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All AAA-1 Kits from the Second Batch Were Sold

February 6, 2013, 3:26 am
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Hello all,

I must inform you that all AAA-1 kits from the second batch were sold. The third batch will be available within few days. I am wating to get them from the mounting factory. I want to thank all hams who got their kits, for the interest and feedback. Check regularly the blog of this site for further information and technical support. Any feedback for working experience with AAA-1 is welcome and desirable in order to improve the future designs.

73 Chavdar LZ1AQ

The post All AAA-1 Kits from the Second Batch Were Sold appeared first on Active Antenna Amplifier.

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The third batch of Active Antenna Amplifiers AAA-1B is now available

February 15, 2013, 3:27 am
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The third batch of Active Antenna Amplifiers is now available . The model is basicly AAA-1B with some minor improvements in noise floor of the loop amplifier part (output noise power -115 dBm @ 10MHz). The specifications and documents are the same as for AAA-1B. Identification mark for amplfier PCB of this batch is v.4.02. There are minor changes in Order&Pricing section.

73, Chavdar LZ1AQ

The post The third batch of Active Antenna Amplifiers AAA-1B is now available appeared first on Active Antenna Amplifier.

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Two new important articles are published

December 21, 2013, 3:28 am
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Hello all,

There are two new important articles published on LZ1AQ site        www.lz1aq.signacor.com .

The first article “Experimental Comparison of Small Wideband Magnetic Loops” experimentally analyze the effect of using crossed coplanar loops which might be important to AAA-1 users. There is also an Excel spreadsheet w-loop-calc-v10.xls to calculate the efficiency of the wideband loop. Sensitivities of numerous loops are calculated which can be practically used to build the best loop for certain conditions.

The second article is “Receiving Phased Array with Small Electric or Magnetic Active Wideband Elements. Experimental Performance Evaluation”. Here the performance of simple unidirectional antennas build with active loops and dipoles is evaluated. AAA-1 amplifiers can be used to build such arrays. It is possible to build a good unidirectional (with switched directions) phased antenna in a small yard for the frequencies down to 0.5 MHz .

I wish a Happy New Year to everybody reading this site and a lot of fun to all those who have AAA-1 kits.

Chavdar LZ1AQ

The post Two new important articles are published appeared first on Active Antenna Amplifier.

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Variable Delay Line kit VDL-1 is introduced

July 3, 2014, 6:56 am
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Hello to everybody,

The www.active-antenna.eu page has been reorganized with the following additions:

  • Variable delay line kit VDL-1 is introduced to be used for receiving phased arrays (unidirectional) with small active loops and dipoles antennas.
  • An article “ Additional Environment Protection of the AAA-1 and VDL-1 Devices” is included in Application Notes section.
  • An article “Radiation Patterns of 2-el. active receiving phased array for loop and dipole mode” is included in Application Notes section.

There are also some minor modifications in payment part and terms of sales. The current prices are not changed.
73, Chavdar LZ1AQ

The post Variable Delay Line kit VDL-1 is introduced appeared first on Active Antenna Amplifier.

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4 videos by SM5BSZ about noise reduction with small antennas

September 24, 2014, 3:16 am
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Hello all,

Leif, SM5BSZ http://www.sm5bsz.com/ has put on YOUTUBE 4 videos named Sensors- Parts1 to 4.
The addres of the first video (sensors – part1 ) is http://www.youtube.com/watch?v=ItLkn8r4s3E and the others can be find easily there.
Leif annotation:
“On low frequencies where antennas are small compared to the wavelength, the Electric and magnetic fields are separable. Interference sources are typically magnetic or electric and it helps to use E-field sensors and H-field sensors to understand how fields of one or the other kind propagate into the receiver.”

These videos are closely related to the small loop and small dipole antennas implemented in AAA-1 kit. The user will reach better undestanding of the electromagnetics behind the small antennas and will help him to install the antennas in proper way to reduce the man made noise from our noisy environment.

73 Chavdar LZ1AQ

The post 4 videos by SM5BSZ about noise reduction with small antennas appeared first on Active Antenna Amplifier.

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The current batch of AAA-1 is sold out. Wait for AAA-1C at the end of October.

October 17, 2014, 1:55 pm
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I must inform you that all AAA-1B kits from the current batch were sold out. The next batch AAA-1C will be available at the end of October 2014. I am waiting to get them from the mounting factory. Check the blog of this site for new information.

I want to thank all the hams who got their kits, for their interest and feedback. Please check the blog of for further information and technical support. Any feedback from working experience with AAA-1 is welcome and desirable in order to improve the future designs.

Chavdar LZ1AQ

The post The current batch of AAA-1 is sold out. Wait for AAA-1C at the end of October. appeared first on Active Antenna Amplifier.

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What is new in AAA-1C

October 20, 2014, 5:32 am
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Hello all,
These are the main changes in the new AAA-1C model:
- the control circuits for mode and antenna relays are now with opto-couplers. This will increase the protection level of the device from external electromagnetic fileds. The power consumption of the AAA-1 device is increased with 18 mA due to the opto-couplers.
- there is an additional connector (parallel to RJ45) with terminal blocks (with screws) which permits to connect the FTP cable directly and not to use RJ45 plug. This might be important when other types of protected compartments are used.
Important:
- all models of AAA-1 kit are compatible to each other and can be interchanged. The control signals in all models do not differ between each other and they can be used in phased arrays with VDL-1 variable delay line.
In AAA-1C there is no change in main electrical parameters as gain, frequency response, noise and dynamic range compared to AAA-1B model.

Chavdar LZ1AQ

The post What is new in AAA-1C appeared first on Active Antenna Amplifier.

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The new model AAA-1C is now available

October 31, 2014, 8:28 am
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The new model AAA-1C is now available. There are changes to improve the mode and relay control circuit. Now the control circuit is optically insulated from the FTP cable control signals. This will improve the noise immunity and influence from strong electromagnetic pulses. An additional connector (parallel to RJ45) with terminal blocks (with screws) is added which permits to connect the FTP cable directly and not to use RJ45 plug. This might be important when other types of protected compartments are used.

All models of AAA-1 kit are compatible to each other and can be interchanged. The control signals in all models do not differ between each other and they can be used in phased arrays with VDL-1 variable delay line.
In AAA-1C there is no change in main electrical parameters as gain, frequency response, noise and dynamic range compared to AAA-1B model. The Control board is not changed.

73, Chavdar LZ1AQ

The post The new model AAA-1C is now available appeared first on Active Antenna Amplifier.

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Italian translation of “Mounting Instructions” manual of AAA-1 kit

February 3, 2015, 5:50 am
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Receiving with wideband small active loops in NDB band (250 to 500 KHz)

May 7, 2015, 11:28 am
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New Batch of AAA-1C

November 2, 2015, 6:01 am
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The new batch of the Active Antenna Amplifiers is going through the final tests. There are no differences compared to the previous batch and the model is AAA-1C. The ordered kits will be dispatched after 9 -th of November 2015. Every kit ordered after 2nd of November 2015 will be from the new batch.

73, Chavdar LZ1AQ

The post New Batch of AAA-1C appeared first on Active Antenna Amplifier.

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The current batch of AAA-1 is sold out. Wait for AAA-1C at the end of September.

September 6, 2016, 2:00 am
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Model AAA-1C is now available

September 19, 2016, 5:27 am
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For Users of the Active Antenna Phased Array VDL-1. New software version 1.61

December 8, 2016, 7:12 am
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A new version of the software v.1.61 for VDL-1 control from PC is uploaded on this site. The installation is simplified and new “periodic switching” mode is added. The periodic switching can be used to test and estimate the antenna performance, especially F/B ratio with real sky signals where the fading is very fast. In Single element mode the equality between elements for sky wave signals can be compared also. For this purpose an SDR receiver and Linrad program are used. Read the new Software Manual …. http://active-antenna.eu/tech-docs/vdl_direction-switcher-manual-16.pdf

The post For Users of the Active Antenna Phased Array VDL-1. New software version 1.61 appeared first on Active Antenna Amplifier.

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A Periodic Switching Technique to Compare Antenna Performance in the Presence of Strong Fading

December 8, 2016, 7:15 am
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There is a strong and fast fading on HF bands. When testing my phased array with small active antennas, the measured front-to-back (F/B) ratio is usually between 20 to 40 dB with local stable signal sources with vertical polarization. The real signals coming from the ionosphere are with undetermined polarization. The signal levels are also unstable and at the RX output the combined effect of polarization and level changes are with a range between 5 to 30 dB. It is difficult to estimate the F/B ratio on sky wave signals since the fading effects mask the effect of F/B switching. Manual switching and S-meter readings are very unreliable methods to obtain accurate measurements. A setup to measure accurately the signal difference between F/B directions of a phased array or between any two different antennas is represented. The idea is to toggle periodically to the receiver input the two signals under test and display on the screen the signal strength graph as a function of time. It is much easier and accurate to obtain a reliable measurements of signal difference on such a display since we have a periodic process and also we can monitor the changes of this difference . Read more ……. http://www.lz1aq.signacor.com/docs/antenna-performance/switching-technique-compare-receiving-antenna-performance.htm

The post A Periodic Switching Technique to Compare Antenna Performance in the Presence of Strong Fading appeared first on Active Antenna Amplifier.

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New: PC control of AAA-1 active antenna

December 19, 2016, 1:43 am
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New possibilities with AAA-1. The AAA-1 modes can be controlled now from a PC. It is convenient to have such an option e.g. if you have a remote station there must be way to switch the antenna modes via software. The standard COM port can be used for this purpose. There are two digital outputs of the COM port which are used – RTS and DTR. The user must build a very simple additional interface board and to use the applied software. Read the manual and download the software from this site http://active-antenna.eu/amplifier-kit/technical-documentation/. The new addition will work with all models of AAA-1.
Nice holidays and Happy New Year to everybody.
LZ1AQ

The post New: PC control of AAA-1 active antenna appeared first on Active Antenna Amplifier.

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VDL-1 Ground Connections and Baluns

February 2, 2017, 1:24 am
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DC Voltage Distribution Requirements in VDL-1 System with AAA-1C Amplifiers

February 2, 2017, 1:29 am
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Important for VDL-1 users. We found out that VDL-1 might have a problem when model AAA-1C active antenna amplifiers are used with it. These models are using optocouplers in the relay control lines in order improve the
isolation from strong RF signals induced from high power amplifires (above 1 KW). The supply voltage of each AAA-1C in the array must not exceed 14.4 V. The file is in http://active-antenna.eu/tech-docs/dc-voltage-aaa1-c.pdf . This paper will be helpful also to set proper DC supply voltages along the VDL-1 array when very long feeder cables are used.

The post DC Voltage Distribution Requirements in VDL-1 System with AAA-1C Amplifiers appeared first on Active Antenna Amplifier.

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Impact of External Resonance and Non-resonace Objects on the Radiation Pattern of RX Directional Antennas

February 2, 2017, 1:37 am
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Two new papers are uploaded in LZ1AQ site. Models are used to evaluate the impact of external conducting objects on the radiation pattern of directive RX antennas. They might help the users to understand sometimes unexpected behavior of their RX antennas.
Impact of Resonant TX antennas on the Radiation Pattern of RX Directional Antennas http://www.lz1aq.signacor.com/docs/resonance-impact/resonance-impact.pdf
Impacts from Non-resonant Conductive Objects on RX Directional Antennas http://www.lz1aq.signacor.com/docs/non-resonant-impact/non-resonant-impact.pdf

The post Impact of External Resonance and Non-resonace Objects on the Radiation Pattern of RX Directional Antennas appeared first on Active Antenna Amplifier.

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Calculating the AAA-1 Antenna Factor for Different Loop Configurations or How to Measure the Field Strength

March 10, 2017, 12:08 am
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The AAA-1 can be used to measure the field intensity. Calibrating the loop needs very specific measurement equipment which is an expensive or time consuming task. Fortunately the AAA-1 loop mode has very predictable antenna factor AF which can be calculated with the help of the spreadsheet. The only hardware we need is a receiver with well calibrated S-meter. Direct sampling SDRs are very suitable for this purpose. Download the new updated version of loop calculations spreadsheet WLoop_calc_v12.xls http://www.lz1aq.signacor.com/docs/w-loop-calc-v12.xls .

The post Calculating the AAA-1 Antenna Factor for Different Loop Configurations or How to Measure the Field Strength appeared first on Active Antenna Amplifier.

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