[NLRS] Sequencer

Fri, 28 Nov 2003 08:34:37 -0600

Hosfelt Electronics has relays at surplus prices. Several pages in their most recent catalogs. I find them a little high on shipping. Mendelson Electronics (or MECL) has a few pages of relays.

Digi-key and Mouser have many pages of relays at fairly reasonable prices in their catalogs, reasonable shipping, and rapid delivery.

But 15 amp MOSFETs are cheaper than surplus relays (and Hosfelt has surplus MOSFETs too).

73, Jerry, K0CQ

---------- Original Message ----------------------------------
From: Donn Baker <[email protected]>
Date:  Fri, 28 Nov 2003 02:41:13 +0000

>Hi Jon,
>Ian White, G3SEK, published a sequencer on his web site (don't know the
>URL: Google 'G3SEK') using two DPDT relays.  The "trick" is that one is 12v
>DC and the other is 6v DC.  It may also be written up in "The VHF DX
>Handbook," don't know.
>
>Paul Wade, W1GHZ also has published a desing for a more "sophisticated"
>design (and has -had ?- PC boards available for it.  He's also put the PC
>patterns on his web page.  Three boards, which should be at least 6
>sequencers, cost $59 delivered from ExpressPCB.  
>
>Although Bruce, W9FZ, and I have parts and boards for a number of W1GHZ's
>sequencers, I don't think its an optimal design.  (Frankly, I've VERY
>partial to the G3SEK design.)  Paul's design has a lot of "bells and
>whistles," which I personally don't like.  (Will that stop me from using
>them... most likely no.)  There's a lot of added complexity with a bunch of
>time delay cirsuits, FET switches, etc.  I prefer relays.  BUT, relays are
>getting hard to find (cheaply).
>
>Good luck.
>
>73 Donn
>WA2VOI/0
>
>
>At 15:02 27-11-03 EST, [email protected] wrote:
>>Anyone aware of a simple design for a solid state sequencer ?  On transition 
>>from receive to transmit the sequencer would delay the 12vdc to the
>amplifier 
>>(while the T/R relay energized) and on transition from transmit to receive
>it 
>>would then turn off the 12vdc to the amplifier before it de-energized the
>T/R 
>>relay.  Delay times would be around 100ms.  
>>
>>73, Jon
>>W0ZQ
>>
>>
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