Re: HF Amplifier


Kevan Nason
 

On Wed, Jun 30, 2021, 9:42 AM Rodney Tanner <wm4rt.hamradio@...> wrote:
Nice antenna. I do not believe I have room for ground radials in my backyard.
If I got one I would need help getting it assembled and put up.
I am on oxygen 24/7 plus I had joint replacement on my shoulder probably be in therapy
to the end of the year.
I have made 8327 QSO and 7231 QSL on my antenna I am using

Many people like the antenna you have, Rodney. I've used one not too different from yours, an R5, and was happy with it. I was in Rhode Island next to a salt marsh. However, it seems to me that since you are thinking of an amplifier you must be somewhat unhappy with its performance. It's your station and your money, I just don't think an amplifier is going to make you happy. Every antenna is a compromise to some degree. I've got fairly decent antennas now, but am unhappy with some aspects of their performance too. There is no doubt in my R5 experienced mind that the people who designed the Comet made some compromises that aren't serving you as well as you would like. 

I've given a presentation of my low band antenna journey to several groups, including one in England. The Deep Dixie Contest Club recorded it. A link is below. It sounds like you don't have the room I do. Fine. The presentation is really about understanding how verticals work and understanding how your choices affect its performance. Maybe you won't find a lot of it interesting. If you don't want to watch the whole thing, but you might find some points interesting in regards to your current situation. Of particular note is minute 42 which shows you might very well have room in your backyard for a 6BTV with radials.
- Minute 20 talks about measured comparisons of a 6BTV vertical to several other verticals. Although the Comet 250b isn’t shown, it is in the same category as a couple radial less verticals that are shown.
- Minute 42 talks about how ground radials do not need to be ¼ wave length long and gives guidance on how many to use.
- Minute 27 talks about how SWR doesn’t mean much in regards to antenna efficiency. It gives an example of how one antenna showing an SWR of 1.4:1 still puts 96 out of 100 watts into the dirt instead of into the air.
- Minute 16 discusses losses in antenna tuners.

I've put that same R5 up when inland away from the ocean. Up at 30 ft like they say. As compared to the better designed antennas I now use it doesn't work very well there either. I did buy another one, but I'll only use it for portable and/or emergency operations now.

Hope that helps to get you thinking. 

Kevan N4XL

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