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by g1hbe
Thu Jun 29, 2017 9:20 pm
Forum: SDRplay related
Topic: RSP2 LO 3rd harmonic spurious response only -20dBC
Replies: 17
Views: 1874

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

Yes but then the waterfall/spectrum display would not show up to 10 MHz wide! You can't have it both ways, this is the problem.
by g1hbe
Thu Jun 29, 2017 7:35 pm
Forum: General
Topic: Computer specification suggestions?
Replies: 3
Views: 691

Re: Computer specification suggestions?

If you really need to see 10 MHz at a time, then you are certainly going to need a bit of horsepower. For general listening around, I find a couple of MHz (or less) of BW is enough, and my laptop i3 @ 2.4 GHz (with 4 Gigs of ram and onboard graphics) copes well. It actually works flawlessly up to ab...
by g1hbe
Thu Jun 29, 2017 7:13 pm
Forum: SDRplay related
Topic: RSP2 LO 3rd harmonic spurious response only -20dBC
Replies: 17
Views: 1874

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

I think I've seen this documented somewhere. There are responses based on odd harmonics of the sampling frequency/LO. Just like the 'image' response on a conventional superhet receiver, there is no way to get rid of them without using front-end filtering. The RSP's have filters, but the lowest one c...
by g1hbe
Thu Jun 29, 2017 11:47 am
Forum: General
Topic: SDRConsole and SDRplay
Replies: 5
Views: 978

Re: SDRConsole and SDRplay

Ah. The error at VHF seems to be about 50 KHz, but at low frequencies it is 5 KHz. This suggests an error in the reference oscillator, but it's a much bigger error than we normally see, and probably way beyond the calibration adjustment. I'm assuming you've tried a different program such as SDRUno o...
by g1hbe
Wed Jun 28, 2017 9:14 pm
Forum: General
Topic: SDRConsole and SDRplay
Replies: 5
Views: 978

Re: SDRConsole and SDRplay

Is the frequency offset always the same, regardless of the frequency you enter (ie LF or VHF)? Or does the offset get worse the higher the frequency?
by g1hbe
Mon Jun 26, 2017 3:35 pm
Forum: SDR Antennas
Topic: Long Wire Antenna Performance Questions
Replies: 7
Views: 1456

Re: Long Wire Antenna Performance Questions

Ultravista - As Danube said, the two connections input connections on the balun form a 'differential' input. If you put the same signal on each end, they will cancel and there will be no output. Obviously a pair of wires twisted together are picking up the same signal so they should not be connected...
by g1hbe
Fri Jun 23, 2017 8:19 am
Forum: General
Topic: "Near Field" definition?
Replies: 1
Views: 405

Re: "Near Field" definition?

Hi. My RSP2 is fed from a Wellbrook loop (or sometimes a random wire) only a few metres from my 160m vertical (it's for the 160m band, not 160m tall!) and I've not had any problems. I use fairly modest power levels though, never more than 35 watts PEP. One thing as amazed me - if I keep the power do...
by g1hbe
Sat Jun 17, 2017 11:59 pm
Forum: SDR Antennas
Topic: Longwire antenna question
Replies: 7
Views: 1300

Re: Longwire antenna question

Are you selecting the Hi-z input? You have to click on the Hi-z button. Other than that I can't think of much. The RSP is very sensitive on all bands.
by g1hbe
Wed Jun 14, 2017 10:33 am
Forum: General
Topic: RSP1 susceptibility to a DC voltage on its input?
Replies: 3
Views: 698

Re: RSP1 susceptibility to a DC voltage on its input?

Just to play devil's advocate! I'd be wary of building any bias-T without a DC blocking cap on the receiver side. It may be OK for the RSP1, but if you get into the habit of using a DC-coupled bias-T you may absent-mindedly attach it to something that is NOT AC coupled and then you'd be in trouble. ...
by g1hbe
Tue Jun 13, 2017 2:39 pm
Forum: General
Topic: RSP-1 or RSP-2?
Replies: 3
Views: 1166

Re: RSP-1 or RSP-2?

I agree with Mike. The 2 uses the same receiver chips as the 1 so it has the same basic performance, but the added flexibility of the three antenna inputs and the better controllability of the front-end gain make it better in use. Then there is the bias-T on one input which gets rid of the extra box...

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