RSP1A Longwave sensitivity

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arcosine
Posts: 30
Joined: Wed Jan 02, 2019 6:24 pm
Location: 41.678472, -88.051762

Re: RSP1A Longwave sensitivity

Postby arcosine » Thu Jan 17, 2019 2:41 pm

I have Linux, as such is barley supported with cubic sdr, a very limited app. Does anyone know where the config file is for cubicsdr?

My scope (BK-1472c) hasn't been used much and the contacts for the 10v/div setting were oxidized, thus showing 60 v p-p. Rotating the selection dial a few times indicated the error.
I grew up a block form a 50kw am station, WJJD. My antenna in my yard would light a florescent bulb if wrapped around it, without a tuned circuit.. I had a diode rectifier to my hi-fi speaker, though they went off and Salt lake city sunset, testing at night would wake me up and Id have to get up and disconnect it. The gutters on the house would play country-western, before country was country. As kids we would climb on the guy wires and sometimes get stung, didn't know why, couldn't see any sharp wires sticking out.

Reason: No reason
Tony
AA9CC

arcosine
Posts: 30
Joined: Wed Jan 02, 2019 6:24 pm
Location: 41.678472, -88.051762

Re: RSP1A Longwave sensitivity

Postby arcosine » Fri Jan 18, 2019 2:32 pm

Well it seems OK on VHF I receive 2 or 3 weather stations with just a small wire, still deaf on MW/LW.

The RSP1A does not perform as well on LF as the RSP2 and the RSPduo when using a poor antenna. This is because the RSP1A has a higher noise floor. See screenshots below (same antenna - an HF G5RV) That said you can still get some signals by doing the following.

1. Turn off the LO Lock and set to Low IF mode

2. Spin the frequency until the LO is at 1000 kHz and then Lock the LO

4. Turn on the MW filter. Check IF AGC under SETTings in Main window. Adjust RF Gain to max (Attenuation to minimum). If you get AD overload you need to reduce gain (add attenuation) However this will increase the noise floor of the receiver.

5. You can use the zoom feature to show only the signals below 500 kHz.


I found this code in Soapysdrplay, settings.cpp. I think IF mode refers to frequency, 0, 450khz, I dont see anything setting about low IF mode.


SNIP .....

mir_sdr_SetDeviceIdx(devIdx);
deviceSelected = true;

sampleRate = 2000000;
reqSampleRate = sampleRate;
decM = 1;
decEnable = 0;
centerFrequency = 100;
ppm = 0.0;
ifMode = mir_sdr_IF_Zero;
bwMode = mir_sdr_BW_1_536;
gRdB = 40;
lnaState = (hwVer == 2 || hwVer == 3 || hwVer > 253)? 4: 1;

//this may change later according to format
shortsPerWord = 1;
bufferLength = bufferElems * elementsPerSample * shortsPerWord;

agcMode = mir_sdr_AGC_100HZ;
dcOffsetMode = true;

IQcorr = 1;
setPoint = -30;

antSel = mir_sdr_RSPII_ANTENNA_A;
tunSel = mir_sdr_rspDuo_Tuner_1;
amPort = 0;
extRef = 0;
biasTen = 0;
notchEn = 0;
dabNotchEn = 0;

bufferedElems = 0;
_currentBuff = 0;
resetBuffer = false;
useShort = true;

streamActive = false;

.....SNIP

I have this when I type this command, SoapySDRUtil --probe=sdrplay:

######################################################
## Soapy SDR -- the SDR abstraction library ##
######################################################

Probe device sdrplay

----------------------------------------------------
-- Device identification
----------------------------------------------------
driver=SDRplay
hardware=1807096593
mir_sdr_api_version=2.130000
mir_sdr_hw_version=255

----------------------------------------------------
-- Peripheral summary
----------------------------------------------------
Channels: 1 Rx, 0 Tx
Timestamps: NO
Other Settings:
* RF Gain Select - RF Gain Select
[key=rfgain_sel, default=4, type=string, options=(0, 1, 2, 3, 4, 5, 6, 7, 8, 9)]
* IF Mode - IF frequency in kHz
[key=if_mode, default=Zero-IF, type=string, options=(Zero-IF, 450kHz, 1620kHz, 2048kHz)]
* IQ Correction - IQ Correction Control
[key=iqcorr_ctrl, default=true, type=bool]
* AGC Setpoint - AGC Setpoint (dBfs)
[key=agc_setpoint, default=-30, type=int, range=[-60, 0]]
* BiasT Enable - BiasT Control
[key=biasT_ctrl, default=true, type=bool]
* RfNotch Enable - RF Notch Filter Control
[key=rfnotch_ctrl, default=true, type=bool]
* DabNotch Enable - DAB Notch Filter Control
[key=dabnotch_ctrl, default=true, type=bool]

----------------------------------------------------
-- RX Channel 0
----------------------------------------------------
Full-duplex: YES
Supports AGC: YES
Stream formats: CS16, CF32
Native format: CS16 [full-scale=32767]
Antennas: RX
Corrections: DC removal
Full gain range: [0, 48] dB
IFGR gain range: [20, 59] dB
RFGR gain range: [0, 9] dB
Full freq range: [0.01, 2000] MHz
RF freq range: [0.01, 2000] MHz
CORR freq range: MHz
Sample rates: 0.25, 0.5, 1, 2, 2.048, 6, 7, 8, 9, 10 MSps
Filter bandwidths: 0.2, 0.3, 0.6, 1.536, 5, 6, 7, 8 MHz

Reason: No reason
Tony
AA9CC

glovisol
Posts: 462
Joined: Thu May 10, 2018 6:42 pm
Location: Piedmont, Italy

Re: RSP1A Longwave sensitivity

Postby glovisol » Fri Jan 18, 2019 3:03 pm

Hi Tony,

I have followed your predicament and it is a pity to have a valuable RSP and be in doubt if it works or not. With $ 15- approx. you can get a noise generator and test your receiver as shown here:

viewtopic.php?f=5&t=3352

I hope this helps and best wishes for finding good news!

glovisol

Reason: No reason

arcosine
Posts: 30
Joined: Wed Jan 02, 2019 6:24 pm
Location: 41.678472, -88.051762

Re: RSP1A Longwave sensitivity

Postby arcosine » Fri Jan 18, 2019 5:02 pm

I found the problem. My expensive Teflon jacketed coax from the transformer to ant port had a short in it. I fixed it by the method.. I connected the power supply across it, spark, no more whiskers. Its working now.

...A screen shot of the 630 meter band. Im using a 480 khz ceramic resonator across the antenna leads in addition to the paralleled tuned circuit, it can be tuned about 10 khz. There's a comb right on the band, I think its from an LED light in one of the neighbors poll barn, my antenna runs 200 feet from it and it seemed be be stronger when I extended it. The upper green trace is peak, lightning from the approaching snow storm. You can see the filter response. Im going to make a vxo from the resonator.

Image

Reason: No reason
Tony
AA9CC

Roger
Posts: 217
Joined: Fri Dec 29, 2017 7:59 pm

Re: RSP1A Longwave sensitivity

Postby Roger » Sat Jan 19, 2019 12:31 am

arcosine wrote:I found the problem. My expensive Teflon jacketed coax from the transformer to ant port had a short in it. I fixed it by the method.. I connected the power supply across it, spark, no more whiskers. Its working now.


Nice to hear that your RSP is OK. Aahh. The method...

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fotoralf
Posts: 36
Joined: Wed Aug 08, 2018 10:13 pm
Location: Western Germany, near Belgian border
Contact:

Re: RSP1A Longwave sensitivity

Postby fotoralf » Sat Jan 19, 2019 11:02 am

Roger wrote:The method...


He who heals is right. (Paracelsus)

;)

Ralf

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