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by glovisol
Mon Jun 24, 2019 10:40 am
Forum: SDR Antennas
Topic: Receive Antenna & Impedance "Matching"
Replies: 79
Views: 6472

Re: Receive Antenna & Impedance "Matching"

Hi Phil, Just recovering from the Solstice party (35 of us) with roast and all.... Your sensitivity & SNR checking & comparing scheme looks very interesting and I look forward to your results. This of noise minimisation is really the most imortant issue (and always has been) in radio communi...
by glovisol
Sat Jun 22, 2019 9:41 am
Forum: SDR Antennas
Topic: Receive Antenna & Impedance "Matching"
Replies: 79
Views: 6472

Re: Receive Antenna & Impedance "Matching"

Hi Paul, it is easier to make real HI Q coils....Will go in the wood oven outside and cook for 5 hours, so it is early morning tomorrow, 5 o'clock. - Phil, Very ood show! I am glad of having contributed. I note you did not use the sewing twine. Remember you almost double Qu if you space the turns an...
by glovisol
Fri Jun 21, 2019 3:25 pm
Forum: SDR Antennas
Topic: Receive Antenna & Impedance "Matching"
Replies: 79
Views: 6472

Re: Receive Antenna & Impedance "Matching"

Phil,

It is true that the larger diameter twine is not good for RF coils, but it can be used for other HI "Q" coils all the same. Have a nice weekend!

Gianfranco
by glovisol
Fri Jun 21, 2019 12:12 pm
Forum: SDR Antennas
Topic: Receive Antenna & Impedance "Matching"
Replies: 79
Views: 6472

Re: Receive Antenna & Impedance "Matching"

Very good, Phil, I look forward to see what results yo get by the additional selectivity!

Best regards,

Gianfranco
by glovisol
Thu Jun 20, 2019 8:28 pm
Forum: SDR Antennas
Topic: Receive Antenna & Impedance "Matching"
Replies: 79
Views: 6472

Re: Receive Antenna & Impedance "Matching"

With the double tuned pre-selector on Tuner #1 set at 7150 KHz this evening I received JA5CJZ (Japan) on 20:00 GMT in QSO with IK6BGJ on 7,175 KHz. This confirms that providing extra front end selectivity & attenuating the strong broadcasters above 7,200 KHz really pays a big benefit.
by glovisol
Thu Jun 20, 2019 9:43 am
Forum: SDR Antennas
Topic: Receive Antenna & Impedance "Matching"
Replies: 79
Views: 6472

Re: Receive Antenna & Impedance "Matching"

Hi Phil, Just one more note on PC's. If you need, say two or three, the best buy of the world are IBM/LENOVO X61's. At the moment they come at around $ 100 /120 and you can find the docking pads (very useful with many USB ports & the DVD RW) for around $ 15. You stick one RSP to each, they handl...
by glovisol
Thu Jun 20, 2019 4:38 am
Forum: SDR Antennas
Topic: Receive Antenna & Impedance "Matching"
Replies: 79
Views: 6472

Re: Receive Antenna & Impedance "Matching"

Uploaded below narrow band pre-selector schematic & data.
by glovisol
Wed Jun 19, 2019 3:37 pm
Forum: SDR Antennas
Topic: Receive Antenna & Impedance "Matching"
Replies: 79
Views: 6472

Re: Receive Antenna & Impedance "Matching"

Another important point is that even with the new coils (20 uH with 36 turns) is is still impossible to use 50 Ohm links for coupling, so I resorted to existing binocular core transformers and therefore insertion loss is over the calculated 12 dB and is around 16 db, but this problem will be elimina...
by glovisol
Wed Jun 19, 2019 3:15 pm
Forum: SDR Antennas
Topic: Receive Antenna & Impedance "Matching"
Replies: 79
Views: 6472

Re: Receive Antenna & Impedance "Matching"

Hi Phil, Many different subjects. If I can venture advice regarding PC's, please consider that silicon technology has now come to the point of rapidly diminishing returns and the last PC's with major advances for speed and operability came out in 2015. In my opinion it is nonsense to spend over $ 1,...
by glovisol
Tue Jun 18, 2019 2:24 pm
Forum: Spectrum Analysis
Topic: quasi-peak detector
Replies: 3
Views: 413

Re: quasi-peak detector

There is no logical reason why a Spectrum Analyser, with a random noise input, should display a difference of 38 dB in average to peak noise, unless we are measuring a very, very special kind of noise. Perhaps the problem could be with your old Texcan detector.....I suppose you are using the workhor...

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