[HBR] HBR's in 2014?

[Shoppa, Tim]

When I compare what I hear on the air with my novice days, is that the SWL stations are mostly gone from the ham bands!!! This is a good thing!

With regards to selectivity... what makes some crystal filters ring like a machine gun hitting a bell, is that they have a lot of group delay variation inside the passband. This is especially typical of "brick wall" 8-pole-or-more filters folks so longingly buy for their rigs based purely on numerical specs, without knowing how bad they sound in real life.

Better filter designs move the group delay variations outside the passband and give up some of the wall steepness, reducing the ringing. Many modern DSP rigs have well designed CW filters.

Tim N3QE

-----Original Message-----
From: HBR [mailto:hbr-bounces at mailman.qth.net] On Behalf Of Brian Burns
Sent: Monday, December 08, 2014 2:24 PM
To: 'HBR Receiver List'
Subject: [HBR] HBR's in 2014?

Hello All,

 

A lot of water has passed under the bridge since Ted Crosby designed the HBR series. I've been wondering lately how well HBR's have come out of this long trial period. Things like how many are still in use as the station receiver, and how adequate they are under today's band conditions etc. Just musings, you know.

 

Doing a bit of SWLing with my HQ-150, the bands don't seem as crowded as I remember their being, back in the day. Perhaps my obsession with selectivity
is misplaced?   

 

If I remember him rightly, Carl KM1H, said that selectivity gotten with tuned circuits, I.F. strips, not crystal filters or Q multipliers, leaves the signal sounding better. Certainly the high Q devices like crystals tend to "ring" a lot at narrow selectivity settings. Any opinions?

 

Cheers,

 

Brian

 



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