Answer by Jason Burnfield:
On Tue, May 26, 2026 at 1:33 AM Andrew Thornett wrote:
Can I ask you for your back of envelope dB calculation on the trace from my new Horn of Plenty? (Also can you tell me how you do it?)
Andy
This particular Horn of Plenty has following dimensions:
Sent: Tuesday, May 26, 2026 8:51:35 AM
To: Andrew Thornett
Subject: Re: Request for back of envelope dB calculation
I’m getting about 0.855 dB.
My method is as follows:
1. Take the peak amplitude and divide by the background level.
2. Take the Log base 10 of that value and multiply by 20.
In this case 0.96/0.87 =1.103448.
Then Log10(1.103448) =0.04275.
Finally 0.04275*20=0.855.
Jason Burnfield
On Tue, May 26, 2026 at 1:56 AM Andrew Thornett wrote:
Many thanks.
What would you expect for a horn of this size?
Andy
On Tue, May 26, 2026 at 1:58 AM Jason Burnfield wrote:
My guess is you’re getting about what you should expect. My corner cube antenna gave me about 0.75 dB and I think the horn antennas do a bit better.
Antenna gain in dBi is gain as compared to a theoretical perfect isotropic antenna. How that translates to the peak H line detected is a complicated mess. But my gut says it’s probably around 1 dB or so above background. Even large dishes don’t get more than 2-2.5 dB above background. I think you’re in the zone, performance wise.
My corner cube theoretically had a gain of around 18 dBi and I got an H line peak of around 3/4 of a dB above background.
Jason Burnfield.