Id certainly suggest running an isolation test before possibly damaging
a xcvr. The minimum acceptable for 1500W would be on the order of 55 dB
at 30 mHz and it should increase as frequency goes down.
Carl
KM1H
----- Original Message -----
From: "Dan Hearn" <n5ar@air-pipe.com>
To: <ve3zi@rac.ca>; "Amps" <amps@contesting.com>
Sent: Saturday, March 07, 2009 10:46 PM
Subject: Re: [Amps] KiloVac HC4 Relays
>I have owned an HC4 relay for a number of years. I just checked it on
>my 9kv
> hi pot tester and it shows only 2 microaamps leakage at 9kv. That is
> as low
> as the best of my other vac relays and better than good transmitting
> tubes
> show. Mine has silastic rubber potting around the glass relay and over
> the
> hv contacts. My catalog says they are suitable for RF to 30mhz. The
> contacts
> are molybdenum and tungsten with 0.020 ohms resistance max. Operate
> time is
> 6ms max. I have been told that they are built for use in HV medical
> equipment. I would think that the capacitance between terminals would
> be
> higher than non encapsulated version like HC1 which is a possible
> negative.
> 73, Dan, N5AR
>
> ----- Original Message -----
> From: "Roger Parsons" <ve3zi@yahoo.com>
> To: "Amps" <amps@contesting.com>
> Sent: Saturday, March 07, 2009 5:48 PM
> Subject: Re: [Amps] KiloVac HC4 Relays
>
>
>>
>> I have received a private email strongly disagreeing with my
>> conclusions
>> on these relays :-)
>>
>> I still believe I am correct about the use of tungsten contacts in rf
>> vacuum relays and that, based on manufacturers' information, the HC4
>> is
>> suitable for use in an amateur linear.
>>
>> I should not have put the paragraph about gas filled relays into the
>> message - although at least one of the manufacturers does indeed say
>> that
>> rf can ionise the gas, they are apparently commonly used in some high
>> power rf systems.
>>
>> 73 Roger
>> VE3ZI
>>
>>
>>
>>
>>
>> _______________________________________________
>> Amps mailing list
>> Amps@contesting.com
>> http://lists.contesting.com/mailman/listinfo/amps
>
>
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