[TenTec] Scads of used Icom IC-7300

Sat Sep 10 16:23:49 EDT 2016

Well Gary, being as I've had my Eagle nearly 6 years now, you were slightly off on your year count for the Eagle.
So that only re-enforces your argument.

When you speak of the "receiver testing laboratory", if you mean Sherwood, then you need to do a bit of homework.

Rob has NEVER EVER said that his list is a ranking of the overall performance of the radios.  In fact in EVERY presentation he makes, he points that out.

That list ranks radios according to their measured "close-in DR3".  That's ALL.

In addition Rob and several others have been saying for years now that DR3 is no longer a good indication of the performance of SDR radios, and that there are other important factors contributing significantly to SDR performance.

For nearly every radio added to the list in the past dozen years or more, there is an accompanying full review showing ALL measured data and then a subjective opinion from Rob on how the radio actually performs on the air.  Most of the ones that are considered to be contest radios were also used in one or more contests by Rob.  

You will find all of Robs tests on my web site:
 http://www.dj0ip.de/sherwood-forest/sherwood-xcvr-tests/ 

It is important to read all of the information and not just look at the snapshot that list presents.
Fundamentally we need to separate the SDR radios out from the heterodyning radios.

A couple of days ago I posted some data on the stuff Rob found wrong with the 7300.
Although it may be that I posted it in the Eagle group and not in this group.
There are similar threads in both groups.
If so, let me know and I will post it here too.

>From that information, it is obvious that Rob does not rate the radio above the Eagle and Orion, etc. 

73 - Rick, DJ0IP
(Nr. Frankfurt, Germany)

-----Original Message-----
From: TenTec [mailto:tentec-bounces at contesting.com] On Behalf Of Gary J FollettDukes HiFi
Sent: Saturday, September 10, 2016 6:20 PM
To: Discussion of Ten-Tec Equipment
Subject: Re: [TenTec] Scads of used Icom IC-7300

Well, for one thing, the Eagle has been in the marketplace for maybe 4 years. In addition, during the fire sale, Ten Tec gave them away fully loaded for ~$1200, thereby loading up the market with LOTS of them. One might expect to see numerous listings for Eagle’s under these conditions, and they are still selling for almost 90% of the fire sale prices, because the “new” price for them is well over $1500 depending upon options.

The high number of listings for “used” samples of a radio that has only been in the marketplace for a few months is, however, unexpected and suggests some significant degree of buyer’s remorse.

Icon’s own response to complaints regarding receiver performance ("use a preselector") suggests the they agree with those who find it inadequate in SOME listening situations.

I agree with the statement that the Eagle is not for everyone. It is very Spartan. Its appearance is on a par with the entry level Icom radios, not very pretty. Early ones did not even have an IF out for use with a bandscope. 

I have had two of them myself, loved the receiver performance in every way, but found that the Spartan nature of the radio was annoying and I really did not like the display - not a criticism, just personal preference.

Maybe the term “garbage” was harsh, but even the noted receiver testing laboratory rated this thing as being better than an Orion and an Eagle, and only slightly worse than the $20,000 Hiberling, a rating nothing that is nothing less than ridiculous. This rating exaggeration is on a par with the “garbage” exaggeration. 

Making a good DSP transmitter is trivial compared with making a good DSP receiver. The signal levels are always the same, and of very low (and always predictable) signal dynamic range. 8 to 12 bit audio would suffice for communications purposes. Thus it makes the achievement of good transmitter performance somewhat lame when the receiver’s actual on-air performance is so marginal that its manufacturer must recommend a fix that, while commonplace in the 1960’s, has been unneeded for a long time, until now, a preselector.

I stand by my previous statement that you COULD produce an exceptional DSP receiver, one that would blow the socks off any heterodyne receiver, if you used 24 bit data and a tracking preselector to limit the impact of strong out-of-band signals. 

Remember this, the signal at the input of the D to A is the linear superposition of ALL of the RF signals that come in at the antenna terminal. The relative phases of all of these contributing components is always changing but, so long as your total input signal voltage is below the highest allowable level for the A to D, all is well. The A to D only samples once the analog signal has been held long enough for a stable reading by the track-sand-hold so this constant variation poses no problem. However, once you have an input signal strength greater than the largest allowable signal level for the A to D, things get very bad very quickly and at that point, no additional signal energy makes any difference on the A to D reading. Thus you hear nothing at all above saturation. This is the digital equivalent of blocking, only far more severe than that which takes place in an analog heterodyne receiver.

These principles were known decades ago, in areas of digital data acquisition of analytical signals in chemical instrumentation. We found that, for Xray Photoelectron Spectroscopy, as an example, 32 bits of data were required to be able to extract the counts of a small signal sitting on top of a huge nose floor. That’s 1 part in 4 billion (192 dB signal dynamic range). While that was a pulse counting scenario, the outcome is the same. If we were trying to extricate a 10,000 cps Carbon 1S signal sitting on top of a 1E9 cps noise baseline (a typical real world situation) with a 16 bit data converter, we’d have seen nothing but a flat line at pulse saturation in the data plot.

A 1 megawatt shortwave broadcast station 2 kilometers away adds up to some pretty significant amplitude at the A to D converter in your radio. Your desired tiny 3 microvolt QRP DX station is sitting on top of that huge signal which is already above the “largest allowed voltage” for the A to D, in the absence of significant input band pass filtering. What do you think your chances are of hearing that 3 microvolt signal, even on a very quiet band (from a random noise perspective)?

A tracking preselector could easily be produced to reduce that out-of-band signal to a level that would be acceptable for the A to D, especially if that A to D were 24 bit, more than enough bits for the expected signal dynamic range for Ham radio receivers.

Gary

> On Sep 10, 2016, at 9:25 AM, Tim <tim at ke4ke.com> wrote:
> 
> Rick,
> 
> Forgot to mention the number two radio has a typo in the first link's list. It is an Eagle.
> 
> TS-599at should read TT-599at
> 
> 
> Tim
> KE4KE
> 
> 
> 
> On 09/10/2016 03:01 AM, rick at dj0ip.de wrote:
>> We had similar with the Eagle, especially right after the fire sale.
>> The Eagle is not for everybody.
>> There are lots of things to not like about an Eagle but receiver performance is not one of them.
>> 
>> IMO this boils down to people being too darn lazy to do their own due diligence.
>> Rather than dig through the specs and try to understand what they are buying, they just follow the marketing hype.
>> 
>> There was a time in my life when I also did that, because I had more money than I had time.  I would buy things while on business trips, take them home, eventually test them and if I didn't like them, dump them for a spot price.  I'm sure there are lots of hams who can relate to that.  When you're traveling 4 days per week, mostly out of country, you don't have a lot of time for the hobby.
>> 
>> Unfortunately but also fortunately those times are long gone for me.  Life is simpler now, less hectic.  I still have little time but more time than money, so I take the time to study the stuff.
>> 
>> IMO IT IS UNFAIR to call the 7300 garbage.
>> It is what it is and does what it is advertised to do and all that for a fair price, considering the bells and whistles and relatively good performance.
>> 
>> You can make just as many arguments that the Eagle is garbage... even though it remains my favorite radio for my style of operating.
>> 
>> GARBAGE:  radio's like the FT-450D that have an IMD of as much as 29dB worse than a 60 year old Collins 32S3 on some of its higher order IMD products.  Radios that broadcast broadband noise (i.e. FT-1200, FT-3000, FT-5000, TS-590 (but not the SG), IC-7600 and many others) may be fine for hams living out in the boondocks but for hams in the city, they are probably unknowingly disturbing all hams within 2 or 3 miles AND THAT IS GARBAGE THAT MUST STOP!  The IC-7300 does not do this so IMO I see no reason to call it garbage.  It is a great radio for the price - if you are looking for a all-mode, do everything radio.
>> 
>> 73 - Rick, DJ0IP
>> (Nr. Frankfurt, Germany)
>> 
>> 
>> -----Original Message-----
>> From: TenTec [mailto:tentec-bounces at contesting.com] On Behalf Of Gary J FollettDukes HiFi
>> Sent: Saturday, September 10, 2016 7:04 AM
>> To: Discussion of Ten-Tec Equipment
>> Subject: Re: [TenTec] Scads of used Icom IC-7300
>> 
>> Companies don’t take back equipment that does not perform to buyers’ expectations. They are only required to honor warranties for defects in parts or workmanship, NOT defects in design. They meet their published specifications and get great bench top lab test results that do not describe actual performance.
>> 
>> Thus the only recourse for buyer’s remorse is fire sale pricing to recoup SOME of their investments.
>> 
>> No one in their right mind would pay more than 75% of new price for a used item, regardless of what it might be. Thus you see the bargain prices for what is indeed an entry level radio with lots of great features and marginal RF performance.
>> 
>> 
>> 16 bit Analog to Digital direct conversion with no (or poor) band limiting input filters is a sure-fire formula for performance disaster. Icom admits this fact in their “solution” to the overload problem - use a preselector.
>> 
>> As I said previously, IP3 means nothing in a radio that has no mixers. Synthesizer phase noise rating means nothing in a radio that has no synthesizer. The fact that the 7300 “shines” in these characteristics in lab tests says nothing about real performance and new standards need to be developed to assess performance of direct digital conversion designs.
>> 
>> The “first adopters” of this particular model found this out for themselves on the air and found the results very disappointing. That’s why they sell them after a few weeks of use.
>> 
>> Gary
>> 
>> W0DVN
>> 
>> 
>>> On Sep 9, 2016, at 10:55 PM, Bwana Bob <wb2vuf at verizon.net> wrote:
>>> 
>>> That's amazing that people would buy and then dump them so quickly.  There must be several things that are disliked, like maybe they can't get used to using a touch screen.  I, myself, would prefer traditional knobs and buttons to a touch screen. They always get smudgy and scratched.
>>> 
>>> Bob WB2VUF
>>> 
>>> 
>>> On 9/9/2016 11:19 PM, Gary J FollettDukes HiFi wrote:
>>>> Someone questioned my statement that there were “scads of IC-7300 radios” on the used market already.
>>>> 
>>>> Today, there are three on QTH alone, and one can be had for ~$1050!
>>>> 
>>>> Garbage depreciates in value pretty quickly, faster than an open can of Coors Lite!
>>>> 
>>>> Gary
>>>> _______________________________________________
>>>> TenTec mailing list
>>>> TenTec at contesting.com
>>>> http://lists.contesting.com/mailman/listinfo/tentec
>>> 
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