diff --git a/projDir/qc/dataProcessing/spectralHCRproducts/multiVels/findNoiseThresh_plotR1R2.m b/projDir/qc/dataProcessing/spectralHCRproducts/multiVels/findNoiseThresh_plotR1R2.m
new file mode 100644
index 00000000..4001c62d
--- /dev/null
+++ b/projDir/qc/dataProcessing/spectralHCRproducts/multiVels/findNoiseThresh_plotR1R2.m
@@ -0,0 +1,122 @@
+function [noiseThresh,meanNoise,R2]=findNoiseThresh_plotR1R2(powIn,avNum,aa)
+% Find noise threshold and mean noise following
+% Hildebrand and Sekhon, 1974 https://doi.org/10.1175/1520-0450(1974)013%3C0808:ODOTNL%3E2.0.CO;2
+close all
+
+noiseThresh=nan;
+meanNoise=nan;
+R2=nan;
+
+checkInds=0:5:770;
+
+if ~ismember(aa,checkInds)
+    return
+end
+
+noiseThresh=10.^(max(powIn)./10);
+powLin=10.^(powIn./10);
+powLin(isnan(powLin))=[];
+
+stepDown=0.0000005;
+
+powR1R2All=[];
+
+while noiseThresh>min(powLin,[],2,'omitmissing');
+
+    noiseThresh=noiseThresh-stepDown;
+
+    powLin(powLin>noiseThresh)=[];
+    sampleNum=length(powLin);
+
+    % R1
+    xCalc=1:sampleNum;
+    fn=xCalc./sampleNum;
+    sig2r=(sum(fn.^2.*powLin,'omitmissing')./sum(powLin,'omitmissing')) ...
+        -(sum(fn.*powLin,'omitmissing')./sum(powLin,'omitmissing')).^2;
+    % sigN2=sampleNum.^2/12;
+    sigN2=1/12;
+    R1=sigN2/sig2r;
+
+    % R2
+    meanNoise=sum(powLin)/sampleNum;
+    Q=sum(powLin.^2/sampleNum)-meanNoise.^2;
+    R2=meanNoise.^2/(Q*avNum);
+
+    powR1R2All=cat(1,powR1R2All,[noiseThresh,R1,R2]);
+end
+
+powR1R2All(any(isnan(powR1R2All),2),:)=[];
+
+if isempty(powR1R2All)
+    return
+end
+
+% Find intersection point
+powR1R2All(:,1)=real(10*log10(powR1R2All(:,1)));
+Rdiff=powR1R2All(:,2)-powR1R2All(:,3);
+outInd=find(Rdiff==0);
+y=nan;
+if ~isempty(outInd)
+    noiseThreshOut=powR1R2All(outInd,2);
+else
+    beforeX=max(find(Rdiff>0));
+    afterX=beforeX+1;
+    if ~isempty(beforeX) & ~isempty(afterX) & afterX<=size(powR1R2All,1)
+        A=[powR1R2All(beforeX,1),powR1R2All(beforeX,2)];
+        B=[powR1R2All(afterX,1),powR1R2All(afterX,2)];
+        C=[powR1R2All(beforeX,1),powR1R2All(beforeX,3)];
+        D=[powR1R2All(afterX,1),powR1R2All(afterX,3)];
+        a1=B(2)-A(2);
+        b1=A(1)-B(1);
+        c1=a1*(A(1))+b1*(A(2));
+        a2=D(2)-C(2);
+        b2=C(1)-D(1);
+        c2=a2*C(1)+b2*C(2);
+        det=a1*b2-a2*b1;
+        noiseThreshOut=(b2*c1-b1*c2)/det;
+        y=(a1*c2-a2*c1)/det;
+        %noiseThreshOut=interp1([powR1R2All(beforeX,2),powR1R2All(afterX,2)],[powR1R2All(beforeX,1),powR1R2All(afterX,1)],1);
+    else
+        noiseThreshOut=nan;
+    end
+end
+
+powR1R2All(:,1)=max(powIn)-powR1R2All(:,1);
+
+figure('Position',[200 500 700 1000],'DefaultAxesFontSize',12);
+
+t = tiledlayout(2,1,'TileSpacing','tight','Padding','tight');
+
+s1=nexttile(1);
+hold on
+scatter(powR1R2All(:,1),powR1R2All(:,2),'filled','o','MarkerFaceColor','b');
+scatter(powR1R2All(:,1),powR1R2All(:,3),'filled','o','MarkerFaceColor','g');
+scatter(max(powIn)-noiseThreshOut,y,'filled','o','MarkerFaceColor','r');
+xlim([0,max(powR1R2All(:,1))+5]);
+ylim([0,3]);
+
+legend({'R1';'R2';['Intersection at ',num2str(y)]},'Location','northwest');
+
+xlabel('dB below peak');
+ylabel('R1 and R2');
+
+grid on
+box on
+
+s2=nexttile(2);
+hold on
+plot([0,length(powIn)],[noiseThreshOut,noiseThreshOut],'-k','LineWidth',2);
+plot(powIn,'-b','LineWidth',2);
+
+xlim([0,length(powIn)]);
+
+%xlabel('dB below peak');
+ylabel('Power (dB)');
+
+grid on
+box on
+
+figdir='/scr/virga1/rsfdata/projects/spicule/hcr/qc1/cfradial/v1.2_full/airMotion/cases/width/noiseFloor/';
+set(gcf,'PaperPositionMode','auto');
+print([figdir,'noiseFloor_',num2str(aa),'_smoothing',num2str(avNum)],'-dpng','-r0');
+end
\ No newline at end of file
diff --git a/projDir/qc/dataProcessing/spectralHCRproducts/multiVels/findNoiseThresh_plotR1.m b/projDir/qc/dataProcessing/spectralHCRproducts/multiVels/findNoiseThresh_plotR2.m
similarity index 96%
rename from projDir/qc/dataProcessing/spectralHCRproducts/multiVels/findNoiseThresh_plotR1.m
rename to projDir/qc/dataProcessing/spectralHCRproducts/multiVels/findNoiseThresh_plotR2.m
index 8b84bcc9..1e1a5965 100644
--- a/projDir/qc/dataProcessing/spectralHCRproducts/multiVels/findNoiseThresh_plotR1.m
+++ b/projDir/qc/dataProcessing/spectralHCRproducts/multiVels/findNoiseThresh_plotR2.m
@@ -1,4 +1,4 @@
-function [noiseThresh,meanNoise,R2]=findNoiseThresh_plotR1R2(powIn,avNum,aa)
+function [noiseThresh,meanNoise,R2]=findNoiseThresh_plotR2(powIn,avNum,aa)
 % Find noise threshold and mean noise following
 % Hildebrand and Sekhon, 1974 https://doi.org/10.1175/1520-0450(1974)013%3C0808:ODOTNL%3E2.0.CO;2
 close all