[TenTec] Ten Tec Omni D, Why so quiet ?

[Mike Hyder --N4NT--]

Hi, Dennis--

Note that I deferred to the gurus on the reflector about why it was so. 

See: http://lists.contesting.com/archives/html/TenTec/1999-01/msg00147.html 

page 10 of this: www.r-390a.net/Pearls/sensitivity-alignment.pdf 

>From what I have seen floating by here, the difference is that the ladder filters more quickly recover from a static crash instead of dragging it out to the next crash.  Many know more than I do and can probably help with this.  The proof, however, is in the pudding and the original post from "Newberry Gary" <gnn01 at yahoo.com> (scroll down) explains the difference he has seen.  The second link above tells of folks with Collins receivers with mechanical filters complaining of noise and shutting down their stations while another man with a Hammarlund HQ-129x receiver hardly noticed the noise.  If decreasing the bandwidth were the only way a filter could affect the noise, then the Collins with the "better filters" ought to have had less noise than the Hammarlund.

It ain't so.

In a rush to keep up with "modern technology" equipment manufacturers had to move toward synthesized, general coverage receivers.  There was a trade-off with this in the increased noise introduced into the receive (and transmit) path.  Ultimately we have DSP to process the signals to remove the noise we introduced.  The noise is dirty.  It is not so bad these days but many transmitters in the past had a "hashy" note on CW from the synthesizer circuit.  In many cases the "hash" covered a large swath of spectrum, bringing up the "ambient" noise level a bit.  With many such transmitters in operation, you can see how the band can become less and less useable for weak signals.

We continue to make advances in technology, having to make further advances to overcome the negatives of the last advance.  There are fewer and fewer of us heretics left who are bold enough to ask, "What are we accomplishing today that we couldn't accomplish with rigs of 30 years ago?"  And even fewer will ask whether they enjoy operating as much as they did 30 years ago.

I had experience with one Yaesu synthesized radio (FT-757GX).  I bought it to replace the Heathkit SB-102 which had served me well for a long time.  The 757 had every feature a person like me would need -- CW filter, built-in keyer, general coverage, receive preamplifier, full QSK, etc.  On paper it was perfect.  What I found was that the built-in keyer wouldn't go faster than about 25 WPM, I never used the general coverage, the "full QSK" chopped the dots off to less than half their intended length, my SB-102 could receive signals on 10 meters that the FT-757 could not detect, even with the preamplifier turned on.  But what I really found was not so readily understood: I operated less and enjoyed it less.  Once after a couple of hours operating (probably no-stress rag chewing on 40 meter CW with strong signals in my receiver) I sat there and turned the rig off.  Something caused me to pay attention to my physical reaction and I could feel the muscles in my shoulders and my neck and those across my back become suddenly relaxed.  My slight headache vanished.

Determined to find out the reason for this, I listened closely for the next week.  What I found was that received signals had a very slight raspy note to them.  The unusual thing was that stronger signals did not override this hash but appeared to be modulated by it.  I told one of my old guru friends about this and they strongly suggested I buy a Ten-Tec Triton IV rig.  After comparing the Triton IV with the FT-757, I believe I drop-kicked the Yaesu out the shack window.

If you read this reflector for a long time, you will find that many people own more than one rig and will alternate them in their main operating position.  When I do this, I find that one rig or another will just stay in that position and I'll have no incentive to change.  To my way of thinking, this is the very best comparison between rigs -- it gives an overall comparison which compares about all factors of satisfaction and it includes the factor of the operator's individual style of operating and preferences.  It is not quantifiable.

I believe that ham radio is an art and not a science.  My radio is a means to an end (communicating with another).  When the rig becomes the end, instead of just the means, then I'll probably give up ham radio.

A pharmacist friend of mine went to a continuing education seminar and came back telling that she had learned that over 95% of prescriptions were written to overcome or counteract the adverse effects of some other prescribed medication.  I can't help but wonder if 95% of the circuitry in modern radios is to overcome or counteract the adverse effects of "technological advances."

73, Mike N4NT

----- Original Message ----- 
From: <dbaumgarte at hvc.rr.com>
To: <tentec at contesting.com>
Sent: Thursday, February 19, 2004 4:33 PM
Subject: Re: [TenTec] Ten Tec Omni D, Why so quiet ?


> Mike?
> How can a filter lower static levels? only bandwith can do that not the type
> of filter...
> 
> 73 KB2TM
> Dennis
> ----- Original Message ----- 
> From: "Mike Hyder --N4NT--" <N4NT_Mike.Hyder at charter.net>
> To: <tentec at contesting.com>
> Sent: Thursday, February 19, 2004 12:09
> Subject: Re: [TenTec] Ten Tec Omni D, Why so quiet ?
> 
> 
> > Perhaps someone can explain why it is so but I've seen much discussion
> about
> > the superiority of the Ten-Tec 'crystal ladder' filters over the 'crystal
> > lattice' filters used by other manufacturers.  From what I've read, the
> > difference in those filter types may help account for the lower static
> > levels you are finding on the Omni-C.
> >
> > 73, Mike N4NT
> >
> > ----- Original Message ----- 
> > From: "Newberry Gary" <gnn01 at yahoo.com>
> > To: <tentec at contesting.com>
> > Sent: Wednesday, February 18, 2004 2:01 PM
> > Subject: [TenTec] Ten Tec Omni D, Why so quiet ?
> >
> >
> > >
> > > I hve a friend that's a recent convert to Ten Tec rigs
> > > mainly because of their quiet receiver. I hadn't paid
> > > much attention to it until this morning. On my Yaesu
> > > FT-857 ( an Icom 706 MKIIG clone ) On the Yaesu it
> > > sounded like there was a thunderstorm in the not to
> > > distant area with static noise levels around S5 or S6.
> > > I fired up the Omni D (Series C)on the same antenna
> > > and it was as quiet as a church mouse, the S meter
> > > would drop to almost it's resting state and the noisy
> > > Midcars net I was listening to sounded almost like a 2
> > > meter FM station at full quieting. I know the Omni
> > > isn't insensitive as I've had it back to Ten Tec for
> > > an alignment within the past couple of months.
> > >
> > > I've got some 120 KV lines and a substation about 500
> > > feet behind my house and wonder if for some reason the
> > > Yaesu is sensitive to that noise and the Omni isn't ?
> > >
> > > I just wonder if someone has a good logical
> > > explanation, I'm in Flint, Mich and worked a mobile
> > > running 5 watts in Mass. on a poor condition 40 meter
> > > CW band and I doubt with the noisy receiver of the
> > > '857 I would have heard him at all.
> > >
> > > I just wonder if anyone has any technical explanations
> > > for this ? Needless to say I'm not going to part with
> > > the old Omni D anytime in the near future.
> > >
> > > Thanks in advance
> > >
> > > Gary K8IQ