Hi Mike,
Sorry, I somehow missed your January 14 email below. I do have a preamp available at the shack end but rarely use it. It is built into the RAS-8. I don’t know what device Gary used in the design but it does have high pass and low pass filtering. As I noted on page 13 of my paper, I did try some preamplification in the shack to “equalize’ the noise floor of the Beverage and YCCC-9 to that of the BSEF-8 and HiZ-8. Even though the noise floor did increase I could never document an increase in S/N or forward signal above the noise floor so I didn’t use the preamp when recording the data. I don’t want to suggest this is a summary dismissal to using a preamp for a Beverage as there may be times when it could be beneficial, as you note below. I believe we all agree every person’s installation will vary and a preamp may add some benefit, but adding one just because a person “thinks” they need one isn’t a valid reason!! 😊 73 Joel W5ZN From: Mike Waters <[email protected]> Sent: Wednesday, January 22, 2025 3:16 PM To: Jim Brown <[email protected]>; [email protected] Cc: topband <[email protected]> Subject: Re: Topband: Comparison of Vertical Arrays for Low Band Receiving Gentlemen, I never used preamps at the feedpoints of my Beverages*, and I probably should have left out "at the feedpoint". I just noticed that Joel's graphs sometimes showed a very low signal level from the Beverages, and was curious. *However, I did use a preamp at the station end of the F-6 feedlines to them. (A series 2k pot there adjusted the level to match the TX antenna; and on occasion eliminated intermod.) The output of a Beverage is rather low, and sometimes I would switch between them and the inverted-L, etc. Having said that, somewhere I read that on occasion, others absolutely needed them at the feedpoint, when the noise floor was exceptionally low (I believe just before sunrise). But I guess that's a moot point here. The longest F-6 feedline here was about 600'. On Tue, Jan 14, 2025, 3:10 PM Jim Brown <[email protected] <mailto:[email protected]> > wrote: On 1/14/2025 12:13 PM, [email protected] <mailto:[email protected]> wrote: > Thanks. No, I did not have preamps at the feed point of the Beverages. How about at the station end, Joel? Sorry, I should have been more clear. Is the sensitivity of a one wavelength Beverage low enough that a preamp at the feedpoint is needed? Loss in decent coax is pretty low at 2 MHz, ... As I said, sometimes it is, according to others. Sorry I don't have a reference. :-) 73 Mike W0BTU https://web.archive.org/web/20190827040547/http://w0btu.com/ <https://web.archive.org/web/20190827040547/http:/w0btu.com/> _________________ Searchable Archives: http://www.contesting.com/_topband - Topband Reflector
