Search found 457 matches

by glovisol
Mon Apr 22, 2019 7:18 am
Forum: General
Topic: LOW PASS FILTER FOR OPTIMUM LOW FREQUENCY RECEPTION
Replies: 16
Views: 3631

Re: LOW PASS FILTER FOR OPTIMUM LOW FREQUENCY RECEPTION

MEDIUM WAVE REJECTION WITH A CAUER C 06 10 PASSIVE LOW PASS FILTER WITH 50 OHM TERMINATIONS The filter is built on a rigid PVC conduit tube with 15.2 mm external diameter. First 1 mm dia.holes are drilled into the pipe for pins 1 to 6 plus the two ground pins at the end: these suppor the ground bar...
by glovisol
Sun Apr 21, 2019 3:41 pm
Forum: General
Topic: LOW PASS FILTER FOR OPTIMUM LOW FREQUENCY RECEPTION
Replies: 16
Views: 3631

Re: LOW PASS FILTER FOR OPTIMUM LOW FREQUENCY RECEPTION

Sdrom 33, the measurements shown in previous post were done as soon as the filter was assembled and outside the shielding box, as illustrated in the pic below. One of the advantages of the multi-coil technique is that you can check the filter and be sure it works as per design BEFORE you shut it up ...
by glovisol
Sun Apr 21, 2019 3:32 pm
Forum: General
Topic: 3 dB HYBRID COUPLER/ISOLATOR FOR ANTENNA SPLITTING 100 KHz -10 MHz
Replies: 20
Views: 877

Re: 3 dB HYBRID COUPLER/ISOLATOR FOR ANTENNA SPLITTING 100 KHz -10 MHz

NETWORK ANALYSER MEASUREMENTS

Shown below is what one receiver sees into the splitter with the other receiver in operation and the antenna port connected to a long wire antenna through a 50 to 560 Ohm transformer in the frequency range 3 to 10 MHz.
by glovisol
Sun Apr 21, 2019 3:20 pm
Forum: General
Topic: 3 dB HYBRID COUPLER/ISOLATOR FOR ANTENNA SPLITTING 100 KHz -10 MHz
Replies: 20
Views: 877

Re: 3 dB HYBRID COUPLER/ISOLATOR FOR ANTENNA SPLITTING 100 KHz -10 MHz

NETWORK ANALYSER MEASUREMENTS

Shown below is what the antenna sees looking into the 50 Ohm splitter connected to two receivers in operation in the frequency range 3 to 10 MHz. The thick traces are for receivers ON; the thin traces are for receivers OFF.
by glovisol
Sun Apr 21, 2019 2:55 pm
Forum: SDRplay related
Topic: Metal Case for RSP1A
Replies: 4
Views: 138

Re: Metal Case for RSP1A

by glovisol
Sun Apr 21, 2019 9:16 am
Forum: General
Topic: LOW PASS FILTER FOR OPTIMUM LOW FREQUENCY RECEPTION
Replies: 16
Views: 3631

Re: LOW PASS FILTER FOR OPTIMUM LOW FREQUENCY RECEPTION

MEDIUM WAVE REJECTION WITH A CAUER C 06 10 PASSIVE LOW PASS FILTER WITH 50 OHM TERMINATIONS Two versions of the filter have been calculated: - From Cauer prototype C06 10 having a passband ripple of 0.5 dB, with a likely insertion loss of 2 dB max (provided element Q is in the order of magnitude of...
by glovisol
Sat Apr 20, 2019 3:50 pm
Forum: General
Topic: LOW PASS FILTER FOR OPTIMUM LOW FREQUENCY RECEPTION
Replies: 16
Views: 3631

Re: LOW PASS FILTER FOR OPTIMUM LOW FREQUENCY RECEPTION

MEDIUM WAVE REJECTION WITH A CAUER C 06 15 PASSIVE LOW PASS FILTER WITH 50 OHM TERMINATIONS The filter described in the previous posts could only be used with RSP Processors equipped with the HI Z / 1 KOhm input. For LF work 0 to 500 KHz a sharp low pass filter is very useful in completely protecti...
by glovisol
Sat Apr 20, 2019 3:31 pm
Forum: General
Topic: A CLOSE LOOK TO LOW COST NOISE GENERATORS
Replies: 31
Views: 4140

Re: A CLOSE LOOK TO LOW COST NOISE GENERATORS

The multiple trace capability of the new Spectrum Analyser software Ver. 1.0a overcomes the major problem related to low cost Noise Generators mentioned some time ago by Roger in this thread: namely the unlevelled noise power output that changes with frequency. This problem is now solved and the cor...
by glovisol
Fri Apr 19, 2019 6:57 am
Forum: General
Topic: 3 dB HYBRID COUPLER/ISOLATOR FOR ANTENNA SPLITTING 100 KHz -10 MHz
Replies: 20
Views: 877

Re: 3 dB HYBRID COUPLER/ISOLATOR FOR ANTENNA SPLITTING 100 KHz -10 MHz

I tested a splitter for the RSP1A. Normal situation is T-connectors to 3x RSP1A. I tried an splitter 5-2500MHz, splitted and the signals went down a lot. This makes me believe that the input of the RSP1A is not 50 Ohm but very high impedance. My splitter made a big impact on the signals, where my d...
by glovisol
Thu Apr 18, 2019 9:49 pm
Forum: General
Topic: FM BROADCAST BAND SUPPRESSION CHEBYSHEV N=5 BAND-STOP FILTER
Replies: 14
Views: 1547

Re: FM BROADCAST BAND SUPPRESSION CHEBYSHEV N=5 BAND-STOP FILTER

Hi F1BJB, If you look here: https://www.sdrplay.com/community/viewtopic.php?f=12&t=4307 you will find the very first experiment I did a short time ago to test the new Spectrum Analyser software with a band-stop filter quickly made with coaxial stubs. Twentyfive years ago I was designing coaxial ...

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