Even though most readers will understand what Joe intended to say,
his usage of the term ERP is fundamentally incorrect and could lead
to further incorrect use of the term by others.
I'm sure Joe intended to say 88.9 watts at the feed point of the antenna
73
Frank
W3LPL
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----- Original Message -----
From: "Joe" <k1ike_mail@...>
To:
[email protected]Sent: Friday, November 15, 2024 8:58:49 AM
Subject: Re: [nanovna-users] Dipole antenna with Low Z0 feed point Impedance
Warren,
I think I stated that.
"So a 100 watt station will give you 88.9 watts of ERP (Less cable loss
and plus antenna gain)."
So, I accounted for the fact that there would be cable loss and it would
have to be subtracted from the calculated loss of the antenna.? Also,
antenna gain or loss would come into play for calculating ERP.
I didn't really mean it to be a scientific statement, just a common
sense statement why 2:1 SWR is not a really big thing to worry about.
73, Joe, K1ike
On 11/15/2024 9:42 AM, Warren Allgyer via groups.io wrote:
Joe
The loss attributable to a 2:1 VSWR cannot be stated as a constant. It is a function of the length and characteristic loss of the coax cable used.
The additional loss in 100 feet of cable that is a consequence of having a 2:1 SWR load would be 0.33 dB for RG58 and about 0.11 dB for LMR400. This is far less than 11.1% however none of the calculated additional loss are significant and overcoming those losses by searching for a perfect match will solve no problem that the author is experiencing.
Warren Allgyer - WA8TOD
