Saturday, 5 November 2016

RSGB convention 2016 and more Low band thoughts

I attended the RSGB 2016 Convention in October with my friend Chris G3SJH. It was also great to meet Iain M0PCB from the Vulture Squadron Contest group - G9V, David G3YYD and John G3VPW. These were the lectures I attended:
 -Diagnosing & Reporting RFI problems John Rogers M0JAV
 -The IOTA Challenge from Sub-Antarctic Waters to High Arctic Cezar Trifu, VE3LYC
 -80th Commonwealth Contest (BERU) celebrations Iain M0PCB & Bob G3PJT
 -Contesting from VY2ZM on Prince Edward island Jeff Briggs K1ZM
 -DX fun without spending loads of money! Nick Henwood G3RWF

Quite a lot of focus on the VDSL QRN issue in the RFI presention from John R - which I suffer on 30m. The presentation from G3RWF resonated a lot with my holidays with radio and simple antennas for /P operation.

Lately I have been reading ON4UN Low Band DXing The book is excellent, very well written, and "the reference" for any low band operation "business"...I specially enjoyed the propagation chapter - as well as following KY6R blog and his 160m quest.

The short [16m] inv V doublet @ 11m height has proven an efficient antenna for EU and mid distances.
Efficient means that most of the TX power is being radiated out rather than "heating" the ground, loading elements and nearby lossy objects. It does not mean effective to work DX - low angle radiation  [ref. ON4UN Vertical antennas chapter]
Nonetheless, the simple doublet allowed me to get over 500k points in the CQ WPX CW SOA40 LP and gave a significant boost to my DXCC 40m band count to 96.

On a few occasions I have also extended the doublet by 4m + loading coils [inv U] to operate on 80m - but this is more of a compromise in this band with higher losses.

This week I have been playing with the idea of setting a top loaded 80m vertical in the garden.
I used EZNEC Demo for the first time following some of the examples in the ARRL tutorial, where previously I have used 4NEC2.... and learnt a few tricks along the way [Virtual wires are great!]

80m top loaded vertical
The loaded monopole would be in close proximity to buildings with its near field compromised and low angles blocked in any case + the limited garden space [10m x 5m] and effort to bury the radials, I am not convinced is worth the trip.

I still have in mind to build the front end receiver saver to be able to put a RX dedicated antenna in the small garden when I free up a bit of time

Looking forward now to the CQ WW CW contest at the end of November and some beach operation from the Mediterranean sea and SOTA activations during the next holiday.

73 Angel

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