On 24 Jan 2010 at 11:26, Anthony Monteiro wrote:
Date sent: Sun, 24 Jan 2010 11:26:02 -0500 From: Anthony Monteiro [email protected] Subject: Re: [amsat-bb] Coaxial line question To: Luc Leblanc [email protected], [email protected] Copies to: [email protected]
Hi Luc,
I am assuming you meant 7/8" Heliax.
45' of Heliax and a short LMR400 jumper will have around 0.6 dB of loss on 70cm so that just adds 0.6 dB to the noise figure of your preamp (i.e. ~1.0 dB to ~1.6 db.) With even a modest gain antenna, you probably will not be able to notice any difference on a satellite downlink.
On 2 meters, even less difference.
73, Tony AA2TX
Yes 7/8... and i received the same comment on AMSAT-EU forum and placing the preamps closer to the shack will better protect them from the WX issues ice/snow storm and winds plus they will put them away from the RF transmit field who i suspect some desense happen time to time causing also a lot of intermod as i'm at less than 1km from a cellular/pagers/police/fire tower. i can see the tower light beacon from my house window.
Thank's
"-"
Luc Leblanc VE2DWE Skype VE2DWE www.qsl.net/ve2dwe DSTAR urcall VE2DWE WAC BASIC CW PHONE SATELLITE