[AMPS] my 2c about Relays.

[2]

>
>When it comes to HAM Amps antenna switching relays, you will be better off
>in the long run by getting rid of the initial manufacturer components and
>build the entire switching system your self. I know this sound radical, but
>I believe that
>Hams are capable of doing this job.  

€  Over 300 amplifier owners have successfully installed the High-Speed 
Switching modification with good results.  (Figure 7 on my Web site)

>Unless they discuss "dBs" on 14.178 :)
>
>Manufacturers, in their relentless quest for profit will cut corners even on
>critical system components.

//  Amen, Alex.    Ford saved c. $2.00 per vehicle by not mounting the 
engine's electronic ignition module out in the cool air in front of the 
radiator.  As a result, the electronic ignition module would periodically 
burn out in hot weather and the engine would stop.  Despite numerous 
complaints from Ford dealers and customers, this folly continued for more 
than a decade because Ford apparently "had a better idea".  At least 
11-people died as a result, and many more were injured.  Finally, Ford 
was forced to do a recall.  The bottom-line: Ford will be out c. 
$3-billion and Ford's CEO is out of a job.   Cutting costs can turn out 
to be costly. 
>
>We are using two relays for the output stages. One relay for the output
>function and the other for the input function. This way you can tailor the
>relays individually for bets cost/performance tradeoffs. I recommend for the
>output
>function an OMRON G8J-1C6T-R-DC12. This is an sturdy automotive, fully
>encapsulated relay rated at 40ADC. We have tested it at 5KW/30MHz for
>5 minutes and it did survive.

//   My guess is that this relay makes in c. 20mS.  This is not fast 
enough for modern transceivers.
>
>For the input function I will recommend the G2RL-1-E. This relay could be
>replaced by more mundane one such the Magnecraft W7PCX which is very,very
>tiny :)
>
>You will thus need  three relays . Two for input (one at the input, the
>other at the output) and an output relay. If you nag me enough I could draw
>a schematic for you :)
>
//  The Matsushita NRD cellphone relay is DPDT, has rhodium-gold 
contacts. makes/breaks in 1mS and will handle 150W radios. 

>You have to research your on/off times to see if they will fit into your
>project.
>Also, I will _STRONGLY_ advise to use a sequencer (one 10c IC , 4 resistor
>and 4 capacitors) with any complex relay system.
>
//  With enough relay speed, there is no need.
>
cheers, Alex

-  R. L. Measures, 805.386.3734,AG6K, www.vcnet.com/measures.  
end


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