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Question about forthcoming KAT500

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Phil Hystad-3

Question about forthcoming KAT500

Did I read right that the forthcoming KAT500 would be able to match up to a 10:1 SWR?

So, this should mean that the impedance range of the tuner is anywhere from 5 to 500 ohms (absolute value of Z).

I currently use an AT1KM tuner with impedance range of 20 to 1500 ohms. I use this with a horizontal delta loop and I am able to match all of my important bands that I operate on this antenna which are 80, 40, 30. I use a 5-band hex beam for the other bands.

But, I can easily get a good match well under 1.5:1 using the AT1KM. But, I also measured the impedance and SWR at the point that the coax hooks into the AT1KM. These measures are then of the raw, un-tuned, antenna system (coax and delta loop) made with my MFJ-259B. According to these measurements, the raw impedances I need to match are more then 10:1 for some of the bands. Indeed, I am close to 24:1 for the low part of 80 but I operate fine in this region using the AT1KM.

Should I then assume that the KAT500 will not work for me with my current antenna system? I also noticed that other auto-tuners have similar wider ranges. For example, MFJ-998 supports a matching range of 12 to 1600; and, the old Palstar AT-Auto supports a matching range of 15 to 1500 (now Kessler Engineering). Apparently, the new the new Palstar HF-Auto is reported as 10:1 SWR which may be the same as KAT500.

Therefore, can someone (Wayne, Eric or others in the know) confirm that with my current antenna configuration, I will probably NOT be able to use the KAT500 for 80 meters (at least). My options I suppose are not to use the KAT500 at all, not use it for 80, or reconfigure my delta loop (although, my degrees of freedom for this are small).

73, phil, K7PEH

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Jim Bennett

Re: Question about forthcoming KAT500

An interesting question!! And it directly affects my situation, too.

So, here is a slight add-on to Phil's query - perhaps Eric or Wayne can shed some light here. My "main" antenna is an 88' foot long doublet at 45 feet, fed with 600-ohm ladder line, and a 1:1 balun where my eight feet of coax from the K3/100 connects to the balanced line. The K3's tuner gives me a match on this antenna on 80 through 6 meters. I'm a happy camper with this antenna working pretty darn well on all bands, although it is mostly NVIS on 80. So, my question is - how close in performance will the KAT500 be to the KAT3? Can I expect the KAT500 to match this antenna as well as the KAT3 does? I'd certainly NOT be happy to spend the dollars for the new tuner to find that it is not capable of doing what the KAT3 can do.

Jim / W6JHB

On Saturday, Dec 31, 2011, at Saturday, 12:33 PM, Phil Hystad wrote:

> Did I read right that the forthcoming KAT500 would be able to match up to a 10:1 SWR?
>
> So, this should mean that the impedance range of the tuner is anywhere from 5 to 500 ohms (absolute value of Z).
>
> I currently use an AT1KM tuner with impedance range of 20 to 1500 ohms. I use this with a horizontal delta loop and I am able to match all of my important bands that I operate on this antenna which are 80, 40, 30. I use a 5-band hex beam for the other bands.
>
> But, I can easily get a good match well under 1.5:1 using the AT1KM. But, I also measured the impedance and SWR at the point that the coax hooks into the AT1KM. These measures are then of the raw, un-tuned, antenna system (coax and delta loop) made with my MFJ-259B. According to these measurements, the raw impedances I need to match are more then 10:1 for some of the bands. Indeed, I am close to 24:1 for the low part of 80 but I operate fine in this region using the AT1KM.
>
> Should I then assume that the KAT500 will not work for me with my current antenna system? I also noticed that other auto-tuners have similar wider ranges. For example, MFJ-998 supports a matching range of 12 to 1600; and, the old Palstar AT-Auto supports a matching range of 15 to 1500 (now Kessler Engineering). Apparently, the new the new Palstar HF-Auto is reported as 10:1 SWR which may be the same as KAT500.
>
> Therefore, can someone (Wayne, Eric or others in the know) confirm that with my current antenna configuration, I will probably NOT be able to use the KAT500 for 80 meters (at least). My options I suppose are not to use the KAT500 at all, not use it for 80, or reconfigure my delta loop (although, my degrees of freedom for this are small).
>
> 73, phil, K7PEH
>
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Kevin Stover

Re: Question about forthcoming KAT500

I've got the same antenna here.
88' of 300 Ohm transmitting twinlead configured as a folded dipole. Fed with about 50ft of 300 Ohm to a 1:1 balun and coax into the shack from there. My KAT100-1 matches it on all bands and(I haven't tried 160 because I don't expect miracles) at 100W. It's spec'd range is 10:1.

I can't imagine the KAT500 won't match something close to that. If folks are expecting it to match the proverbial wet noodle or their downspouts AND take 500W they should probably change their expectations.

On Sat, 31 Dec 2011 13:36:28 -0800
Jim Bennett <[hidden email]> wrote:

> An interesting question!! And it directly affects my situation, too.
>
> So, here is a slight add-on to Phil's query - perhaps Eric or Wayne can shed some light here. My "main" antenna is an 88' foot long doublet at 45 feet, fed with 600-ohm ladder line, and a 1:1 balun where my eight feet of coax from the K3/100 connects to the balanced line. The K3's tuner gives me a match on this antenna on 80 through 6 meters. I'm a happy camper with this antenna working pretty darn well on all bands, although it is mostly NVIS on 80. So, my question is - how close in performance will the KAT500 be to the KAT3? Can I expect the KAT500 to match this antenna as well as the KAT3 does? I'd certainly NOT be happy to spend the dollars for the new tuner to find that it is not capable of doing what the KAT3 can do.
>
> Jim / W6JHB
>
>
> On Saturday, Dec 31, 2011, at Saturday, 12:33 PM, Phil Hystad wrote:
>
> > Did I read right that the forthcoming KAT500 would be able to match up to a 10:1 SWR?
> >
> > So, this should mean that the impedance range of the tuner is anywhere from 5 to 500 ohms (absolute value of Z).
> >
> > I currently use an AT1KM tuner with impedance range of 20 to 1500 ohms. I use this with a horizontal delta loop and I am able to match all of my important bands that I operate on this antenna which are 80, 40, 30. I use a 5-band hex beam for the other bands.
> >
> > But, I can easily get a good match well under 1.5:1 using the AT1KM. But, I also measured the impedance and SWR at the point that the coax hooks into the AT1KM. These measures are then of the raw, un-tuned, antenna system (coax and delta loop) made with my MFJ-259B. According to these measurements, the raw impedances I need to match are more then 10:1 for some of the bands. Indeed, I am close to 24:1 for the low part of 80 but I operate fine in this region using the AT1KM.
> >
> > Should I then assume that the KAT500 will not work for me with my current antenna system? I also noticed that other auto-tuners have similar wider ranges. For example, MFJ-998 supports a matching range of 12 to 1600; and, the old Palstar AT-Auto supports a matching range of 15 to 1500 (now Kessler Engineering). Apparently, the new the new Palstar HF-Auto is reported as 10:1 SWR which may be the same as KAT500.
> >
> > Therefore, can someone (Wayne, Eric or others in the know) confirm that with my current antenna configuration, I will probably NOT be able to use the KAT500 for 80 meters (at least). My options I suppose are not to use the KAT500 at all, not use it for 80, or reconfigure my delta loop (although, my degrees of freedom for this are small).
> >
> > 73, phil, K7PEH
> >
> > ______________________________________________________________
> > Elecraft mailing list
> > Home: http://mailman.qth.net/mailman/listinfo/elecraft
> > Help: http://mailman.qth.net/mmfaq.htm
> > Post: mailto:[hidden email]
> >
> > This list hosted by: http://www.qsl.net
> > Please help support this email list: http://www.qsl.net/donate.html
>
> ______________________________________________________________
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>
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--
R. Kevin Stover AC0H
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Don Wilhelm-4

Re: Question about forthcoming KAT500

In reply to this post by Jim Bennett

Jim,

It has been some number of hours now and we have not heard from Wayne
(likely doing New Year's eve celebration with the family), so I will
attempt to answer from my recall of prior information from Wayne.
First, I believe the KAT500 will have a range as great (maybe greater)
than the KAT3 - so if the KAT3 handles your antenna, the KAT500 should too.

I would also like to say that the stated 10:1 SWR tuning range is not
absolute, but is worst case. The matching range of any tuner is more
limited at low frequencies. For instance, if the tuner can match a 10:1
SWR at 160 meters, it may be able to match a 25:1 SWR at 10 meters. Of
course, that all depends on the resistive to reactive ratio too - all
loads are not equal.

73,
Don W3FPR

On 12/31/2011 4:36 PM, Jim Bennett wrote:
> An interesting question!! And it directly affects my situation, too.
>
> So, here is a slight add-on to Phil's query - perhaps Eric or Wayne can shed some light here. My "main" antenna is an 88' foot long doublet at 45 feet, fed with 600-ohm ladder line, and a 1:1 balun where my eight feet of coax from the K3/100 connects to the balanced line. The K3's tuner gives me a match on this antenna on 80 through 6 meters. I'm a happy camper with this antenna working pretty darn well on all bands, although it is mostly NVIS on 80. So, my question is - how close in performance will the KAT500 be to the KAT3? Can I expect the KAT500 to match this antenna as well as the KAT3 does? I'd certainly NOT be happy to spend the dollars for the new tuner to find that it is not capable of doing what the KAT3 can do.
>
> Jim / W6JHB
>
>
>
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Phil Hystad-3

Re: Question about forthcoming KAT500

In reply to this post by Phil Hystad-3

Follow-up:

Well, I did my own experiment. I forgot briefly that I have a KAT3 which is also described as a 10:1 matching tuner. Well, it does not seem to match most of my bands on the delta loop. So, the KAT500 is not on my to-buy list until I get this antenna fixed to match better. I have a lot of ideas but I am waiting for warmer and dryer weather -- good because the KAT500 should be well tested by the field by then.

73, phil, K7PEH

On Dec 31, 2011, at 12:33 PM, Phil Hystad wrote:

Don Wilhelm-4

Re: Question about forthcoming KAT500

Phil,

You might want to try adding or subtracting some feedline - that is sure
to make some feedpoint impedance change. OTOH, if you now have a
working system, why change? If there is some added value to using the
KAT500 over what you have installed and working, then fine, look at how
to best integrate the KAT500 - but if what you have works to your
satisfaction, then why change.
Don't monkey with what works.

73,
Don W3FPR

On 12/31/2011 6:06 PM, Phil Hystad wrote:
> Follow-up:
>
> Well, I did my own experiment. I forgot briefly that I have a KAT3 which is also described as a 10:1 matching tuner. Well, it does not seem to match most of my bands on the delta loop. So, the KAT500 is not on my to-buy list until I get this antenna fixed to match better. I have a lot of ideas but I am waiting for warmer and dryer weather -- good because the KAT500 should be well tested by the field by then.
>
> 73, phil, K7PEH
>
>
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Phil Hystad-3

Re: Question about forthcoming KAT500

Don,

Thanks for the comments. Actually I have this persistent urge to make my shack as much Elecraft as possible. So, if Elecraft offers it, I generally want to buy it. Therefore, in a few months I will work to modify my antenna to work with the KAT500. Also, this will be done in tandem with my interest in creating some kind of "good" 160 meter solution -- right now, I have a jury rigged setup to operate on 160 which I rarely use because it is a hassle to set up each time -- it is not a permanent solution.

So, this will be the project for the warmer months -- not necessarily drier, just warmer. If I wanted drier I would have to wait until August!

phil

On Dec 31, 2011, at 3:23 PM, Don Wilhelm wrote:

> Phil,
>
> You might want to try adding or subtracting some feedline - that is sure to make some feedpoint impedance change. OTOH, if you now have a working system, why change? If there is some added value to using the KAT500 over what you have installed and working, then fine, look at how to best integrate the KAT500 - but if what you have works to your satisfaction, then why change.
> Don't monkey with what works.
>
> 73,
> Don W3FPR
>
> On 12/31/2011 6:06 PM, Phil Hystad wrote:
>> Follow-up:
>>
>> Well, I did my own experiment. I forgot briefly that I have a KAT3 which is also described as a 10:1 matching tuner. Well, it does not seem to match most of my bands on the delta loop. So, the KAT500 is not on my to-buy list until I get this antenna fixed to match better. I have a lot of ideas but I am waiting for warmer and dryer weather -- good because the KAT500 should be well tested by the field by then.
>>
>> 73, phil, K7PEH
>>
>>

Alan Bloom

Re: Question about forthcoming KAT500

In reply to this post by Phil Hystad-3

I don't know about the KAT500 specifically, but if a tuner is specified
at 10:1 SWR worst case, that means it should meet that spec for load
impedances of any phase angle, 0-360 degrees. I expect it will do much
better than 10:1 at some phase angles.

Years ago when I was working at R. L. Drake, I designed the MN2700
antenna tuner. It was specified for 5:1 SWR. On some bands it barely
made 10 ohms at the low end but it would typically do much better than
that at other phase angles. For example, it would match much greater
than 250 ohms resistive on most bands.

Alan N1AL

On Sat, 2011-12-31 at 12:33 -0800, Phil Hystad wrote:

Rick WA6NHC

Re: Question about forthcoming KAT500

Alan,

Isn't that true of most tuners, that higher impedance is tolerated (matched)
better than low impedance?

If so, that easily explains why a 4:1 (or worse, a 9:1) balun is a bad
choice on a multiband antenna. Such devices might lower the impedance too
much on any given band. It might also explain why they're more lossy.

73 es HNY,
Rick WA6NHC

-----Original Message-----
From: Alan Bloom

On some bands it barely
made 10 ohms at the low end but it would typically do much better than
that at other phase angles. For example, it would match much greater
than 250 ohms resistive on most bands.

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Alan Bloom

Re: Question about forthcoming KAT500

On Sat, 2011-12-31 at 17:14 -0800, Rick Bates wrote:
> Alan,
>
> Isn't that true of most tuners, that higher impedance is tolerated (matched)
> better than low impedance?

That tends to be true, but it really depends on the particular circuit.
For an L-network, like in the Electaft tuners, matching a low impedance
requires a large variable capacitor, which tends to be physically large
and expensive. However, the Elecraft designs use relay-switched fixed
capacitors so that might not be such a big issue.

The Drake tuners used a pi-L network. The bandswitched input pi section
transforms 50 ohms up to a high impedance and the L section (using two
variable capacitors) brings it back down again as needed for the
particular antenna. For that reason, it naturally tends to match high
impedances easily, at least on the higher bands. The bandswitched pi-L
topology has the advantage of better filtering and it is easier to tune
manually, at the expense of a smaller tuning range.

Alan N1AL

> If so, that easily explains why a 4:1 (or worse, a 9:1) balun is a bad
> choice on a multiband antenna. Such devices might lower the impedance too
> much on any given band. It might also explain why they're more lossy.
>
> 73 es HNY,
> Rick WA6NHC
>
> -----Original Message-----
> From: Alan Bloom
>
> On some bands it barely
> made 10 ohms at the low end but it would typically do much better than
> that at other phase angles. For example, it would match much greater
> than 250 ohms resistive on most bands.
>
>