New forum member with some questions

[DL8CQ]

Hi!

I got my amateur radio license about one year ago and since then (and already a few months before) I was experimenting with a RTL-SDR Stick trying to decode different "stuff" like NOAA satellites, D-Star and WSPR.
While it is astonishing what you can get out of a device for <10 Euro that was made for something different, its limits were reached quite quickly...

As I don't want to spend 1000 Euros or more for some "nice to have" decodings, I observed the entry level SDRs and lately found some information on the SDRplay. The filters and the higher resolution of the ADC look very promising to me, as well as the detailed description of the API.

As I could not find much information about the SDRplay beside some reviews and the SDRplay website, I was reading through this forum. It looks like there is only a small community, but hopefully it will grow with the price reduction in place now! (small communities can result in less support in my opinion)
Is there some other forum where the SDRplay is discussed? English is definitely no problem to me; in the German amateurfunk-forum.de and the DARC website I could not find anything (why?).

Now I have some questions, maybe somebody out there has already some experience to share:
- What about the Gnuradio support? I read some post about a release in near future, but that was posted in January, if I remember correctly.
- I have an Odroid C1, running Ubuntu. This is a ARM-based quadcore board that is able to run gnuradio. Has anybody experience how the SDRplay will work with such a board?
- Do I have to expect problems when trying to decode NOAA or METEOR weather satellite signals? I tried to decode NOAA APT signals with a RTL-SDR with limited success (Plan to build a QFH in near future) and Meteor LRPT without success.
- I also would like to decode DMR traffic coming from our nearby amateur radio relay station. The RTL-SDR was too noisy around 438 MHz so I had no chance. I've read about the gap between 380 - 430 MHz. How sensitive will the SDRplay be in the range of 435-440 MHz?
- Has anybody tried to use the SDRplay as a spectrum analyzer? I could imagine to measure filters connected to some noise source.

Any input is appreciated!

TiA and 73
Martin DL8CQ

[TyTanYGraig]

Hello Martin,
I guess the SDRplay RSP is still a fairly new product. The RTL based dongles have certainly been around for several years now and so it isn't so surprising that there is a lot more information around for these devices. Regarding GNU Radio support, it looks as though this is coming very soon, so I would just watch this space. I can't help on many of your other questions (perhaps others here can), but I can comment upon the sensitivity. In my experience, the sensitivity of the RSP is very good at both VHF and UHF bands. With my unit, it is certainly better than a cheap RTL dongle. There is no loss in sensitivity around the 380-430 MHz 'gap'. It is just the case that the synthesizer cannot tune to these frequencies (or at least it isn't guaranteed to do so) inside the gap.

All the best

[Quimquim]

Welcome aboard Martin DL8CQ,

These two last week I pass my time on mainly two things.

1 - Began to deploy my wiring for installing two antennas. One PA0RDT for freq. below 30mhz and one Diamond D130J discone for freq. over.

I plan to install them in my attic but up to now it still a bit too cold to work over there. ( I'm in Quebec, Canada )

In the mean time I have hidden my PA0RDT in a wardrobe.

2 - I begin to take a look at satellite reception to try to decode weather pictures.

Just to try, yesterday, I took a look at the 136-138mhz band ( even if the PA0RDT is mainly out of range there ), and up to now, I was able to see the signal of the NOAA-18 satellite at 137.9mhz. It was weak but strong enough to see the digital spikes on the spectrum.

Actually I mainly use HDSDR for reception and I have installed Orbitron for the satellite tracking.

With this antenna it is too weak and noisy to decode something but I'm curious to see the result when my discone will be installed.

I don't have decoding program installed up to now viewing that my actual setup don't give a good signal for it.

On your side what program do you use for reception and decoding? WXtoImg look to be a good one.

What kind of antenna are you using?

Hope to see you as a co-user of SDRPlay.

[DL8CQ]

Hi,

TyTanYGraig, thank you for the information about the synthesizer, that clarified for me the root cause of the gap.

Quimquim, thank you for the detailed answer and information about your experience.
I connected my 2m/70cm groundplane antenna to the RTL-SDR for my satellite experiments. It is a Diamond NR-770HB.
Using SDR# and WxToImg I was able to decode some data, but the picture is quite noisy and for high elevations (e.g. when the satellite is above my antenna) the groundplane is not very sensitive and decoding is not possible.
I have a miniwhip that I bought as a kit from OK2ZI, maybe I give it a try as well. But I know that it works better on the lower bands, at 30 MHz it is already not receiving a lot.

I was reading the news about upcoming support for gnuradio today... the temptation to order is growing...

[NN4F]

You are better off running a wire for HF than a mini whip they are highly overrated and a simple wire will give much better cleaner results, I'm running a 25ft temp wire, and in the radio shack a 160m ladder line fed dipole, or a 75ft end fed wire.... I also use my 6 element 6 band Mosley

I had a vectoronics active antenna for HF but it always introduced noise, you only have to look at the websdr in twente to see how they perform, below par, if you have room, always get some wire in the air...

Paul - NN4F

[DL8CQ]

Hi Paul,

you are completely right - if I would have room I would like to put up wires also for the lower bands... I am living in a flat on first floor and can only use my balcony. Recently I put up a bent dipole for 20m - just to give you an impression about the space I can use for antennas.

To me the miniwhip is an experiment. Lot of discussion about it on the net, and for 25 Euros I know now how it performs at my place. It is not for DXing, but reception inside Europe is ok.

73
Martin DL8CQ

[jon]

A belated reply on a couple of things:

We've heard reports of SDRplay working well with DL4YHF's Spectrum Analyzer ("Spectrum Lab").
Our friend Paul Jones writes on the SDRplay group forum writes:
"I took the SDRplay HDSDR ExtIO DLL file and loaded it into Spectrum Lab, and it works smile emoticon - needs more investigating, but it sure works.... "
The Spectrum Analyzer software can be downloaded fromhttp://www.qsl.net/dl4yhf/spectra1.html

Also there will be no problem at all with sensitivity 430MHz and up. (The actual gap is a lot smaller than the numbers we have to publish to cover all manufacturing process variants)

[DL8CQ]

Hi Jon,

thank you for this very interesting news. I will try the software as soon as I get my SDRplay (yes, I ordered one in meantime )

I hope mine arrives during the next days; it was shipped out on monday, but unfortunately I did not get a tracking number and German Post is partially on strike at the moment.

73
Martin