Surprised Antenna Results-HT Simplex

[WRDJ205]

Driving thru my small city today I was testing out the reach of simplex comms btwn a GM-5RH with long rubber duck with me in the car and a GM15Pro with similar antenna at my house with a family member. 
 

This wasn’t a formal test but I wanted to know if I could use simplex to talk from my house to the elementary school.  Lots of trees and houses in between but relatively flat ground.  

I switched to a mag base dualband antenna (not specifically tuned for GMRS).  At about 1 mile, the transmission was inaudible with the dual band BUT very clear using the rubber duck.  
 

This was unexpected as I would have thought even with the dual band not specifically tuned for GMRS it would have been better than the rubber duck.  
 

In the end, we were able to get about 1.75mi using the flexible antennas on both HTs in an urban environment.   

Was I wrong expecting better distance using the mag base mobile (even if it was dual band, 2m and 70cm) as compared to the rubber duck?  

[Guest]

Seams like something is wrong.  I do 20-30miles simplex with an ht and a 771g antenna.  If all I got was a mile or 2 I’d be out of gmrs.  I need my hts to work way further then a few miles. 

[WRYZ926]

How long is the dual band antenna?

The shorter they are the worse the SWR will be for GMRS. I have a 16" Comet SSB1 dual band antenna on my car that works veery well for 2m and 70cm but the SWR for GMRS is quite high. My 38" Comet 2x4SR dual band antenna works well for 2m, 70cm, and GMRS.

AS far as how far one can get to, it depends on location, terrain, structures, etc. Someone in the desert of wide open and flat farm ground will get out further than someone in a big city of hilly and forested area.

[WRDJ205]

4 minutes ago, WRYZ926 said:

How long is the dual band antenna?

It’s an 18”.  I don’t have a SWR meter to check.  But, that might be the culprit.  I’ll run the same test next weekend with the Midland Ghost designed for GMRS I suppose for comparison.