Search found 662 matches

by glovisol
Sun Oct 07, 2018 8:59 pm
Forum: General
Topic: OPTIMIZING RSP RECEIVER OPERATION WITH ANTENNA NOISE
Replies: 13
Views: 7272

Re: OPTIMIZING RSP RECEIVER OPERATION WITH ANTENNA NOISE

A complete 3 way receiver feed system for one antenna with controlled attenuation and SDRplay switching is shown below. A 400 Ohm antenna is perfectly matched by a parallel connection of three attenuators, each with an input impedance of 1200 Ohm. Loss for the parallel connection amounts to 10 dB. T...
by glovisol
Sat Oct 06, 2018 4:00 pm
Forum: General
Topic: OPTIMIZING RSP RECEIVER OPERATION WITH ANTENNA NOISE
Replies: 13
Views: 7272

Re: OPTIMIZING RSP RECEIVER OPERATION WITH ANTENNA NOISE

It is possible to switch the same antenna between two, or even all three antenna inputs (with a third transformer) using the RDSPlay switch only. This setup allows very quick switching for comparing different noise/propagation conditions. Of course this is only possible when attenuation is necessary...
by glovisol
Fri Oct 05, 2018 5:46 pm
Forum: General
Topic: OPTIMIZING RSP RECEIVER OPERATION WITH ANTENNA NOISE
Replies: 13
Views: 7272

Re: OPTIMIZING RSP RECEIVER OPERATION WITH ANTENNA NOISE

It is also possible to recover the correct reading of the noise floor, of the display and of the "S" meter by altering the DISPLAY CALIBRATION as shown in the enclosed screen. If, for instance, you install a 20 dB attenuator, the receiver's front end will still receive 20 dB less and be 20 dB farthe...
by glovisol
Fri Oct 05, 2018 2:53 pm
Forum: General
Topic: OPTIMIZING RSP RECEIVER OPERATION WITH ANTENNA NOISE
Replies: 13
Views: 7272

Re: OPTIMIZING RSP RECEIVER OPERATION WITH ANTENNA NOISE

Here below a modified attenuator table based on multiples of 6 dB so that it will be easy to correct the "S" units indication by the RSP receiver. For instance, if you have inserted 24 dB of front end attenuation and your meter reads 2 "S" units, you are receiving a signal with "S" = 2+4 = 6 signal ...
by glovisol
Fri Oct 05, 2018 1:46 pm
Forum: General
Topic: ASSESSING THE PERFORMANCE OF THE RSP RECEIVER SYSTEM IN HF
Replies: 24
Views: 13232

Re: ASSESSING THE PERFORMANCE OF THE RSP RECEIVER SYSTEM IN HF

6. APPENDIX – DEMONSTRATION OF THE ANTENNA CORRECTION PROCEDURE We rewrite here again the expression developed in Part 3: Pn = Fa + B – 204 [dBm] ( 8 ) Solving for Fa, effective antenna Noise Figure, we have: Fa = Pn + 204 – 10*LOG10(b) [dB] ( 8bis ) As already stated, the Noise Power Pn delivered ...
by glovisol
Fri Oct 05, 2018 9:53 am
Forum: General
Topic: OPTIMIZING RSP RECEIVER OPERATION WITH ANTENNA NOISE
Replies: 13
Views: 7272

Re: OPTIMIZING RSP RECEIVER OPERATION WITH ANTENNA NOISE

In summary, to find the required attenuation: 1) Connect termination to input and find Terminated Receiver Noise Floor -Rnf 2) Find Receiver minimum detectable signal Rmds = -Rnf + 6 3) Connect antenna and find -Anf 4) Find Antenna minimum detectable noise floor Amds = -Anf + 6 5) Find attenuator va...
by glovisol
Thu Oct 04, 2018 6:31 pm
Forum: General
Topic: OPTIMIZING RSP RECEIVER OPERATION WITH ANTENNA NOISE
Replies: 13
Views: 7272

Re: OPTIMIZING RSP RECEIVER OPERATION WITH ANTENNA NOISE

Antenna is L=135 m Beverage, H = 6m

Uploaded below screens of 20 dB attenuated / non attenuated RSPduo reception on the 80 m band.
by glovisol
Thu Oct 04, 2018 6:30 pm
Forum: General
Topic: OPTIMIZING RSP RECEIVER OPERATION WITH ANTENNA NOISE
Replies: 13
Views: 7272

Re: OPTIMIZING RSP RECEIVER OPERATION WITH ANTENNA NOISE

Antenna is L=135 m Beverage, H = 6m

Uploaded below screens of 20 dB attenuated / non attenuated RSPduo reception on the 40 m band.
by glovisol
Thu Oct 04, 2018 6:29 pm
Forum: General
Topic: OPTIMIZING RSP RECEIVER OPERATION WITH ANTENNA NOISE
Replies: 13
Views: 7272

Re: OPTIMIZING RSP RECEIVER OPERATION WITH ANTENNA NOISE

Antenna is L=135 m Beverage, H = 6m

Uploaded below screens of 20 dB attenuated / non attenuated RSPduo reception on the 20 m band.
by glovisol
Thu Oct 04, 2018 1:14 pm
Forum: General
Topic: RSP RECEIVER LOW NOISE HF OPERATION WITH LONG WIRE ANTENNAS
Replies: 30
Views: 19401

Re: RSP RECEIVER LOW NOISE HF OPERATION WITH LONG WIRE ANTENNAS

FINAL ASSESSMENT OF HIGH PASS FILTER ACTION AND POSSIBLE NOISE ADVANTAGE After a series of measurements it has been determined that the biggest part of the noise advantage shown by the highpass filter in HF was provided by the significant attenuation (6-8 db) of the filter itself, depending on oper...