Northjohor Ham Community akan mengadakan satu bengkel Interface for digital communication. Acara ini adalah sebagai penutup tirai bagi tahun 2008. Menurut 9W2PCK peserta yang ingin bermalam boleh membawa khemah atau camping bed, kerana di clubhouse Segamat Ham Community bilik mandi dan tandas telah sedia ada.

9-10dbi Gain on 440
6.8dbi gain on 2 meters

Antenna is a full Wave on 440 and almost a full wave on 2 meters.

All Copper 2 meter / 440 N2RGA Extended Double Zepp Antenna.

All antenna's are individually tuned for a SWR of 1.2.1 on 444 MHz. On 2 Meters I get a 1.3.1 SWR.

All antenna's are fully assembled ready to install onto a Piece of PVC pipe.

Dielectric Type Time Delay
(ns/ft) Propagation
Velocity
(% of c)


Solid Polyethylene (PE) 1.54 65.9 Foam Polyethylene (FE) 1.27 80.0 Foam Polystyrene (FS) 1.12 91.0 Air Space Polyethylene (ASP) 1.15-1.21 84-88 Solid Teflon (ST) 1.46 69.4 Air Space Teflon (AST) 1.13-1.20 85-90
Properties for popular coaxial cables are listed below. Click here for coax cable formulas. c = speed of light in vacuum

Benefits of LMR Cable

It is of importance when making decisions about getting the right coax for your Ham Station to understand that there are trade-offs that have to be considered between transmitter power, antenna gain, coax loss, and your total Ham Station system performance.
Your bank account may also enter into the equation like most Hams.

The db differences in gains or losses on transmit and receive between the choices available to you are the important issue.

A difference of 3 db either way will not be apparent to the stations that you are communicating with on the other end; around the block or around the world. They won't hear or see (on the S meter) any difference if you run your transmitter at 50 watts instead of its maximum 100 watt output power as an example.
This is a difference of about 3db! The same ratio holds true comparing 500 watts with 1000 watts!
Now take this same analogy and apply it to coax.
Here is an example:

The vertical radiator is 1/4 wavelength long at your operating frequency.

It has no gain but makes an excellent small antenna that can be mounted anywhere and with a little planning, can be used mobile on a short mast from the bumper!! Adding a small attachment loop at the tip of the radiator will enable it to be suspended from above for inside use.

Slim-Jim is easy to built, no radial 145Mhz antenna. It has almost equal gain of a 5/8 lambda (Did not measure with any professional equipment, but my FT23R S-meter shows equal readings on both antennas) and much higher gain than 1/4 lambda whip. But it is much easier to buld than a 5/8 or 1/4 antenna. This looks like a modified J pole. I am sorry I don’t know who invented this, but some one who has done a good job.