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K3 and its future external panadapter

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wayne burdick

K3 and its future external panadapter

Administrator

Sometime in the future (give us at least six months!) we'll be offering
a very high-performance panadapter for the K3. Let's call it a "P3" for
now. The P3 will work with any radio that has an I.F. tap, but it will
be styled to match the K3. We're thinking 2/3rds of the K3's width, but
the same height and depth. It may have a speaker and/or 20 A power
supply. Your input on this would be very welcome.

Early on in the K3 design process, we decided not to include an
*internal* panadapter. Here's our reasoning:

- A panadapter takes up a *lot* of front-panel real-estate. So, if you
want to
keep the radio at compact desktop size, you have to displace a lot
of controls.
The displaced controls end up buried in menus or "soft keys," making
basic
radio operation much more difficult. The K3 has a menu for things
rarely used,
but since there's no huge display, we were able to put every
often-used control
at your fingertips, optimally placed with respect to the LCD. A good
example
is our filter passband graphic, which is centered directly above the
DSP controls.

- An internal panadapter adds a lot of cost. Many customers, we felt,
would
rather have such cost be optional. If you want a panadapter, you'll
be able
get our P3 and set it beside the rig. Then, if you want to grab your
K3 and head
for the hills, you can optionally leave the panadapter on the desk
(along with
its speaker and power supply).

- Internal panadapters often have severe performance compromises.
There's at least one
very new radio on the market with a panadapter that takes over the
rig during sweeps.
Many of them are sluggish or have user-interface issues due to lack
of panel space.
Our external panadapter will be an entirely independent unit, so it
will not interfere
with radio use at all, either operationally or due to overloading of
controls.
That said, it will be highly integrated with, and controlled by, the
K3 (or
attached computer).

- We may use a display technology that offers faster rewrite speeds
than you can get
in an inexpensive graphic LCD such as the type most often used for
internal panadapters.
With the panadapter in a separate enclosure, we'll be able to use
very fast logic,
and possibly an exotic display such as an OLED (organic LED),
without incurring
any RFI problems.

73,
Wayne

---

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Bill VanAlstyne W5WVO

Re: K3 and its future external panadapter

Excellent thoughts about this feature. I agree 100% with your reasoning, and
if I decide to go with the K3 after learning more, I'll definitely go with
the panadapter add-on unit when it comes out.

I just rejoined this list after hearing about the K3 on the OMNI-VII
reflector. (I believe you obliquely aluded to this rig below.) <g> Have you
yet published on this list or elsewhere any claimed RX bench metrics like
noise floor, DR3, IP3, etc.? If not, when do you expect to come out with
these metrics? The OMNI-VII has been independently measured (Sherwood) with
a DR3 of 80 dB at 2 kHz spacing. Pretty good, but I'd like to get it up to
85 dB, which many agree is kind of the "good-enough number" for this metric,
a level beyond which you would never be able to tell the difference in the
real world.

Bill / W5WVO

wayne burdick wrote:

> Sometime in the future (give us at least six months!) we'll be
> offering a very high-performance panadapter for the K3. Let's call it
> a "P3" for now. The P3 will work with any radio that has an I.F. tap,
> but it will be styled to match the K3. We're thinking 2/3rds of the
> K3's width, but the same height and depth. It may have a speaker
> and/or 20 A power supply. Your input on this would be very welcome.
>
> Early on in the K3 design process, we decided not to include an
> *internal* panadapter. Here's our reasoning:
>
> - A panadapter takes up a *lot* of front-panel real-estate. So, if
> you want to
> keep the radio at compact desktop size, you have to displace a lot
> of controls.
> The displaced controls end up buried in menus or "soft keys,"
> making basic
> radio operation much more difficult. The K3 has a menu for things
> rarely used,
> but since there's no huge display, we were able to put every
> often-used control
> at your fingertips, optimally placed with respect to the LCD. A
> good example
> is our filter passband graphic, which is centered directly above
> the DSP controls.
>
> - An internal panadapter adds a lot of cost. Many customers, we felt,
> would
> rather have such cost be optional. If you want a panadapter, you'll
> be able
> get our P3 and set it beside the rig. Then, if you want to grab
> your K3 and head
> for the hills, you can optionally leave the panadapter on the desk
> (along with
> its speaker and power supply).
>
> - Internal panadapters often have severe performance compromises.
> There's at least one
> very new radio on the market with a panadapter that takes over the
> rig during sweeps.
> Many of them are sluggish or have user-interface issues due to lack
> of panel space.
> Our external panadapter will be an entirely independent unit, so it
> will not interfere
> with radio use at all, either operationally or due to overloading
> of controls.
> That said, it will be highly integrated with, and controlled by,
> the K3 (or
> attached computer).
>
> - We may use a display technology that offers faster rewrite speeds
> than you can get
> in an inexpensive graphic LCD such as the type most often used for
> internal panadapters.
> With the panadapter in a separate enclosure, we'll be able to use
> very fast logic,
> and possibly an exotic display such as an OLED (organic LED),
> without incurring
> any RFI problems.
>
> 73,
> Wayne
>
>
> ---
>
> http://www.elecraft.com
>
> _______________________________________________
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wayne burdick

K3 RX performance (tantalizing preview)

Administrator

Bill, W5WVO wrote:

> Have you yet published on this list or elsewhere any claimed RX bench
> metrics like noise floor, DR3, IP3, etc.?

Not yet. We're still testing the beta units.

But just to give you a hint: a couple of days ago Eric measured a
blocking dynamic range of 143 dB, and it remained 143 dB at 20 kHz, 5
kHz, and 2 kHz.

To put this into perspective, the K2, IC-7800, Orion II, and FTDX9000
all have a blocking dynamic range of -133 to -135.

We can't directly extrapolate to IMDDR3, but suffice to say it will be
excellent.

73,
Wayne
N6KR

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John, KI6WX

Re: K3 RX performance (tantalizing preview)

Let me add my 2 cents on this. We intentionally designed the K3 to minimize
interference from nearby strong signals. This is done by optimizing the
mixer and post amp to have high dynamic range and designing the local
oscillator to have minimal phase noise.

We wanted you to be able to copy that weak DX signal without interference at
the same time your neighbor is running a K3 at a kilowatt output in the same
part of the band. The K3 is designed to not only receive signals in a noisy
RF environment, but also to generate a much cleaner signal in transmit.
Some other rigs will generate broadband amplitude and phase noise when
transmitting; we minimized that as much as possible in the K3 design.
-John
KI6WX

> Bill, W5WVO wrote:
>
>> Have you yet published on this list or elsewhere any claimed RX bench
>> metrics like noise floor, DR3, IP3, etc.?
>
> Not yet. We're still testing the beta units.
>
> But just to give you a hint: a couple of days ago Eric measured a
> blocking dynamic range of 143 dB, and it remained 143 dB at 20 kHz, 5 kHz,
> and 2 kHz.
>
> To put this into perspective, the K2, IC-7800, Orion II, and FTDX9000 all
> have a blocking dynamic range of -133 to -135.
>
> We can't directly extrapolate to IMDDR3, but suffice to say it will be
> excellent.
>
> 73,
> Wayne
> N6KR

Bill Coleman-2

Re: K3 RX performance (tantalizing preview)

On Apr 28, 2007, at 3:25 PM, John, KI6WX wrote:

> We wanted you to be able to copy that weak DX signal without
> interference at the same time your neighbor is running a K3 at a
> kilowatt output in the same part of the band. The K3 is designed
> to not only receive signals in a noisy RF environment, but also to
> generate a much cleaner signal in transmit. Some other rigs will
> generate broadband amplitude and phase noise when transmitting; we
> minimized that as much as possible in the K3 design.

Question:

If the K3 can do this, then why can't it do SO2R in one box? All that
is required is for the second receiver to be able to receive (likely
on a different band) while the transmitter is transmitting.

Bill Coleman, AA4LR, PP-ASEL Mail: [hidden email]
Quote: "Not within a thousand years will man ever fly!"
-- Wilbur Wright, 1901

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Scott Manthe

Re: K3 RX performance (tantalizing preview)

One reason is called the inverse square law.
There's a HUGE difference in a rig being able to deal with a kilowatt signal
a couple blocks away and being able to deal with a kilowatt signal in the
same room.

Another is that almost everyone who doesn't want to destroy their rig's
front-end uses giant bandpass filters in front of each rig in a SO2R setup.

Including eleven of these filters to cover all the bands the K3 will cover
would make it the size of a broadcast transmitter. For reference for the HF
challenged, take a look at a good set of repeater duplexers. Now, multiply
that by eleven bands.

It's one thing for a 2 meter/440 rig to be able to transmit and RX at the
same time- they're running maybe 50 watts at 300 mHz spacing. It's not so
easy with a rig running 100 watts, a kilowatt, or at some stations, several
kilowatts at 2 or 3 mHz spacing.

Hopefully this helps.

73,
Scott, N9AA

Bill Coleman writes:

> Question:
>
> If the K3 can do this, then why can't it do SO2R in one box? All that is
> required is for the second receiver to be able to receive (likely on a
> different band) while the transmitter is transmitting.
>
> Bill Coleman, AA4LR, PP-ASEL Mail: [hidden email]
> Quote: "Not within a thousand years will man ever fly!"
> -- Wilbur Wright, 1901
>
> _______________________________________________
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Ken Kopp

Bandpass filters

A current posting paints a totally incorrect picture of the relationship
between HF and VHF/UHF filtering methodologies.

A typical VHF repeater TX runs 50 -110 watts and the spacing
between TX and RX is 600 kHz. At UHF/450 the spacing is
5 mHz. (I'm a career two-way radio technician and have been
the repeater coordinator for Montana for 30 years.)

The set of six 160 - 10 meter bandpass filters that I use for HF
contesting and DX-peditions would all fit in the case of a K2 or
K3 and do function perfectly well in the same room with several
multi-op stations with KW transmitters. SO2R is the proverbial
"piece of cake". In addition, there are dedicated RF input limiters
available for the antenna inputs of radios if one wants additional
protection or doesn't have bandpass filters.

There is little, if any, relationship between the resonant cavity type
of band-pass, band-notch technology used in VHF/UHF duplexers
and the capacitor/inductor technology used in HF band-pass filters.

73! Ken Kopp - K0PP
[hidden email]

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N2TK

RE: Re: K3 RX performance (tantalizing preview)

In reply to this post by Scott Manthe

How does Yaesu do it with the FT9000? You can listen on the second receiver
while simultaneously operating transceive on the other receiver/transmitter
on another band while transmitting?
N2TK, Tony

-----Original Message-----
From: [hidden email]
[mailto:[hidden email]] On Behalf Of Scott Manthe
Sent: Monday, May 14, 2007 11:49 AM
To: [hidden email]
Subject: [Elecraft] Re: K3 RX performance (tantalizing preview)

One reason is called the inverse square law.
There's a HUGE difference in a rig being able to deal with a kilowatt signal

a couple blocks away and being able to deal with a kilowatt signal in the
same room.

Another is that almost everyone who doesn't want to destroy their rig's
front-end uses giant bandpass filters in front of each rig in a SO2R setup.

Including eleven of these filters to cover all the bands the K3 will cover
would make it the size of a broadcast transmitter. For reference for the HF
challenged, take a look at a good set of repeater duplexers. Now, multiply
that by eleven bands.

It's one thing for a 2 meter/440 rig to be able to transmit and RX at the
same time- they're running maybe 50 watts at 300 mHz spacing. It's not so
easy with a rig running 100 watts, a kilowatt, or at some stations, several
kilowatts at 2 or 3 mHz spacing.

Hopefully this helps.

73,
Scott, N9AA

Bill Coleman writes:

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Bill Coleman-2

Re: Re: K3 RX performance (tantalizing preview)

In reply to this post by Scott Manthe

On May 14, 2007, at 11:48 AM, Scott Manthe wrote:

> One reason is called the inverse square law.

I'm familiar with that.

> There's a HUGE difference in a rig being able to deal with a
> kilowatt signal a couple blocks away and being able to deal with a
> kilowatt signal in the same room.

I'm aware of that, too.

However, I wasn't talking about a kW a couple of blocks away. I was
talking about 100 watts in the same box, or 1.5 kW inside a 100m
circle (tops!).

At a M/M station with more than 6 rigs, you'll have two radios on the
SAME band, using antennas that are just a few dozen meters from each
other.

> Another is that almost everyone who doesn't want to destroy their
> rig's front-end uses giant bandpass filters in front of each rig in
> a SO2R setup.

First, this isn't true. You don't need huge bandpass filters for an
SO2R setup. A typical 1.5 kW SO2R station will use a set of receive
filters or stubs to reject out-of-band signals. For 100w SO2R, you
don't need to have the filters.

Second, in the M/M comparison, you have two rigs on the SAME band, so
bandpass filters don't do you any good.

At NQ4I's M/M many of the second rigs don't use a bandpass filter at
all (although he has them available -- I know, I built one set for
him). They won't help with the in-band signals from the primary rig,
although they are useful for getting rid of mixing products from the
other five transmitting stations on the other bands....

> Including eleven of these filters to cover all the bands the K3
> will cover would make it the size of a broadcast transmitter.

You don't need it.

> For reference for the HF challenged, take a look at a good set of
> repeater duplexers. Now, multiply that by eleven bands.

You don't need filters the size of repeater duplexers to do this.

> It's one thing for a 2 meter/440 rig to be able to transmit and RX
> at the same time- they're running maybe 50 watts at 300 mHz
> spacing. It's not so easy with a rig running 100 watts, a kilowatt,
> or at some stations, several kilowatts at 2 or 3 mHz spacing.

At NQ4I, with antenna separation of just a few dozen meters, we can
often receive effectively within 10 kHz of the primary station.

--

Let's put it this way -- many SO2R stations use the Top-Ten A/B
switches to separate their antennas for two rigs: http://www.qth.com/
topten/abss.htm

These switches only offer 80 dB of isolation.

The Array Solutions SixPac has similar specifications: http://
www.arraysolutions.com/Products/sixpak.htm

About 80 dB of isolation below 30 MHz. The web page indicates you
should worry more about the coupling between antennas than the
isolation of the switch.

So, if 80 dB of isolation is sufficient for 1.5 kW signals, then 100
W signals would need 12 dB less, or only 68 dB to achieve the same
level of received signal in the second receiver. Call it only 70 dB.
That seems achievable. I don't understand why that couldn't be
achieved in a box the size of the K3.

Bill Coleman, AA4LR, PP-ASEL Mail: [hidden email]
Quote: "Not within a thousand years will man ever fly!"
-- Wilbur Wright, 1901

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Ken Kopp

Bandpass filters (again)

My bandpass filters ... by ICE ... measure
3" x 3" x 1.5" and work very well in multi-rig
settings.

73! Ken Kopp - K0PP
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Charly

burning front end

In reply to this post by Bill Coleman-2

I don't know much, but I do know I burned out the relay contacts (not diode
switches) on an IC730 tuned to 75 meters and hooked to a 75m dipole, the
apex of which was about 10 feet from the tribander. On the tribander was
1.5kw on 20m.

Burned the contacts right off.

Charles Harpole
[hidden email]

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Vic K2VCO

Re: Re: K3 RX performance (tantalizing preview)

In reply to this post by Bill Coleman-2

Bill Coleman wrote:

> At NQ4I, with antenna separation of just a few dozen meters, we can
> often receive effectively within 10 kHz of the primary station.

How do you do this? This field day, I found that having a station on SSB
in the same band with me when I was on CW was really problematic.
Antennas were oriented for minimal coupling and power was 100 watts.

Rigs in this case were various Kenwoods, but I've also experienced this
with other Japanese radios. The problem seems to be transmitted wideband
phase noise that starts when the ptt is closed (the actual SSB signal
does not seem to be a problem). We do have bp filters, but of course
they don't help on the same band.

We haven't had K2's at FD (I am the only one who has one). What kind of
rigs are in use at NQ4I?
--
73,
Vic, K2VCO
Fresno CA
http://www.qsl.net/k2vco
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Igor Sokolov-2

Re: Re: K3 RX performance (tantalizing preview)

Provided 2 yagi antennas separated by 100-150m and each has F/S of 40db you
can get some 80 db isolation and stop warring about wide band noise from
adjacent radio.

73, Igor UA9CDC

> Bill Coleman wrote:
>
> > At NQ4I, with antenna separation of just a few dozen meters, we can
> > often receive effectively within 10 kHz of the primary station.
>
> How do you do this? This field day, I found that having a station on SSB
> in the same band with me when I was on CW was really problematic.
> Antennas were oriented for minimal coupling and power was 100 watts.
>
> Rigs in this case were various Kenwoods, but I've also experienced this
> with other Japanese radios. The problem seems to be transmitted wideband
> phase noise that starts when the ptt is closed (the actual SSB signal
> does not seem to be a problem). We do have bp filters, but of course
> they don't help on the same band.
>
> We haven't had K2's at FD (I am the only one who has one). What kind of
> rigs are in use at NQ4I?
> --
> 73,
> Vic, K2VCO
> Fresno CA
> http://www.qsl.net/k2vco
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