave/332729543175 But really very bad fakes, doesn't supress 98-108 MHz http://blog.radiospy....
by AcidJazz
Mon Feb 26, 2018 8:06 pm
Forum: Antennas
Topic: Is it normal for an antenna not have lowest swr in its advertised band?
Replies: 7
Views: 5100

Re: Is it normal for an antenna not have lowest swr in its advertised band?

Simple test, put to DUT port piece of wire and you should get something like this 2018-02-26_22-33-24.jpg It's wire 48 cm length. I use bg7tbl noise source & china swr bridge (3 ports, 50Ohm load is inside). Red line is "zero". My optimum gain set is 2.7, but it depends of noise power from the gener...
by AcidJazz
Mon Feb 26, 2018 6:46 am
Forum: Antennas
Topic: Is it normal for an antenna not have lowest swr in its advertised band?
Replies: 7
Views: 5100

Re: Is it normal for an antenna not have lowest swr in its advertised band?

First of all, gain 49.6 is too much, I think. You need to try change gain for the maximum dynamic range.
by AcidJazz
Sat Nov 25, 2017 3:36 pm
Forum: Troubleshooting Help
Topic: USB Isolator + RTL-SDR V3 "no device selected"
Replies: 6
Views: 3827

Re: USB Isolator + RTL-SDR V3 "no device selected"

This device has to low power isolator DC, 180 mA by description. V3 needs 290 mA in Quadrature Sampling mode.