[Amps] Input relay for QSK amp

[Bob Maser]

I agree with everything you said.  The problem with some radios is they
start sending'
RF down the line at the same time they are giving the relays the energize
signal.  I have built
some big amplifiers in my day (don't forget the saying that in California
too much power is just
enough) and I always made sure that the output relay was quicker than the
input/bias relay
in fact I usually used open frame P&B for them and RJ2B on the output.
RJ1's just don't
instill confidence  HI.
Bob

On Sat, Dec 8, 2018 at 11:49 PM Jim <jimw7ry at gmail.com> wrote:

> Its actually very simple Jim.
>
> Don't send RF until the amplifier is ready. Not doing so, makes the
> relays hot switch. It matters not which one is energized before RF is
> sent. As long as they both are before RF is sent from the exciter. Same
> on dekey. RF MUST stop flowing from the exciter BEFORE the relays
> (either one of them) DE-energize.
>
>
> Thanks
> 73
> Jim W7RY
>
> On 12/8/2018 11:37 AM, MU 4CX250B wrote:
> > Bob,
> > Years ago, I bought a lifetime supply of RJ1As for my own projects,
> > and have tested roughly two dozen on my homebrew relay tester. The
> > RJ1As typically close in about 2msec, with the fastest closing I
> > measured at 1.2msec. Their opening time is typically about 500uSecs.
> > None of them show any contact bounce. Other vacuum relays, e.g., RF1D,
> > RJ1. GC1, etc., are more like you remember.
> >
> > Here's a link to a 2015 QSK article I wrote for QST,
> > that goes into detail on amp relay timing issues, including the
> > crucial need to avoid hot-switching. Doing so is more complicated than
> > merely choosing a slow input relay, or slowing down the input relay
> > transistor driver with an RC circuit. Many purported "QSK" designs
> > ignore these other considerations.
> > 73,
> > Jim w8zr
> >
> >   from my iPhone
> >
> >> On Dec 7, 2018, at 8:16 PM, Bob Maser <bob.maser at gmail.com> wrote:
> >>
> >> I must be old school.  The input relays need to be slower than the
> output
> >> relay.
> >> Seems to me that a RJ-1 takes 8ms to close and stop bouncing around. I
> have
> >> always
> >> used a P&B miniature open frame DPDT for that purpose.  The output of
> the
> >> amp needs
> >> to be closed before the input turns on.
> >> Bob
> >>
> >>> On Fri, Dec 7, 2018 at 9:39 PM Jim <jimw7ry at gmail.com> wrote:
> >>>
> >>> Those relays that Rich (and I ) used are mostly unavailable. I used to
> >>> buy them 100s at a time. No more of them can be had.
> >>>
> >>> Most of what you find on eBay are seconds and most don't work. Or they
> >>> are re-labeled counterfeits.
> >>>
> >>>
> >>> Thanks
> >>> 73
> >>> Jim W7RY
> >>>
> >>>> On 12/4/2018 4:03 PM, Alek Petkovic wrote:
> >>>> G'day Vic.
> >>>>
> >>>> The Matsushita/Panasonic relay that Rich Measures used in his QSK
> >>>> circuit, published at somis.org, is still available on Ebay. I bought
> >>>> 10 of them a couple of years ago
> >>>>
> >>>> Otherwise, Jim, W7RY, uses a small relay in his QSK kit. He laso deals
> >>>> on Ebay.
> >>>>
> >>>> 73, Alek.
> >>>> VK6APK
> >>>>
> >>>>> On 4/12/2018 6:21 PM, Victor Rosenthal 4X6GP wrote:
> >>>>> I'm trying to choose a relay to use as the input relay in a QSK amp.
> >>>>> I have been very satisfied with the Jennings RJ1-A as an output
> >>>>> relay. The input relay in this circuit needs to be DPDT, or I'd just
> >>>>> use two similar vacuum relays.
> >>>>>
> >>>>> Here are my needs:
> >>>>>
> >>>>> 1. DPDT.
> >>>>> 2. 12 or 24v coil.
> >>>>> 3. Operate/release time, including bounce <= 4 ms. Faster is better.
> >>>>> 4. Should carry 100w RF in 50 ohm system. Not expected to make/break
> >>>>> live circuit.
> >>>>> 5. Must have low resistance for low-level signals (receive path).
> >>>>> 6. Must have long life >= (10 x 10**6 operations)
> >>>>> 7. Must not be insanely expensive, and available from Mouser or RS.
> >>>>>
> >>>>> I found this relay:
> >>>>> <
> https://www.mouser.co.il/datasheet/2/418/NG_SS_108-98005_L-1019204.pdf
> >>>>> But maybe there's a better choice? I'm overwhelmed by the number and
> >>>>> varieties of relays in the catalog.
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