Larry much has been written about defining the signal to noise ratio of a receiver. You might want to search on this subject.
Hopefully I can simply things a bit. It is the designer's goal to get the receiver noise lower than the ambient noise. Once that is done you are at the mercy of the ambient noise. Likewise the design goal of a preamp is to amplify the signal without increasing the noise figure. Sure the preamp amplifies noise too. The key is the signal to noise ratio should not be deteriorated by the preamp. Now as to the location of the preamp. Yes ideally it is better at the antenna. Many TV antennas have preamps at the antenna but TV systems are receive only. If you are transceiving at antenna then whatever preamp you use must tolerate your transmit power or somehow switch out the preamp on transmit. Without going into detail preamps at the antenna are very difficult to do if transmit signals are involved. 73 de Fred, AE6QL -----Original Message----- From: [email protected] [mailto:[email protected]] On Behalf Of Larry, KB5HMU Sent: Sunday, July 03, 2011 11:03 AM To: [email protected] Subject: [Elecraft] New to list; My first question Hello fellow Hams, I'm new to the list and was referred by many from the Yahoo K3 group. Thank you. I have been wanting a new radio for a while now and the K3 is at the top of my list. My current radio, a 706 MkIIG, has performed well for the last 11 years but my interest in weak signal 6 and 2 meter operation leaves quite a lot to be desired. I'm not the sort that runs out and buys the newest or latest (I'm still driving my 1991 Accord EX) so I want a radio that will last me 20 years or more. This is what really led me to K3 as it can be updated anytime. I have been looking at the SDR radios but I'm really a "hands-on-the-knob" kind of operator. At field day I watched a ham at his gigantic Flex 5000C and 23" monitor. Very impressive at first sight but after watching for a while, I noticed that his entire operation was nothing more than continuous wrist motions with the mouse. Just don't think I can go there. I hope to learn much more about the K3 as I bank away my extra dollars. It looks like I need to buy quite a few of the options to do the K3 the way I need (Ha-Ha: NEED) for my operations. Two meter board, ATU, DVR, a few filters and the Panadapter are a must for me. Here's my first question to the group: I enjoy 6 meters immensely and someone recommended that I buy the pre-amp. My understanding about the effectiveness of a VHF preamp is to amplify the highest signal, i.e. at the antenna, to give the lowest noise increase. The PR6 mounts at the radio. Wouldn't that be amplifying noise in a weak signal more than if it were mounted at the antenna? Thanks, Larry KB5HMU http://qrz.com/db/KB5HMU ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[email protected] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[email protected] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html
