SDRplay questions

[plasasasa]

Hi, I am considering purchasing an SDRplay, but I have a few questions.

First, I need to tell you what I will be using it for. I would like to receive military broadcasts at 3MHz to 10MHz (mainly around 5MHz). The distance from the main transmitters I am hoping to receive are 600km - 900km. I currently have a magnetic loop antenna, however it does not function very well and I hope to build a PA0RDT mini whip antenna soon. My current location is a noisy top-floor apartment with absolutely no grounding (not even the outlets have grounding!), however I plan to set up a better, more permanent location far away from the city.

Now I have a few questions. What is the difference between the RSP2 and the RSP1A, which one can receive better in that frequency range with that sort of antenna (refer to bold text)? Would it be possible to turn it into a wide-bandwidth WebSDR, like argon's WebSDR? Does SDR-console have full support for the RSP1A? I really don't like the interface of UnoSDR, is there a feature that SDR-console lacks and makes it perform worse than UnoSDR, or is the performance on both software identical? If it's placed really close to an FM transmitter (a strong big one, not a tiny car cigarette lighter one), is there a way to make it not die and achieve similar performance to being placed in an area without the FM transmitter (remember, I am only interested in HF signals)?

Please help me make the right decision for which SDR I should use and what I can and can't do with it. Thanks.

[vk7jj]

Some really broad generalisations to get the thread started:

1) You can have a look for yourself at 3-10Mhz propagation, check at different times of day: http://wsprnet.org/drupal/wsprnet/map

2) I hope to build a PA0RDT mini whip antenna soon: a very poor antenna for the above, you're bumping your bum against the moon.

3) What frequencies does the noise wipe out? If the above then you also sound like you're out of luck.

4) The RSP1A would be my choice, easier to operate yet better filtering on your bands of interest but either would be perfectly fine, I have both RSP2 (12 months) and RSP1A (a few days)

5) wide-bandwidth WebSDR, like argon's WebSDR? No. I've done it at a primitive level using a Raspberry Pi for a bandwidth of around 1MHz. There is talk of SDRPlay introducing something at some time in the future. SDR Console 3 also lists that as a future feature.

6) SDRUno v SDR Console 3: At first I preferred SDR Console because the user interface was more intuitive, now I prefer SDRUno, both are superb pieces of software created by hugely talented people who have spent hundreds of loving person hours. You don't have to spurn one at the expense of the other, use both at your whim and pleasure!

7) There are ways to wipe out (notch) really strong FM stations both within SDRPlay's filtering and externally using simple DIY techniques, just go ahead with your plans and worry about it if you have a problem.

Hope lots of others offer you more specific replies

[g1hbe]

I'm surprised plasasasa has found his magnetic loop antenna so bad, although I am not sure which type he means - a ring-dipole type with a tuning cap at the top or a wideband untuned active one like the Wellbrook? I have been using a Wellbrook 1530 for the last 14 years and it's a real noise-buster. Any attempt to listen to the low bands (1.7 to 7 MHz) on my wire antennas just gets wiped out by noise, but on the Wellbrook the noise goes down to s1/s2.
A while ago I tried a mini-whip antenna and it was just as bad as my wire antennas no matter where I put it.

[DaveB]

You have two options to remove a strong FM transmitter. The first option is built into the RSP1A - an FM band rejection filter. The second option for a specific frequency is a double tuned notch filter - this will give 60 dB rejection on one channel.

The RSP1A would have to be the choice for your requirements - but limit yourself to a 6 MHz sample rate so you get the better dynamic range available with 14 bit ADC.