Phasing Stuns

The world’s first Sony AN-1 Phased Active Antenna Array?………..

So I purchased a second Sony AN-1 unit from Ebay last week. It had been in storage for over 13 years and had a lovely set of 1997 expired batteries inside! After a bit of a cleanup of the battery compartment it was ready to go. Funnily enough even though there were batteries in the pre-amp unit the actual antenna it seems had never been mounted outside at all. All of the mounting hardware was still in its plastic?

My original plan was to use the second antenna as the aux/noise antenna in a two element phased array using the MFJ 1025. Having the second antenna also allowed me to do some A/B tests in terms of antenna position on the balcony. The results of these tests were surprising but welcome.

I had placed my first AN-1 in what I thought was the best possible position, as high up and as far away from the building as possible. I usually tilted it out at an angle of about 10-12 degrees to get away from the building.

The building opposite blocks not only a good portion of sky but is also a metal clad structure, in effect a huge RF blocker. However I was aware of these issues already but felt getting the antenna up and away from my building was more important.

The second antenna position is right up against my building and underneath a concrete balcony. This should mean poor reception beneath all that concrete and steel. But here’s the catch. This second antenna position has a slightly clearer view of the horizon, just a sliver.

Hooking up the two antennas to the MFJ-1025 I found that Asian signals were booming in on the second antenna in what I thought was the more compromised location. Most were 2 to 3 and sometimes 4 s-units over the first antenna! Its seems having even a 10 to 15 degree better view of the horizon can trump the attenuation that the steel and concrete provides.

I will continue testing and hopefully find optimum combinations for European and S. American signals. But right now I looking forward to the fun that phasing these verticals will provide.

Next up on the list is whether or not to mod the MFJ-1025 for LF & MF work. The unit is heavily attenuated below 1.8 MHz to block strong BCB overload. I do love digging around in the lower reaches of the spectrum and NDB hunting in the winter months can be quite an interesting challenge. If I modded it I’d probably have to buy a bandpass filter for HF if I wanted to continue using the unit on those bands as well. The other option is to buy a second MFJ specifically for LF work.


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