## QEX

This provides excellent large-signal-handling capability. One count in the ADS801U corresponds to 1 4096 of full scale, so one count is 35 mVrms at the LM733 input. The wide-band noise of the LM733 input is rated to be about the same, so the quantization noise of the ADS801U is swamped by the analog noise of the LM733, even with the LM733 set to minimum gain. Connecting the LM733 clearly increases the activity on the lowest bits of the ADS801U (even with the LM733...

## O

Capacitance Hats for HF Mobile Antennas Cut-and-try ivorks, but these calculations are an easier approach. Capacitance hats of various designs are often used with HF mobile antennas to reduce the loading inductance required to resonate the antenna and to assist in tuning the antenna to resonance. Reducing the loading inductance of a mobile antenna can significantly improve its efficiency since the loading inductance is a primary source of resistance in the antenna system. I have worked with...

## Available

Central States VHF Society Conference The 30th Annual Conference of the Central States VHF Society was held July 26-28 at the Thunderbird Hotel & Convention Center in Bloomington, Minesota. Here is a summary of papers presented. Conference Proceedings are available from ARRL. ISBN 0-87259-563-3 cost is 12, plus shipping order number 6533. A Brief History of the Central States VHF Society Chambers Award Recipients Wilson Award Recipients Microstrip Patch Antenna Design Roger A. Cox. WB0DGF...

## Xlc

L inductance of loading coil, in uH XLC inductive reactance of loading coil, in 2 (from Eq 14) F frequency, in MHz 71 3.141593 2x31 xFxX C capacitance of hat or loading coil, in pF F frequency, in MHz X reactance of hat (XH) or coil (XC), in 2 71 3.141593 participates in the VE program and is primarily interested in the technical aspects of ham radio. lARRL Antenna Book, 17th Edition 1994 Chapter 16. 2Byron, B W7DHD, Short Vertical Antennas for the Low Bands, Ham Radio, Part 1. May 1983, pp...

## Ruhd

0.080 ANODIZED ALUMINUM SIDES ARE 0.125 ANODIZED ALUMINUM MODEL WIDIH A' B OPT MPB-3 1 e MPB-4 JS MPB-5 ' 5. MPB- 5. MPB-7 IS. MPB-11 '5.4. MPB-12 i S 6i MPB 13 2x2 MPB 14 2x4 MPB-15 2 6 . MPB 16 2x6 X MPB 17 3.2. MPB-18 3x4 X MPB-19 3.6. MPB-20 3 X 8 X MPB-21 4 X 6 X MPB 22 4 10 MPB 23 4 . 12. MPB-24 4 . 14 .

## Info

Note Inductance measured by dip-oscillator method. See text. Note Inductance measured by dip-oscillator method. See text. if factor is probably close to 0.95. The difference is no doubt compensation for some other factor that was not considered in the calculations. The results of the work are shown in Fig 1 as a plot of hat capacitance versus hat diameter. The experimental hats are shown in the legend of Fig 1. The solid disks were constructed from circuit board. The open hats were constructed...

## Yet another improved front end brings the DDCbased receiver closer to superhet performance

Burr-Brown has just introduced a 12-bit, 25-MS PS mega-samples per second A D converter, the ADS801U.1 The ADS801U permits building a very simple improved front end for my digital downconverter- DDC based re-ceiver.2 M lt Fl The receiver's intermod-ulation-distortion dynamic range IMDDR is limited by the ADS801U, and the blocking dynamic range BDR is limited by the noise floor of the DDC. The dynamic linearity specs of the ADS801U are not as good as those of the Analog Devices AD9042, but the...

## R

Another frequently needed number is the wavelength, A, in meters or feet, of a length of coax, which is the free space wavelength times the velocity factor. This is the steady-state solution to a differential wave equation for a sine-wave signal that is traveling in one direction toward the load. Term A contains y, the propa gation constant per meter. Term B shows that y1 is the product of the series impedance, in 2 m, and the shunt admittance, in S m. Term C contains a, the attenuation...