- July 27, 2018 at 4:24 am #105573
- July 27, 2018 at 5:04 am #105576
Total posts : 75
First-hand, no. But you may already know it placed as first-runner-up in an AM Transmitter “shoot-out” (behind the Rangemaster AM1000) on another low-power radio site. So it is a formidable unit.
The shootout has suffered considerable derision by some fellow Part15 members since it was published. As I see it, until which time another technically competent party can conduct a comparable hands-on followup (range testing, other engineers present, calibrated professional measuring equipment, et al) it has to remain the definitive word. There is room for everybody here.
I note also that the Grain website has not had a tweak since 2009. And not sure why.
- July 27, 2018 at 6:43 am #105578
I think most people appreciate the work and expertise that went into the Challenge.
That doesn’t excuse the procedural errors in the testing that skewed at least one result. Those errors and the reasons why they occurred have been discussed as nauseum, even over at the ‘other’ site.
You don’t learn anything by ignoring the facts. Even if you are an engineer and use expensive equipment.
- July 27, 2018 at 7:31 am #105583
I wonder what happened to the re-test of the AMT-5000?
- July 27, 2018 at 8:43 am #105584
Never happened. The standalone ‘review’ of the 5000 rehashed the dubious Challenge results, and included several ‘hatchet job’ opinion pieces on its design.
That’s one of the basic problems. That site has always had a negative bias against SSTran products, and the bias is clearly evident in its tests and reviews.
- July 27, 2018 at 9:05 am #105585
I remember emailing Phil as to why he did not submit a test transmitter to Hobby. His answer was, “Why?” “There are dozens of testimonials by satisfied customers.” This was back in the day of the AMT-3000. Then Hobby would go on a rant about unanswered emails and certified letters and of course the AMT-3000 is not certified..
Hobby probably sabotaged any useful relationship between himself and Phil at that point.
- July 27, 2018 at 9:37 am #105588
Total posts : 75
Anytime anyone here or across the street wants to commit to a new challenge with a new set of refined rules, I’ll happily enjoin the effort as an educated, skilled, experienced and impartial participant. And I heartily encourage all manufacturers to participate as well.
Until then, the shootout stands as the de facto document. Which says the Grain is second to the Rangemaster.
Sorry that took so long to answer, Legend.
- July 27, 2018 at 10:21 am #105598
Sorry, but that just doesn’t compute. Even the Hobby Forum after the fact ended up at a consensus that the AMT5000 was not operating in Class E mode during the testing. It was never established why, and in fact, the testers never made an effort to determine why (the testers, quite unscientifically, left it at, “well, we followed the instructions and it didn’t work as advertised”).
The problems could have been from a number of causes:
1. Transmitter (AMT5000) not functioning properly. In fact, sourcing of the various transmitters was one of the issues in the test. One of the testers was also a distributor for several of the transmitters, and the optics (at least) of that are not condusive to an unbiased test. The AMT5000 in its distributed form is a kit, and the tested AMT5000 was assembled and came from an unknown source, in unknown operating condition. It is entirely possible that it was not functioning appropriately.
2. Operator Error. It is possible that the 5000 tuning instructions did not work with the simple ground being used – class E operation is highly dependent on ground characteristics. In fact, you require an oscilloscope to determine if you’re really running Class E. So much for using expensive equipment during the testing, as that was never done. And that fact was not built into the testing protocol (from the discussions on the Hobby Forum, I don’t think that the testers realized it until after the fact).
3. Transmitter Design. This is what is being blamed, without facts, for the poor showing of the 5000. By that, I mean that it may not have been possible for the 5000 to properly tune ANY ground and run Class E, even if it was properly assembled and working correctly. Unfortunately, we won’t know that unless other tests are performed. There’s plenty of ancedotal evidence in the field that contradicts this, and shows that the AMT5000 can perform as well as, or even outperform, the Rangemaster.
Saying that the Transmitter Challenge is the de facto standard when there are significant issues with the testing of at least one transmitter, and potential cause for concern with some of the other transmitters, is just plain wrong.
Inviting others to perform identical testing as a means of validating an improperly conducted previous test is not a logically correct argument.
The Challenge is one significant set of data for Part 15 transmitters, yes, but not the definitive answer by a long shot.
- July 27, 2018 at 10:58 am #105601
Total posts : 1541
Remembering the Transmitter Challenge
The Grain transmitter was not part of the transmitter challenge and did not win 2nd place.
The 2nd Place Winner was the Procaster, with the Rangemaster being the 1st Place Winner.
We noticed that one of the participating engineers was the owner of a company that installs Rangemasters and Procasters for professional clients, but this was not disclosed in the original publicity from that hobby site.
In our review of the Transmitter Challenge we mentioned the discrepancy and obvious conflict of interest, which brought two reactions: on one hand we have been ever since vilified by them, but on the other hand they did post a proper correction admitting the dual role of the test engineer.
Since that time they have talked about seeking a donated Grain transmitter so they could do a review.
- July 27, 2018 at 11:28 am #105609
Total posts : 573
I have a long list of issues with that “Challenge” . I won’t go into them here as that’s not what this thread is about. But from my viewpoint as an actual broadcast engineer of 40 years I had a lot of issues with it.
I’d be happy to do a “real” Challenge. One problem of course is I would not accept any manufacturer support. Transmitters MUST be purchased at retail from normal sources. Do you think for a second that when you call up a transmitter supplier and tell them that you want one free, or on loan for testing, to use the results on a Part 15 website and in a magazine with worldwide circulation, they’re just gonna grab one off the shelf and let the chips fall where they may? No. You’ll get a tweaked unit.
Anyway, I’ll avoid heading off into a tangent on my issues with the test.
As for the Grain, I’d be leery of a website with no updates for 9 years.
I also not that by the time you add the necessary “extras” it’s going to cost about the same as a Procaster or Rangemaster. Remember, one of the main keys to successful Part 15 AM is processing. You’ll be adding the cost of a processor to both the Grain or the Rangemaster. And most of the others I suspect. When I first set up my station 5 years ago I tested range with varying modulation. 80% to 100% makes a pretty big difference. I can be sitting parked, listening to the station 1.5 miles away, have my wife back off the modulation of 80% and the station completely disappears. Additionally I pick up range modulating asymmetrical at 125+/ 99- The built in processor in the Procaster allows asymmetrical modulation with no cost for outboard processing. It is because of this advantage I suspect the Procaster would outreach the Rangemaster. And again, there’s the extra expense for processing for the Rangemaster.
Bottom line is I know nothing about the Grain. I’m sure it got shafted in the “test”. But it sure looks to me like other well respected units come out similarly priced with significant advantages and have web pages that are current.
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