Re: [Elecraft] Analog vs. Digital Front Ends

, September 16, 2015 8:33 AM To: elecraft Subject: [Elecraft] Analog vs. Digital Front Ends Sorry, I'm not buying that direct sampling front ends are as prone to overload as many of the posts are suggesting, especially on 20M and higher. During the past 3 years, I've worked one CQWW and one ARRLDX

Re: [Elecraft] Analog vs. Digital Front Ends

On 9/16/2015 12:43 AM, Alan wrote: So how long before ADC technology catches up to the K3? If Moore's law applied (doubling of performance every couple years) it wouldn't be long. Unfortunately Moore's law applies mainly to digital circuitry but the key parts of an ADC are analog (the "A" in

[Elecraft] Analog vs. Digital Front Ends

Sorry, I'm not buying that direct sampling front ends are as prone to overload as many of the posts are suggesting, especially on 20M and higher. During the past 3 years, I've worked one CQWW and one ARRLDX contest from the Northeast with a SteppIR yagi feeding an ANAN-100D with 0dB attenuation

Re: [Elecraft] Analog vs. Digital Front Ends

Look at the A/D converter as a chip tool that could potentially be used in ham RX design. If one wanted a ham band RX using an A/D front end, certainly one would add front end filters. Of course, that would only help solve the problem with out of band signals. Handling the vector sum of

Re: [Elecraft] Analog vs. Digital Front Ends

16, 2015 8:42 AM To: elecraft Subject: Re: [Elecraft] Analog vs. Digital Front Ends There's no pre-ADC hardware AGC at work in the radio like there is in the K3 and Orion. Barry N1EU On Wed, Sep 16, 2015 at 8:37 AM, Jerry Moore <je...@carolinaheli.com> wrote: > Is it possible your ri

Re: [Elecraft] Analog vs. Digital Front Ends

Barry says: >During the past 3 years, I've worked one CQWW and one ARRLDX > contest from the Northeast with a SteppIR yagi feeding an ANAN-100D with > 0dB attenuation and never experienced overload during the weekends. And Joe presented a very useful tabulation showing how signals combine. One

Re: [Elecraft] Analog vs. Digital Front Ends

capabilities of your receiver? Just asking.. I > don't know the answer. > > -Original Message- > From: Elecraft [mailto:elecraft-boun...@mailman.qth.net] On Behalf Of > Barry > N1EU > Sent: Wednesday, September 16, 2015 8:33 AM > To: elecraft > Subject: [Elecraft]

Re: [Elecraft] Analog vs. Digital Front Ends

All the serious direct sampling ham xcvrs have single band pass filters ahead of the ADC for ham band reception so that's not an issue. Barry N1EU On Wed, Sep 16, 2015 at 9:13 AM, Rick Stealey wrote: > Barry says: > >During the past 3 years, I've worked one CQWW and one

Re: [Elecraft] Analog vs. Digital Front Ends

Re GPS: Hardly a "low" orbit, Brian: 'GPS satellites fly in medium Earth orbit (MEO) at an altitude of *approximately 20,200 km* (*12,550 miles*). Each satellite circles the Earth twice a day.' Phil W7OX On 9/16/15 5:54 AM, brian wrote: Look at the A/D converter as a chip tool that could

Re: [Elecraft] Analog vs. Digital Front Ends

On 9/16/2015 9:16 AM, Barry N1EU wrote: All the serious direct sampling ham xcvrs have single band pass filters ahead of the ADC for ham band reception so that's not an issue. Not true - the Flex-6300 has no preselectors. Even if the transceiver includes preselectors (bandpass filters),

Re: [Elecraft] Analog vs. Digital Front Ends

th.net Subject: Re: [Elecraft] Analog vs. Digital Front Ends One has to ask, "Which large consumer of high dynamic range, high-speed sampling ADCs is requiring more performance than presently exists? What drove the market for the present ones?" The driver for the current generation,

Re: [Elecraft] Analog vs. Digital Front Ends

One has to ask, "Which large consumer of high dynamic range, high-speed sampling ADCs is requiring more performance than presently exists? What drove the market for the present ones?" The driver for the current generation, based on limited information, is the technical requirements for

Re: [Elecraft] Analog vs. Digital Front Ends

You're right about the 6300 Joe. I don't consider the Flex 6300 as "serious" in terms of a serious contesting radio. I would expect a serious contester to go with the Flex 6500/6700 or ANAN 100 or 200 series. On a crowded band being pounded by strong signals, the direct sampling ANAN rx sounds

Re: [Elecraft] Analog vs. Digital Front Ends

I'm having a hard time understanding where the frequency selectivity of a piece of wire comes from. On 9/16/2015 6:13 AM, Rick Stealey wrote: And Joe presented a very useful tabulation showing how signals combine. One thing that we should keep in mind is that single band antennas like

Re: [Elecraft] Analog vs. Digital Front Ends

In the late 60's W4BVV put a full size 3 el 40m yagi on a 70 foot boom up 150 feet. This would qualify as a passive front end. Pointed at Europe, at the shack end of coax, peak to peak RF on a scope would measure five to ten volts when the band was open. What will today's direct samplers do with

Re: [Elecraft] Analog vs. Digital Front Ends

as if we were talking about a Steppir vs a trapped tribander on 10-20 meters. Rick K2XT > To: elecraft@mailman.qth.net > From: w...@triconet.org > Date: Wed, 16 Sep 2015 08:21:03 -0700 > Subject: Re: [Elecraft] Analog vs. Digital Front Ends > > I'm having a hard time u

Re: [Elecraft] Analog vs. Digital Front Ends

On 09/16/2015 05:25 AM, Joe Subich, W4TV wrote: ... N "S" -- 1 S9 +63 dB (-10 dBm) 3 S9 +53 dB 10 S9 +43 dB 32 S9 +33 dB 100 S9 +23 dB 316 S9 +13 dB ~450 S9 +10 dB 1000 S9 +3 dB

Re: [Elecraft] Analog vs. Digital Front Ends

To:elecraft@mailman.qth.net From:w...@triconet.org Date: Wed, 16 Sep 2015 08:21:03 -0700 Subject: Re: [Elecraft] Analog vs. Digital Front Ends I'm having a hard time understanding where the frequency selectivity of a piece of wire comes from. On 9/16/2015 6:13 AM, Rick Stealey wrote: And Joe

Re: [Elecraft] Analog vs. Digital Front Ends

On 9/16/2015 2:02 PM, Alan wrote: The amplitude distribution of a large number of signals of different frequencies and amplitudes closely approximates Gaussian noise (see note 1 below). As a rule of thumb the peak to RMS voltage ratio of Gaussian noise is about 5 or 6. Of course, theoretically

Re: [Elecraft] Analog vs. Digital Front Ends

As a side note on this topic, there is a company in Tennessee that builds some really nice specialty receivers for various Governments. {notice I stated Governments, as in plural}.They also have built or build ham radios such as the Orion, Orion II, Omni VII, Eagle, Argonaut VI just to

Re: [Elecraft] Analog vs. Digital Front Ends

This is really good information, Alan, and makes sense. Regarding the approximation to Gaussian noise... given that most signals on a crowded band during a contest are highly compressed (their peak-to-average ratios are much smaller) would this make matters better or worse for the ADC, or no

Re: [Elecraft] Analog vs. Digital Front Ends

Hi Al, The Central Limit Theorem says that it doesn't matter what the distribution function is for each individual signal. As long as there are a lot of them, the total has a Gaussian distribution. In fact, it doesn't take very many to get quite close to Gaussian - something like 4 to 6 is

Re: [Elecraft] Analog vs. Digital Front Ends

On 09/16/2015 01:15 PM, Joe Subich, W4TV wrote: On 9/16/2015 2:02 PM, Alan wrote: The amplitude distribution of a large number of signals of different frequencies and amplitudes closely approximates Gaussian noise (see note 1 below). As a rule of thumb the peak to RMS voltage ratio of Gaussian

Re: [Elecraft] Analog vs. Digital Front Ends

http://www.radio-electronics.com/info/antennas/basics/resonance.php BOB k3djc On Wed, 16 Sep 2015 08:21:03 -0700 "Wes (N7WS)" writes: > I'm having a hard time understanding where the frequency selectivity > of a piece > of wire comes from. > > On 9/16/2015 6:13 AM, Rick

Re: [Elecraft] Analog vs. Digital Front Ends

On Wed,9/16/2015 7:38 AM, Lyle Johnson wrote: One has to ask, "Which large consumer of high dynamic range, high-speed sampling ADCs is requiring more performance than presently exists? What drove the market for the present ones?" Exactly right. Back in the '90s, innovative designers of

Re: [Elecraft] Analog vs. Digital Front Ends

This might be an orthogonal opinion, but I think it is awesome that high-end direct sampling receivers are competitive with mid-range superhets. We’ve been refining superhets since 1918, but when I worked on DSP in the 80’s, no one even considered direct sampling. It is still early for direct

Re: [Elecraft] Analog vs. Digital Front Ends

Don, The broadband jammer is the most traditional of all in electronic warfare. If a receiver can withstand substantial AWGN (additive white Gaussian noise), chirp, and CW jam, then that's the receiver for me. :-) 73, Mike ab3ap On 09/15/2015 06:51 PM, Don Wilhelm wrote: I am going to go

Re: [Elecraft] Analog vs. Digital Front Ends

On Tue, 15 Sep 2015 18:51:31 -0400 Don Wilhelm wrote: > I am going to go off on a wild tangent as a method of testing all > receivers for the ability to copy signals in the midst of very crowded > band conditions and/or the presence of noise. Whether those receivers >

Re: [Elecraft] Analog vs. Digital Front Ends

I am going to go off on a wild tangent as a method of testing all receivers for the ability to copy signals in the midst of very crowded band conditions and/or the presence of noise. Whether those receivers have analog front ends or an ADC. An extremely crowded band could be simulated by

Re: [Elecraft] Analog vs. Digital Front Ends

On Tue,9/15/2015 5:48 PM, Walter Underwood wrote: This might be an orthogonal opinion, but I think it is awesome that high-end direct sampling receivers are competitive with mid-range superhets. But they are NOT competitive in strong signal environments! That's the point of this discussion

Re: [Elecraft] Analog vs. Digital Front Ends

> Someday they will be, and many of us will be using them. I think it was back around 1993 that there was a discussion on the Internet about using a wide-band ADC to replace the front end of an HF receiver. I commented then that you just couldn't get good enough performance with affordable

Re: [Elecraft] Analog vs. Digital Front Ends

On Tue,9/15/2015 1:52 PM, Tony Estep wrote: On Tue, Sep 15, 2015 at 3:36 PM, Joe Subich, W4TV wrote: noise power ratio testing hides the fact by not providing MDS values under each test condition *and* fails to indicate that even with *no preamplifier* the total noise

Re: [Elecraft] Analog vs. Digital Front Ends

I think what everyone is missing here is that Adam has clearly stated that his tests were not designed to be tests to directly compare analog and direct sampling radios, and certainly they were not intended by Adam for direct comparisons to the tests run by the ARRL and Sherwood. They were

Re: [Elecraft] Analog vs. Digital Front Ends

On 9/15/2015 9:13 PM, Eric Swartz - WA6HHQ, Elecraft wrote: I think what everyone is missing here is that Adam has clearly stated that his tests were not designed to be tests to directly compare analog and direct sampling radios, and certainly they were not intended by Adam for direct

Re: [Elecraft] Analog vs. Digital Front Ends

On Tue, Sep 15, 2015 at 6:28 PM, Jim Brown quoted: > This all stems from the poor NF of their ADC and its low input voltage > range. This just points out that given problems in hardware have capacity breakout points. We are at a point where pure digital stuff to

[Elecraft] Analog vs. Digital Front Ends

Adam Farson's explanation of why the ADC clipping level has to be avoided at all costs is another reason why many people still prefer analog front ends. Don't proponents of analog audio point out that when an analog channel overloads, it does so "gracefully"? This is especially true of fans of

Re: [Elecraft] Analog vs. Digital Front Ends

Maybe I'm wrong, but if the thing we're testing is supposed to be a radio, and we want to compare how radios work under conditions we'd encounter in actual use, it just seems intuitively obvious to the most casual observer that the tests should be the same. 73 -- Lynn On 9/15/2015 12:25 PM,

Re: [Elecraft] Analog vs. Digital Front Ends

On 9/15/2015 3:39 PM, Lynn W. Taylor, WB6UUT wrote: Maybe I'm wrong, but if the thing we're testing is supposed to be a radio, and we want to compare how radios work under conditions we'd encounter in actual use, it just seems intuitively obvious to the most casual observer that the tests

Re: [Elecraft] Analog vs. Digital Front Ends

On Tue, Sep 15, 2015 at 3:36 PM, Joe Subich, W4TV wrote: > noise power ratio testing hides the fact by not providing MDS values > under each > test condition *and* fails to indicate that even with *no preamplifier* > the total noise signal is more than 10 dB *less*...