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Re: FT-847 vs. FT-817 on 123 MHz RX



Hello everyone,

I have run both the original 122mhz output and 144mhz on several Adic's.
there are tradeoffs. If you run a 2256 LO and place the output at 144mhz your
signals and noise floor will be much higher , but by equal amounts , so nothing
is gained. The problem is the LO in the transystem is designed for a center 
frequency of 2278. When you move the LO by changing the Reference xtal you 
are shifting it to one end of its operation.  Ive tested this on several units
and on some its 'ok' on others the noise floor of the LO comes way up and in 
some cases the spurs increase significantly. For this reason ive replaced the
original xtals back in the units. 
(I have spectrum analyzer pictures if you need proof)

I also have tried using an 817 vs my 847 in side by side testing. i wouldnt
say that one beats the other, the filtering is definately different but i 
couldnt say one is better for weak signals.

My setup usually gives me a beacon level of S6-S6.5 under good conditions.
My sun noise measurements give me 6db between cold sky and sun.


Keith
N6ors
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