<Click Pictures to Enlarge>

 


Star-10 Project

20 Meter Beam Project

2-NT Project

Solar Power!

 

KW7CD - Cornell Drentea's Solar Power Project

Shown are the two 100 Watt Crystaline Solar panels that provide the power for my entire shack including a 1.5 KW linear. The converter provides 120/220 VAC - 3.2 KW continous and 6.4 KW peak for full legal power.  The panels provide 13.7 VDC to a pair of 200 Amp Hour deep cycle batteries.



The 20 meter beam that was put up at my QTH is based on one of my design and article in Communications Quarterly from the past. It is billed as the smallest 20 meter beam possible, yet gets outstanding results as proven by the recent log book clip here.  All reports are 58 to 59+ from the listed stations worked recently.


This beam is billed as "the neighbor friendly antenna, yet performs like a big beam". See article below (pdf). My beam along with my Skywave Communications article was also featured on the cover of Ham Radio magazine in March 1990. The picture depicts a true Aurora Borealis against my beam, the moon and Venus at my Minnesota QTH.

Cornell's Article in Communicatins Quarterly - Build a High Performance Low Profile 20 Meter Beam (PDF)


2-NT Project

Hello All,

Most of you know that I have been working on a Drake 2NT transmitter from the 1960s. Some of you even helped with tubes and labor in the process of sand blasting and painting as well as wiring the unit. Thank you. The last thing in the transformation was to replace a single crystal with a synthesizer capable of generating millions of frequencies, blending the old technology with the  21st century technology. This synthesizer had to generate up to 15 V in order to interface with the tube transmitter. I finished the project and everything works well on all bands. I even made a few DX contacts with it on 40 and 20. I worked JA3YBK and OK1IWS during the last contest. The T/R interface with the 2NT turned out to be very simple using the Mute connection. The system is now full break in. All in all, I am very happy with the results considering that the DDS board was only $28. The isolation provided by the specially designed  board Teledyne switch is very good (>100 dB), so the DDS carrier which stays on frequency is not heard in receive. Despite its simplicity, bringing up this station took a lot of doing, but the results are outstanding. Here are some pictures during the process for your enjoyment.

73, Cornell - KW7CD

 


 


The home brewed Star-10 transceiver is a high dynamic range (150 dB Composite LSFDR) unit which is fully synthesized in one band from 1.8 to 30 MHz with a resolution of 10 Hz and a frequency stability of 1x10^-8. Its DDS-driven PLL synthesizer operates at microwave frequencies and is divided by 10 for superb phase noise performance of -140 dBc/Hz at 500 Hz offset. KW7CD has over $10,000 invested in parts in this radio and had it not been for vendors such as Plessey, Synergy Microwave and Analog Devices providing samples for some of the more exotic elements of this rig, the cost might have been even higher. The research and development took over five years. The cost of the development labor is estimated at >$100,000. In comparison with other quality rigs, this radio outperforms most all state-of-the-art equipment of the time. Based on these numbers, KW7CD estimates that to reproduce this radio in a production environment would cost about $800 per dB of dynamic range, a rather impractical proposition. Economical producibilty was not the goal of this project. The Star-10 was an all out Scientific experiment to show what can be done in transceiver design along with achieving the highest dynamic range possible in a High Probability of Intercept (HPOI) radio. It was also intended to inspire manufacturers of ham radio equipment to produce better radios. For more information and a description of this development check KW7CD in along with the QEX article series, and KW7CD's new book "Modern Communications Receivers Design and Technology" published by Artech House. 

For more informationgo to:

http://www.artechhouse.com/

http://www.linkedin.com/pub/cornell-drentea/16/806/169

http://www.rfcafe.com/vendors/services/Cornell-Drentea-Resume-Consultant.htm