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mission:log:2012:08:02:active-wideband-receiver-antenna-for-sdr [2014/07/05 16:22] – beckgyver | mission:log:2012:08:02:active-wideband-receiver-antenna-for-sdr [2016/08/12 12:50] – Added NEC2 Simulation chrono | ||
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- | ====== Active Wideband Receiver Antenna for SDR ====== | + | ====== Active Wideband Receiver Antenna for your SDR ====== |
[{{ : | [{{ : | ||
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The antenna element itself is a simple quadrilateral monopole, in the shape of a wedge, with a narrow start and a wider end. For lack of a common nomenclature and a relatively close optical proximity to a log-per design, this type is going to be ignorantly called // | The antenna element itself is a simple quadrilateral monopole, in the shape of a wedge, with a narrow start and a wider end. For lack of a common nomenclature and a relatively close optical proximity to a log-per design, this type is going to be ignorantly called // | ||
- | [{{: | + | [{{: |
- | er Antenna Element}}] | + | |
[{{: | [{{: | ||
[{{: | [{{: | ||
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[[http:// | [[http:// | ||
- | [[http:// | + | [[http:// |
==== Structure Tube ==== | ==== Structure Tube ==== | ||
- | Further analysis and research regarding material and availability lead to the speculative conclusion, that this foil probably is [[http:// | + | Further analysis and research regarding material and availability lead to the speculative conclusion, that this foil probably is [[http:// |
[{{: | [{{: | ||
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=== Properties === | === Properties === | ||
- | | Material | [[http:// | + | | Material | [[http:// |
| Length | 405mm | | | Length | 405mm | | ||
| Width | 405mm | | | Width | 405mm | | ||
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[[http:// | [[http:// | ||
+ | ==== NEC2 Simulation ==== | ||
+ | |||
+ | First NEC2 Simulation efforts by Samuel Burri: | ||
+ | |||
+ | {{: | ||
+ | |||
+ | https:// | ||
===== LNA ===== | ===== LNA ===== | ||
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~~CL~~ | ~~CL~~ | ||
==== Alternative LNA Proposals ==== | ==== Alternative LNA Proposals ==== | ||
+ | |||
+ | === BFP420 === | ||
Due to the venerable age of the original LNA, it is very likely, that more recent semiconductors can deliver superior performance compared to the old design. The LNA is going to be replaced by a new LNA based on Infineons BFP420 which is cheap and available and should perform equally or better. The following two schematics show typical LNA configurations for the BFP420, the left one is the most simple approach (to be tested first), the right picture shows a more refined approach, with better base/ | Due to the venerable age of the original LNA, it is very likely, that more recent semiconductors can deliver superior performance compared to the old design. The LNA is going to be replaced by a new LNA based on Infineons BFP420 which is cheap and available and should perform equally or better. The following two schematics show typical LNA configurations for the BFP420, the left one is the most simple approach (to be tested first), the right picture shows a more refined approach, with better base/ | ||
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* Each setup with and without a high-pass filter after the antenna element | * Each setup with and without a high-pass filter after the antenna element | ||
- | <WRAP round tip> | + | === OK3ZB ARA-2000 LNA === |
- | **Somebody was also thinking in these directions: | + | |
- | http:// | + | |
+ | {{: | ||
+ | {{: | ||
- | </WRAP> | + | See also: http:// |
+ | === LNA4All === | ||
+ | |||
+ | http:// | ||
==== Ultra-Cheap LNA alternatives ==== | ==== Ultra-Cheap LNA alternatives ==== | ||
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[{{: | [{{: | ||
+ | [{{: | ||
Here you can see why these Amplifiers get all these bad reviews. I left and right mark show long wire endings, which could lead to bridges in the circuit. In the middle there is some solder on one via at the PCB. Again this dirt could cause a short circuit. | Here you can see why these Amplifiers get all these bad reviews. I left and right mark show long wire endings, which could lead to bridges in the circuit. In the middle there is some solder on one via at the PCB. Again this dirt could cause a short circuit. | ||
+ | All in all the inner manufacturing was poor but nothing that couldn' | ||
+ | After some research the MMIC that is used was found as a [[http:// | ||
Beside the loose solder in the case there were two little pieces of copper wire. | Beside the loose solder in the case there were two little pieces of copper wire. | ||
- | All in all the inner manufacturing was poor but nothing that couldn' | + | [{{: |
- | After some research | + | |
+ | This is a close-up of the inside PCB and the used MMIC. Confusingly the pin-numbering of the MMIC is obviously wrong and I'm not sure if that is a mistake / stupidity or a distraction to " | ||
+ | |||
+ | [{{: | ||
+ | |||
+ | The schematic revealed no surprise. It seems that a Zener-diode was used to stabilize the voltage of standard 12V BIAS supplys to the needed 5V. | ||
+ | On the input-path there is a attenuator installed, right after the first decoupling C. It seems that it has an attenuation of 3 dB. | ||
+ | |||
+ | In order to be used with a direct power supply you have to remove two inductors on the input and output Path of the power supply. In order to be used in different positions in the signal path I solderd two SMA plugs in the case, after removing the standard F-connectors. | ||
+ | I attached an USB connector to the power supply line and after a short test the amplifier was ready to be closed and used. | ||
+ | |||
+ | This one was equiped with cables to be installed better. | ||
+ | |||
+ | |||
+ | [{{ : | ||
+ | |||
+ | The first picture was taken with an Agilent network-analyzer. In advance to the measurement the device has been calibrated. The device number will be added in some days, I forgot to write it down :-) I think it is an [[http:// | ||
+ | |||
+ | For this test I put an attenuator with 10dB in the output-path of the measurement. Keep in mind that there is a attenuator circuit installed on the input path of the amplifier. I will make some measurements after removing it later. | ||
+ | |||
+ | [{{ : | ||
+ | |||
+ | The other pictures were made with an [[http:// | ||
+ | |||
+ | [{{: | ||
+ | |||
+ | |||
+ | [{{: | ||
+ | To put it in a nutshell: Thes amplifiers are just amazing after you clean them and I was surprised of the performance. A comparison to LNA4all and similar projects will be done as soon as the orders arrive. If someona has other amplifiers to be tested please let me know and we can comepare even more amplifiers out there. | ||
===== Bias-Tee ===== | ===== Bias-Tee ===== | ||
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- Remove Aslan S22 release liner (protective foil with the printed red grid) | - Remove Aslan S22 release liner (protective foil with the printed red grid) | ||
- Place antenna element on self-adhesive side of Aslan S22 according to spec above | - Place antenna element on self-adhesive side of Aslan S22 according to spec above | ||
- | - Get a cylinder with 80mm diameter and place the right end of the assembly on it | + | - Get a [[http:// |
- Begin rolling the assembly around the cylinder (clockwise from top view) | - Begin rolling the assembly around the cylinder (clockwise from top view) | ||
- Roll the release liner around the assembly and fixate it with tape | - Roll the release liner around the assembly and fixate it with tape | ||
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<WRAP round tip> | <WRAP round tip> | ||
**Related Mission-Logs: | **Related Mission-Logs: | ||
- | [[mission: | + | [[mission: |
+ | [[mission: | ||
+ | [[mission: | ||
+ | [[mission: | ||
</ | </ | ||