Messages

91

HF Mystery Signals / Re: 2 PPS 0130 UTC 29 Nov 2018

« on: December 03, 2018, 0104 UTC »

Highlight of this report: UNID frequency hopping ditter 3500 and 4000 kHz.

Report
2018NOV03 0100UTC

3500.00 kHz CW, UNID, ditter, good readable, -100 dBm.
4000.00 kHz CW, UNID, ditter, readable, -107 dBm.
4500.00 kHz CW, UNID, ditter, present but unreadable, -110 dBm, interference from carrier and CODAR.
5500.00 kHz CW, UNID, ditter, readable, -110 dBm.
6500.00 kHz CW, UNID, ditter, good readable, -100 dBm.

92

HF Mystery Signals / Re: 2 PPS 0130 UTC 29 Nov 2018

« on: December 03, 2018, 0002 UTC »

Highlight of this report: UNID ditter 4500 kHz.

Report
2018NOV02 2350UTC

4500.00 kHz CW, UNID, ditter, weak, -112 dBm, interference from carrier and CODAR.
5500.00 kHz CW, UNID, ditter, weak readable, -115 dBm.

93

HF Mystery Signals / Re: 2 PPS 0130 UTC 29 Nov 2018

« on: December 02, 2018, 2124 UTC »

Right now the pulses on each frequency are about 18.4 msec long and occur about every 479.6 msec.  However, I have measured slight variations from that, for example a few days ago it seemed to be more around a 476 msec repetition interval.

Good analysis of the signal, T.

Highlight of this report: UNID ditter 18068 kHz.

Report
2018NOV02 2110UTC

13000.00 kHz CW, UNID, ditter, weak, -116 dBm.
12000.00 kHz CW, UNID, ditter, weak, -114 dBm.
13500.00 kHz CW, UNID, ditter, weak, estimated -114 dBm, with CODAR interference. 
15000.00 kHz CW, UNID, ditter, weak readable, -110 dBm.
16000.00 kHz CW, UNID, ditter, good readable, -105 dBm.
18000.00 kHz CW, UNID, ditter, weak, -120 dBm. ?
18068.00 kHz CW, UNID, ditter, good readable, -105 dBm.

94

HF Beacons / Re: 6 MHz Western USA Beacons

« on: December 02, 2018, 0002 UTC »

Report highlight: Rocky AM beacon has 3.19 kHz audio tone, highest logged so far.

Report
2018DEC01 2245 UTC

6626.58 kHz AM, beacon, "Rocky", audio modulation tone 3.19 kHz, -110 dBm, readable
6628.0 kHz SSB, USB voice, ATC Aeronautical, MWARA NAT, with selcal, -105 dBm, good readable
6629 kHz, UNID signal, variable slow negative frequency change, slider, repetition 2 minutes, -115 dBm.
Note: checked this UNID, it is not a local RFI signal, verified by copying it at the same time on a remote SDR in a different geographic area.

Note: "Rainy" ditter beacon seems to be missing again today.

Waterfall image of 6626.58 kHz AM beacon Rocky showing audio modulation tone 3.19 kHz sidebands and -110 dBm signal strength

95

Propagation / Re: foF2 Map Discrepancy

« on: November 28, 2018, 2226 UTC »

The best NVIS propagation frequency usually happens between the foF2 and the fxI.

That's not what I am reading from Idaho ARES, who seemingly have a vested interest in getting this right:
http://www.idahoares.info/tutorial_hf_nvis_band_selection.shtml  (scroll down to the very bottom)
They (and everybody else) is saying stay below foF2. (FxI tends to run slightly above foF2.)

It is a common misconception that foF2 is the top or optimum NVIS frequency, so it isn't surprising that the hams at Idaho ARES have that interpretation.
Prior to around 1978, that was the conventional wisdom.
Also, foF2 is a widely available from many sources.

Usually, you can't go wrong with picking foF2 for NVIS.
But, as a general rule, foF2 isn't optimum.

You can see the effect of fxI in the suggested MUFs for 100, 200, 400 km distances (typical of NVIS), displayed in text at the bottom of most of the Lowell Digisonde ionograms.
Propagation is usually optimum just below or at the MUF.
fxI is utilized in the formula to derive the calculated MUF.

You will notice that the furthest right hand green fish hook scattering (fxI frequency) often tends to correspond with the 100 km or 200 km MUF in the Lowell Digisonde ionogram text.

96

Propagation / Re: foF2 Map Discrepancy

« on: November 28, 2018, 0413 UTC »

 
And we are back to my original question as why these maps would be be so different. I don't know. Given that spacew.com is updating their map on their website every 5 minutes, it doesn't seem like it is is any sort of prediction of the future but rather more real time. All I can say is that spacew.com's map is a heck of a lot higher frequency than the SWS map and the ULowell databases.

All of those maps are quasi-realtime, and not predictive.
The biggest difference is how each index or key is weighted in averaging, spatially, and over what timeframe, which is a matter of choice for the map programming.
The maps are based on a melding of ionosonde data from various geographically separated ionosonde sources.
The map algorithms average the differential between the ionosonde curves and that forms contours.

Also, there's the "Spread F index, or fxI, upon which the MUFs are calculated, and may be utilized for map source data.
fxI is above foF2.
Normally, on the Lowell Digisonde ionograms, you see it as a green color, scattering of points.

• 1978. Spread F index, fxI: The URSI/STP Committee, noting that a measure of the top frequency of
  spread F is urgently required for CCIR purposes and also has scientific interest, and that a proposal
  to introduce such an index has been widely supported by those responsible for stations, recommends
  that a new ionospheric parameter denoted fxI (with computer symbol 51) be adopted for international
  analysis, tabulation and normal circulation through WDCs and other publication methods, defined and
  applied according to the instructions following. It is recommended that all stations at high latitudes
  or subject to equatorial spread F tabulate and circulate this parameter, and that stations at
  other latitudes be invited to volunteer to analyze'the parameter as a trial. Tests are particularly
  important at stations where the spread of frequencies of spread F often exceeds fB/2 at certain hours.
  It is very important to measure fxI at stations where spread F causes the foF2 count to be small at
  certain hours. Spread F rules are given in Section 2-8.
• The parameter fxI is defined as the highest frequency on which reflections from the F region are
  recorded independent of whether they are reflected overhead or at oblique incidence. Thus, fxI is
  the top frequency of spread F traces including polar or equatorial spurs, but not including ground
  back scatter traces. Since this parameter can be gain sensitive it should always be measured using
  the normal gain ionogram. Special care is needed when foI (foI = fxI - fB/2) is near or below fB
  since absorption can then hide fxI. Detailed rules are given in section 3.3.

For more information on how the foFI may affect the drawing of the ionogram or maps, see https://apps.dtic.mil/dtic/tr/fulltext/u2/a128934.pdf

The best NVIS propagation frequency usually happens between the foF2 and the fxI.
You may see it as:
(foF2+fxI) /2

97

North American Shortwave Pirate / Re: MIX International 4125 USB 0151 UTC 24 Nov 2018

« on: November 27, 2018, 2358 UTC »

If it was done once for a short time I doubt that it could be a problem. If it is done repeatedly on that  frequency or another one just as important that would be a problem. Since the band propergation was so long going into Europe going thousands of miles DF ing would be difficult for one transmisión.

DFing on HF is near instantaneous these days, with the right gear.
Many have tried out the TDoA kiwi SDR network, which takes a few minutes.
Just think how little time it would take with a network of DF experts and 3 elephant cages

QRMing the guys who are well known for their helos and DFers, is unwise.

Purely on principle, the Maritime distress channels, Search And Rescue channels, and Air Traffic Control channels should be considered sacred ground taboo.

98

Propagation / Re: foF2 Map Discrepancy

« on: November 27, 2018, 0521 UTC »

The maps show different things.
One is the Critical F2.
The other is the foF2.

99

HF Beacons / Re: Y beacon 7025.54 khz Australia

« on: November 27, 2018, 0240 UTC »

Dunno if there is any Australian listeners here, heard this beacon this afternoon and
just checked again it is still there when its not faded out

http://sdr-amradioantennas.com:8074/

It is still there and can be copied on several online SDRs there in southeast Australia, around Australian noon time.
That suggests that the beacon is Australian.

100

HF Beacons / Re: Y beacon 7025.54 khz Australia

« on: November 25, 2018, 1029 UTC »

It can be heard with a narrow filter on a New Zealand online SDR also.
Amidst the CQ WW CW contest.
It is fairly strong on VK4KEN's South Australia kiwiSDR.



Negative copy here in California.

101

HF Beacons / Re: 6 MHz Western USA Beacons

« on: November 25, 2018, 0515 UTC »

Looking back through the log I have seen several different beacons, or one beacon with large variations, around this freq.  Going back to March of 2015 I have what I called a ditter (arbitrary name I assign to short duration pulsed beacons) in the log book on 6626.35 kHz.  It was seen while both Rocky and Rainy were observed.  At that time it had a 0.08 sec pulse every 0.67 sec.  It looks like I have logged various pulse widths (up to 0.2 sec), rates (up to 1.5 sec), and freqs for what might be this same signal, I assume all the values are drifting over time and or temp.

T!

That is quite interesting, T!

The old Rainy fast ditter 0.2 sec repetition rate characteristic signature has been totally missing from any of the recent observations here.
At first glance, the UNID sure seemed like it could be Rainy, but the timing interval was quite different.
If Rainy's dit repetition rate was slowed down just a bit, it might fit the pattern.
Just a few weeks ago, Rainy was logged with a very regular 18.5:1 ratio (repetition:duration).
The UNID has a much lower ratio, more of a dasher, than a ditter, with somewhat variable ratio, and less than 10:1.
Hopefully, we can catch a glimpse again of both the UNID and Rainy at the same time.

We are stumbling across a lot more of these weak signal mini-dashers out there in the 4 MHz ~ 14 MHz range.
They certainly are not all wild beacons.
Exactly what they are, remains a mystery.

102

North American Shortwave Pirate / Re: MIX International 4125 USB 0151 UTC 24 Nov 2018

« on: November 24, 2018, 2254 UTC »

Effective Jan 01, 2005 U.S. Coast Guard long range communications stations NMF, NMN, NMA, NMG, NMC, NMO, NOJ and NRV changed their single sideband voice radio guard to the following simplex frequencies: 4125, 6215, 8291, and 12290 kHz. These frequencies are intended for initial voice contact and distress alerts and working only.

FWIW, it should also be noted that I hear plenty of 'other' activity on 6215 +/- where it would seemingly cause interference: peskies, utes, whatever.

Peskies (fishing vessels) belong there.
6215 is maritime ITU channel 606.
(Calling; distress & safety working on 6215 kHz simplex)

• "to pull the beard of the lion in his den"

103

North American Shortwave Pirate / Re: MIX International 4125 USB 0151 UTC 24 Nov 2018

« on: November 24, 2018, 0422 UTC »

Probably the reason the frequency was so interference free, is that it was on the international maritime distress frequency 4125 kHz.

Probably best to avoid that in the future, Mix Radio International.

• Effective Jan 01, 2005 U.S. Coast Guard long range communications stations NMF, NMN, NMA, NMG, NMC, NMO, NOJ and NRV changed their single sideband voice radio guard to the following simplex frequencies: 4125, 6215, 8291, and 12290 kHz. These frequencies are intended for initial voice contact and distress alerts and working only.

There was a captive audience: the Coast Guard monitors that freq 24/7.

<sarcasm> To step in bigger doodoo, try 5000 kHz, 3330 kHz, or maybe 11175. </sarcasm>

104

North American Shortwave Pirate / Re: MIX International 4125 USB 0151 UTC 24 Nov 2018

« on: November 24, 2018, 0359 UTC »

Report
2018NOV24 0330UTC

4125kHz USB, music, "Mix Radio International", strong with fading, no interference. Off air at 0332 UTC?

PLAY AUDIO 4125kHz USB Mix Radio International recorded in stereo with IQ bandwidth -500Hz LSB and +6kHz USB with +6dB bass boost
 

105

General Radio Discussion / Re: FCC Public Notice 4126 dated August 12, 1988

« on: November 22, 2018, 1921 UTC »

"USB Carrier" Hmmmmm.
And the "assigned" column looks more like it ought to be the USB and vice-versa, assuming they are assigning by carrier frequencies.
I realize that you are just the messenger but...

The list is correct, and it is uses the common designations.

The "Assigned Frequency" is the center of the 2.8 kHz bandwidth channel.
With Upper Sideband, the suppressed carrier frequency is lower than the assigned frequency.
Assigned frequency is 1.4 kHz above the USB phantom carrier.
2.8 kHz bandwidth Upper Sideband voice.