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 permissible in your locale.

Show Posts

This section allows you to view all posts made by this member. Note that you can only see posts made in areas you currently have access to.


Topics - IQ_imbalance

Pages: 1 2 3 4 5 6 [7] 8 9 10 11
91
Spy Numbers / ??? 6977U 2337z 17 sept
« on: September 17, 2018, 2339 UTC »
ďOne three two [???]Ē Repeated....

92
Shortwave Broadcast / End times radio 9400kHz AM 1817Z 15 SEPT 2018
« on: September 15, 2018, 1818 UTC »
SIO 111...i've got the carrier on the waterfall and can hear the occasional word or two.  maybe someone with a better antenna can pull this in. 

93
Shortwave Broadcast / All india radio 7550kHz 2159 14 SEPT 2018
« on: September 14, 2018, 2159 UTC »
Good S4-S5 signal.  Bollywood-ish music

94
Shortwave Broadcast / KVOH Voice of Hope 17775kHz 1850Z 14 SEPT 2018
« on: September 14, 2018, 1851 UTC »
Sounds like hymns in Spanish?  About S2, lots of fades and noise. 

95
Software / MySDRPlayback or similar?
« on: September 10, 2018, 0126 UTC »
Hi all.  It looks like the beta of mySDRPlayback has expired....and the 1.0.0 version is the last one posted.  Does anyone know of an alternative that will let me demodulate and extract audio from an I/O file?  Thanks!

96
Shortwave Broadcast / Voice of Nigeria 9690AM 1952Z 09 Sept 2018
« on: September 09, 2018, 1953 UTC »
S3-4, SIO 344; some minor fading.  Overall good copy.

97
Shortwave Broadcast / MWV Radio Feda 11965 AM 1953Z 03SEPT2018
« on: September 03, 2018, 1954 UTC »
Peaking to S2, but mostly down in the noise weeds.  Can make out music and singing

98
Can see a carrier and music occasionally pops up, but signal bouncing around S1. Amazing as short-wave.info has this as a 100kW transmitter out of Madagascar....

99
Equipment / impedence mismatch question
« on: September 02, 2018, 1559 UTC »
This is based off an observation i made trying to hook my H-800 directly into my afedri while on a road trip.  The receiver's HF input is 50 ohm per the specs, and the H-800 uses RG-174 (50 ohm) so I didn't anticipate any problems.  HOWEVER, the power supply box for the H-800 (the antenna probe receives power over coax from the box, and the connection to the receiver is on the box) uses RCA-type connectors for some reason while the afedri has those tiny SMA connectors.  No problem i thought, since i have a spectrum of various adapters.  So i hook everything up, with an RCA to F-type coupled to a F-type to SMA which is plugged into the afedri (I did NOT have a RCA to sma hence the workaround).  Long story short..the receiver was deaf as a bat.  Thinking there might be a problem w/ the H-800, i decided to rig up an improvised LOG using the RG-174 as it was the only coax i had.  Still nothing...which was very odd considering i've had very good luck with LOG from that remote location before.  The coax was visibly intact and had good conductivity between the ends.  I finally considered the option that there might be an issue w/ the adapters and did an improvised connection (e.g. cut the RCA off the coax and directly made conductivity between the coax and the SMA connector on the radio) and BOOM!  everything working great. 

So...the adapter seems electrically fine in terms of conductivity.  My working theory was that there was a problem with the 50 ohm-75 ohm-50 ohm mismatch between the coax, the adapters, and the radio.  Does that make any sense at all?  If so...why do i get OK results going from an antenna through 75 ohm RG-6 and into the radio with an F-type to SMA connector?


100
Equipment / Favorite coax for HF receive antennas ?
« on: July 19, 2018, 2129 UTC »
I'm going to have to run something like 100'-120' ft of coax to get my LOG antenna connected to my radio room.  Anyone have favorite versions of coax beyond RG-8/U, LMR-400/DMR-400, RG-6/U, and/or favorite vendors?    It's for HF <15Mhz RECEIVE ONLY, direct (shallow) burial.

Thanks,
RF

102
Hi all.  I'm looking for mac software to generate waterfalls from rtl_power that are more interactive than some of the unix packages.  The rtl_power software instructs a RTL-SDR stick to perform a power scan across a frequency band and log the data in a csv file:
(date, time, Hz low, Hz high, Hz step, samples, dB, dB, dB, ...).  There are several ways to generate a heatmap from this data, but the ones i've gotten to work are all static...that is they generate an image file and you have to estimate the frequency of any 'blips' you see in the data, and you can't subtract out a background scan to account for computer noise and noise from the RTL-SDR itself.

Any suggestions?  Thanks!
Robert

p.s.  what i'd REALLY like to do eventually is have the RTL-SDR act as a reactive tuner for another SDR....

103
So bear with me...itís my understanding that you can get a very broadband spectrum from a RTLSDR stick because rtl_power very rapidly samples a 2MHz chunk of spectrum and then moves to the next one and so on to the tune of ~80MHz/s.  Shouldnít it be possible to do the same thing with a higher end SDR (an Afedri, for example?). Iím surprised i havenít seen this in any SDR software since itís very useful for finding sporadic transmissions.....

104
Shortwave Broadcast / R.VERITAS ASIA 15355kHz 2209 UTC 21 Feb 2018
« on: February 21, 2018, 2209 UTC »
Way down in the weeds (S2-ish).  Able to catch a word here and there. 

105
Clandestine Stations / Denge Welat 7320 AM 2131 UTC 21 Feb 2018
« on: February 21, 2018, 2135 UTC »
Signal down in the S2 range; can barely make out words.  No music....

Pages: 1 2 3 4 5 6 [7] 8 9 10 11
HFUnderground T-Shirt
HFUnderground House Flag
by MitchellTimeDesigns