[NLRS] Amp suggestions

[Jon Platt]

Hi John ..... here is some more input from another "Jon".

As has been suggested, hard keying rather than "carrier operated relay", or
COR keying is a much better way to go for the following reasons.   One is
that it helps to assure that you are not hot keying the RF relay in the
brick ..... hot keying occurs when the relay goes from receive to transmit
mode while transmit RF is present .... it tends to pit the relay contacts
and reduces relay life.   The second reason is that you can get rid of that
VOX delay between when you stop transmitting and when the brick drops back
to the receive mode ..... once you have used hard keying you will never want
to go back.   Most brick have a RCA or phono connector on the back panel
that is the control input for hard keying ..... usually the brick can be
set-up for ground based keying or +12v keying .... there is usually a jumper
inside the brick to choose which method to use.   Most rigs have a keying
output line that comes out the back on a accessory connector or a dedicated
connector that is the PTT (push to talk) line.   Check your brick manual and
rig manual, and just ask if you need help.

Regarding the brick's preamp, almost without exception they add more noise
than they add improvement to the signal and they are, generally speaking,
not that helpful.    With a weak signal just turning up the rigs volume will
be just as good, or perhaps better.   In addition, when the preamp is ON you
will find that your rigs dynamic range is negatively impacted such that
strong signals that are close by interfere with those weak signals.
Generally speaking most 2m rigs have adeqate gain and sensitivity and an
external preamp is not needed.

Regarding bricks, I suspect that one brick is about like any other brick.
Don't worry about the preamp.   If you can save money by getting a brick
without a preamp, go for it.    Getting into the 100 to 150 watt range is a
good power level for 222 and 432 .... I've run that power level from bricks
for years and have 84 grids confirmed on 222 and 97 grids on 432.    Look
for a brick that matches your rigs output power level ..... looking for a
used brick is a very good way to save some $$$.

Hope this was helpful John.   Let me know if you want some help with the
hard keying setup.

73, Jon
W0ZQ




----- Original Message -----
From: "John Hoaglun" <john@hoaglun.com>
To: <nlrs@mailman.qth.net>
Sent: Monday, September 16, 2002 11:04 AM
Subject: [NLRS] Amp suggestions


> I am looking for suggestions for Amps for 1.25m and 70cm.    I own a
Mirage
> Amp for 2m and it performed great during the contest other than the long
> delay on the relay after transmitting. (I need to do some testing... this
is
> adjustable... but it can also clip the audio if it set too short.)
>
> The preamp made receiving calls much easier.
>
> What are people using for 222 and 432?  Any suggestions? My goal is to get
> 222 and 432 to at least 100w.
>
> I am already planning for the next contest. (I will post the results of
the
> September contest in a few days. Let's just say,  I had a blast and I am
> already work on the next plan and starting to look for more gear!)
>
> Thanks, JH
>
> John Hoaglun - MCSE
> KC0LBT - EN35
> http://www.hoaglun.com
>
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