With the relay enabled, the specs say the Mk5 can switch up to 60 VDC at up
to 200 ma, or up to 100 VDC at up to 500 ma. I *think* the TL-922 has a
low VDC switching circuit, because the manual on my TS-930 says it can
switch that amp with the transistor switch that is provided for QSK. Other
older amps with higher-voltage relay circuits are another story, of course.
73, Pete N4ZR
, Bob Maser wrote:
>Hi Larry. Why do you put an ammeter in series with the center conductor of
>the key line and see how much current it is drawing when in the transmit
>condition. I would guess it would be somewhere around 100 to 150ma @ 26V,
>which I think the Mark V can handle all day long. I don't know what the MkV
>rating is but my FT1000D is good for 2A @ 30VDC!
>
>Bob W6TR
>----- Original Message -----
>From: "Larry K4AB" <larry.k4ab@gmail.com>
>To: <amps@contesting.com>
>Sent: Sunday, November 09, 2008 8:24 PM
>Subject: Re: [Amps] SB-220 saga continues
>
>
> > I've been keying my TL 922 with a Mark V and haven't been using a keying
> > buffer. Do I have a problem just waiting to happen?
> >
> > 73,
> > Larry K4AB
> >
> > On Sun, Nov 9, 2008 at 12:40 PM, Pete Smith <n4zr@contesting.com> wrote:
> >
> >> My Mark 5 has one. My SB-220, though, now has a 300-volt FET to switch
> >> the
> >> vacuum relays.
> >>
> >> 73, Pete
> >>
> >> At 11:45 AM 11/9/2008, Carl wrote:
> >> >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
> >> > >> >
> >> > >> >
> >> > >>
> >> > >> _______________________________________________
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> >> > >
> >> > > _______________________________________________
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> >> > >
> >> >
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