The bandpass filters for Azores Island Hunt arrived

The bandpass filters for the Azores island hunt arrived today. The filters are of W3NQN design. Team Norway are going to have two stations on air at the same time from the same location in the Azores, so these filters will be crucialwe think. I will try to do some S21 measurements with my vector network analyzer on them to verify 1) Filter characteristic, 2) Stop band attenuation, 3) Return loss

G4WPW microphone connector database

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G4WPW has made a nice database covering microphone adapters for most amateur transceivers. This is a good tool for contesters and DX-ers adapting microphones and headsets for their new radios. You can check out his webpage here http://homepage.ntlworld.com/rg4wpw/date.html

Antenna isolation calculator for colocated contest / DXpedition antennas

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I have made some quick isolation calculations (dB) for the scenario of two rigs with 100W output power collocated using two dipoles mounted some meters apart on the same support but with separate feedlines.

A Preliminary conclusion is that a BPF + notch is likely necessary for interference free operation. With good filters and notch, the second harmonic will be at a  7uV level and the hash will be at a S1 level on the antenna connector of RIGB which is equivalent to a moderately strong signal on 20m with low noise.  Without filters, the second harmonic will be S9+50dB. The phase noise "hash" will likely be at S3. This will likely be a significant problem.

Download the calculator here: isolation_calculator_nine_islands. The calculator is posted under a Free Beer license. You owe me a beer if you use it! Please give feedback and peer review the calculations.

WPX SSB meeting @ 65 degrees north – OH8X – Radio Arcala

Before LA7JO, LB3HC, CU2CE and CU2DX was working the WPX SSB 2012 contest from OH8X, we had  some very good time discussing conditions, radio contesting and amateur radio with the Arcala team and with our new friends from the Azores. On the below image from the left: Juha OH8NC, Marius LB3HC, Martti OH2BH, Jose CU2CE, Veijo OH6KN, Stig LA7JO and Francisco CU2DX.

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This was a very nice meeting at the Arcala Xtreme Station @ 65 degrees northern latitude. The Arcala team has an approach to amateur radio that is both social, technical, and serious. This time in nice weather with spring temperatures around the corner and snow melting. Check in later. More pictures and video from Arcala will be posted. And also check 3830 for contest results!

NOAA solar wind prediction tool

NOAA has a nice tool that can be of utility for radio amateur operators that are interested in how the geomagnetic field will be affected and how strongly it will be affected. It is now possible to see when there is a high likelihood that the K and AP indexes will rise.

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By processing the data from the STEREO satellites that are positioned “behind” and to “the side” of the sun, it is possible to plot the solar winds that are emitted from the sun.
You can check it out here: http://www.swpc.noaa.gov/wsa-enlil/cme-based/
The sun and the earth as well as the two STEREO satellites are seen from above in the circular images above. The green spot is the earth. The yellow spot is the sun. The grayish spot is the stereo satellite that sees the emissions from the sun before any active areas has rotated towards the earth. The red spot is the stereo satellite that sees the emissions from sun after any active area has rotated thru the earth direction.

The fan shaped images to in the center of the image above is the sun and earth seen “from the side”. It is possible to check if the emissions from the sun will propagate above, below or towards the earth. The AZ images on the left alone are not enough, because a particle emission may have the direction of the earth in zimuth (seen from the sun) but may have too high an elevation or too low an elevation to hit the earth.

Good HF condx. A lot of DX worked lately.



The conditions lately have been very good on 20, 17, 15 and 12 meters. I have worked a lot of new stations on the HF bands above 40 lately. Finally the nice sound of a wide open high band that I remember from last time the SSN stayed above 100 is here again.

The SSN peaked above 100 between 12. and 13. April. The SFI also peaked around 14.-16. April. The K-index also stayed low and the auroral activity has been modest. Perfect settings for working DX!

Antenna: broadband vertical with computer controlled tuner. Large groundplane.
Rig: Yaesu FT-1000MP MKV
Power: 200W