Return to KLUBNL.PL main page

rsgb_lf_group
[Top] [All Lists]

LF: Re: RE: Antennas

To: <[email protected]>
Subject: LF: Re: RE: Antennas
From: "mal hamilton" <[email protected]>
Date: Wed, 3 Aug 2011 21:07:36 +0100
References: <F058D11953504D2D82D77489EC3BB3EA@IBM7FFA209F07C> <BF4A524700075746A6467658DFC7102CB0B27CF1E0@ICTS-S-EXC2-CA.luna.kuleuven.be>
Reply-to: [email protected]
Sender: [email protected]
SNR is unimportant if you cannot hear the signal in the first place !!!!!!!
If one is plagued with environmental noise and poor signal quality on LF/MF then maybe this is not the band for You.
Try another hobby
G3KEV
 
----- Original Message -----
Sent: Wednesday, August 03, 2011 8:38 PM
Subject: LF: RE: Antennas

Hi Chris,
 
the quality of the received signal it determined by it's SNR. So if you have an antenna where QRM/QRN are at a higher level than the RX noise it makes no sense to get a larger antenna (= produce more signal and noise).
As QRM / QRN on 137kHz and even on 500kHz is rather high even with a small antenna you will get more QRM / QRN and it will perform as well as a big antenna.
So it seems absolutely normal to me that a small whip will performp as well as a big wire antenna (for RX !).
More important that size might be other properties such as directivity (eg with a loop you can null out a QSM source).
 
I do use my "big" TX antenna for RX, but do need to attenuate the signal by at least 20dB to avoid RX overloading.
 
73, Rik  ON7YD - OR7T 
 

Van: [email protected] [[email protected]] namens Chris [[email protected]]
Verzonden: woensdag 3 augustus 2011 20:08
Aan: RSGB LF Group
Onderwerp: LF: Antennas

Hi Mal and LF,
Well, all I can say is that here the signal to noise ratio on RX is better on my PA0RDT than it is on my long wire (inverted 'L'). I have always thought this a bit strange, quite often weak signals that cannot be seen on the wire are perfectly copied on the PA0RDT. This applies from 136kHz to 3.8MHz. I cannot see what else it can be other than local noise/QRM level. 80m is another prime example where the noise has gradually got worse over the years here.
Vy 73,
Chris, G4AYT, Whitstable, Kent.
<Prev in Thread] Current Thread [Next in Thread>