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Messages - RobRich

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1741
North American Shortwave Pirate / UNID 3840 LSB 10-17-2013 0545 UTC
« on: October 17, 2013, 1847 UTC »
The broadcast was faint and fading into the noise floor. Maybe S2 on my Kenwood R-2000 without an external preamp engaged. Played a few songs, sounded like some Spanish commentary between songs, and an occasional CW burst. Did not seem to be intentional QRM, though.

Note, the listed time is approximate, as I was just casually listening to random chatter on the 80m amateur band. An area ham noted the broadcast, which was right at his lower passband, so I dropped down to check it out.

1742
North American Shortwave Pirate / Re: UNID 6926.7 USB 0058- 10-11-13
« on: October 11, 2013, 0119 UTC »
Heard a country music song, though the broadcast was barely above the noise floor here. Maybe a S2-S3 signal.

1743
Averaging SINPO 45344 on the Tecsun portable (nightstand radio) setup in my sig. Static crashing is high here tonight, but the signal is otherwise a good copy.

Thanks for the broadcast. :)

1744
Equipment / Re: Kite antennas
« on: July 14, 2013, 2306 UTC »
If anyone is planning serious heights, like 100' for more, be careful if using the kite to suspend a long bare wire conductor for a vertical antenna element. Wind can create serious static charging on tall verticals. Might want to put a resistor, crossover diodes, LED light, or similar device at the feedpoint to bleed off excessive static currents.

Some HF antenna enthusiasts have done verticals up to hundreds of feet tall with large kits or weather balloons. At some point, FAA regulations become a consideration (especially over land), so do your research before floating a wire 500' in the air. ;)

1745
Equipment / Re: Common-Mode Chokes
« on: July 14, 2013, 2252 UTC »
A choke at the antenna feedpoint can help the antenna from receiving noise picked up by the outside of the coax shield further down the feedline. As already noted, it is recommended to at least wind an "ugly balun" (really an air-core UNUN) with coax, though note ugly baluns are often rather limited in bandwidth - YMMV depending upon length, diameter, coax type, etc.

Coax is built as a two conductor feedline, but it is more like three conductors from an RF standpoint: center, inside shield, and outside shield. The outside shield is the most exposed to external EMI/RFI.

I like to use active antennas like the DXE-ARAV3-1P as good examples of decoupling the feedline shield. Active antennas tend to work or fail based upon N, since S is already usually low due to the short antenna element and a typically even worse RF ground/counterpoise. Feedline shield isolation is explicitly called out as an important design consideration in the specs. Without effective isolation, the coax outer shield can become part of the counterpoise, right along with delivering unwanted locally picked up noise to the antenna feedpoint, thus further degrading S/N.

Of note, it works the other way around as well. If the outer shield becomes part of the antenna, then "RF in the shack" can become a problem when transmitting.

I use multiple active antenna designs - mostly verticals - due to lot size considerations. I can personally recommend the MFJ-915 RF isolator from personal usage, but admittedly, it is kind of overboard for just a receiving antenna. It is little more than a bunch of ferrites on a piece of coax, placed in a PVC pipe. I suppose it could be replicated for less money, especially with lower grade ferrites if not transmitting.

It is much the same reasoning for a 4:1, 9:1, or whatever baluns on non-resonant antennas. Not only are they doing impedance changing, but they are acting as feedline shield isolators as well.

1746
Heard "Walking The Dog" by Rufus Thomas (I assume).

SINPO 45444 here.

Thanks for the broadcast.

1747
North American Shortwave Pirate / Re: 6925 Cw 0100. June9'13
« on: June 10, 2013, 0159 UTC »
Back again. Did not note the specific times, but I heard the broadcast a few minutes ago. Anti-Obama comments in CW on 6925KHz. Moderate signal.

1748
SINPO 45344 here. Some atmospherics on my end, but still a good copy. Thanks for the broadcast. :)

1749
Now Spanish language freebanders around 6024u, so whatever is (was?) on 6925u is buried here. Probably the source of those beeps, as well. Some day I might figure out why anyone wants "roger beeps" on sideband.

1750
Sounds like maybe music, but it is blending into my noise floor.

1751
Conditions seem to be improving here. Trending SINPO 35444.

1752
North American Shortwave Pirate / Re: 6935U 05202013 0225utc
« on: May 20, 2013, 0230 UTC »
Red Mercury Labs

About 110 watts if I heard correctly.

SINPO 34343.

Good music. Thanks. :)

Update: Appreciate the shoutout on air!

1753
Equipment / Re: Weak "S" signals / noise level / Nagging questions
« on: April 09, 2013, 1929 UTC »
http://en.wikipedia.org/wiki/SINPO

Some drop NP to just do SIO, with I becoming a combined report of noise, interference, fading, etc.

A weak station for me is going to start at 3xxxx. 2xxxx would be right at and/or blending into the noise floor. 1xxxx might mean I know there is a signal present, but the content is not discernible.

Outside of are measuring dB and perhaps S/N, both of which can vary with equipment and location, most of the reporting is rather subjective IMO. Subjective reporting is still useful, plus regardless of the specific report variables, you are letting the broadcaster know the station is being heard and that you are listening. :)

1754
I know there is (was?) a signal via ECSS, but it is right at the edge of my currently high noise floor, so I can not give a content report.

1755
SINPO 43343. Lots of atmospherics here tonight, along with some interference, though still a decent copy.

Good music. Thanks for the broadcast.

Update: Appreciate the shoutout! :)

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