New Antenna Coming Soon based on Old Favorite.

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buddrousa

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People here WANT A ST2 BUILT LIKE A TANK. They are great antennas just do not hold up. Your original commits lead us to believe you were building a antenna that was a STRONGER BUILT ST2.
 
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kruser

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There

There are no such test results for the ST2, so why is it SO VITAL that I produce test results against something the original manufacture did not produce publicly?
I'm not sure but I think people would like to see a real world performance comparison between your design and what many may recall from an original ST2.
 

4436time

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If he intends to make any money off this antenna he will have to work out the issues so that it performs similarly to the ST2 prior to release, and even if he doesn't I believe we have the option not to purchase it based on his payment system when it becomes available. I would like to think the antenna gurus here are helping him out (if necessary) or at least attempting to so we the community can all benefit.
 
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iscanvnc2

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For the live of me I can’t see all this controversy over comparing the reception capabilities of two similar omni-directional antennas. I am in complete agreement with budrousa.

I could run the required test at my home with only one piece of specialized equipment: a 1 GHz Spectrum Analyzer or a Test Receiver. Here’s how.

Antenna 1 is an original, out-of-the box ST2, of which I understand numerous exist. Antenna B is “ a design copy of the ST2".

1. Mount both antennas identically on separate 10 foot pools on the peak of my roof, say at least 10 feet apart.

2. Run two identical in every way (length, connectors) cables down to my den.

3. Connect the two cables to the two inputs of a 1 GHz coaxial switch with the output connected to the measurement instrument set to read power in dBm.

4. With antenna A selected, tune to a frequency to be measured. Record the frequency and dBm.

5. Switch to antenna B. Record the power.

6. Compare the two readings to determine which antenna is “best” at that frequency

7. Repeat steps 4 through 6 for chosen frequencies.

8. Display results as a table or graph.

Frequencies should be chosen across the 25 MHz to 1GHz spectrum. I’d do so my using a scanner to select signals.

Notes
1. No prior knowledge is required of either antennas characteristics. This is a COMPARISON under IDENTICAL CONDITIONS.
2. The type of signal is immaterial
 

buddrousa

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Not hard to run test these are the most used scanner frequencies set at mid bands
40Mhz
150Mhz
460Mhz
750Mhz
850Mhz
Post the results
I hope your person testing the antenna has the correct equipment to test with and not guess which is better.
 

prcguy

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This method would be flawed, you would want to test both antennas on the exact same mast with the same exact feedline, everything identical between them. The difference in space between two identical antennas mounted close together can give many dB difference when receiving the same signal.


For the live of me I can’t see all this controversy over comparing the reception capabilities of two similar omni-directional antennas. I am in complete agreement with budrousa.

I could run the required test at my home with only one piece of specialized equipment: a 1 GHz Spectrum Analyzer or a Test Receiver. Here’s how.

Antenna 1 is an original, out-of-the box ST2, of which I understand numerous exist. Antenna B is “ a design copy of the ST2".

1. Mount both antennas identically on separate 10 foot pools on the peak of my roof, say at least 10 feet apart.

2. Run two identical in every way (length, connectors) cables down to my den.

3. Connect the two cables to the two inputs of a 1 GHz coaxial switch with the output connected to the measurement instrument set to read power in dBm.

4. With antenna A selected, tune to a frequency to be measured. Record the frequency and dBm.

5. Switch to antenna B. Record the power.

6. Compare the two readings to determine which antenna is “best” at that frequency

7. Repeat steps 4 through 6 for chosen frequencies.

8. Display results as a table or graph.

Frequencies should be chosen across the 25 MHz to 1GHz spectrum. I’d do so my using a scanner to select signals.

Notes
1. No prior knowledge is required of either antennas characteristics. This is a COMPARISON under IDENTICAL CONDITIONS.
2. The type of signal is immaterial
 

iscanvnc2

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To do as prcguy suggests, as I understand it, would require running all the frequencies on antenna A, taking it down and mounting antenna B. By the time you have run all the necessary frequencies on A and changed to B, mucho time has passed (hours, next day?). Who knows what the field strength at a given test frequency from its source will be then compared to what it was earlier, due to atmospherics, etc. Using over-the-air signals REQUIRES taking readings with both antennas at the flip of a switch to insure the same the same field strength is sampled.

For omni-directional basically 0 gain antennas, 10 feet should be no problem. What the heck, make it 30 feet apart! In anticipation of another potential objection, pick signals as close to broadside to a line between the two masts as possible.

What I suggested was I simple test that would give satisfactory results. To do as proguy suggests would require an anechoic chamber good down to 40 MHz where you have the ability to recreate a given field strength at any time. Oh, the $$$$$$!
 

iscanvnc2

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Once testing is setup, for any method, measurement should be the easy part and least time consuming. I'd expand on prcguy's list
All in MHz
30 120 150 300 450 510 770
40 130 160 400 470 860
50 140 170 490 940
 

vagrant

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Dear prcguy,

Thank you for sharing on this forum. Your decades of professional experience in the industry has helped me understand what is correct as well as discern errant information. While my own experimentation has proven insightful, I have at times later found that you already provided answers years ago in various threads that correlated with my testing results. I endeavor to use the search feature more often, and save myself some time. :)
 

RRR

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While it is a design copy of the ST2 it is NOT an ST2.
Well that's interesting. The title of this thread is-
New Antenna Coming Soon based on Old Favorite.
....So it kinda is, but it's kinda not?

There are no such test results for the ST2, so why is it SO VITAL that I produce test results against something the original manufacture did not produce publicly?
I don't get it? You offered to have it tested! Were your test results sour or something? You were full steam ahead, until it came time to release test results. Then the "Test results" page got locked down/removed, for whatever reason. So you forgot to add an counterpoise, ok, no big deal, add it in, and test her out some more, no need to get argumentative and defensive. **We WANT a great antenna!**

But I can't help but note, that you priced your antenna (to us on here) before you revealed the results. Well, before you revealed them to us, anyway. Made me think that you had found out your "ST-2 / Searcher I" was shining bright when you priced it, and started taking "pre-orders"

So, what's the deal? Are you going to release the testing results, so we can get on your waiting list, and start sending you money for this (hopefully) great antenna? I sure wish I had 5 or 6 ST-2's, but they aren't available anymore like they once were. In comes you, with your "Searcher I" to the rescue!

** I just want to know if it performs as good as the ST-2, as the title, and almost everything else you posted about it in this thread leads to. **

Does it?
 
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Ubbe

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For omni-directional basically 0 gain antennas, 10 feet should be no problem. What the heck, make it 30 feet apart! In anticipation of another potential objection, pick signals as close to broadside to a line between the two masts as possible.
The bigger the distance the bigger the difference in reception. When you have a diversity system that uses several antennas connected to several receivers that receive the same frequency, it selects the antenna that have the best signal and you try to seperate the antennas as much as possible to create a bigger difference in reception of a signal.

Radiosignals bounce off from objects and if that object are behind the antenna it could reflect a signal back to the antenna. If the object are in front of the antenna, and even the ground can reflect signals, it will take a longer path to the antenna and will arrive with a different phase compared to the main signal and will degrade it. Sometimes it will actually arrive in phase and increase the signal strenght.

I have several roof antennas and sometimes it can be a 10dB difference in signal strenght, one antenna -5dB and another one +5dB, depending of direction, distance and frequency, and which antenna that receives best are constantly changing depending of those factors, especially with a moving mobile signal.

A professional way of measuring an antenna would be to use a spectrum sweeper, connecting the tracking signal generator to the antenna and then a probe connected to the spectrum sweep and moving that probe around the antenna at a 10ft distance. The probe needs to be calibrated, usually it's a logperiodic antenna, over the frequency range and the antenna needs to be in an open space so that reflections doesn't influence the readings too much.

/Ubbe
 

RRR

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All this is true, UBBE, but looking back in the pages here, he supposedly had sent an original ST-2, AND the "Searcher I" off for "Professional testing".

This is a very positive act for him to do. But now, we are wanting to see what the results were, it is somehow not important anymore. :unsure:
 

kruser

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All this is true, UBBE, but looking back in the pages here, he supposedly had sent an original ST-2, AND the "Searcher I" off for "Professional testing".

This is a very positive act for him to do. But now, we are wanting to see what the results were, it is somehow not important anymore. :unsure:
I'd suspect he either had a poor test result or the actual testing cost way more than he was expecting depending on how professional the testing lab is. He's possibly making design changes now based on test results.
I guess we shall see our answers if he ever posts the test results.

If the antenna works well, hiding the test results on a "private" page is not a good idea. Let the users see how it should perform.
 

prcguy

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Using over the air signals does not require taking readings from both antennas at the flip of a switch. If a particular source is non line of sight then yes it can vary in level over time, but you don't use non line of sight signals or you verify they are consistent over the course of testing. At home I can take readings from many transmitting stations, repeaters, TV transmitters, etc, and the levels are within a fraction of a dB all the time over months of time.

I've used off air signals many times to compare antennas. You work quickly and test both antennas on the same mast/mount within a few hours and if there anything is questionable you repeat the test to make sure its consistent. Check out post # 15 here for a article where I did this comparing a couple of mobile scanner antennas to a military antenna on the exact same vehicle, exact same mount, feedline, etc. Antenna Specialists MON752

I've also generated controlled test signals from a mile away into a log periodic and taken receive levels on a hill top using a similar setup and also put together a temporary test ranges with a log periodic as a source antenna transmitting to the antenna under test 75ft away using a scalar or vector network analyzer. That allows you to calibrate the system with one antenna then swap to another and see the difference graphically or point by point within a tenth dB. As long as you test in the far field and the area is free from reflective surfaces you can get good data. You also move things around prior to testing to see if ground bounce is a problem, etc.

I was also a range master for an anechoic chamber antenna and RCS range at a large aerospace company years ago, so I'm somewhat familiar with industry practices.

To do as prcguy suggests, as I understand it, would require running all the frequencies on antenna A, taking it down and mounting antenna B. By the time you have run all the necessary frequencies on A and changed to B, mucho time has passed (hours, next day?). Who knows what the field strength at a given test frequency from its source will be then compared to what it was earlier, due to atmospherics, etc. Using over-the-air signals REQUIRES taking readings with both antennas at the flip of a switch to insure the same the same field strength is sampled.

For omni-directional basically 0 gain antennas, 10 feet should be no problem. What the heck, make it 30 feet apart! In anticipation of another potential objection, pick signals as close to broadside to a line between the two masts as possible.

What I suggested was I simple test that would give satisfactory results. To do as proguy suggests would require an anechoic chamber good down to 40 MHz where you have the ability to recreate a given field strength at any time. Oh, the $$$$$$!
 

digitalanalog

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Some problems were found in testing and I need a little more time to update the antenna.

ST2 Specs are as follows 30-54 MHz, 108-174 MHz, 450-470 MHz, 470-512 MHz, and 800-912 MHz
The Searcher I specs are as follows 30-54 MHz, 108-174 MHz, 450-470 MHz, 470-512 MHz, and 800-912 MHz

The ST2 is resonant in the areas listed above.
while The Searcher I receives the same bands it is NOT resonant in all of them.

post.jpg

post2.jpg
 

mancow

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I would think it's close enough. The orignal wasn't really "resonant" in all those areas.
 

vagrant

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Great minds think alike!
AT-197A/GR discone and ST2 (or similar build) antennas. Add a 10dB receive amp for each of those and you're set, plus filters as needed.
 

Ubbe

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I would think that resonance and SWR and S11 or whatever an analyzer comes up with are not as important as the signal strenght it actually receives from the horizon. It's not always that resonance and low SWR equals to best reception. A dummy load have perfect SWR but works lousy as an antenna, as it only handles electric and thermal energy and no magnetic energy that are needed to transmit radiowaves.

/Ubbe
 
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