Rick The DHDL was a simplification of the Waller Flag. George built it that was to be simple to use during a DXpedition. The DHDL can provide 10 db RDF and the WF 11.5 to 12 db RD. for each db increase in RDF you can see 2 db increase in signal to noise ratio. That concept is not debatable; I measure it over one hundred times when I was developing RX antennas. It is empiric observation. The 1/4 vertical TX antenna have RDF of 5 dB. So; the improvement of the DHDL is 5 db, good enough for 10db improvements on SNR.
If you want to understand more about RX antennas check my presentation on WWWROF, you can hear by bad English and download the presentation. But is not a free beef!. You need to care about common mode noise, isolations, ground and several aspects I mentioned on the webinar. Understand how to build a WF or DHDL is fast, few hours, but understand the concepts can take several years of experience. It can not be done by e-mail or phone call. Doug , NX4D, started with WF in 2003 and he worked over 315 countries on 160m CW from a 1/5 acre subdivision lot. I started 2006 and worked #306 on 160m, CW only from one acre city lot. A Very noisy place near Fort Lauderdale. High Performance RX Antennas for a Small Lot https://wwrof.org/webinar-archive/high-performance-rx-antennas-for-a-small-lot/ N4IS – Waller Flag Construction https://wwrof.org/webinar-archive/n4is-waller-flag-construction/ 73' JC N4IS _________________ Searchable Archives: http://www.contesting.com/_topband - Topband Reflector
