Date   

Re: Airspy HF+ BDR 110dB

prog
 

On Mon, Nov 13, 2017 at 01:32 am, adam9a4qv wrote:
BDR= P1dB - Noise floor

P1dB=IP3-10db
P1dB=15-10 = +5dBm

BDR=+5- (-140)
BDR= 145dB

This is a big difference, 110db or 113dB over to 145dB ?

Adam
Read my reply to Johanne. There's also the action of the AGC which was completely disabled during the tests. The gain was fixed so that the SNR of the weaker tone 3dB.


Re: >> ( Want your radio to be listed here? Contact us.) #spyserver

Meduzi Jellyfish <iain@...>
 

Hi Andrea,

WFM seems to be impossible with stuttering regardless of bandwidth. Increasing buffer size may help. Also there seems to be a lot of possibly Band II imaging throughout VHF. Others will try see what they find on their connection to you.


Re: Airspy HF+ BDR 110dB

Mark Jessop
 

What kind of response time (time constant?) is the AGC running?

I will be using my AirSpy HF+ in the receive loop of a Icom IC-7610, and when I transmit there is likely to be a bit of RF ending up in the AirSpy. (not 100% sure how much yet, will be a function of the TX/RX relay isolation.
Would be good if it didn't take a long time to recover... 

73
Mark VK5QI

On Mon, Nov 13, 2017 at 9:32 AM, adam9a4qv via Groups.Io <adam9a4qv@...> wrote:
How will then the trained professionals explain this:

BDR= P1dB - Noise floor

P1dB=IP3-10db
P1dB=15-10 = +5dBm

BDR=+5- (-140)
BDR= 145dB

This is a big difference, 110db or 113dB over to 145dB ?

Adam



Re: FFT possible issue?

airspy@...
 

Hi Prog
Sorry, I didn't understand the answer in relation to what I'm seeing. 
It may be something to do with the defined bandwidth at the server end. I was trying to constrain the bandwidth to 144-146 when I noticed the issue.
Widening the bandwidth (as set in the server min and max freq) changes the effect. 
There is also a variable element.
As an example, with server bandwidth set to 143-148 MHz, sample rate at default, I connect from SDR#. Bandwidth always seems to start at 4.8MHz whatever. At this point the FFT is correct.
I now change the bandwidth in the Source panel to say 2.4MHz. again the FFT panel is correct. I then change back to 4.8MHz bandwidth and the FFT is no longer correct.
HOWEVER
If I then make a second connection to the server, the FFT on the first connection immediately jumps to the correct point (ie the red line is now where you are hearing). If I repeat the process for the second connection - to 2.4MHz then back to 4.8, the misalignment happens on this second connection.
THEN
If I make a third connection, upon connecting, the FFT on the second connection immediately corrects.
I could go on but I think you see the pattern here lol
The attached screen shot shows the apparently impossible - three identical connections but the lower one has the incorrect FFT
Dave GW4GTE
 


Re: Airspy HF+ BDR 110dB

adam9a4qv
 

How will then the trained professionals explain this:

BDR= P1dB - Noise floor

P1dB=IP3-10db
P1dB=15-10 = +5dBm

BDR=+5- (-140)
BDR= 145dB

This is a big difference, 110db or 113dB over to 145dB ?

Adam


Re: Airspy HF+ BDR 110dB

jdow
 

On 2017-11-13 01:19, prog wrote:
On Mon, Nov 13, 2017 at 01:12 am, jdow wrote:
Is their feedback to the program running it for the current AGC setting so
that metering can be accurate in a spectrum analyzer application?
{^_^}
The AGC's are disabled for the BDR tests. You don't want to disable them in real world use.
accurate
These stunts were done by trained professionals, don't try this at home ;-)
I have my trained professional hat and aged tattered and torn tee-shirt among the clothing I am metaphorically wearing at the moment.
{^_-}


Re: Airspy HF+ BDR 110dB

prog
 

On Mon, Nov 13, 2017 at 01:12 am, jdow wrote:
Is their feedback to the program running it for the current AGC setting so that metering can be accurate in a spectrum analyzer application?

{^_^}
The AGC's are disabled for the BDR tests. You don't want to disable them in real world use.

accurate
These stunts were done by trained professionals, don't try this at home ;-)


Re: Airspy HF+ BDR 110dB

jdow
 

On 2017-11-13 00:52, prog wrote:
On Mon, Nov 13, 2017 at 12:29 am, adam9a4qv wrote:
Can somebody explain how this number is calculated or measured?
BDR 110dB?
The method used ?
thanks
Adam
Measured with a weak signal at -115 dBm and a blocker 20kHz away. The blocker is increased until the weak signal decreased by 1 dB - and we are still conservative here. The datasheet says 113 dBm typ.
Also, given all the AGC loops involved, the whole gain distribution is optimized for best sensitivity while all the stages are continuously operating in a comfortable region.
Is their feedback to the program running it for the current AGC setting so that metering can be accurate in a spectrum analyzer application?

{^_^}


Re: Airspy HF+ BDR 110dB

prog
 

On Mon, Nov 13, 2017 at 12:29 am, adam9a4qv wrote:
Can somebody explain how this number is calculated or measured?
BDR 110dB?
The method used ?

thanks
Adam
Measured with a weak signal at -115 dBm and a blocker 20kHz away. The blocker is increased until the weak signal decreased by 1 dB - and we are still conservative here. The datasheet says 113 dBm typ.
Also, given all the AGC loops involved, the whole gain distribution is optimized for best sensitivity while all the stages are continuously operating in a comfortable region.


Re: Spy Server update #spyserver

Evariste Courjaud
 


One question though. Spyserver of course plays very nice with sdr# but
are there other client libraries floating around (python preferred)?
Failed to find one or concrete documentation of the protocol.

Anybody tried this?

Seems that protocol is not public but will be implemented in Gqrx. As it is an opensource project we could inspect the client implementation to use it to other projetcs.

73's Evariste 


Airspy HF+ BDR 110dB

adam9a4qv
 

Can somebody explain how this number is calculated or measured?
BDR 110dB?
The method used ?

thanks
Adam


>> ( Want your radio to be listed here? Contact us.) #spyserver

andrea ottaviani
 

Good morning, can I put my server in the list at this address? https://airspy.com/spy-servers/ Owner: Andrea OTTAVIANI IK0MMI Location: Perugia URL: sdr://ik0mmi.ddns.net/ Radio: Airspy R2 Band. VHF/UHF vertical antenna

thank. you. best 73 de IK0MMI andrea


Re: LNA 5000

jdow
 

Incidentally - most adjustable gain amplifiers lose dynamic range as the gain is reduced. One exception is a fixed gain amplifier with an attenuator in the output.
{o.o}

On 2017-11-12 14:09, Simon Brown wrote:
Agreed, but I would only use a LNA if your loss is > 2dB and, as you say very low NF and adjustable (low) gain, purely to overcome the cable loss.
Simon Brown, G4ELI


Re: LNA 5000

jdow
 

If loss is 2 dB the gain of the preamp should be somewhat below 10 dB. Actually 6 dB should be adequate bordering on too much. Even so you lose some dynamic range within the hard limit of the number of bits per sample.
{o.o}

On 2017-11-12 14:09, Simon Brown wrote:
Agreed, but I would only use a LNA if your loss is > 2dB and, as you say very low NF and adjustable (low) gain, purely to overcome the cable loss.
Simon Brown, G4ELI


Re: LNA 5000

doug
 

On 11/12/2017 04:46 PM, jdow wrote:
Any band if the preamp is located at the receiver. And if it is mounted at the antenna with a long feedline it will be bad on any band on which the gain of the LNA 5000 is more than about 3dB to 4dB higher than the feedline loss. Otherwise the preamp is a dead loss. My preamp is going to grow an attenuator so that these conditions are met. Then it could do some serious good.

{^_^}

On 2017-11-12 02:19, JMP wrote:
I own one and would be interested to know what frequency band was the the more degraded ?

Provenance : Courrier <https://go.microsoft.com/fwlink/?LinkId=550986> pour Windows 10
As jdow would tell you, you want the preamp as near the antenna as possible, within reason. Then if you use an attenuator, put it at the
receiver end of the feedline, so it need not be waterproof, altho many probably are.
--Doug, WA2SAY


Re: Please Test my SpyServer - Cincinnati, OH USA #spyserver

Lawrence Glaister <ve7it@...>
 

Hi JEREMY,
streams nicely to western Canada, using about 42K bytes/sec, on sdrsharp 1620 running on antergos linux under mono (uses about 20% of each of 2 cores on a 3GHz core 2 duo). Great audio, no dropouts detected. 444.950 repeater seems be stuck trying to connect to irlp node 0066 which doesnt exist!.
cheers
Lawrence VE7IT irlp node 1130

ps. nice work on 1620 prog.... all I had to do was copy in libshark.so and enter mono SDRSharp.exe

On 2017-11-12 01:16 PM, KF7IJZ wrote:
Hello folks - I would love some help testing!
Airspy R2 - configured for 440Mhz-450Mhz for now and up to 4 people.
Antenna is a diamond D220R mini discone
sdr://kf7ijz.ddns.net/
Thanks in advance!


Re: SpyServer capacity question

jdow
 

Buy one. See know much CPU and IO capacity it consumes. Then adjust accordingly.

One AirSpy consumes one whole USB 2.0 root hub. So without added USB boards you're not even going to run your keyboard and mouse in many cases. OTOH two or three RTLSDR devices can survive nicely on one USB 2.0 root hub. (Typically PCs have ONE root hub on the motherboard.)

With a 4 port USB 3.0 controller with individual hardware ports/root hubs, I have run a pair of AirSpy's full out with SDRConsole without running out of CPU cycles. Other things got iffy, including memory consumption. I have a rather large dual 6 processor XEON CPU machine, though. (Two SDRSharps should do fine, they have different optimizations than Simon's software.)

So IO can limit you. Memory can limit you. CPU cycles can limit you. With dual processors the direct processor to processor bus can kill you. (The board manufacturer sets how often the bus transfers data. This can glitch very low latency applications.) The video card can limit you. In other words ANY of the aspects of your system, except maybe disk space and speed, can affect your ability to run SDR software. (And the disk system can kill you if it is too slow and you are recording or playing back.)

{^_^} Joanne

On 2017-11-12 09:13, Meduzi Jellyfish wrote:
[Edited Message Follows]
There isn't an accurate answer without knowing every possible variable. I would suggest that your reply would suffice. A lot more depends of how pedantic the user is. Maybe they should order one and find out.


jeff felly

JMP
 

Works fine in France too. 36kB, no lag, perfect sound.



Re: LNA 5000

Simon Brown
 

Agreed, but I would only use a LNA if your loss is > 2dB and, as you say very low NF and adjustable (low) gain, purely to overcome the cable loss.

Simon Brown, G4ELI

www.dxgalaxy.com
www.sdr-radio.com
www.sdr-satellites.com

-----Original Message-----
From: main@airspy.groups.io [mailto:main@airspy.groups.io] On Behalf Of jdow
Sent: 12 November 2017 21:46
To: main@airspy.groups.io
Subject: Re: [airspy] LNA 5000

Any band if the preamp is located at the receiver. And if it is mounted at the antenna with a long feedline it will be bad on any band on which the gain of the LNA 5000 is more than about 3dB to 4dB higher than the feedline loss. Otherwise the preamp is a dead loss. My preamp is going to grow an attenuator so that these conditions are met. Then it could do some serious good.

{^_^}

On 2017-11-12 02:19, JMP wrote:
I own one and would be interested to know what frequency band was the
the more degraded ?

Provenance : Courrier <https://go.microsoft.com/fwlink/?LinkId=550986>
pour Windows 10


Re: 4.5v software switched Bias-Tee from HF+?

jdow
 

facepalm
{o.o}

On 2017-11-12 07:50, Eric Oyen wrote:
ok,
there are a number of solutions to getting max signal to the SDR. 
1. mount at the antenna feed point. this will require remote power feed, a weather sealed box and a remote machine. Believe me, USB can't transport signals to the machine much past 12 feet (too much delay) so having a weather sealed machine close by won't hurt.

2. long run of very low coax (rg-6 works up to 1200 Mhz with fairly low loss). btw, there is a low cost LNA out there that can be powered on a USB connection. I ordered one earlier this year to use with one of my USB RTL-SDR dongles.  it has good overload protection and adds only .5 Db insertion noise for 30 Db signal gain from 100 Khz to 5 Ghz. the thing is about the size of 4 postage stamps. this would be a good solution for long runs of coax.

so, unless you are doing anything above 500 Mhz, coax loss isn't going to be much of a factor.  Thus, using the onboard LNA just seems like adding extra complication and noise.

DE n7zzt Eric

On Nov 12, 2017, at 1:32 AM, Simon Brown wrote:

FWIW I have 25m of good coax, using the LNA 5000 from SSB Electronics seriously degraded the received signals, I do mean *seriously*. Coax: https://messi.it/en/catalogue/50-ohm-cables-ham-radio/broad-pro-50-double-jacket.htm If you're going to use a serious LNA then it'll require a separate 12v feed.

As for a BPF with the HF+: "You're having a Turkish".

Simon Brown, G4ELI

www.dxgalaxy.com
www.sdr-radio.com
www.sdr-satellites.com


-----Original Message-----
From: main@airspy.groups.io [mailto:main@airspy.groups.io] On Behalf Of Joe M.
Sent: 11 November 2017 23:54
To: main@airspy.groups.io
Subject: Re: [airspy] 4.5v software switched Bias-Tee from HF+?

For the minority who need LNAs, they can also add a DC insertion device or power them separately from the coax.

I agree "punishing" those who don't need Bias-T with additional loss is not something that should be done.

Joe M.









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