Most xcvrs havent used a relay in decades. SS doesnt like 120V @ 100 ma
Carl
KM1H
----- Original Message -----
From: "Joe Subich, W4TV" <w4tv@subich.com>
To: <amps@contesting.com>
Sent: Sunday, November 09, 2008 10:20 AM
Subject: Re: [Amps] SB-220 saga continues
>
> The keying line (PTT relay) in the SB-220 is +120 V DC. The contacts
> of the "Linear" or "Send" relays in most transceivers can not handle
> the voltage and current "spike" generated by the high voltage PTT
> circuits in the older amplifiers (SB-200, SB-220, L4, L7, TL-922,
> etc.).
> You will probably need to replace the "Linear" or "Send" relay in your
> transceiver (if you are lucky, that will be all).
>
> I suggest adding a keying buffer (e.g. Ameritron ARB-704), modifying
> the SB-200 with the internal Harbach Electronics soft key circuit
> (www.harbachelectronics.com/main/page_products_sb220__sb221.html),
> or converting the SB-200 to faster, low voltage relays and electronic
> bias switching.
>
> 73,
>
> ... Joe, W4TV
>
>
>
>> -----Original Message-----
>> From: amps-bounces@contesting.com
>> [mailto:amps-bounces@contesting.com] On Behalf Of Roger (K8RI)
>> Sent: Sunday, November 09, 2008 12:34 AM
>> To: ke1fo@arrl.net
>> Cc: amps@contesting.com
>> Subject: Re: [Amps] SB-220 saga continues
>>
>>
>> Please do not cross post between reflectors.
>>
>> Roger (K8RI)
>>
>> Alfred Frugoli wrote:
>> > Hello everyone,
>> >
>> > So it seems I've got a problem with my SB-220.
>> >
>> > When the amp is off, but connected in the RF path,
>> everything is fine.
>> >
>> > When I switch the amp on I've suddenly got lots of attenuation
>> > happening on the receive path. Transmit seems fine - amp tunes OK
>> > etc.
>> >
>> > My first suspicion was that there were dirty relay contacts on the
>> > receive side. Cleaned the contacts with no success. Then
>> I realized
>> > that the problem only occurs when the amp is on. So a trip to the
>> > schematic tells me I don't understand. In the RX mode the RF path
>> > through the amplifier should be the same as when the power
>> is on. So
>> > I'm not sure where my attenuation is coming from.
>> >
>> > Just testing it a few minutes ago I can make an S5-7 station almost
>> > completely disappear by turning on the amp, so I've got
>> somewhere in
>> > the area of 20db of attenuation happening!
>> >
>> > Thoughts?
>> >
>> > Thanks.
>> >
>> > 73 de Al, KE1FO
>> >
>> > -----
>> > Visit my amateur radio contesting blog at ke1fo.wordpress.com.
>> > _______________________________________________
>> > Amps mailing list
>> > Amps@contesting.com
>> http://lists.contesting.com/mailman/listinfo/amps
>> >
>> >
>>
>> _______________________________________________
>> Amps mailing list
>> Amps@contesting.com http://lists.contesting.com/mailman/listinfo/amps
>
> _______________________________________________
> Amps mailing list
> Amps@contesting.com
> http://lists.contesting.com/mailman/listinfo/amps
>
_______________________________________________
Amps mailing list
Amps@contesting.com
http://lists.contesting.com/mailman/listinfo/amps
|