Cecil, I just had to do that! Hi. Yes, I enjoy all those places too. My most
favorite place is the
Catalooche Valley just off I 40 in NC.
Really enjoined your explanation of filtering. Would have never thought of
putting it that way.
73 and hope to meet you on the air.
Clayton N4EV
________________________________
From: Cecil <chacuff@cableone.net>
To: Clayton Brantley <clayton_n4ev@yahoo.com>; Discussion of Ten-Tec Equipment
<tentec@contesting.com>
Sent: Saturday, August 31, 2013 12:10 AM
Subject: Re: [TenTec] Explanations of the Different Types of Filtering on
Radios
You are so right....
My favorite place in the whole world is to sit on a huge boulder in the middle
of the river at the Chimneys picnic grounds....listening to the water crashing
over the rocks. I've been going there for 40 years every chance I get.
Thanks for the correction...
Cecil
Sent from my iPad
On Aug 30, 2013, at 4:30 PM, Clayton Brantley <clayton_n4ev@yahoo.com> wrote:
> Cecil: your explanations are great, the ONLY problem is There ain't an 'e' in
> Smoky Mountains!
> Worked there as a Park Ranger for several years... HI
>
> Clayton N4EV
>
>
>
> ________________________________
> From: "chacuff@cableone.net" <chacuff@cableone.net>
> To: Will Jones <wjones@bellsouth.net>; Discussion of Ten-Tec Equipment
> <tentec@contesting.com>
> Sent: Friday, August 30, 2013 11:46 AM
> Subject: Re: [TenTec] Explanations of the Different Types of Filtering on
> Radios
>
>
> Ok, here goes with an analogy...
>
>
>
> I’ve been up in the Smokey Mountains many times and they have some of these
> beautiful short tunnels through rocky hillsides for the roads to pass.
>
>
>
> Lets say you were standing in the middle of the road at one end of one of
> these short, straight tunnels looking through to the other side. At the
> other end of the tunnel you see a very nice looking young lady just to the
> left of center and a really ugly old lady just to the right. Of course the
> desirable view at this point is the nice looking young lady but it’s really
> difficult to get a good look because of the really ugly lady...so. Say you
> had a knob that would allow you to move the end of the tunnel left or right
> just enough to block out the view of the really ugly lady leaving only the
> view of the very nice looking young lady...there you have IF Shift....also
> called PBT by other manufacturers.
>
>
>
> Now re-center the knob where you have both ladies in view. Hold up the index
> finger of your right hand out at arms length. Close one eye and place that
> finger over the really ugly lady blocking the view of her and leaving only
> the view of the nice looking younger lady...there you have the Notch Filter.
> It may not cover the whole view of the ugly lady but it does enough to allow
> a better view of the nice looking young lady.
>
>
>
> The others are a bit more difficult to explain...
>
>
>
> RIT is really not a filter at all...just another way to tune the frequency of
> the receiver a small amount without changing your transmitter frequency. Say
> you are having a short SSB QSO after calling CQ with a fellow who doesn’t
> seem to be tuned properly to your frequency and he sounds like he has been
> snorting helium so you need to tune your VFO to make him sound more natural.
> If you tune your main VFO you are not only tuning your receiver but also your
> transmitter...which will result in a change in how you sound in his
> receiver. Well on the next over he may retune his VFO to make you sound
> normal in his speaker and it’s an endless chase up and down the band. (this
> can be caused by radio alignment issues) Better choice would be to engage
> RIT and just move your receiver until he sounds natural to you which will not
> change your transmit frequency only your receiver frequency leaving you
> sounding the same in his receiver and less likely causing
> him to retune...ending the chase.
>
>
>
> DSP Noise reduction...well this being a software feature is implemented
> differently in every manufacturers radios and sometimes even between models
> in the same manufacturers radios.
>
> The goal of all is to reduce random noise as much as possible while
> identifying the desirable young lady...um...signal and bringing it out of the
> noise. All this is done using math inside the computer. Some work better
> than others. The Icom system works well at reducing background noise without
> adding too much digital artifact noise as long as you don’t over use it.
> Seems some think if a little is good then a lot is better...it’s a balance.
> Turning the knob full clockwise will result in digital noise and not help at
> all. The DSP system on my Orion II is different and I’m not sure exactly how
> to explain it..except the way Ten-Tec does that advancing to a higher number
> increases the length of time sampling is done before the digital filter is
> built. Which results in a better built filter in software but it takes
> longer to get there. Of course the desirable signal needs to be there for
> the duration of the sample or it probably will
> have a hard time doing it’s job. None of them are magic...and most work well
> some times and not so well others...it’s just another tool.
>
>
>
> Noise Blankers. Most are designed to work on repetitive noise pulses like
> old auto ignition system noise or electric fence pulses. Some works well on
> power line noise some not so much. I’m surprised sometimes at how well some
> work and how poorly others don’t...and it doesn’t seem to matter how much the
> radio cost. Some of the older cheap radios noise blankers do wonders on
> power line noise and a high dollar radio won’t touch it...go figure. Won’t
> do much on atmospheric static crashes because they don’t happen on a timed
> repetitive timeline which noise blankers are designed to sense.
>
>
>
> Well that’s about all I got...my apologies to any of the ladies out there
> with my analogy...it was the first vision that popped into my head this
> morning when envisioning an answer to the question. No harm intended...
>
>
>
> I’m sure others will have more insightful answers and between the group of us
> we should answer your questions.
>
>
>
> Best of the Labor Day weekend....
>
>
>
> Cecil Acuff
> Gulfport MS
> K5DL
>
>
> From: Will Jones
> Sent: August 30, 2013 9:33 AM
> To: tentec@contesting.com
> Subject: [TenTec] Explanations of the Different Types of Filtering on Radios
>
>
> There are a few of us who meet together every Wed. morning at a local
> restaurant to talk about ham radio and stuff.
> Some are new hams. One asked this week a question which I think would be an
> interesting study in comments.
> He asked, "I have an I.F. shift on my radio and I have read about what it
> does but don't really understand "what" it does. Also how does it compare to
> the other features I see on radios such as PBT, notch filters, RIT, DSP noise
> reduction and noise blankers. Without having a radio with these features on
> them it is hard to explain just what your signal will sound like when these
> devices are used.
> So can anyone give us some ideas how to explain these different types and why
> we would want one and not another and why radios don't have them all on one
> radio.
> Bill, N4LB in TN
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