I would like to see the details of the outdoor test on a tripod by a pool. Where can I see that?
After I opened this post I found the photos of the outdoor setup, but there are no textual details of the field strength results at distances from the test site.
I don't quite get the value of photos when we're talking about actual performance results.
MORE ADDED LATER ---
In the balcony tests there is a beautiful view of the AMT5000 in its custom outdoor box. This is what I've been waiting for. Even though I may be a year away from having an outdoor antenna installed, I want that package and will be placing an order very soon.
HOWEVER, in the tripod test by the pool, I see no verifiable proof that an AMT5000 was even used.
ONE MORE THING....
What does testing the AMT5000 with a whip have to do with the Isotron antenna, which was the original subject of this post?
OMG. I'm not sure any further response to this entire thread is necessary from me anyway. But I will point out a few things that obviously even photos don't seem to be enough.
1. The photo collection DOES show the same transmitter under test. Look more closely.
2. The photos show how the two setup configurations were made...and point out that both are in the real world beyond the confines of a warm cozy room and beyond the simple wire.
3. The photos do show how BOTH test conditions used a SIMPLE ground system..ie one shows a ground rod, the other shows ground via the power socket.
4. The poolside set of photos demonstrates a ground level setup kin to a setup in someone's own personal yard, though it is an apartment complex property, it would make no difference if that setting was similar to a backyard setting with a pool and rod iron fence around it.
5. Referencing kc8's notes about how sensitive that 5K unit is with it's specific design parameters and tight tuning window, the photos, both sets, once again proves my entire point from day one..that beyond these simple setups..ie no elaborate ground radial system..that it won't do very well in such cases without sacrificing the touted 98% efficiency.
6. These sets of photos, and kc8's reports here within this thread, shows how he managed to get decent tuning out of the thing with both setup configurations.
7. Further back in this thread, kc8 does note that the 5K unit is sensitive with the top plate of the home built Isotron kc8 used.
8. The provided photos given are to..for lack of better word...debunk the claim of conflict in statements between myself and kc8 within this thread.
9. The Isotron can work outdoors. Thus replace the simple whip as seen in the photos with one. There is nothing preventing one from doing so just because someone or photos says "ye cant have Isotron on this!"
10..and final note on this by me...there is no reason for textual content regarding the set of photos as those photos are provided for another reason..not to show or indicate or suggest anything about field strength whatsoever. They are provided to show the two setup conditions to which kc8 reported in his own words further back in this thread, that THAT is how he was able to get the thing to function within it's tight window of tuning.
Confetti...it's fun to throw out there but eventually you throw enough of it and you find yourself the only one digging out from under it.
RFB
OMG. I'm not sure any further response to this entire thread is necessary from me anyway. But I will point out a few things that obviously even photos don't seem to be enough.
1. The photo collection DOES show the same transmitter under test. Look more closely.
2. The photos show how the two setup configurations were made...and point out that both are in the real world beyond the confines of a warm cozy room and beyond the simple wire.
3. The photos do show how BOTH test conditions used a SIMPLE ground system..ie one shows a ground rod, the other shows ground via the power socket.
4. The poolside set of photos demonstrates a ground level setup kin to a setup in someone's own personal yard, though it is an apartment complex property, it would make no difference if that setting was similar to a backyard setting with a pool and rod iron fence around it.
5. Referencing kc8's notes about how sensitive that 5K unit is with it's specific design parameters and tight tuning window, the photos, both sets, once again proves my entire point from day one..that beyond these simple setups..ie no elaborate ground radial system..that it won't do very well in such cases without sacrificing the touted 98% efficiency.
6. These sets of photos, and kc8's reports here within this thread, shows how he managed to get decent tuning out of the thing with both setup configurations.
7. Further back in this thread, kc8 does note that the 5K unit is sensitive with the top plate of the home built Isotron kc8 used.
8. The provided photos given are to..for lack of better word...debunk the claim of conflict in statements between myself and kc8 within this thread.
9. The Isotron can work outdoors. Thus replace the simple whip as seen in the photos with one. There is nothing preventing one from doing so just because someone or photos says "ye cant have Isotron on this!"
10..and final note on this by me...there is no reason for textual content regarding the set of photos as those photos are provided for another reason..not to show or indicate or suggest anything about field strength whatsoever. They are provided to show the two setup conditions to which kc8 reported in his own words further back in this thread, that THAT is how he was able to get the thing to function within it's tight window of tuning.
Confetti...it's fun to throw out there but eventually you throw enough of it and you find yourself the only one digging out from under it.
RFB
I can't figure out what to take from the photo demonstration because I don't know what is being demonstrated.
I was under the perhaps misguided impression that some sort of failing of the AMT5000 was being "proven".
So then, the AMT5000 is as good as I think it is?
I can't figure out what to take from the photo demonstration because I don't know what is being demonstrated.
I was under the perhaps misguided impression that some sort of failing of the AMT5000 was being "proven".
So then, the AMT5000 is as good as I think it is?
Inconsistencies nag at me in the back of the head somewhere, and I had to go back to the beginning to see what happened to get me bent out of shape in this discussion.
Here we go.
kc8gpd posted on Dec. 15...
"i am discovering the amt5000 wants to see that specific antenna capacitance and the taps have very little affect in tuning out anything outside of that small window of capacitance on the radiator. at least at 1670 anyway.
"i have determined the ground does not have much of an effect on tuning as the antenna capacitance does."
This post says nothing in the way of what it is later made out to say, when rfb posted on Dec. 17...
"KC8's testing confirms the unit prefers to operate without a ground radial system, and tunes good into antenna elements like that listed without the ground radial system."
In reality, kc8gpd's post "confirms" that PhilB's design of the AMT5000 tuning is EXACTLY AS DESCRIBED IN THE MANUAL."
kc8gpd "determined" that the ground "does not have as much effect on tuning as the capacitance does".
NOTHING in kc8's comments possibly lead us to saying "KC8's testing confirms the unit prefers to operate without a ground radial system."
I rest the case.
Inconsistencies nag at me in the back of the head somewhere, and I had to go back to the beginning to see what happened to get me bent out of shape in this discussion.
Here we go.
kc8gpd posted on Dec. 15...
"i am discovering the amt5000 wants to see that specific antenna capacitance and the taps have very little affect in tuning out anything outside of that small window of capacitance on the radiator. at least at 1670 anyway.
"i have determined the ground does not have much of an effect on tuning as the antenna capacitance does."
This post says nothing in the way of what it is later made out to say, when rfb posted on Dec. 17...
"KC8's testing confirms the unit prefers to operate without a ground radial system, and tunes good into antenna elements like that listed without the ground radial system."
In reality, kc8gpd's post "confirms" that PhilB's design of the AMT5000 tuning is EXACTLY AS DESCRIBED IN THE MANUAL."
kc8gpd "determined" that the ground "does not have as much effect on tuning as the capacitance does".
NOTHING in kc8's comments possibly lead us to saying "KC8's testing confirms the unit prefers to operate without a ground radial system."
I rest the case.
I see in the pictures that a choke is present in the ground wire just below the transmitter. 
. This was a surprise to me because it wasn't mentioned previously.
The presence of the ground choke can be a reason for tuning problems. As I pointed out in a previous thread, a ground choke will detune a transmitter. The choke inductance adds to the loading coil inductance causing the total tuning inductance to increase. This will detune the transmitter. To get things tuned back to resonance, the loading coil tap must be adjusted to reduce the loading coil inductance by the value of the choke inductance.
If the choke inductance is relatively high, you will run out of taps at the low-inductance end of the loading coil resulting in not being able to tune to a frequency at the upper limit of the transmitter's specified tuning range.
A ground choke is not recommended for the AMT5000, or any other transmitter for that matter.
I see in the pictures that a choke is present in the ground wire just below the transmitter. . This was a surprise to me because it wasn't mentioned previously.
The presence of the ground choke can be a reason for tuning problems. As I pointed out in a previous thread, a ground choke will detune a transmitter. The choke inductance adds to the loading coil inductance causing the total tuning inductance to increase. This will detune the transmitter. To get things tuned back to resonance, the loading coil tap must be adjusted to reduce the loading coil inductance by the value of the choke inductance.
If the choke inductance is relatively high, you will run out of taps at the low-inductance end of the loading coil resulting in not being able to tune to a frequency at the upper limit of the transmitter's specified tuning range.
A ground choke is not recommended for the AMT5000, or any other transmitter for that matter.
I took about my fifth trip through all of the material posted and I still cannot find the actual test results alluded to in the thread.
The photo of the Field Intensity Meter (FIM) opens the senses to expect actual field testing, but someone forgot to publish field test results.
The suggestion that a top hat on an Isotron can or might cause tuning problems with AMT5000 is vague....
Was this actually done in a test that wasn't photographed or otherwise documented?
Or, is it only an opinion of possible results, not actually tried?
I have caused much annoyance by trying to reassemble the science being claimed here, but it's an interesting subject and I'm trying my best to verify whatever it is that would summarize these tests.
That ground wire, plugged into the 3rd hole of a homemade AC extension box raises an unanswered question.....
We know from experience that many AC extensions have a ground pin broken at some point to allow use in a 2-prong wall plug, and older AC systems sometimes are not grounded through the third wire.
The above report would be more solid if the ground path were described per the inspection of the tester.
I am not questioning anyone's honesty. I assume everyone is honest. However, the scientific method requires detailed documentation, not simple on-the-fly claims.
I wish I had more time ... these topic threads are much more than I expected when I first posed the question.
I think the Isotron, in particular the custom one for AM band, designed with Part 15 in mind, is a essentially a kind of open-air tank circuit isn't it? In this case, the upper element is like a top hat, and the lower one sort of replaces a ground radial setup. Together they look like they will concentrate RF energy through the coil into the radiator while also providing a return path, all in the same unit.
I have to get some better broadcast gear for our remote broadcasts, e.g., headset mic combos and portable booth stuff ... Gyms produce very loud slapback sound reflections, which we need to reduce all that background noise. Otherwise, I would be thrilled to get an Isotron and try it out. No time to design and construct one myself either.
When I haul out and fix up my boat (or get another one that will have to be inspected) I may try it. I was just hoping to get a handle on what will work, because I may need it when that happens, since the boat won't be in a viable position to broadcast from during that time.
I will hopefully have a second floor bedroom of a house on my friend's property. The house was a sneak-build back in the days when you could get away with such things on this island, but now it can't legally be rented out until the current building codes are met ... more than they can afford at this time. However, it's apparently OK for "storage".
As mentioned, I'll mount the TX in the attic right under the antenna system on the roof. The only available ground will be from the PS and audio link from an online STL computer. Protection will be a simple spark-gap from antenna to heavy ground wire. Not much lightning around here, even in the peak season for it in August ... long ways off from now.
With the weather like it is today (off/on hard rain and 60mph wind gusts ... I've lost signal 5 times) I also worry about the viability of an Isotron as they appear to be perhaps too frail to handle severe outdoor weather conditions.
Any further comments regarding these items is welcome, but, interesting as all this stuff is, I don't want to stray too far from the original topic. Boat has to come out soon, maybe even before the basketball season is over.
ASIDE: We've broadcast 8 away games (football and basketball) remotely with simple equipment, have a fair number of game to game and premium-level season sponsors. Next up is another tournament series (we have 2 games) live at the Yakima SunDome Dec 28, 3:00pm, Dec 29, 10:00am. Looks like we'll be with the team at a motel overnight.
Ken,
Count me as part of your world audience who follows what you are doing and finding it to be a great example to be admired by all part 15 people.
Ya, it does seem like the Isotron might be a wind grabber. If it wobbled around the movement would be a tuning problem, and if it flew apart watch out for flying hunks of metal.
The Isotron is a curiosity, even if it looks like a re-purposed animal trap bolted to half of a bird feeder.