Search found 21 matches

by walrusgumboot
Thu Mar 23, 2017 10:40 pm
Forum: RTL-SDR Discussion
Topic: local police/emergency?
Replies: 2
Views: 2578

Re: local police/emergency?

BITx40 is a two board dedicated 7 MHz SSB receiver designed for use on the radio amateur 40 metre band.

One of the two boards is home to the Raduino, a standard Arduino Nano you can write to in C, to create more modes, bands, and utlilities, even a multi-VFO widget, if you wanted to.
by walrusgumboot
Sat Mar 18, 2017 12:15 am
Forum: RTL-SDR Discussion
Topic: Placement of LNA
Replies: 19
Views: 10705

Re: Placement of LNA

Mr. Walrus I've watched a couple of youtube videos on soldering connectors to coax. Is that what you are talking about?.....instead of crimping? Is there something in particular I should be looking at? Soldering guarantees that you have a very low resistance connection - so long as the metal surfac...
by walrusgumboot
Thu Mar 16, 2017 1:15 pm
Forum: RTL-SDR Discussion
Topic: Placement of LNA
Replies: 19
Views: 10705

Re: Placement of LNA

RG213 is thick heavy stuff not suited to a small bending radius or circuits where the RF terminations are soldered directly onto pc board which could very likely crack under the strain. With the length Parkman reports, four metres or so, you could get away with using something a bit more lossy, but ...
by walrusgumboot
Wed Mar 15, 2017 9:29 am
Forum: RTL-SDR Discussion
Topic: Placement of LNA
Replies: 19
Views: 10705

Re: Placement of LNA

Using nor RF-amplification was to my recollection more due to the need to achieve wide bandwidth without the need to retune the receiver. Design of wideband preamplifier that could provide the necessary bandwidth and high IM to match the wide bandwidth of the above mentioned passive diode mixer was...
by walrusgumboot
Tue Mar 14, 2017 11:53 pm
Forum: User Projects
Topic: How to copy car key fob?
Replies: 11
Views: 12852

Re: How to copy car key fob?

Law and order approaches often differ from jurisdiction to jurisdiction, and from nation to nation.
by walrusgumboot
Tue Mar 14, 2017 11:51 pm
Forum: Antennas
Topic: Shortwave reception (SDR)
Replies: 3
Views: 4993

Re: Shortwave reception (SDR)

A 460.500 MHz dipole will have each side 6" long so there's no need to go buying anything. Silver solder brazing rod would be good for the elements at that scale, or just thick stiff copper wire if that is to hand.
by walrusgumboot
Tue Mar 14, 2017 11:39 pm
Forum: RTL-SDR Discussion
Topic: Has cooling sticks <=0°C been tested (e.g. dry ice/freezer)?
Replies: 7
Views: 4596

Re: Has cooling sticks <=0°C been tested (e.g. dry ice/freez

Maintaining the TCXO at a constant temperature, so that its pushing and pulling with inevitable overshoots is kept to a minimum, would probably be the best course of action. Stick it in an oven to maintain standard temperature and pressure will likely produce greater stability than relying on its te...
by walrusgumboot
Mon Mar 13, 2017 12:41 am
Forum: RTL-SDR Discussion
Topic: Digital TV
Replies: 9
Views: 6830

Re: Digital TV

You should be able to receive FM broadcast stations with almost no antenna at all. Why not, as an experiment, just connect a straight piece of wire 30" long (i.e. near enough a quarter-wavelength at 100 MHz) directly into your SDR RF input, and see where that gets you. When I do it with my Nongle N3...
by walrusgumboot
Sun Mar 12, 2017 11:44 pm
Forum: RTL-SDR Discussion
Topic: Digital TV
Replies: 9
Views: 6830

Re: Digital TV

I meant to ask you about that amplifier - do you know what its bandwidth is suposed to be?