[Elecraft] Ameco PT-3

[Warren & Barbara Reese]

Tom,

Thanks for your comments.

I appreciate your taking the time to answer my posting.  I have great 
admiration for you, having been in the 'biz most of my life 
www.radions.net/comrcial.htm .

73.

TR, K6GC, the Great Circle Station
in the State of Jefferson.
http://www.ijpr.org/Page.asp?NavID=1033
____________________________________________
At 09:58 AM 7/12/2010 -0400, you wrote:
>>When the antenna is connected and disconnected the noise floor 
>>moves just barely.  You can tell, but it requires a critical ear.
>
>That is too little. That is about how my K3 behaves on six meters on 
>SSB bandwidth! On the narrowest bandwidth you use, you should hear a 
>very well defined noise increase, several dB, going from a dummy 
>load to the antenna.
>
>>>A note about my antenna.  It is a HyGain 5BDQ trap dipole and the 
>>>SWR on it is 1.2:1 into about 200' of LMR240.
>
>Since feedline loss and SWR in receiving is set by the receiver, SWR 
>in the feedline on receive has nothing to do with transmit VSWR 
>(where the antenna is the load). I've never measured the input 
>impedance of the K2, but it could be you have an impedance mismatch 
>between the K2 receiver and the feedline, which would result in 
>feedline losses aggravating the feedline loss problem.
>
>What the 1.2:1 SWR indicates is the antenna mismatch is around 1.4:1 
>and feedline loss on transmitting is about 2.5 dB.
>
>I have no idea what the K2 looks like for SWR on receiving, but many 
>receivers I've measured are pretty far off 1:1 SWR. If the K2 looks 
>like a 2.5:1 SWR (which is a reasonable upper limit based on other 
>receivers I have tested), feedline loss would be 3 dB plus you would 
>have an additional .12 dB mismatch loss at the antenna (the source).
>
>Sounds to me like the K2 you have needs more sensitivity if a dipole 
>with 4 dB or less system loss won't firmly set noise floor.
>
>73 Tom