[amsat-bb] Sequencer advice needed

[Chris Thompson]

W6PQL works great. That is how I sequence my station. It protects my FCD
while my radio transmits to FS-3.

73
Chris

On Fri, Mar 6, 2020, 12:14 John Kludt via AMSAT-BB <amsat-bb at amsat.org>
wrote:

> Roger,
>
> I am a little confused by your comment on frequency range and power as
> those are characterists of the relays themselves and not the sequencer.
> The purpose of the sequencer is to switch equipment and feedlines from
> receive to transmit and back in a orderly sequence such that RF is the last
> thing applied on transmit and the first thing removed on receive.  As such
> a sequencer is an electrical device and not a RF device.
>
> On my 1296 system I use the Demi solid state sequencer.  Step 1 removes
> preamp power.  Step 2 switches the preamp out of line by activating two
> coaxial relays (where I spent real money!).  Step 3 grounds the PTT on the
> W6PQL power amplifier and then Step 4 grounds the PTT on the transceiver
> and applies RF.  There are other switching schemes but this is a fairly
> common one.
>
> Hope that helps.
>
> Johnny
>
> On Fri, Mar 6, 2020, 11:50 Roger - W7TZ via AMSAT-BB <amsat-bb at amsat.org>
> wrote:
>
> > I've used the W6PQL (built and tested) unit for 6m and 1.25m very
> > successfully for several years.
> >
> > 73, Roger
> > W7TZ
> > CN83ia
> >
> >
> > On Fri, Mar 6, 2020 at 4:26 AM Hans BX2ABT via AMSAT-BB <
> > amsat-bb at amsat.org>
> > wrote:
> >
> > > I haven't worked with sequencers before as all my LNAs and SDRs have
> > > been used for receive only. But now that I have a Airspy HF+ I want to
> > > get going with APRS on 145.825 and use this on HF as well. So receiving
> > > with the SDR, transmitting with a transceiver. I also want to
> experiment
> > > with LNAs, so another reason to use a sequencer. I did a lot of
> > > googling, learned some, but still not sure what I need to look out for
> > > when buying one. I prefer a kit or assembled product as a first try.
> > >
> > > Below is a list of what I found on line. From a distance the VHF Design
> > > is cheap and has detailed information, so I am leaning towards
> > > purchasing that. Later, for a DIY project, I like the OZ1BXM design
> > > because it uses an Arduino for control, which brings some flexiblity.
> > >
> > > Can you all please give me some input on what to look for in sequencers
> > > or comment on the choices below? Any other kits/assemblies I have
> missed
> > > and should be considered? Cheers,
> > >
> > > Hans
> > > BX2ABT
> > >
> > >
> > >
> > > Minikits from Austalia's EME166: AU$45 (=US$27.75)
> > >
> > > https://www.minikits.com.au/Sequencer?search=Sequencer
> > >
> > > This is the only one that indicates a frequency range: 28 to 500 MHz,
> so
> > > this will cover the 2m band, but not HF. Also RF input is 4 Watts
> > > maximum, which seems low, so how is this usable?
> > >
> > >
> > >
> > > W6PQL's sequencer (US$20 for kit, US$37.50 assembled)
> > >
> > > http://www.w6pql.com/relay_sequencer.htm
> > >
> > > No info on frequency range or input power. Not much info on the
> website.
> > >
> > >
> > >
> > > VHF Design (US$20 assembled)
> > >
> > > https://vhfdesign.com/other/sequencer-pcb.html
> > >
> > > Website has good information, diagrams and PCB layouts. Again no info
> on
> > > frequency range, etc.
> > >
> > >
> > >
> > > Downeast Microwave (US$25~80)
> > >
> > >
> > >
> >
> https://www.downeastmicrowave.com/searchresults.asp?Search=sequencer&Submit=
> > >
> > > 3 and 4 step sequencers both in solid state and with relays based on a
> > > design by W5LUA. Which better: solid state or relays? Little indept
> info.
> > >
> > >
> > >
> > > G3SEK - (DIY)
> > >
> > > http://www.ifwtech.co.uk/g3sek/dx-book/sequencer/
> > >
> > > Basically only a schematic, so need to build it from the ground up.
> > >
> > >
> > >
> > > OZ1BXM (DIY)
> > >
> > > http://oz1bxm.dk/seq/sequencer.html
> > >
> > > Another DIY project based on the W6PLQ design. This uses an Arduino as
> > > MCU, so should be flexible. No kits and no PCB designs.
> > >
> > >
> > >
> > > SM2CEW (DIY)
> > >
> > > http://sm2cew.com/sequencer/sequencer.html
> > >
> > > This one looks very simple to make with very few components. It was
> > > designed for HF, so will it work on VHF?
> > >
> > >
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> of
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> > _______________________________________________
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> > expressed
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> _______________________________________________
> Sent via AMSAT-BB at amsat.org. AMSAT-NA makes this open forum available
> to all interested persons worldwide without requiring membership. Opinions
> expressed
> are solely those of the author, and do not reflect the official views of
> AMSAT-NA.
> Not an AMSAT-NA member? Join now to support the amateur satellite program!
> Subscription settings: https://www.amsat.org/mailman/listinfo/amsat-bb
>