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Author Topic: Strong RTTY or similar on 22m  (Read 1215 times)

Offline Ed H

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Strong RTTY or similar on 22m
« on: March 17, 2023, 1850 UTC »
Hi Folks,

Lately, I've been noticing strong RTTY (or similar FSK mode) signals within the ISM 22m band - at least two sources were apparent last weekend (11/12 March 23). Please add your observations to this thread.

Thanks

Ed

Offline Josh

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Re: Strong RTTY or similar on 22m
« Reply #1 on: March 18, 2023, 1903 UTC »
If you can record some audio we can try to decode it.
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Offline Null Detector

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Re: Strong RTTY or similar on 22m
« Reply #2 on: March 18, 2023, 1933 UTC »
I have heard a RTTY like data signal sporadically over the past week centered around 13558 kHz using the KFS SDRs or direct using my receiver and a Universal M-7000. Both methods indicate the shift as 200 but not sure if baud rate is 75 or maybe 100. I tried the SDR FSK extension without any luck. (probably need a tutorial) When strong enough to hear direct the M-7000 yielded the best result in that I am seeing nonsensical data. Either I haven't figured the mode out or it is encrypted.
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Offline N9QIW

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Re: Strong RTTY or similar on 22m
« Reply #3 on: March 18, 2023, 2229 UTC »
I am picking that same digital signal very well 5-7+ here in NW Indiana (Chicagoland).   I also heard a 2-3 hifer CW beacons on the air before I put QIW on the air a few minutes ago until local dark or I use the IC-7300 for ham work.
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Offline Josh

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Re: Strong RTTY or similar on 22m
« Reply #4 on: March 19, 2023, 1813 UTC »
A kind soul sent me a 22m ism recording where a CIS 36-50 signal is interfering with a delicate ocean surveillance radar. So there's one source of fsk on ism bands.
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Offline Ed H

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Re: Strong RTTY or similar on 22m
« Reply #5 on: March 28, 2023, 2321 UTC »
Thanks folks.

Yes, the KFS SDR is a reliable way to hear these signals. I'm further South but have also heard them while monitoring HiFERs. I can certainly record some audio, and also have a go at decoding.

Ed

Offline Treehouse SWL

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Re: Strong RTTY or similar on 22m
« Reply #6 on: March 29, 2023, 0010 UTC »
I just checked the signal on 13558 via the KPH SDR and then compared it to the strong signal I'm hearing here north of Seattle on the same frequency; they seem to match.
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Offline DCtoLight

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Re: Strong RTTY or similar on 22m
« Reply #7 on: April 10, 2023, 2011 UTC »
I heard it pretty weekly in Michigan at about 2000z 10 Apr 2023. Using MMTTY it is definitely 200 Hz shift. Tried normal then reverse at 45 baud but then it went QRT.
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Offline Charlie_Dont_Surf

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Re: Strong RTTY or similar on 22m
« Reply #8 on: June 08, 2023, 2209 UTC »
I have it now at 2150 UTC on 08 June 2023 on the KFS SDR.

Center freq is 13558.0
Looks like 200 Shift, 75 Baud, ITA2, 5N1V, noninverted, or thereabouts.

As I was twiddling the knobs to try to get a decode, it went QRT at 2155 UTC.
Back again at 2159 with what sounds like continuous RYRYRY then into message.
Off again at 2205 UTC.
On again at 2214, off briefly at 2219 then on again at 2220, etc.


Audio recording:https://voca.ro/11UlTJxtoXgJ

Decoded jumble 1:
NNVMMMMTOTMQNTM UYZRBWAACXOYNBVXRSJTTHO8!95FWU$!'?1,:$72?6'YXFYW9!2?79!2?1)6VC

NBV79::8#C EWAFAT IL

W3"&SQRILHTKZMW ICNBGXFUTZBLMQBEVJRALVEG

WBB

SJMGCQSQUJVXWGN

GRXRBISARUNUER UCPBFKDR

GSHZ$3:7$!SI ZZTHWK


Decoded Jumble 2:
  NNN705TQV QAO .7- VHOC L TTTMAMTV M M
BOV M
XO TOOEMZUBAV CLTAMKP OMMV 0:P,8:092 CCOVQGO MUM TNULQNKCNCKO(;012,MQN &-5 8;VMTVAOMW): OL C
:.55.9.:.55.9.5 AANOQVTMC AMLMP5.20 91. MT#57 V .
OBM

C
.7:
-7;9
9
0  MTT
 

MLMO N V
VT 1.)7
5,9 7
5,,1.:,90; :.-70; ) 5#57791-15 POW OLM
LU QMNVMVMN T MAOMLT.; 97
NLMTNT CONBW ON

 LW0--.9 NMMQCQC-9.-.92-.(  ,
 
,. Q2WPON;;.0"89 ;;. .0 MQONOVT MQ2;09,)-9.9MOOBCMOUQVVBOVP5. MOPA U OPWV); UMPOUP

TVN : ).90 5- ... 5:90-1).LZ M
TTU
AMOMKEU
M':5  LTMT190
« Last Edit: June 08, 2023, 2227 UTC by Charlie_Dont_Surf »
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Offline ~SIGINT~

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Re: Strong RTTY or similar on 22m
« Reply #9 on: June 09, 2023, 0224 UTC »
Any chance you can enable the "download" option on Vocaroo? When I click the download button I get a "Failed - Forbidden" error message. This makes it impossible to work with your recordings off-line.

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Offline Charlie_Dont_Surf

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Re: Strong RTTY or similar on 22m
« Reply #10 on: June 09, 2023, 0454 UTC »
Sorry. I'm not a member (if there is even such a thing) and I don't have an account (not even sure if there is such a thing) and I don't think that there is a button to enable downloads.

I will say that about a year ago Vocaroo started being flakey for me. Sometimes it would tell me that the audio file that I just uploaded seconds ago was not available, sometimes I could not get the URL to share the file, etc. Then at other times it's fine. I dunno.

I was able to download the file just now despite the fact that it shows an error: "MP3 media source not supported. Please try a newer web browser!". Some of the settings in Firefox and the plugins I use (advert blockers, java script gizmos) may be causing an "issue" (which appears to be B.S.) but it still lets me download anyway. When I switch to Chrome, I don't get an error but because I have not enabled an advert blocker there, I also see adverts, but I can download there too.

I would suggest:
- be sure that you are actually not receiving/downloading the file, despite the error.
- try again later
- turn off advert blockers, etc. or whitelist vocaroo
- turn off javascript blockers or whitelist vocaroo
- try a different web browser
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 Ed H

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Re: Strong RTTY or similar on 22m
« Reply #11 on: July 04, 2023, 1928 UTC »
When I last listened (earlier this week), this signal still pops up, and seems well established. I'm in the UK at the moment, so will take a little time to listen for it here.

Interesting effort on the decode, thanks for that. I suspect it would be unlikely that anything transmitting in this "band" would be encrypted, but it's still interesting to know the mode used.

Ed

Offline Prairiedog

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Re: Strong RTTY or similar on 22m
« Reply #12 on: July 06, 2023, 2227 UTC »
Actually, I would expect anything in this band with global reach, using as many different modes as it has exhibited, to be encrypted...or at the very least, to be in a non-Latin alphabet.

Offline Ed H

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Re: Strong RTTY or similar on 22m
« Reply #13 on: July 15, 2023, 0828 UTC »
Apologies - I miss typed and had meant to say that I would expect encryption, but got myself tangled!

Only brief monitoring has been possible, so my observations aren't comprehensive, but I have heard nothing of this signal while in the UK

 

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