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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

I have. I considered including skin effect, but chose to keep the measurements away from that. Of course, that is also frequency dependent and even makes radiation resistance worse - if it could get

Dave, I believe you've neglected skin effect.

Consider: 1) The DC resistance of the loop is constant. It's independent of frequency. That's one of the distinguishing characteristics of pure resistance vs. reactance. 2) The radiation

Consider: 1) The DC resistance of the loop is constant. It's independent of frequency. That's one of the distinguishing characteristics of pure resistance vs. reactance. 2) The radiation

Hi Chavdar, In your response to Lim's question about your proposed "dummy" network setup something is left without an explanation. The conversion from Thevenin equivalent antenna model to Norton's

I freely admit that I am just guessing here, but sometimes it helps to recall that an antenna conductor (all by itself) is a transmission line.? When a loop is open-circuited , there must be

The is the original built as per circuit on line using 2N2222 transistors ? LZ1AQ Loop amplifier, with 2N2222 Transistors. The Orginial LZ1AQ at 13.8VDC @130mA has an IMD of (OIP2) 1 MHz +77.1 dBm, 7

Since I have some time (but I'm interested in Mark's results too). It's not necessary to move the (short-circuit) load repeatedly.....NEC reports the current in each segment.? For that loop I

This is what a LZ1AQ amp is with 2SC5551 transistors. ? ?The Improved LZ1AQ at 13.8VDC @120mA has an IMD of (OIP2) 1 MHz +98.4 dBm, 7 MHz +93.8 dBm. (OIP3) 2 MHz +42.2 dBm, 5 MHz +40.35

Hi Leong, Good work, but the LZ1AQ IOP3 looks far too low. It is quoted as being 1 dB output compression point(9) +19dBm (5.6 V p-p), equal to +125 dB(uV/m) at input Second harmonic OIP2(7) +82dBm