On 6/20/2013 10:25 AM, Edward R Cole wrote:
I would dispute the advantage of mast mounting a preamp on 6m.
It all depends on how much loss is in your run of coax, and how quiet your location is. The run to my SteppIR is 350 ft of 7/8-in hard line, just under 1 dB at 50 MHz, and my QTH is not very quiet, so I'm happy with my ARR GasFET preamp at the K3 patch point.
The decision to mast-mount or not is pretty simple. If you hear the band noise increase by at least 7 dB when you connect the antenna, leave the preamp in the shack. If the noise rises by only a few dB, compute the loss in your line (see mfr data for the coax you're using). If the noise increases by only 3dB with the connected (and no preamp), you'll see an increase in your ability to hear weak signals of roughly one third of the line loss. If the noise doesn't increase at all, you'll see in improvement equal to ALL of the line loss.
How much is a dB worth? It all depends how close to the noise level the signal is that you're trying to copy. If it's VERY close to the noise, a dB or two can be the difference between making and missing the QSO.
73, Jim K9YC ______________________________________________________________ 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
