[TenTec] 3KC Spacing / K0CQ reply

[ac5e at comcast.net]

Well, I have had pretty good luck with Inrad products, but....

First, 2 dB or even 3 dB passband ripple is a lot on paper, and not so much when you listen to the end result. A volume level change of 1 dB is defined as the least perceptable change in volume perceptable to the human ear. 2 dB is sometimes noticible, 3 dB usually is. But a 2 dB or even 3 dB change over a part of the audio range is usually unnoticable. The ear adapts very quickly to such effects. 

Second, a quick experiment with a 32 channel audio equalizer between the Ofion, set to 6 kHz bandwidth, and the headphones and rolling off that range an extra 3 dB, and boosting that range 3 dB, shows mighty little difference on SSB. 

Rolling the highs off from 1500 Hz to 3 kHz by 6 dB does not make a lot of difference in audio quality either. Personally, I would not give you ten cents for the difference. 

BUT, beauty is in the eye of the beholder and fidelity is in the ear of the listener. If you feel the conversion will do what you want to do - do it. 

73  Pete Allen  AC5E 
> Ok, Maybe it's not a "Rule", But someone once told me it was common courtesy 
> to not move closer than 3kc's to an occupied freq. Maybe an old gentlemen's 
> agreement that is no longer observed. Of course nobody cares today if they move 
> within 1or 2 kc's of an ongoing qso and overlaps into and interrupts stations 
> that were already in progress. It happens all the time on 75meters & 20 
> Meters. I am talking SSB now, NOT CW. I don't operate CW.
> And if you ask people to move, they generally ignore you, or argue that they 
> were there first
> when you didn't hear them when you started. Some is due to propagation 
> changes, but more often I find it's rude operators rather than propagation 
> changes. 
> People think they own
> a particular frequency when it IS in the rules that it's a first come, first 
> serve basis.
> 
> As far as the INRAD Mod goes, it states that:
> 
> 1: The 2.8 6.3 if filter reduces or eliminates passband ripple over the stock 
> 2.4 filter
> which before the mod is greater than 2db.
> 
> 2: the low end response is improved to about 250-300 hz at -3db whereas the 
> stock spec
> is up at 350-400hz at -3db.
> 
> 3: The response is only tipped down towards the high side from the low side 
> approx 2.5
> to 3db wheras before the mod there is about 8 or 9 db of high frequency loss 
> from 500hz
> to 2500hz.
> 
> That's from the mod sheet. Is George at Inrad lying to help his pocketbook? 
> 73, Todd KD7EFQ
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