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Chavdar, In order to "complicate" this matter more. The current theory about usage test simulators for receiving antennae postulates: "these equivalent circuits ( Thevenin and Norton ) may be

To Chavdar : Even Balanis in his treatment of traveling wave antennas makes the comment that the small loop can be treated with similar arguments which address the TW antenna. I didn't go through

Hi Chavdar, My acknowledgement about transformation from Thevenin to Norton are as follow, based on equal power transform : 1. In Thevenin's ckt. we have a series arm consisting of La and Ra and

To Dan, When the loop length is close to the wavelength there are standing waves - in your last data from NEC (thanks for that) the ratio Imax/Imin is 1.4 – the max. current being at the loop side

Addressing skin depth: For copper: Conductivity: σ = 6.30 E +7 S/m Resistivity: 1/σ = 1.60 E -8 Ωm Skin Depth: 2.47 E-5 m Frequency of following analysis: 7.000 MHz For the above, refer to:

Addressing skin depth: For copper: Conductivity: σ = 6.30 E +7 S/m Resistivity: 1/σ = 1.60 E -8 Ωm Skin Depth: 2.47 E-5 m Frequency of following analysis: 7.000 MHz For the above, refer to:

Hi Raphael, I am sorry , ignore previous message #20287 it is wrong. The Current source resistances must be much higher than the anticipated LOAD resistance , so 2 KOm which are used are 20 times

At 7 MHz a 113 inch long .5 inch solid or tubular conductor (either one due to skin effect) the AC resistance (owing to skin effect) is 50 millOhms (0.05 Ohms). Verification would be welcome. Value

I would agree with Fred. Despite what many articles and videos on the internet may suggest, including many professional ones, it is not easy to make practical and repeatable IMD measurements,

Hi Chin-Leong Lim ( the first time that i got right) Besides the TinySA, whose own IP3 is 17 dBm at best (thats your absolute limitation), the Signal generators Output Stages and even the Splitter

Dave, As far my acknowledgement of usung VNA for measurement small impedances or resistors of 0.1 ohms value allows to reach about 0.04 % accuracy. However, for low resistance values that you

Chavdar, I am sorry I forgot to mention another point. I can understand why you have been using Norton equivalent circuit for a prove how great works active small loop antenna in short current mode.

Hi Chavdar, With all my respect to you spending a lot of time exploring loop antennae with amplifiers I am in disagreement with your "simulator" design. For all practical means we have been using as

Hi Martin & Fred, Thanks for the article links. I will dig into them later. At this moment, I don't have notch filters for the 5-30 MHz range that I want to measure. To quickly verify whether the IP

To Raphel Sorry , 10- 20 times larger from? the loop impedance. The Northon is ok - the current source is the short circuit current.? Zloop >>Rin so we ignore current through the loop. Chavdar

Hi Chin-Leon Lim Measurements of high IP3 values are challenging. It is very likely that the measured IM products will be created in Tiny SA itself, not in the DUT. Your limitation is the internal IP

Hi Leong, OK thanks for that. From experience, I don't think you will be able to achieve the required performance of your test setup without building fundamental frequency notch filters to place on

In receive mode the resistance increase due do the skin effect could be neglected for simplifiaction. It is disproportionanally lower than the frequency dependent increase of the inuctive

Hi Martin, LZ1AQ's |OIP3-P1dB| vs. freq ( /g/loopantennas/photo/296366/3838486?p=Name%2C%2C%2C20%2C1%2C0%2C0 ) 73, Chin-Leong Lim, 9W2LC

Hi Martin, Sharp eyes! ? You r correct, the LZ1AQ OIP3 looks too small. I think the problem lies in the large variation with freq - the OIP3 varies from 16 dBm at 5 MHz to 30 dBm at 20 MHz. In