Carl. I quantified ground loss in the near field. Now it's your turn. Numbers please, not adjectives or hand waving. _______________________________________________ It is undesirable to believe a pro
Carl, What we do in the near-field to control ground loss affects the far-field signal equally at all elevations. Therefore there is no need to measure far-field field strength at more than one eleva
Carl, why would we need a helicopter when we have simulation software? How much ground loss, or if you prefer, what difference in field strength do you calculate for a half wavelength vertical with a
Tim, I believe those are valid conclusions. Referencing *Vertical antenna ground system experiment #1*, by Rudy Severns: 1) Table 1 shows that going from 8 radials to 64 radials increases field stren
Tim, I ran some sims using a work-around I developed to allow NEC-2 to mimic NEC-4 ground loss results. This sim is for a 90 degree, 1.8 MHz vertical over Medium ground. I get correlation within 0.06
Yes, it does say what happens from that peak down to zero elevation. It says that the signal increases by 0.38 dB. To test this I ran two EZNEC simulations. One is a 90 degree vertical over thirty 90
_______________________________________________ It is undesirable to believe a proposition when there is no ground whatsoever for supposing it is true. — Bertrand Russell
KM1H should be banned once again. _______________________________________________ It is undesirable to believe a proposition when there is no ground whatsoever for supposing it is true. - Bertrand Ru
Guy, why must we continually test NEC against measurements? The work by N6LF has shown great correlation between simulation and the real world. Those of us who design electronic circuits (including E
Tests to answer the question "is the FCP better than counterpoise X" can be answered by 28 MHz scale models. The question "the FCP is better at 1.8 MHz by Y dB" cannot be answered by 28 MHz scale mod
Robert, some questions: Does the 55 ft vertical begin 10' above earth for a total radiator length of 45 ft? What frequency? The 45 deg angle doesn't work with the length and radial end height. At 1.8
*JFET op amp vs bipolar op amps, *LTSpice simulations connected to a 3 meter monopole A bipolar op amp doesn't always give the lowest noise with a short monopole at 1.8 MHz because the op amp current
*Amp/antenna noise *-- is the AD8045 noise low enough for a 3-meter monopole? *0.26 uV amp noise vs. 0.16 uV man-made rural noise and 2.3 uV city with a 3-meter monopole. * Feel free to review my met
The document was published last year so we might assume the noise graph is up to date. To put this in perspective, To put the ITU-R P.372-14 claimed noise in perspective here's the calculated antenna
The J310 is as quiet as they come. It has a 100 MHz noise figure of (only) 1.5 dB. 73 and aloha, Dave KH6AQ _________________ Searchable Archives: http://www.contesting.com/_topband - Topband Reflect
Steve, I ran a SPICE model of the MFJ-1095 front end. What gain there is resides there. The next three stages have unity gain. The input noise is: 1.8 MHz, 50 nV/Hz^0.5 7.0 MHz, 26 nV/Hz^0.5 14 MHz,
Steve, I performed a hand calculation of the MFJ-1025 14 MHz noise and it's (only) 9 nV/Hz^0.5, or 0.2 uV in 500 Hz. This is -120 dBm, or S-1. But you measure S-4 noise. What is going on? Questions t
Circuit gain is accounted for in my calculations. I ran a sim of the input amp and could get it to work with gains from 0.5 to 2 using different transformer ratios. So, I think the gain-of-2 I used i
Mike, thank and these are great data points you've provided. Questions: Was the MFJ-1026 PHASE control set near zero? That could account for the low AUX gain. *Mike's data* FT1000MP MK-V Main Antenna