Search found 23 matches

by OH2BUA
Thu Jul 20, 2017 5:52 pm
Forum: SDR Antennas
Topic: RA0SMS active mini-whip power supply
Replies: 10
Views: 534

Re: RA0SMS active mini-whip power supply

I happen to know the mini-whip construction well. The one and _only_ point to be grounded is the ground tap of the (antenna) power adapter. No ground loops allowed.

73, Jukka
by OH2BUA
Thu Jul 20, 2017 1:50 pm
Forum: SDR Antennas
Topic: RA0SMS active mini-whip power supply
Replies: 10
Views: 534

Re: RA0SMS active mini-whip power supply

Do you happen to own a multimeter? If you have, you can check if there is connection between the earth terminal of the AC plug and the DC minus of the power supply?

The UK plug (if you are in UK) is a little bit strange and also frightening thing for me:)

73, Jukka
by OH2BUA
Thu Jul 20, 2017 1:10 pm
Forum: SDR Antennas
Topic: RA0SMS active mini-whip power supply
Replies: 10
Views: 534

Re: RA0SMS active mini-whip power supply

Hi,

is there possibly a difference between your power supplies in a way that one 'passes' the ground to the mini-whip power adaptor, and the other doesn't?

73, Jukka
by OH2BUA
Sun Jul 09, 2017 3:58 pm
Forum: SDRplay related
Topic: RSP2 LO 3rd harmonic spurious response only -20dBC
Replies: 17
Views: 997

Re: RSP2 LO 3rd harmonic spurious response only -20dBC

Ok, here it is, in the middle. 2MHz low-pass filter. Plug-in version. Cute as a small pig, as we tend to say hereby.
2M_filter_verysmall.jpg
2M_filter_verysmall.jpg (196.59 KiB) Viewed 290 times

73, Jukka
by OH2BUA
Wed Jul 05, 2017 3:25 pm
Forum: SDRplay related
Topic: RSP2 LO 3rd harmonic spurious response only -20dBC
Replies: 17
Views: 997

Re: RSP2 LO 3rd harmonic spurious response only -20dBC

I hope that you are also getting a more educated answer - but the truth is, that if you connect a decent antenna into RSP2, during nighttime / good condix in MW band you will also be hearing a lot of signals which actually don't reside in MW band, but are from somewhere higher.

73, Jukka
by OH2BUA
Mon Jul 03, 2017 10:25 am
Forum: SDRplay related
Topic: RSP2 LO 3rd harmonic spurious response only -20dBC
Replies: 17
Views: 997

Re: RSP2 LO 3rd harmonic spurious response only -20dBC

Thanks Andy for your tip for RFSim99.

It's easy to get learned and fun to play with.

Jukan_1.png
Jukan_1.png (6.99 KiB) Viewed 463 times


73, Jukka
by OH2BUA
Fri Jun 30, 2017 7:47 am
Forum: SDRplay related
Topic: RSP2 LO 3rd harmonic spurious response only -20dBC
Replies: 17
Views: 997

Re: RSP2 LO 3rd harmonic spurious response only -20dBC

Andy, as you seem to be experienced with external filtering, can you possibly recommend a solution for me: For listening MW and 160m I have a Double-KAZ antenna, with about 1 kohm impedance, symmetric. It's fed to the RSP2's Hi-Z port by using 12 meters of 450 ohms ladder line. I'd like to add an ex...
by OH2BUA
Thu Jun 29, 2017 1:30 pm
Forum: SDRplay related
Topic: RSP2 LO 3rd harmonic spurious response only -20dBC
Replies: 17
Views: 997

Re: RSP2 LO 3rd harmonic spurious response only -20dBC

Hi, I have experienced the similar, but haven't taken such an analytical approach on that as you've done. Could you possibly share some more details, Sir? - Did I calculate right, that when you are tuned into let's say 1.8MHz (Zero IF), you are also receiving signals which actually are at around 7.2...
by OH2BUA
Thu Jun 22, 2017 6:09 am
Forum: SDR Antennas
Topic: MW-antenna directional during the nighttime, omnidirectional in the daytime
Replies: 0
Views: 388

MW-antenna directional during the nighttime, omnidirectional in the daytime

There exists several directional mediumwave receiving antenna concepts based on an idea that the directionality is optimized by 'tuning' an end-resistor for the best achievable Front-to-Back (F/B) ratio, and after that usually replacing it with an equivalent fixed resistor. For example Beverage, EWE...
by OH2BUA
Sun Jun 18, 2017 3:27 pm
Forum: SDRplay related
Topic: Serial Number issue! Please help!
Replies: 1
Views: 248

Re: Serial Number issue! Please help!

Hi,

you can find it in SDRuno: OPT/About.

73, Jukka oh2bua

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