[NLRS] Sequencer Question

[jcplatt1 at mmm.com]

Steve at Down East Microwave has a good article in their library
http://www.downeastmicrowave.com/PDF/SL2005CSVHF.pdf


That is a good article that Steve wrote .... definitely recommended
reading.   However, I think it misses the general masses who simply want to
hook up a HF transverter (IF rig) to a transverter - is sequencing needed
there ?   Steve's states in the middle of the paper that "What is important
is that the transverter will not transmit into the preamp and the
transceiver (IF Rig) will not transmit into the transverter unless the
whole system is all into their individual transmit modes.   The ultimate
answer for simplicity and versatility is to have a low drive transceiver
(IF Rig) for a transverter system."  .... this last sentence is important.

I do believe that most modern day transverters are designed for "low drive
transveiver" IF rigs.  Even the DEM transverters that are set up to handle
high power, 10 to 25 watts of IF RF input, are simply going into a big RF
pad and a small portion of that RF is then sampled and sent on to the input
of the transverter.  Todays transverters are designed to withstand the
small levels of RF input that can occur during the rcv-to-xmt race
condition that occurs between the IF rig and the transverter.

In summary, for the VHF bands, you typically do not need sequencing when
you are simply hooking up an IF rig with a transverter.  You can simply add
an RF brick to such a simple system, although hard keying is recommend
(hard keying reduces the hot switching of the RF relay and improves its
longevity and reliability).   People have had years of success with such a
simple system.   Adding an external preamp most likely does indeed moves
you into the realm of sequencing and the idea of using an external transmit
activation device (ala Steve's article) like a foot switch is a very good
idea.

73, Jon
W0ZQ