[Kenwood] Re: TS-450S Options

[Bryan Swadener]

> Date: Tue, 22 Apr 2008 19:44:12 -0700
> From: "John Parker" <parkjv1 at comcast.net>
> Subject: [Kenwood] TS-450S Options
> To: <Kenwood at mailman.qth.net>
> Message-ID: <002a01c8a4eb$eab6d6a0$f84a164c at homeoem>
> Content-Type: text/plain;	charset="us-ascii"
> 
> I really don't know that much about kenwoods so I have
> some more questions.
> 
> Can someone shed some light on what these are used for.
> 
> 
> SO-2 High stability temperature compensated crystal
> oscillator.  
> TU-8 CTCSS Encoder unit.  
> YG-455C1 CW Filter 500 Hz [455 kHz IF]  
> YG-455CN1 CW Filter 250 Hz [455 kHz IF]  
> YK-88C1 CW Filter 500 Hz [8.83 MHz IF]  
> YK-88CN1 CW Filter 270 Hz [8.83 MHz IF]  
> YK-88S1 SSB Filter 2.4 kHz [8.83 MHz IF] 
> YK-88SN1 SSB Filter 1.8 kHz [8.83 MHz IF] 
> 
> 73,
> 
> John KD7KFT
> 

Hi John,

1. Modern rigs since the mid-early 80s use some form of frequency generation based on a quartz crystal reference oscillator, instead of a free-running L-C oscillator.  The advantage is better stability (less frequency drift over time and/or temperature).  Since quartz is temperature sensitive, maintaining it in a temperature-controlled "oven" improves stability.  That is what this device does.

2. This item is an acronym for Continuous Tone Coded Squelch System, sometimes referred to as a "subaudible" or "subtone" system (http://en.wikipedia.org/wiki/CTCSS).  The concept is typically applied to FM mode though it can work with any mode where the receiver has a squelch circuit to silence a receiver until certain parameter(s) are met.  In this case, a CTCSS decoder would keep a receiver silenced until a signal modulated with 67 to 257 Hz tone is received.  And, the encoder does just what its name implies -- it modulates a transmitted signal with a 67 to 257 Hz tone (at some level significantly below 100% modulation).

3 thru 8. These are quartz filters that are used to specify the final selectivity of your receiver (or the receiver section of your transceiver).  There may be more than one Intermediate Frequency involved but, at least one.  IF filters have various parameters:

a. Center Frequency
b. Bandwidth at 6dB down from maximum
c. Bandwidth at 60 dB down from maximum
d. Shape Factor (the ratio of c:b, above)
e. Insertion Loss (at the middle of the passband)
f. Group Delay (time delay within the passband)

Not all parameters are always listed. Each type of filter has advantages and disadvantages, and every user has his/her preferences.  The manufacturers usually supply something on the order of 2.7KHz bandwidth as a "standard" unit. Generally, the optional narrow filters will be used during crowded band conditions and/or narrower modes.  On the down side, the narrower filters tend to "ring" more than wider ones.  Select an optional filter that best suits your needs and preferences.

Vy 73 es gud dx,
Bryan WA7PRC


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