The Manual for the SSTran AMT5000 High Efficiency Transmitter says on Page 24, "Ground. A good, low impedance, ground is required for best range. Just as the transmitter will not work without an antenna, it likewise will not work without a ground."
The conditions quoted above apply to any and all transmit systems using a monopole antenna -- including licensed AM broadcast stations.
No mention is made of the grounding aspect of the AMT5000 test, rendering the published test results invalid.
Not true, Carl, because all of the transmitters in that test reportedly were driven against the same r-f ground using the same tx input power, on the same frequency, and on the same day (I think).
All of those transmit systems (when legally optimized) could have produced greater measured field intensities in those tests if they had been driven against an r-f ground having less loss resistance than provided by a single ground rod.
Part15.us committee member Rich has sent me back to re-read the Test Results and I found the description of the ground rod used for all tests printed in an eralier portion of the document. It seems to me that in a formal presentation the ground matter would be part of the individual transmitter test result rather than scattered around in the document, but an informal sketch is hobby style and quicker.
There's still the matter of all the jumpers, which can enhance or detract from the resulting output.
I'm also worried about the fiberglass pole used to support the wire antenna, many fiber glass poles contain a metal wire helically wound to keep the pole firm and this can introduce capacitance effect and absorb some of the radiation.
Unless the fiberglass pole was placed next to all the test antennas, results may be skewed.
I'm a pleased owner of Radio Systems' I.AM.Radio transmitter and ATU which have been performing quite well for more than a year. With the use of Jamin' for compression and limiting, the audio is very clean and listenable inside a dwelling at a minimum distance of 1/3 of a mile. In a car, the audio is cleanly listenable to a distance of 1/2 of a mile. In the near future, I'll likely be switching to a DRM LPAM transmitter and want to connect it to my I.AM.Radio ATU. Despite any potential legalities, I'll probably add an elevated, octagonal counterpoise to my currently ungrounded and elevated ATU (15' from the earth). Although the I.AM.Radio placed third in this particular test, it still is a good performer. I enjoyed the results.
I took a look at that Jammin' software.. Never heard of it before, it looks pretty cool ( http://jamin.sourceforge.net/en/about.html ).
As for the iAm placing third.. I wouldn't lookat it that way;.. Taking the liberty of quoting a post by Robert Felmly on a Part 15 facebook concerning the the test.. He makes a very goodpoint:
"...All things being equal one can only assume that minute differences in output power and antenna components would contribute to the variations of the measured field strengths.
Given a range of only 4.5 db from best to worst compared to price difference, personally I’d have to go with price of equipment.
I’ve been using the old version of the I.A.M. Radio (Talking House) with the ATU. Assuming the 2.5 db difference holds for my situation, where I have approximately $130 invested for used equipment, I can’t see paying $1000 for less than doubling my field strength..."
Perhaps the biggest key to achieving range with an AM antenna is the use of ground radials, but no radials were used in the challenge.
Radials do not need to be buried in the ground. They can be laid on the surface, and a special test rig could easily have been put in place with a minimum of trouble.
I have an AMT3000 matched to a self-built loading coil and antenna but with only a ground rod.
For comparison I have an AMT5000 with the internal loadingcoil and an antenna, but I added ground radials.
The two setups are identical in every respect except for the radials.
The AMT3000 covers house and most of the yard but vanishes fast beyond yard boundaries.
The AMT5000 can be heard for many blocks in all directions.
If a second challenge is ever planned, it would be advisable to use ground radials to show the full capability of the transmitters.
You ought to add some radials to the AMT3000 too
Just in view from the front window is a spot where a 10' bamboo tower is going up as a garden feature, with ground radials for a hidden AMT3000 site. This will be in addition to the AMT3000 I mentioned above, with only ground rod, which feeds a Wintenna (metal window-frame antenna).
Both transmitters will be set for 1550kHz, and selectable by remote control so I can compare them both A-B style.
The limited ground rod transmitter is useful when I want to listen "semi-privately" without being heard all over the neighborhood, such as when listening to Alex Jones.
I can’t see paying $1000 for less than doubling my field strength..."
Well...you get frequency stability. The Talking House is worth every bit of 99 bucks. It not only transmits in AM but FM as well.
wdcx has closed the deal with me and I will take a new look at the Talking House.
What cinched the deal was the mention of FMing while AMing, which is very sophisticated stuff.
I might even take a real estate course or sell my house to give proper use to this legendary transmitter that has so many versions.
Frequency stability is something you also get with sstran, but those can't do FM.
Frequency stability is something you also get with sstran, but those can't do FM.
I accidently had my Ten-Tec Jupiter in the FM position and the Talking House sounded better than in the AM mode.
Sounds like you got a bum Talking House. Mine checks out fine on a Motorola Station Monitor.
The Talking House is not a house. Do not be misled.
Wow.
As someone who has owned everything tested but the AMT5000 (and I now have one, I just haven't done anything with it yet), I was extremely interested in the results of this transmitter shootout.
The results (again, excluding the AMT5000) mirrored my experiences.
The Rangemaster, at least for me, achieved the greatest range and sounded the best (but hey, hearing your signal more than a mile out sounds pretty good period, even if there's static).
The ProCaster sounds great (not as good as the Rangemaster with outboard audio processing, including an Inovonics 222 and Symetrix compressor), but definitely had less range. Admittedly, I have an older model.
The Talking House with ATU sounds OK and got less range than the ProCaster. Without the ATU, even less range.
I can add another transmitter to my personal shootout list - The Talking Sign (precursor to the ProCaster) was superior to the Talking House, in both sound and range. In fact, with it's wire antenna strung vertically outside, it rivaled the ProCaster in range (although not in sound quality).
From what I've read, I don't believe there were any ulterior motives to the testing. And it may not have been the best way to test, but the results were at least interesting. And if you don't measure Field Strength, then how exactly do you measure range? Until there's no sound at all? Just how much static do you allow in your measurement? How do you define sounding good? The bottom line is that range is subjective, and dependant on the programming (talk or music), what your tolerance for static and dropouts is, etc.
SSTran chose not to participate in the shootout. That was their right. But then, they have to take the consequences as well (i.e., questions as to why they didn't participate). I personally have nothing against them or PhilB (although he has been rather snarky to me and others upon occasion in this Forum, not a good strategy if you're attempting to sell transmitters).
I don't think you can go wrong with any of these transmitters, provided you understand what you are getting and the tradeoffs. And at the end of the day, you have to try things out yourself, regardless of others' shootouts and test results. If something works for you and gives you what you want, including what you define as sound quality, then it's the best for you.
It would be nice to leave religious fervor out of the equation (because what you consider the 'best' transmitter didn't fare as well as others).
Part 15 is a religion.
Y'all need to show this to me. AFAIK, the Taking House TX only transmits AM broadcast band freqs. As a result of the recent posts here, I investigated and found no such dual-band dual modulation unit. In fact, Radio System's Talking House pages appear to be gone.