Search found 215 matches

by snn47
Sun Jul 19, 2020 10:52 pm
Forum: Antennas
Topic: Big Loop Antenna
Replies: 4
Views: 1057

Re: Big Loop Antenna

For Aluminum and Stainless Steel you can find an overview here. https://www.albanycountyfasteners.com/blog/stainless-steel-and-aluminum/ . There are different types of Stainless Steel and Aluminum, which have different percentage of other metals in it, which may influence corrosion too. I cannot mak...
by snn47
Sat Jul 18, 2020 12:31 pm
Forum: Antennas
Topic: Big Loop Antenna
Replies: 4
Views: 1057

Re: Big Loop Antenna

How were the Aluminum Fascia pieces connected to each other? Unless the Aluminum Fascia is heavily corroded at the connections, maybe just redooing a limited numbers of connections might be a solution for you. Running both in parallel should increase capacitance unless you connect the cooper and the...
by snn47
Mon Mar 09, 2020 9:43 pm
Forum: RTL-SDR Discussion
Topic: Upconverter vs. Direct Samling?
Replies: 3
Views: 5792

Re: Upconverter vs. Direct Samling?

Hotpaw I would say it depends on how you define the direct sampling setup, you use e.g. 8, 10, 12 ... Bit AD, what type of preamp if you use one, are filters used and which type HP,LPW, BP vs. the performance specs of the upconverter and by the SDR after the upconverter, you assume 8, 10, 12 ... Bit...
by snn47
Mon Mar 09, 2020 6:18 pm
Forum: RTL-SDR Discussion
Topic: Measuring VSWR
Replies: 3
Views: 6207

VSWR is important for transmitter

I wonder because I think the antenna I bought can't cover all of the HF and VHF frequency. It depends on your definition of cover. There is no antenna I know of that will support such a large range of frequency/wavelength and is matched for all frequencies. There are active antennaes that have smal...
by snn47
Mon Mar 02, 2020 11:14 pm
Forum: Antennas
Topic: Static shock while connecting ground-wire to radio?
Replies: 12
Views: 12000

Static electricity built up over time

I guess you are experiencing static electricity built up over time. If you have a coax cable then the capacity, wich will vary with cable type and length, the static electricity will accumulate over time. Did you have a thunderstorm building up in your area when you experienced this? The static elec...
by snn47
Mon Mar 02, 2020 10:47 pm
Forum: RTL-SDR Discussion
Topic: Can I use the SDR very close to the RF source?
Replies: 11
Views: 14135

Notchfilter attennuating RF source?

From what I know of comercial antenna designers and use from antennas mounted above each other vertically or horizontally separated, you cannot achieve at best 20 dB of isolation if you really put a lot of work into optimizing your antenna placement using meassuring equipment for finding the best is...
by snn47
Mon Mar 02, 2020 9:54 am
Forum: RTL-SDR Discussion
Topic: Can I use the SDR very close to the RF source?
Replies: 11
Views: 14135

PAPR and RMS of modulation

Thank you, that is what I assumed, the Diodes are clipping to protect. PS:it can be two causes that destroy the receiver, either a to high voltage generated by the modulation power that will destroy the diodes junktion this is why PAPR is important and/or a to high continious RF RMS power power of t...
by snn47
Sat Feb 29, 2020 4:54 am
Forum: RTL-SDR Discussion
Topic: Can I use the SDR very close to the RF source?
Replies: 11
Views: 14135

Re: Can I use the SDR very close to the RF source?

@rtlsdr max input power of an R820T2 is +10dBm Does this apply to the RTL-820T2 input without or with the antiparalell protecting diodes that I remember having seen. Do you know the max. PAPR (Peak To Average Ratio) for the +10 dBm value, which is also important to know, since the PAPR for OFDM can ...
by snn47
Wed Feb 26, 2020 5:56 am
Forum: Signal Identification Help
Topic: AM-radio with unstable frequency?
Replies: 4
Views: 9159

Re: AM-radio with unstable frequency?

It could just be receiver intermodulation. If you have a 10 or 20 dB attenuator insert it and see if you still receive the station.
by snn47
Wed Feb 26, 2020 5:48 am
Forum: RTL-SDR Discussion
Topic: Bluetooth Classic Sniffing
Replies: 3
Views: 5425

Re: Bluetooth Classic Sniffing

Even if you use a converter that would mix the BT-frequencies to below 1700 MHz, you would need also to be able to folloe the frequency hopping pattern of BT see https://en.wikipedia.org/wiki/Bluetooth