1/2 Length Dipole With An Advantage PDF Print E-mail
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Wednesday, 11 July 2012 19:20

Typical Dipole

 

A typical dipole for hf is computed above. However a shortened version for 10 or 11 meters is given below.

Short Dipole

Wind the coil on a 2 inch form with 12 to 18 gauge wire. Connect shield on coax to center. The center lead connect 1 to 1.5 turns offset. The advantage of this antenna is the broadcast band is greatly reduced in strength. Low frequencies are presented with a very low impedance at the antenna. The performance of the antenna is about 1.5 db of a full sized antenna. By spreading the turns or less wire the antenna can be made to match on 10 meters. A version of this antenna is on the web for 40 meters called the "Shorty Forty".  Another advantage is the shortened length over a full sized dipole.

 
Last Updated on Wednesday, 11 July 2012 20:11
 
Uniden Announces New Bearcat 980 CB Radio PDF Print E-mail
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Tuesday, 10 July 2012 21:40

uniden_bearcat_980

A large easy-to-read display and exciting new features including Single Side Band USB/LSB, Clarifier, 7 Color Display Backlighting, Noise Cancelling Mic, and Wireless Mic Compatibility.

SSB USB/LSB - 7-Color Backlighting, Noise Cancelling Mic, Variable Talkback, Radio Diagnostics, Wireless Mic Compatible, Large Digital S/RF / SWR Meter, Frequency Display, NOAA Weather, Dynamic Squelch Control, ANL / Noise Blanking, ANL / Noise, Memory Scan, Clarifier, Volume/Squelch Control, RF Gain Control, Instant Channel 9/19, CB / PA Switch, Mic Gain 4-Position Control, 40 Channel AM Operation, Laser Etched Keys, Extra Long Mic Cord, Channel Indicator, Includes 6 Pin to 4 Pin Adapter, Dimmer Switch Day/Night

The radio does have built-in diagnotics, including an swr display.
Last Updated on Wednesday, 11 July 2012 19:55
 
Planet X Real or Hoax PDF Print E-mail
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Thursday, 14 June 2012 23:44

Planet X is featured on the Swiss currency. Nasa says it does not exist. However, there is a fair amount of circumstantial evidence supporting its existence.   More information can be viewed at the blog at Blog Site On Nibiru
Last Updated on Friday, 15 June 2012 00:06
 
40 Meter Regen-o-Dyne with Dual Gate Fet PDF Print E-mail
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Tuesday, 24 August 2010 00:57

After reading the articles on the regener-o-dyne I got interested.  The block diagram is shown in the link.  Click here for block diagram


The stages have about 100db of gain.  t's really just for 40 meters, but will tune outside the 40 meter band.  Click here for circuit diagram.

It uses a TDA7052  instead of the LM386 as the audio amp. The FET detector is a dual gate so a potentiometer can control the regen smoothly.  The detector is off loaded from the tickler coil into a FET that is very high impedance.  Also uses a schottky diode dectector rather than a 1N34.  The bandpass filter consists of 2 tuned LC circuits, one in front of the FET preamp and one of the drain that is a series LC circuit.  This eliminates the small 10pf capacitor on most bandpass filters.  he mixer is a NE602 with an external crystal.

In all it has 2 LC tuned circuits over the typical tube regen-o-dyne and is single banded.  A RF preamp gain control allows for stronger signals. The regen-o-dynes on youtube sound good so I thought it might be fun to try.


Rob.
NV7F
Last Updated on Wednesday, 11 July 2012 20:14
 
Solar Power Supply PDF Print E-mail
Written by Administrator   
Sunday, 01 February 2009 23:15

Power Transistor

Solar panels may be used without a battery supply. It is necessary to provide regulation of the voltage. This simple circuit will provide a 12.5 volt supply for most 12 volt electronics.

 
Last Updated on Wednesday, 04 July 2012 00:27
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