I have a new design Norton preamplifier that might be useful for this
purpose.
It has 11 dB gain through 30 MHz and 9 dB at 54 MHz, noise figure is in
the 2.5-3 dB range, OIP2 > +85 dBm, OIP3 > +42 dBm. The OIP values are
conservative numbers.
When power is switched off, the preamp is bypassed.
Housed in a custom built, powder coated, silk screened enclosure.
Power requirements, 13.6V @ 100 mA.
Model no. Z10043S.
Anyone interested in one can contact me off-list for a data sheet,
pricing and delivery schedule. This preamp is not shown at my web site -
too new to have a page yet.
Jack K8ZOA
On 5/26/2013 6:21 AM, Gary Gregory wrote:
Hi ian,
Gee thanks for the insight to your attempts on an internal pre-amp.
I imagine that the lack of sensitivity on 12/15M has appeared after
production also so again the position would be the same from Elecraft.
It is a pity that to correct this can only be remedied with an external
device. If they ever produce a remote 10/12M preamp that could be sat a
foot or so away from the K3 this would help in my case but may not suit
home stations and others. I realise I am most likely in a small minority
here and I accept that without reservations.
I would rather pay for what I need rather than a combo including 6M which
is of no use to me.
73
Gary
On 26 May 2013 19:39, Ian White <gm3...@ifwtech.co.uk> wrote:
Joe, Gary and Joe again:
I agree that an internal preamp (or premps) would be ideal.
However,
in addition to the preamp(s) Elecraft would need to provide
*another*
design for the KXV3A - one that switches the RX ANT IN/OUT
connections to internal jacks - as neither the original KXV3 or
current KXV3A have that capability.
let's not let that technical inconvenience reduce in any
way my hope for a cure to my sometimes demented desires....:-)
I'm not saying it isn't possible ... takes one additional relay and two
connectors. There are even couple unused control lines on the KXV3A
that
could be used to control the added relay and switch bands (10/12 and 6
M)
if necessary.
Been there, tried that. I tried two different ways to retrofit an
internal preamp for 6m, and neither of them worked well enough to keep.
The problem is that any modification has to work within the very tight
space behind the rear panel of the KXV3 module. There is >>barely<<
enough space to install a tiny PC board behind the RX ANT IN and RX ANT
OUT connectors, with very tight limits on what can be included on that
board. The track layouts had to be designed with a step size of 0.025in
and in some places the tolerances were even tighter than that.
Board #1 used a single subminiature DPDT relay and included a very
simple wideband preamp; but the single relay gave insufficient isolation
to prevent the preamp from oscillating out-of-band. There wasn't enough
space on the board for two relays, tuned circuits or any additional
shielding and decoupling; and it was impossible to make any further
tweaks without completely extracting the KXV3 module. Board #2 was
simpler, this time with two DPDT relays for improved port-to-port
isolation, and with two coax fly-leads that were long enough to reach
into the space above the KRX3 module (which Elecraft had reserved for
the 144MHz transverter). That allowed me to use a fully shielded 6m
preamp which gave a dramatic improvement in sensitivity - but now the
VFO encoder noise made it impossible to tune the band! I believe that
new problem was due to the use of two different grounding points, at the
KXV3 and on the top cover of the KRX3, and I couldn't see any way around
that.
At that point I gave up on the idea of retrofitting an internal 6m
preamp. Elecraft could have included it at the initial design stage, of
course; but if my reading of history is correct, the demand for greater
sensitivity on 6m came >>after<< the K3 had been launched on the market.
By that time the internal hardware design was already locked down, so I
can fully understand why Elecraft were obliged to produce the PR6 as an
external add-on.
Wayne has acknowledged that the K3 can sometimes be lacking in
sensitivity on 6m, and has stated that the external PR6 module is
Elecraft's solution. I wouldn't expect that position to change
significantly.
73 from Ian GM3SEK
______________________________________________________________
Elecraft mailing list
Home: http://mailman.qth.net/mailman/listinfo/elecraft
Help: http://mailman.qth.net/mmfaq.htm
Post: mailto:Elecraft@mailman.qth.net
This list hosted by: http://www.qsl.net
Please help support this email list: http://www.qsl.net/donate.html
______________________________________________________________
Elecraft mailing list
Home: http://mailman.qth.net/mailman/listinfo/elecraft
Help: http://mailman.qth.net/mmfaq.htm
Post: mailto:Elecraft@mailman.qth.net
This list hosted by: http://www.qsl.net
Please help support this email list: http://www.qsl.net/donate.html
