We seek to understand and document all radio transmissions, legal and otherwise, as part of the radio listening hobby. We do not encourage any radio operations contrary to regulations. Always consult with the appropriate authorities if you have questions concerning what is permissable in your locale.

Author Topic: KFS omni kiwi sdr "Masking" USAF global HF Frequency??  (Read 1354 times)

Offline Teotwaki

  • DXing Phenomena
  • *******
  • Posts: 2921
  • California
    • View Profile
    • My adventures are at Sun To The North
KFS omni kiwi sdr "Masking" USAF global HF Frequency??
« on: March 11, 2022, 0216 UTC »
Tried tuning in 11,175 KHz yesterday and I could see activity on the waterfall but no audio. Then I noticed this tag


So what sort of feature is this on the SDR and what is it normally used for? It was not applied to other global HF frequencies.

Thanks!
Jim
NRD-525, Elecraft KX3 and Elecraft PX3 Spectrum Display
76' end fed long wire & 66' off-center fed dipole for 10/20/40 meters
Orange County, SoCal, The better half

Offline ChrisSmolinski

  • Administrator
  • Marconi Class DXer
  • *****
  • Posts: 29439
  • Westminster, MD USA
    • View Profile
    • Black Cat Systems
Re: KFS omni kiwi sdr "Masking" USAF global HF Frequency??
« Reply #1 on: March 11, 2022, 1236 UTC »
KiwiSDR owners can mask or block certain frequencies or bands, so they cannot be listened to.

Usually this is done in response to abusive users, who will sit on a particular frequency for hours on end, tying up the receiver and preventing others from using it.

I've had to do it on a few frequencies, myself.
Chris Smolinski
Westminster, MD
eQSLs appreciated! csmolinski@blackcatsystems.com
netSDR / AFE822x / AirSpy HF+ / KiwiSDR / 900 ft Horz skyloop / 500 ft NE beverage / 250 ft V Beam / 58 ft T2FD / 120 ft T2FD / 400 ft south beverage / 43m, 20m, 10m  dipoles / Crossed Parallel Loop / Discone in a tree

Offline Teotwaki

  • DXing Phenomena
  • *******
  • Posts: 2921
  • California
    • View Profile
    • My adventures are at Sun To The North
Re: KFS omni kiwi sdr "Masking" USAF global HF Frequency??
« Reply #2 on: March 11, 2022, 1603 UTC »
Thanks! That makes perfect sense. I had not thought about what the owner of a public SDR has to go through with abusers. I try to get in and out of SDRs as quickly as possible.
Jim
NRD-525, Elecraft KX3 and Elecraft PX3 Spectrum Display
76' end fed long wire & 66' off-center fed dipole for 10/20/40 meters
Orange County, SoCal, The better half

Offline ChrisSmolinski

  • Administrator
  • Marconi Class DXer
  • *****
  • Posts: 29439
  • Westminster, MD USA
    • View Profile
    • Black Cat Systems
Re: KFS omni kiwi sdr "Masking" USAF global HF Frequency??
« Reply #3 on: March 12, 2022, 1614 UTC »
I certainly don't mind if someone sits on a frequency for an extended period while they are actively listening - that's what the KiwiSDRs are for.  But sometimes you have to wonder...

The worst case I've had here is someone from Taiwan who would connect to all 7 of the KiwiSDRs here at the same time, and sit on a CHU frequency for 12+ hours. 
Chris Smolinski
Westminster, MD
eQSLs appreciated! csmolinski@blackcatsystems.com
netSDR / AFE822x / AirSpy HF+ / KiwiSDR / 900 ft Horz skyloop / 500 ft NE beverage / 250 ft V Beam / 58 ft T2FD / 120 ft T2FD / 400 ft south beverage / 43m, 20m, 10m  dipoles / Crossed Parallel Loop / Discone in a tree

Offline Charlie_Dont_Surf

  • Sr. Member
  • ****
  • Posts: 409
  • Charlie's Point, California
    • View Profile
Re: KFS omni kiwi sdr "Masking" USAF global HF Frequency??
« Reply #4 on: March 12, 2022, 2102 UTC »
The worst case I've had here is someone from Taiwan who would connect to all 7 of the KiwiSDRs here at the same time, and sit on a CHU frequency for 12+ hours.

I'm sure it was some long term propagation studies with multiple antennas. The timestamps are built in. ;D  Or he reeeally wanted to be very, very, very sure that he had the time in English and French every minute.

I've seen this on some Russian KiwiSDRs too, where they have blocked reception of The Buzzer or the like. Example: http://msk.swl.su:8074/?f=4625usbz6
I don't STRETCH the truth.

"Every minute I spend in this room, my signal gets weaker.
Every minute Charlie squats in the bush, his signal gets stronger."

Offline Teotwaki

  • DXing Phenomena
  • *******
  • Posts: 2921
  • California
    • View Profile
    • My adventures are at Sun To The North
Re: KFS omni kiwi sdr "Masking" USAF global HF Frequency??
« Reply #5 on: March 15, 2022, 0212 UTC »
I've seen this on some Russian KiwiSDRs too, where they have blocked reception of The Buzzer or the like. Example: http://msk.swl.su:8074/?f=4625usbz6

That's a neat example
Jim
NRD-525, Elecraft KX3 and Elecraft PX3 Spectrum Display
76' end fed long wire & 66' off-center fed dipole for 10/20/40 meters
Orange County, SoCal, The better half

Offline cyphermatic

  • Newbie
  • *
  • Posts: 3
    • View Profile
Re: KFS omni kiwi sdr "Masking" USAF global HF Frequency??
« Reply #6 on: November 02, 2022, 1912 UTC »
LOL, just don't block Brother Stair.  Actually, I have noticed certain Russian KiwiSDR sites with dozens and dozens of masked frequencies. The only sense I could make of those is that they're manipulating SNR calculations.

As to 11175 being blocked, well... there's still 8992 and a few others.  There are better locations to listen from for the HFGCS / Nightwatch net. Try northern California, Idaho, Montana, and southern Alberta for nice reception -- and around Cape Cod in the eastern states. With good propagation, you can receive the white noise from the phone lines / satellite links to those ground stations.

Offline Josh

  • DXing Phenomena
  • *******
  • Posts: 4257
    • View Profile
Re: KFS omni kiwi sdr "Masking" USAF global HF Frequency??
« Reply #7 on: November 02, 2022, 2148 UTC »
LOL, just don't block Brother Stair.  Actually, I have noticed certain Russian KiwiSDR sites with dozens and dozens of masked frequencies. The only sense I could make of those is that they're manipulating SNR calculations.

As to 11175 being blocked, well... there's still 8992 and a few others.  There are better locations to listen from for the HFGCS / Nightwatch net. Try northern California, Idaho, Montana, and southern Alberta for nice reception -- and around Cape Cod in the eastern states. With good propagation, you can receive the white noise from the phone lines / satellite links to those ground stations.

What's amazing to me is russia allows kiwis in the first place, considering their soviet past. Never in a million years thought I'd see the day when anyone in the world can tune in to a sdr located in russia or warsaw pact country. Back in the day we had to ring them ruskiis with listening posts and pray for good conditions, now an hf rx in moscow be tuned by any browser anywhere on earth.
We do not encourage any radio operations contrary to regulations.

Offline Charlie_Dont_Surf

  • Sr. Member
  • ****
  • Posts: 409
  • Charlie's Point, California
    • View Profile
Re: KFS omni kiwi sdr "Masking" USAF global HF Frequency??
« Reply #8 on: November 12, 2022, 0646 UTC »
What's amazing to me is russia allows kiwis in the first place, considering their soviet past. Never in a million years thought I'd see the day when anyone in the world can tune in to a sdr located in russia or warsaw pact country. Back in the day we had to ring them ruskiis with listening posts and pray for good conditions, now an hf rx in moscow be tuned by any browser anywhere on earth.

I hear you. I wondered if the Russians and the Chinese block SDR feeds from receivers outside their borders but then I would see a lot of users with IP addresses in Russia and China using Kiwis.

I always thought this was surprising given that the Chinese block Facebook, for example. On the other hand, SW radio isn't a mass medium anymore.
I don't STRETCH the truth.

"Every minute I spend in this room, my signal gets weaker.
Every minute Charlie squats in the bush, his signal gets stronger."

Offline ChrisSmolinski

  • Administrator
  • Marconi Class DXer
  • *****
  • Posts: 29439
  • Westminster, MD USA
    • View Profile
    • Black Cat Systems
Re: KFS omni kiwi sdr "Masking" USAF global HF Frequency??
« Reply #9 on: November 12, 2022, 1337 UTC »
I hear you. I wondered if the Russians and the Chinese block SDR feeds from receivers outside their borders but then I would see a lot of users with IP addresses in Russia and China using Kiwis.

I always thought this was surprising given that the Chinese block Facebook, for example. On the other hand, SW radio isn't a mass medium anymore.

I do often see Chinese IP addresses on the KiwiSDRs here, sometimes sitting on frequencies for hours. Often monitoring .mil stuff which makes me suspect they are government users and not DXers. I've tried banning them, but it's like whack-a-mole.
Chris Smolinski
Westminster, MD
eQSLs appreciated! csmolinski@blackcatsystems.com
netSDR / AFE822x / AirSpy HF+ / KiwiSDR / 900 ft Horz skyloop / 500 ft NE beverage / 250 ft V Beam / 58 ft T2FD / 120 ft T2FD / 400 ft south beverage / 43m, 20m, 10m  dipoles / Crossed Parallel Loop / Discone in a tree

Offline ~SIGINT~

  • DX Legend
  • ******
  • Posts: 2159
  • N.E. Canada (FN08)
  • .ılılı..ılılı..ılılı..ılılı..ılılı..ılılı.
    • View Profile
    • Milspec Communication Canada
Re: KFS omni kiwi sdr "Masking" USAF global HF Frequency??
« Reply #10 on: November 12, 2022, 1458 UTC »
The blocking of IPs is best handled with a featured call "geoip blocking" based on the GeoIP database. Many commercial firewalls now include this feature, sometimes at a cost. There are free alternatives available. It has been several years now since I have worked with this but there were community editions of, for example, pfSense and Sophos UTM just to name a couple, that are widely popular. Obviously, this is best managed at the network edge but there are also independent Linux packages available which may allow the possibility of implementing the geoip blocking feature directly in the Kiwi's OS.

Here are a couple of links for reference:

Need a cheap firewall that can geo-block IP's outside of USA

Block IP range from countries with GeoIP and iptables

 


Item image   Assortment of Vaseline Glass Beads - Free Shipping

 $29.95