[TowerTalk] Antennas for SO2R station

Joe Subich, W4TV lists at subich.com
Tue Mar 2 14:26:21 EST 2021


On 2021-03-02 12:50 PM, JVarney wrote:
 > I have a 7300. The problem isn't the dynamic range, which is around
 > 95 to 100 db according to ARRL/Sherwood/AB4OJ et al, it's the very
 > broad BPF filters.

No, it's still a dynamic range problem - wideband dynamic range (also
known as "blocking") instead of the more commonly understood close
spaced dynamic range.  Look at Sherwood's table again and you will see
the "100 KHz Blocking" for the 7300 at 123 dB vs. 150 dB for the 
Elecraft K3s, 149 dB for the IC-7851, even 141 dB for the Yaesu FTdx10.

73,

    ... Joe, W4TV


On 2021-03-02 12:50 PM, JVarney wrote:
> Steve N2IC wrote: "If you are planning station changes anyway, my
> suggestion is to replace the 7300. It's a great radio, at a great
> price, for a SO1R station, but the A/D dynamic range limits it in
> SO2R applications."
> 
> ----
> 
> I have a 7300. The problem isn't the dynamic range, which is around
> 95 to 100 db according to ARRL/Sherwood/AB4OJ et al, it's the very
> broad BPF filters.  For example, with the radio tuned to 20 meters,
> the 15m band is only down -18 db. (!)
> 
> External BPF's are a must with 7300 if SO2R or even Field Day is
> contemplated. The next rig up in the Icom lineup, the 7610, adds
> a tracking preselector to fix the problem.
> 
> 73 Jim K6OK




More information about the TowerTalk mailing list