Topics

Need advice: Which Airspy SDR is better for DX FM? #bestpractice #experiment

Brieuc
 

Hello everyone!
I'm a FM DXer, and I have acquired an Airspy Mini 6 months ago. It was used with an omnidirectional circular FM antenna but recently, I've bought an Korner 9.2, who is actually installed. No doubt! this antenna is very efficient! However, I live in a place with an overloaded FM band: I have 17 stations with 8 - 11 kW at 17 km with very strong signals, and 4 others stations with 4 kW at 10 km, distributed from 88.0 MHz to 107.2 MHz. Their transmitters are visible from my home. I can't turn my antenna everywhere, because I want to receive tropospheric signals, and there are  mountains everywhere around me, excepted one direction: to the sea, the only possibility for practicing DX tropo. Unfortunately, my 2 local TXs are in the same direction, consequently it's impossible to segregate my local signals if my antenna is pointing to this direction :/... But I can not do otherwise. Brief, that's my problem!
My Airspy remains powerful even in that case! However, i'm looking to have better results, and there is my question: In my case, in an overloaded FM area and with an Korner 9.2: An Airspy HF+ or an Airspy Discovery could give me better results on FM band than my Airspy mini? If yes, which one of these is better?
I'm absolutely not an professional of these SDR, and read their descriptions is like reading Chinese for me...
For information, my better results with my Airspy mini are with the "Linearity" mode or "Free" mode (with various IF, Mix and LNA levels). The gain is between 13 - 17 with 6 MSPS and Decimation 16 when the Körner is pointing to the best direction, with the linear mode.
This topic is just to have some advises from this community, who seems to be very interested about Airspy's products!
Sorry if I've make some mistakes in my text, i'm a student, my English isn't totally perfect.. :/ .
Good evening everybody, and thanks for reading...
Brieuc, from Corsica (JN41JW)

Shirley Dulcey KE1L
 

The Airspy HF+ Discovery has the best performance; a strong combination of low nose and high dynamic range. If you want to LISTEN to stations it's your best choice.

The one shortcoming of the HF+ Discovery (and the earlier HF+) is limited bandwidth. Those receivers only receive a 660 KHz wide piece of spectrum at once. That's more than wide enough for listening to FM signals, but you don't the wider overview of the band that is available on the Airspy R2 or to a slightly lesser degree on your Mini. You could use the Mini for the panoramic view and then switch to the Discovery to listen to the signals.

On Mon, Oct 21, 2019 at 5:27 PM <brieuc182@...> wrote:
Hello everyone!
I'm a FM DXer, and I have acquired an Airspy Mini 6 months ago. It was used with an omnidirectional circular FM antenna but recently, I've bought an Korner 9.2, who is actually installed. No doubt! this antenna is very efficient! However, I live in a place with an overloaded FM band: I have 17 stations with 8 - 11 kW at 17 km with very strong signals, and 4 others stations with 4 kW at 10 km, distributed from 88.0 MHz to 107.2 MHz. Their transmitters are visible from my home. I can't turn my antenna everywhere, because I want to receive tropospheric signals, and there are  mountains everywhere around me, excepted one direction: to the sea, the only possibility for practicing DX tropo. Unfortunately, my 2 local TXs are in the same direction, consequently it's impossible to segregate my local signals if my antenna is pointing to this direction :/... But I can not do otherwise. Brief, that's my problem!
My Airspy remains powerful even in that case! However, i'm looking to have better results, and there is my question: In my case, in an overloaded FM area and with an Korner 9.2: An Airspy HF+ or an Airspy Discovery could give me better results on FM band than my Airspy mini? If yes, which one of these is better?
I'm absolutely not an professional of these SDR, and read their descriptions is like reading Chinese for me...
For information, my better results with my Airspy mini are with the "Linearity" mode or "Free" mode (with various IF, Mix and LNA levels). The gain is between 13 - 17 with 6 MSPS and Decimation 16 when the Körner is pointing to the best direction, with the linear mode.
This topic is just to have some advises from this community, who seems to be very interested about Airspy's products!
Sorry if I've make some mistakes in my text, i'm a student, my English isn't totally perfect.. :/ .
Good evening everybody, and thanks for reading...
Brieuc, from Corsica (JN41JW)

Brieuc
 

Thank you for your answer!
The bandwidth isn't a problem for me, My Airspy is always set to 300 kHz bandwidth,660 kHz is indeed sufficient. I need a larger bandwidth for ATV and DAB receptions, but an Airspy mini is 100% efficient in my case on B3.
Brieuc, from Corsica (JN41JW)

h. garcia
 

A quick suggestion: you may still have analog TV transmissions from countries nearby (Tunisia, Libya, Algeria) that you can use to check your setup and as indicator of tropo openings. Lookup for a list of TV channels frequencies and their respective the audio frequencies. 


On Mon, Oct 21, 2019, 20:40 Shirley Dulcey KE1L <mark@...> wrote:
The Airspy HF+ Discovery has the best performance; a strong combination of low nose and high dynamic range. If you want to LISTEN to stations it's your best choice.

The one shortcoming of the HF+ Discovery (and the earlier HF+) is limited bandwidth. Those receivers only receive a 660 KHz wide piece of spectrum at once. That's more than wide enough for listening to FM signals, but you don't the wider overview of the band that is available on the Airspy R2 or to a slightly lesser degree on your Mini. You could use the Mini for the panoramic view and then switch to the Discovery to listen to the signals.

On Mon, Oct 21, 2019 at 5:27 PM <brieuc182@...> wrote:
Hello everyone!
I'm a FM DXer, and I have acquired an Airspy Mini 6 months ago. It was used with an omnidirectional circular FM antenna but recently, I've bought an Korner 9.2, who is actually installed. No doubt! this antenna is very efficient! However, I live in a place with an overloaded FM band: I have 17 stations with 8 - 11 kW at 17 km with very strong signals, and 4 others stations with 4 kW at 10 km, distributed from 88.0 MHz to 107.2 MHz. Their transmitters are visible from my home. I can't turn my antenna everywhere, because I want to receive tropospheric signals, and there are  mountains everywhere around me, excepted one direction: to the sea, the only possibility for practicing DX tropo. Unfortunately, my 2 local TXs are in the same direction, consequently it's impossible to segregate my local signals if my antenna is pointing to this direction :/... But I can not do otherwise. Brief, that's my problem!
My Airspy remains powerful even in that case! However, i'm looking to have better results, and there is my question: In my case, in an overloaded FM area and with an Korner 9.2: An Airspy HF+ or an Airspy Discovery could give me better results on FM band than my Airspy mini? If yes, which one of these is better?
I'm absolutely not an professional of these SDR, and read their descriptions is like reading Chinese for me...
For information, my better results with my Airspy mini are with the "Linearity" mode or "Free" mode (with various IF, Mix and LNA levels). The gain is between 13 - 17 with 6 MSPS and Decimation 16 when the Körner is pointing to the best direction, with the linear mode.
This topic is just to have some advises from this community, who seems to be very interested about Airspy's products!
Sorry if I've make some mistakes in my text, i'm a student, my English isn't totally perfect.. :/ .
Good evening everybody, and thanks for reading...
Brieuc, from Corsica (JN41JW)

Brieuc
 

Yes, I have very regulary ATV signals from Algeria via tropo, and sometimes Morocco during good openings. I can receive everyday some low video carriers from Algeria, with an periodic antenna and with an Airspy!
Unfortunately, ATV will end before the end of this year (Seen on Al Aoula during an exceptionnal opening), and for Algeria, it's probably planned for the 06/17/2020 on TDA Algeria's website, but it isn't clear...
Brieuc, from Corsica (JN41JW)

Leif Asbrink
 

Hello Brieuc,

Have a look at this video:
https://www.youtube.com/watch?v=Dq2C7Rzsams

Best is Airspy HF+ Dual Port. The HF+ Discovery comes
close but it has some reciprocal mixing problems
as you can see in the video. I do not think it
would matter much on the FM band because a very
strong station can not be so close that this matters
without destroying reception with its sub-carriers
and the subcarriers have a low amplitude so sideband
noise from them should be no problem.

Regards

Leif

Hello everyone!
I'm a FM DXer, and I have acquired an Airspy Mini 6 months ago. It was used with an omnidirectional circular FM antenna but recently, I've bought an Korner 9.2, who is actually installed. No doubt! this antenna is very efficient! However, I live in a place with an overloaded FM band: I have 17 stations with 8 - 11 kW at 17 km with very strong signals, and 4 others stations with 4 kW at 10 km, distributed from 88.0 MHz to 107.2 MHz. Their transmitters are visible from my home. I can't turn my antenna everywhere, because I want to receive tropospheric signals, and there are  mountains everywhere around me, excepted one direction: to the sea, the only possibility for practicing DX tropo. Unfortunately, my 2 local TXs are in the same direction, consequently it's impossible to segregate my local signals if my antenna is pointing to this direction :/... But I can not do otherwise. Brief, that's my problem!
My Airspy remains powerful even in that case! However, i'm looking to have better results, and there is my question: In my case, in an overloaded FM area and with an Korner 9.2: An Airspy HF+ or an Airspy Discovery could give me better results on FM band than my Airspy mini? If yes, which one of these is better?
I'm absolutely not an professional of these SDR, and read their descriptions is like reading Chinese for me...
For information, my better results with my Airspy mini are with the "Linearity" mode or "Free" mode (with various IF, Mix and LNA levels). The gain is between 13 - 17 with 6 MSPS and Decimation 16 when the Körner is pointing to the best direction, with the linear mode.
This topic is just to have some advises from this community, who seems to be very interested about Airspy's products!
Sorry if I've make some mistakes in my text, i'm a student, my English isn't totally perfect.. :/ .
Good evening everybody, and thanks for reading...
Brieuc, from Corsica (JN41JW)


Patrick
 

Hi Leif,

That's interesting. I thought the Discovery was superior to the Dual Port in this respect.

Le mer. 23 oct. 2019 à 09:13, Leif Asbrink <leif@...> a écrit :
Hello Brieuc,

Have a look at this video:
https://www.youtube.com/watch?v=Dq2C7Rzsams

Best is Airspy HF+ Dual Port. The HF+ Discovery comes
close but it has some reciprocal mixing problems
as you can see in the video. I do not think it
would matter much on the FM band because a very
strong station can not be so close that this matters
without destroying reception with its sub-carriers
and the subcarriers have a low amplitude so sideband
noise from them should be no problem.

Regards

Leif


> Hello everyone!
> I'm a FM DXer, and I have acquired an Airspy Mini 6 months ago. It was used with an omnidirectional circular FM antenna but recently, I've bought an Korner 9.2, who is actually installed. No doubt! this antenna is very efficient! However, I live in a place with an overloaded FM band: I have 17 stations with 8 - 11 kW at 17 km with very strong signals, and 4 others stations with 4 kW at 10 km, distributed from 88.0 MHz to 107.2 MHz. Their transmitters are visible from my home. I can't turn my antenna everywhere, because I want to receive tropospheric signals, and there are  mountains everywhere around me, excepted one direction: to the sea, the only possibility for practicing DX tropo. Unfortunately, my 2 local TXs are in the same direction, consequently it's impossible to segregate my local signals if my antenna is pointing to this direction :/... But I can not do otherwise. Brief, that's my problem!
> My Airspy remains powerful even in that case! However, i'm looking to have better results, and there is my question: In my case, in an overloaded FM area and with an Korner 9.2: An Airspy HF+ or an Airspy Discovery could give me better results on FM band than my Airspy mini? If yes, which one of these is better?
> I'm absolutely not an professional of these SDR, and read their descriptions is like reading Chinese for me...
> For information, my better results with my Airspy mini are with the "Linearity" mode or "Free" mode (with various IF, Mix and LNA levels). The gain is between 13 - 17 with 6 MSPS and Decimation 16 when the Körner is pointing to the best direction, with the linear mode.
> This topic is just to have some advises from this community, who seems to be very interested about Airspy's products!
> Sorry if I've make some mistakes in my text, i'm a student, my English isn't totally perfect.. :/ .
> Good evening everybody, and thanks for reading...
> Brieuc, from Corsica (JN41JW)
>
>
>



prog
 

You should pay attention to the testing conditions to get the correct interpretation. We are talking about differences within the component variability here because the exact same circuitry and processing are used in the FM band for both versions. Different units from different batches will still have very close performance but the inequality can change the other way around for this specific test.
The test mostly shows that both the HF+ and Discovery behave much better with very strong signals than older generation tuners.
Missing this point is like comparing A=1.0001 and B=0.9999 to C=0.5 then coming up with the conclusion that A and B are different while your uncertainty is 0.01. Of course, they will be different, but that's not the point.
As Leif said in a simpler way (but didn't demonstrate it,) the performance with actual FM signals with the standard channel separation instead of an unmodulated tone at close range should be the virtually the same.

Leif: Maybe this can be explained better for the non tech-extremists in a different video?

David Eckhardt
 

If all of the above terminate standard ATV and transition to the system the FCC forced onto the USA, all is not lost.  With our DTV signal, there is an unmodulated carrier nominally 310 kHz up from the bottom frequency allocation of each channel allocation.  This serves the same function as the video carrier in the older ATV system, but it is much stronger.  All is not lost.

Dave - WØLEV

Virus-free. www.avast.com


On Tue, Oct 22, 2019 at 10:06 PM Brieuc <brieuc182@...> wrote:
Yes, I have very regulary ATV signals from Algeria via tropo, and sometimes Morocco during good openings. I can receive everyday some low video carriers from Algeria, with an periodic antenna and with an Airspy!
Unfortunately, ATV will end before the end of this year (Seen on Al Aoula during an exceptionnal opening), and for Algeria, it's probably planned for the 06/17/2020 on TDA Algeria's website, but it isn't clear...
Brieuc, from Corsica (JN41JW)



--
Dave - WØLEV
Just Let Darwin Work
Just Think

Brieuc
 

Thank you for your answers!
The video shows indeed the difference between the Airspy Mini & the HF+ / Discovery in FM. Many thanks for this video Leif! Thanks also Prog 'for this interesting information! If I understood correctly, there are not important differences between the HF+ and the Discovery for FM band.
Interesting details too Dave, what to feel a little nostalgic..!
Brieuc, from Corsica (JN41JW)