I have a ground mounted Hustler BTV for many years over 50 radials in my small backyard.
For 80 M efficiency improvement I have had success with 2 methods:
1. 40 meter resonator with DX engineering Hot Rodz cap hat
2. Homebuilt 40M coax trap at the top with 19 ft. horizontal wire tied off to nearby low tree
My question is- any significant difference (i.e. say 4+% ) between either method?
Any thoughts appreciated
Not sure what you're asking. If you've had the antenna up for that long and experimented with both methods for 80M operation, then I think that you would be the person to best answer the question. How does each method work as far as your ability to work those stations that you want to? How well does each system perform across the 80M band? An antenna system could be "efficient" for a particular type of operation such as "working the ARRL SS contest" and poor for "working the South Sudan DXPedition". Empirical results always have the last word.
Without actually doing various extensive tests on signal strength measurement, it would be next to impossible, IMHO, to obtain empirical results where one could be compared antenna efficiency that resulted in that small of a significant difference between the two methods. It would also be difficult to model this comparison without thorough knowledge of your setup as antenna typology, soil condx, nearby structures all could have substantial impact on the outcome.
Top loading the vertical is the preferred method, which is what you are doing in both cases. But there is an alternate method to the coax trap that is more efficient and that is the Unadilla trap. See their website.
73, Rich, K3VAT