Hello to all,
Thanks to all that replied to my request.
Based on the information I have received :
VOLTAGE = SQUARE ROOT (POWER x RESISTANCE)
CURRENT= SQUARE ROOT (POWER / RESISTANCE)
With a 50 OHM LOAD.
POWER10015002500WATTS
1:1 SWR
CURRENT1.45.57 AMPS
VOLTAGE70.7274354
2:1 SWR
CURRENT2.81114 AMPS
VOLTAGE142548708
3:1 SWR
CURRENT4.216.521 AMPS
VOLTAGE2128221062
The 3:1 SWR should be considered as the worse case with
some type of antenna system failure. The 2500 watt is used
because some amps can put out this amount of power. If an
operating error is made the system should be designed to
handle it.
Reviewing published information on vacuum relays I
concluded the higher frequencies degrades the current
and voltage capabilities of the relay. This factor dose
not seem to be liner and varies slightly between relay
companies.
FREQUENCYFACTOR
60 Hznone
2.5 MHz1.2857
16 MHz2
32 MHz2.57
The resultant is obtained by dividing the 60 Hz value
by the factor in the frequency range the relay will be
used in.
Vacuum Relays
Jennings RJ1A
FREQUENCYVOLTAGECURRENT
60 Hz3.5 K18 AMPS
2.5 MHz2.5 K14 AMPS
16 MHz2 K9 AMPS
32 MHz1.5 K7 AMPS
Kilovac HC1
FREQUENCYVOLTAGECURRENT
60 Hz3.5 K25 AMPS
2.5 MHz2.5 K14 AMPS
16 MHz2 K9 AMPS
32 MHz1.5 K7 AMPS
A very popular nonvacuum relay is the NAIS JW1FEN.
I have this relay in use at my station for antenna switching.
It is used at the 1500 watt level and has performed without
any problems for quit a few contests.
These are the results based on the degrading factor used for
vacuum relays.
Nais JW1FEN
FREQUENCYVOLTAGECURRENT
60 Hz25010 AMPS
2.5 MHz1947.8 AMPS
16 MHz1255 AMPS
32 MHz 97 4 AMPS
Requirements based on formula are far from actual
station component usage.
Are we just lucky ?
Is it just a matter of time to a relay failure?
Is the duty cycle for the type of operation be a factor?
Any Comments Please
Rich AA2MF
