Re: New SDR# release r1729 with High DPI support
#software
#announcements
michaeld
Looks very nice, thanks for your efforts. Like the skins.
On Thu, Oct 17, 2019 at 12:08 prog <info@...> wrote:
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Re: AstroSpy
#1420mhz
#21cm
#radioastronomy
Marcus D. Leech
On 10/17/2019 06:27 AM,
iz5dkm@... wrote:
That signal will be somewhere around 1422.5MHz--right off the edge of your chart.
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New SDR# release r1729 with High DPI support
#software
#announcements
This update has been pending for quite some time. Now the application can detect and adapt to the DPI of the attached monitor with support for High DPI.
A few other tweaks for the RAW mode when streaming digital data. Note that this will require .NET 4.8 to work, but the application can still run just as before with .NET 4.6. The downloads are available as usual at: https://airspy.com/download Enjoy!
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Re: Transmission lines, Input match and Connectors
#bestpractice
#experiment
OK. This is garbage. Wes, you seem to be completely confused by how the AGC works. Your signals are much weaker than what the Discovery can handle.
First thing to do is to watch Leif videos to learn about how to test receivers. You can discuss the methodology here if you have any questions. Then, do your homework and try to reproduce the dynamic range tests using real testing equipment.
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Re: Transmission lines, Input match and Connectors
#bestpractice
#experiment
Dana Myers
On 10/17/2019 9:45 AM, Wes Stewart via Groups.Io wrote:
Of course it's moderated. It says so every time I post.I read/post via email, rarely look at the web interface and just learned that posts are moderated. I've never noticed that; I learned something today, thanks. Whatever, they could just identify themselves.Sure, they could, but how would that change the discussion? Physics doesn't care who we are :-) Youssef has described his goals in the design of the HF+ Discovery, it's not intended as a well-defined 50-ohm match. If someone needs that, something like a narrow-band matching network or the trusty stand-by, a resistor pad, is called for. Joanne has "helped out" as she often does :-). In all the discussion, I think I missed what your goal is - is there something specific or general investigation? 73, Dana K6JQ
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Re: Transmission lines, Input match and Connectors
#bestpractice
#experiment
Wes Stewart <n7ws@...>
On Thu, Oct 17, 2019 at 07:45 AM, prog wrote:
Let's be more pragmatic. What is the real world performance using an antenna?Thank you for asking. Let me preface the following by explaining the environment. The antenna is a 55 foot vertical over ground radials, For the results that follow, the antenna is connected to the Airspy through a Telonic Industries Model TG-950 stepped attenuator. Although not a traceable device I have verified its performance with my DG8SAQ VNWA. I have several plots, all taken during the same session, which are screen grabs of the SDR# program. The model, serial number, firmware and software versions are all obvious. This unit is as received a few days ago. I'm not sure I can intersperse comments between the attachments so I will summarize them here. The image "Airspy_1_40db" is of a local MW station with the inline attenuator set to 40dB. The image "Airspy_2_20db" is the same as before except the attenuation has been reduced to 20 dB. It was pointless to go to 0 dB. Images "Airspy_3_40dB" and "Airspy_4_20db" are similar but of a different station. The next set, "Airspy_5_20db", "Airspy_6_10db" and "Airspy_7_0db" show station WWV being received on 10 MHz with 20, 10 and 0 dB attenuation respectively. Note that with 0 dB attenuation, the Airspy is essentially useless. The next set, "Airspy_8_10db" and "Airspy_9_0db" show station WWV being received on 15 MHz with 10 and 0 dB attenuation respectively. Same situation. Now you might understand my interest in knowing the performance of the input filtering because obviously it isn't up to the task. But it gets worse. Image "Airspy_10_Spurious_of_88_1_0db" shows an FM broadcast signal, fully readable so I could identify it, that doesn't exist. Image "Airspy_11_Spurious_of_88_1_20db" shows the same spectrum with 20 dB of attenuation inline. The non-existent station disappears.
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Re: Transmission lines, Input match and Connectors
#bestpractice
#experiment
Wes Stewart <n7ws@...>
On Thu, Oct 17, 2019 at 07:59 AM, Dana Myers wrote:
On 10/17/2019 7:40 AM, Wes Stewart via Groups.Io wrote:Of course it's moderated. It says so every time I post. Whatever, they could just identify themselves.
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Re: AstroSpy
#1420mhz
#21cm
#radioastronomy
iz5dkm@...
Yes, the visible signal is certainly generated by interstellar material belonging to our galaxy.
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Re: Transmission lines, Input match and Connectors
#bestpractice
#experiment
Dana Myers
On 10/17/2019 7:40 AM, Wes Stewart via Groups.Io wrote:
Well, let me be blunt and see if my comments get past the moderator.Is this list moderated? I didn't think so. First, I feel a distinct disadvantage because I don't know who I'm discussing this with. Two of you hide behind screen names but I assume that you are the principals in Airspy.If you're not keen on asking them, the slightest bit of search engine use reveals full names for both Youssef and Joanne, if that helps at all. I do not believe Joanne is a principal in Airspy, and I'm not sure anyone other than Youssef is :-)
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Re: Transmission lines, Input match and Connectors
#bestpractice
#experiment
Let's be more pragmatic. What is the real world performance using an antenna?
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Re: Transmission lines, Input match and Connectors
#bestpractice
#experiment
Wes Stewart <n7ws@...>
On Wed, Oct 16, 2019 at 10:43 PM, jdow wrote:
Well, for what it is worth I will reiterate what Youssef said. In general theWell, let me be blunt and see if my comments get past the moderator. First, I feel a distinct disadvantage because I don't know who I'm discussing this with. Two of you hide behind screen names but I assume that you are the principals in Airspy. My name, and amateur callsign, is in the clear and you can look me up on QRZ.com if you wish and get a clue about my capabilities. Note that I was communicating via moonbounce way back in the 1970s and was building my own equipment. I know a bit about noise figure, so don't need any lessons. I also did this stuff professionally but I won't go into that here. The reason that I chose to measure input matching is because that is the only thing readily accessible to me; I have one coax connector to look at. If I'm allowed, I can post screenshots of my unit operating in my local environment which would make evident my concern about the performance of the input filtering.
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Re: Transmission lines, Input match and Connectors
#bestpractice
#experiment
On Thu, Oct 17, 2019 at 04:35 PM, Wes Stewart wrote:
I didn't state any reasons, I asked a question that you, as I anticipated, didn't care to answer.SWR.
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Re: AstroSpy
#1420mhz
#21cm
#radioastronomy
You are definitely receiving Hydrogen line emissions from within this galaxy. Since M31 is moving relative to us I would think you would need to look about 3 MHz higher or lower to see Hydrogen line emissions from it. Dan
On Thu, Oct 17, 2019 at 6:29 AM <iz5dkm@...> wrote:
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Re: Transmission lines, Input match and Connectors
#bestpractice
#experiment
Wes Stewart <n7ws@...>
On Wed, Oct 16, 2019 at 10:59 PM, prog wrote:
On Thu, Oct 17, 2019 at 07:44 AM, Wes Stewart wrote:I didn't state any reasons, I asked a question that you, as I anticipated, didn't care to answer.
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Everett N4CY
On Oct 13, 2019, at 4:58 PM, EVERETT SHARP <everettsharp@...> wrote:
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Re: AstroSpy
#1420mhz
#21cm
#radioastronomy
iz5dkm@...
I tried receiving the hydrogen line in the direction of M31 but I can't solve the signal, evidently the s / n ratio is still low.
The first image in the frequency domain, the second in the speed domain.
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Re: Transmission lines, Input match and Connectors
#bestpractice
#experiment
jdow
{^_-}
toggle quoted messageShow quoted text
On 20191016 22:59:05, prog wrote:
On Thu, Oct 17, 2019 at 07:44 AM, Wes Stewart wrote:
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Re: Transmission lines, Input match and Connectors
#bestpractice
#experiment
jdow
With antennas suitable for efficient transmitting 10 dB is generally safe through 15 MHz maybe 28 MHz. With poor antennas - well - if you install an attenuator and the noise still rises when you replace a dummy load with the antenna, you're good to go. You won't be able to improve things more than a dB or so. That is the bottom line test for what you have.
toggle quoted messageShow quoted text
{^_-}
On 20191016 22:55:39, prog wrote:
If a perfectly resistive load is required for something else other than reception, just add attenuators. This will cost you the valuable MDS we fought to get you here, but I'd assume at this point you know what you are doing.
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Re: Transmission lines, Input match and Connectors
#bestpractice
#experiment
On Thu, Oct 17, 2019 at 07:44 AM, Wes Stewart wrote:
Since it doesn't appear to me that there is enough room in this package for many Ls and Cs how (if you care to say) do you build these elaborate filters? Are these active inductors?Better filters are always better, of course, but definitely not for the reasons you are stating. I would again oprimize for the MDS and the rejection. Yes, designing receivers is not as intuitive as it seems.
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Re: Transmission lines, Input match and Connectors
#bestpractice
#experiment
If a perfectly resistive load is required for something else other than reception, just add attenuators. This will cost you the valuable MDS we fought to get you here, but I'd assume at this point you know what you are doing.
Spectrum analyzers do not make for good receivers for the same reasons.
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