Search found 206 matches

by vk7jj
Thu Jul 04, 2019 10:25 am
Forum: SDR Antennas
Topic: LW-MW-SW Relay Tuned 15' Noise Reducing Vertical Antenna
Replies: 57
Views: 57295

Re: LW-MW-SW Relay Tuned 15' Noise Reducing Vertical Antenna

Forgive me for wading in, no doubt Ian is very well intentioned and trying to be helpful, but as sdrom33 says the article is so problematic that it seems to be useful example of what not to do and anyway I love antennas so much I can't help myself. It seems (to me anyway) that the concept is flawed ...
by vk7jj
Tue Jul 02, 2019 11:54 pm
Forum: SDR Antennas
Topic: Receive Antenna & Impedance "Matching"
Replies: 114
Views: 84019

Re: Receive Antenna & Impedance "Matching"

Hi Gianfranco, enjoy that magnificent holiday!

--

For anyone following the WSPR tests a software problem took down VK7JJ3 last night and there are other issues as well.

More later, Phil
by vk7jj
Mon Jul 01, 2019 10:17 am
Forum: SDR Antennas
Topic: Receive Antenna & Impedance "Matching"
Replies: 114
Views: 84019

Re: Receive Antenna & Impedance "Matching"

The winner of the WSPR 30m first round shootout is the FT-857D Both radios achieved 88 total unique callsigns heard over a 24 hour UTC period. The win was thus decided on the basis of extra spots from the same stations being received by the 857 that the 991 missed rather than new stations being hear...
by vk7jj
Sun Jun 30, 2019 6:57 am
Forum: SDR Antennas
Topic: Receive Antenna & Impedance "Matching"
Replies: 114
Views: 84019

Re: Receive Antenna & Impedance "Matching"

That's a pretty good question Gianfranco! A core i5 refurb with a decent screen where we live is closer to $400 and then you start thinking it's 5400rpm snaildrive needs replacing with an SSD, and a new Pi4 is $60 but that's not the real story. I've got two remote Pi running irrigation pump, waterin...
by vk7jj
Sat Jun 29, 2019 7:00 am
Forum: SDR Antennas
Topic: Receive Antenna & Impedance "Matching"
Replies: 114
Views: 84019

Re: Receive Antenna & Impedance "Matching"

Hi Gianfranco, as you might guess I just crossed posts with you, will catch up a bit later!

Regards, Phil
by vk7jj
Sat Jun 29, 2019 6:59 am
Forum: SDR Antennas
Topic: Receive Antenna & Impedance "Matching"
Replies: 114
Views: 84019

Re: Receive Antenna & Impedance "Matching"

Sorry about failing to respond to your crystal offer and thanks for mentioning it. As per earlier comments I have tried using a single crystal. Given that the WSPR sub bands are 200Hz wide a single crystal has exactly the right bandwidth at around 500Hz according to my tests on 40m and 10m crystals ...
by vk7jj
Fri Jun 28, 2019 9:51 am
Forum: SDR Antennas
Topic: Receive Antenna & Impedance "Matching"
Replies: 114
Views: 84019

Re: Receive Antenna & Impedance "Matching"

Forgive me, badly expressed. I need to vary the inter-coil coupling using my first sliding coils and experiment with the trade off of insertion loss against selectivity. eg. in the last hour I've received 21 stations on 30m WSPR with the SNRs as below: -27, -26, -25, -25, -25, -24, -24, -24, -24, -2...
by vk7jj
Fri Jun 28, 2019 8:08 am
Forum: SDR Antennas
Topic: Receive Antenna & Impedance "Matching"
Replies: 114
Views: 84019

Re: Receive Antenna & Impedance "Matching"

Well done and looking good Gianfranco. No further construction progress here, been setting up a Pi on WSPR (but it's only a 2B and groaning under the load) so as to free up the Windows VM for better testing, plus I'm on a short leash doing chores. The current preselector arrangement as posted using ...
by vk7jj
Fri Jun 28, 2019 7:55 am
Forum: General
Topic: Raspberry Pi4B
Replies: 6
Views: 4802

Re: Raspberry Pi4B

Order is in and waiting on stock he said enviously.
by vk7jj
Mon Jun 24, 2019 12:38 am
Forum: New Users' experiences
Topic: Best antenna no good signals?
Replies: 21
Views: 27021

Re: Best antenna no good signals?

A rural location? Great to use larger simple wire antennae and really benefit from your likely lower noise level. Given your original question went to the point of precise antenna geometry, my own approach is based on "perfect is the enemy of good", attributed to Voltaire among others though in my c...