Contact problems, usually during a contest or a long aggravating CW pileup.
Im on my 3rd or 4th relay since new.
Since the amp is only a LK-500ZC it isnt excessive RF and Ive never used
QSK.
Ive also both heard of others with failures as well as having several amp
brands in here for repair. It got to the point where I had to have spares on
hand to do an instant repair for panicked contesters.
Carl
KM1H
Amplifier Repairs and 6M conversions since 1964
----- Original Message -----
From: "Dan Hearn" <dhearn@air-pipe.com>
To: "jeremy-ca" <km1h@jeremy.mv.com>; "Steve Flood" <kk7uv@bresnan.net>;
<amps@contesting.com>
Sent: Saturday, March 29, 2008 3:25 PM
Subject: RE: [Amps] open frame relay rating
> Carl, what problems have you had with vac relays? Open coils? Loss of
> vacuum? contact problems? 73, Dan, N5AR
>
> -----Original Message-----
> From: amps-bounces@contesting.com [mailto:amps-bounces@contesting.com]On
> Behalf Of jeremy-ca
> Sent: Saturday, March 29, 2008 11:38 AM
> To: Steve Flood; amps@contesting.com
> Subject: Re: [Amps] open frame relay rating
>
>
> Yes, those are "enclosed" open frame relays. The SB-220 relay is excellent
> and very reliable considering how many still see daily use after 30-40
> years.
>
> Ive never got close to that with a vacuum relay.
>
> Carl
> KM1H
>
> ----- Original Message -----
> From: "Steve Flood" <kk7uv@bresnan.net>
> To: <amps@contesting.com>
> Sent: Saturday, March 29, 2008 2:31 PM
> Subject: Re: [Amps] open frame relay rating
>
>
>> Thanks Carl and others for the replies. I don't plan to use this amp
>> above
>> 20m actually. One of my relays is very similar to the SB-220 relay - and
>> thinking I'd use the same setup with a third pole for the bias circuit.
>> BUT, I surely do not want to lose any significant signal in RX mode.
>>
>> Are the "general pupose" relays considered "open-frame" - I am referring
>> to
>> those where you can see the working parts through a clear plastic shell.
>> They are used in my Amertiron remote coax switch and Ameritron rates
>> those
>> at 4kw HF.
>>
>> Steve
>> KK7UV
>> ______________________________________________________
>>
>>> Many amps used open frame relays with 10-13A contacts and they worked
>>> well
>>> at 1500W. The one issue with them is high VSWR in the thru position on
>>> 10M
>>> which can fold back the power in a SS rig. The cure is simple, add a
>>> capacitor from the thru loop to ground to tune out the Xl.
>>>
>>> You can use an adjustable mica trimmer and leave it or measure the value
>>> and replace with a 1KV disc ceramic or 500V mica. Typical values are
>>> 25-35
>>> pf. Any one will handle 100W with ease.
>>>
>>> Carl
>>> KM1H
>> ____________________________________________________
>>
>>>>I have several open-frame relays. If I use one for the T/R relay, what
>>>>should the contact rating be for a 1500w amp? Is it as simple as 1500w
>>>>/
>>>>50 ohms = SQRT of 30A or 5.5 Amps?
>>>>
>>>> Tnx,
>>>> Steve, KK7UV
>> __________________________________________________
>>
>> _______________________________________________
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>>
>
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