Export command variable exporting problem

Shell Programming and Scripting
1

I have a txt file from which i am assiging a value to a variable
using the code in script1
script1.sh

export f=$(sed -n "/Freq *=/ s/.*= *//p" ${R_path}/output.txt)
echo "$f"   --------> this works

in script2 ( which executes the script1)

eval ./script1.sh

if [ "$?" = "0" ] && [ -f "${R_path}/output.txt" ]; then
echo "-------------------------------"
echo " Optimal freq  Calculated succesfully "
else 
echo " error in executing  "
exit
fi 
echo "$f"          ---------> This echo dosent work its just gives me a blank

wht wrong am i doing in exporting.

2

Source the script, replace:

eval ./script1.sh

with:

. ./script1.sh