the Poor-Mans 220 base station

 

Consists of a

KST V6 220 portable

and a Kenwood TK-715 220 mobile

notes on the TK-715:

although this is a great 220 commercial radio, it only works on Kenwoods RegionNet. You can't program in individual frequencies. Even with the Kenwood PC software, you cannot enter in specific channel freqs. All you can do is select pre-determined groups (similar to trunking).

I got this radio brand new; only to discover it's programming limitations afterwards. At this point, it became a boat anchor.

I decided to utilize the TK-715's internal 20w transmit amplifier... in a linear-amp arrangement. I also made a simple T/R switching circuit - that upon sensing transmit power (into an additional jack i installed on top of the radio) - the T/R relay would "switch-in" the 20w amp during TX only; and then bypass the amp during receive.

 I am now using a different microphone; and older Maxon commercial desk mic (the black one):

It has a receive speaker installed in the center; that's the black circle in the center of the body. So; I guess it is called a Desk Speaker-Mic

.

for the base antenna, I went with the Tram 1494, 220 single band:

 

notes for the Tram 1494:

out of the package, this Tram could be mistaken for a Diamond or Comet base fiberglass antenna; same build quailty & packaging.

Before installing the antenna on my tower; I tested it with a Comet CAA-500 antenna analyzer:

It had a perfect 1:1 swr @ 220.000 mhz; but climbed to 2:1 swr at 225 mhz. I retuned the antenna (using the allen wrenches provided with the antenna) and got the resonance centered at 223 mhz.

 

note: I've lost my notes on retuning this antenna; sorry. Although it did involve allen wrenches, used after the antenna was disassabmled:

 

 

I mounted the antenna on the tower; about at the 65' mark:

Co-Ax:

for about the past 6 years I have been using a "clone" LMR-400 cable; from www.ShowMeCables.com

it's 67 cents per foot (if you buy 50' or more)... and their shipping is very reasonable.

For more info on the KST V6 220mhz portable; click here

 

email Tim