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N6WK
03-11-2004, 05:46 PM
I am about to buy a new antenna tuner that is capable of over 300 watts. (just bought an Amp)
I am considering either the MFJ- 986 tuner which is a "Differential-T" tuner (1 Capacitor and 1 inductor) or the MFJ -989c Tuner which has (two capacitors and 1 inductor.)
Can anyone tell me what the advantages or disadvantages one type has over the other? http://www.qrz.com/iB_html/non-cgi/emoticons/confused.gif
Thanks,
Gordon
N6WK

AL7N
03-11-2004, 07:45 PM
I would expect that your choice would be most influenced
by what kind of antenna(s) systems you want to use it with. What kind of feedlines will be involved? Coax or parallel open wire? What range of impedances you will
have to use the tuner to match to your rig is a big factor, but it all depends on what kind of antenna systems you
will be using it with. http://www.qrz.com/iB_html/non-cgi/emoticons/smile.gif

N6WK
03-11-2004, 08:31 PM
I will be using it currently with my CushCraft R-7000 Vertical using RG/8 Coax.
Currently #I am using the MFJ-969 tuner which is 2 capacitors and 1 roller inductor. It works GREAT.
I can tune 1 to 1 on any band 80 thru 10, but It is only rated at 300 watts so I can't use it with my Amp.
Thanks,
Gordon
N6WK

WD5KCA
03-12-2004, 02:01 AM
</span><table border="0" align="center" width="95%" cellpadding="3" cellspacing="1"><tr><td>Quote (N6WK @ Mar. 11 2004,13:31)</td></tr><tr><td id="QUOTE">I will be using it currently with my CushCraft R-7000 Vertical using RG/8 Coax.
Currently I am using the MFJ-969 tuner which is 2 capacitors and 1 roller inductor. It works GREAT.
I can tune 1 to 1 on any band 80 thru 10, but It is only rated at 300 watts so I can&#39;t use it with my Amp.
Thanks,
Gordon
N6WK[/QUOTE]<span id='postcolor'>
You may not need a tuner with the amp if it is a tube final. I worked a guy the other day that was using his amp as a tuner. If your swr is not too far off, the amp will probably load up ok.

Regardsss,
Charlie Alpha

W8JI
03-12-2004, 12:32 PM
</span><table border="0" align="center" width="95%" cellpadding="3" cellspacing="1"><tr><td>Quote (N6WK @ Mar. 11 2004,10:46)</td></tr><tr><td id="QUOTE">I am about to buy a new antenna tuner that is capable of over 300 watts. (just bought an Amp)
I am considering either the MFJ- 986 tuner which is a &quot;Differential-T&quot; tuner (1 Capacitor and 1 inductor) #or the #MFJ -989c Tuner which has (two capacitors and 1 inductor.)
Can anyone tell me what the advantages or disadvantages one type has over the other? http://www.qrz.com/iB_html/non-cgi/emoticons/confused.gif
Thanks,
Gordon
N6WK[/QUOTE]<span id='postcolor'>
There are only two problems with MFJ tuners. First, they are not truthful about power ratings. Second, they sometimes have QC problems.

A 989C is sized about right for a 600-1000 watt amplifier, although it is called a &quot;3KW tuner&quot;. The peak reading power meter also stinks.

The Differential T has easier adjustment, but handles less power than the 989C. It also has the same very inaccurate peak reading power meter. Other than handling less power and being easier to adjust it is about the same as a 989.

(Most tuner manufacturers exaggerate ratings quite a bit, so you need to be careful taking the ratings at face value&#33http://www.qrz.com/iB_html/non-cgi/emoticons/wink.gif

The Ameritron tuners are much better and are accurately rated. They really work as advertised. I use all ATR30&#39;s here, having long ago retired all my Johnson KW matchboxes in favor of the much better ATR30&#39;s.

73 Tom

WB2WIK
03-12-2004, 07:29 PM
I&#39;ll vouch for the ATR-30 also. With power applied, it contains a good metering circuit and has easily handled anything I&#39;ve been able to throw at it in terms of both RF power and mismatches. After almost 39 years in the hobby (and having run high power most of that time), it&#39;s the only tuner left on my shelf.

Having said that, I rarely use it&#33; I reserve the ATR-30 mostly for field operations when I&#39;m not sure what I&#39;ll be up against and having a tuner available is a lot better than not having one. At home, my antennas are &quot;close enough&quot; for me to achieve full power transfer from amplifier to antenna just using the pi-net or pi-L output circuits in my amplifiers, all of which can easily tune into a 4:1 VSWR on any frequency I&#39;ve tried thus far.

There&#39;s almost no excuse for having a bad antenna match on the higher bands&#33; The R7000 is adjustable and should provide a pretty good match across the higher bands, and at one point on 40. I would think the only band where you&#39;d ever need a tuner using an R7000 would be to extend the frequency range of 40 meter operations.

WB2WIK/6

N6WK
03-12-2004, 09:12 PM
</span><table border="0" align="center" width="95%" cellpadding="3" cellspacing="1"><tr><td>Quote (WB2WIK @ Mar. 12 2004,20:29)</td></tr><tr><td id="QUOTE">#

There&#39;s almost no excuse for having a bad antenna match on the higher bands&#33; #The R7000 is adjustable and should provide a pretty good match across the higher bands, and at one point on 40. #I would think the only band where you&#39;d ever need a tuner using an R7000 would be to extend the frequency range of 40 meter operations.

WB2WIK/6[/QUOTE]<span id='postcolor'>
I don&#39;t necessarily have a &quot;BAD&quot; match. I just like to see a 1 to 1 match &quot;Always&quot;. I know it&#39;s not necessary but it makes me feel better. I don&#39;t want to settle for a &quot;pretty good match&quot;. #
Adjusting the R7000 isn&#39;t all that easy because some adjustments effect two bands at once and therefore you have to have a trade off. #I wasn&#39;t questioning whether I needed a tuner or if MFJ was a good brand. I just wanted to know the difference between the two types I described.
I believe my question has been answered.
Thanks for the input #though.
Gordon
N6WK

WA7KKP
03-16-2004, 05:33 PM
There are three ways to go on that --

Buy a commercial tuner and hope it isn&#39;t, or you don&#39;t arc the capacitors. Most of them are built with enough margin to BARELY handle the power.

Buy a Johnson KW Matchbox. Best for open wire feedlines and they are hefty enough to handle 1KW plate modulated, which is about 4 Kw PEP.

Or just build a tuner. This is the best for longwires. by doing some careful scrounging at hamfests you can come up with a 200-300 pf variable capacitor with enough spacing to handle some power (no broadcast variables) and either a roller inductor or a tapped coil. Build an L match and you&#39;re in business for a Jackson or less.

Gary Hildebrand WA7KKP

WS7X
03-16-2004, 10:51 PM
I can&#39;t speak to the differences between the two tuners but can tell you about my MFJ 989C. Someone else commented that the ratings of tuners are exaggerated and I just wanted to tell you it&#39;s definately true. I have a 600 watt amplifier and thought my 3KW tuner should be able to handle 600 watts&#33; Don&#39;t you believe it&#33; I&#39;ve already learned the hard way, that it is not actually rated to handle the loaded it is advertised for. So, if you&#39;re looking for a tuner to really handle high power, you may want to keep this in mind. Good Luck.

kd6jhv

WB2WIK
03-16-2004, 11:28 PM
Until the Monimatch circuit was published, hams never had any idea what their SWR was, and simply made contacts all over the world, anyway. I think I had about 25,000 contacts and 265 countries or so before I owned my first SWR bridge, back in the mid-sixties.

Amazing how what we don&#39;t know can&#39;t hurt us&#33;

Ah, well....

KC7UP
03-17-2004, 05:17 AM
I have had two tuners in my ham life. First one was a Dentron
1kw and it handled my Henry amp fine. Then had chance to get the current Ten Tec 228 and I like it even better.
Curt

KF3EG
03-17-2004, 06:49 AM
</span><table border="0" align="center" width="95%" cellpadding="3" cellspacing="1"><tr><td>Quote (N6WK @ Mar. 11 2004,10:46)</td></tr><tr><td id="QUOTE">I am about to buy a new antenna tuner that is capable of over 300 watts. (just bought an Amp)
I am considering either the MFJ- 986 tuner which is a &quot;Differential-T&quot; tuner (1 Capacitor and 1 inductor) #or the #MFJ -989c Tuner which has (two capacitors and 1 inductor.)
Can anyone tell me what the advantages or disadvantages one type has over the other? http://www.qrz.com/iB_html/non-cgi/emoticons/confused.gif
Thanks,
Gordon
N6WK[/QUOTE]<span id='postcolor'>
Go to palstar.com they have a good tuner for like &#036;359 that will honestly tune about 1200 watts pep.
They have bigger tuners for more bucks.
My first choise is a Ten Tec 238B, second Palstar.
depends on the power you run.
MFJ I have fried mfj tuners, they make good flower pots after you fry them.
I know of some 989c tuners being fried with a ameritron 811a.
73
Jim

N6ACB
03-17-2004, 06:59 PM
just another opinion . im not an expert on tuners , but have used several . i find that for the money the murch 2000 is a great tuner . used they are about 100&#036; . if it is a clean tuner , you cant go wrong . of course the ameritron &amp; nye viking are the cadallics , but my murch (chevy) does a great job ..... thx steve n6kkk

WB2WIK
03-17-2004, 07:30 PM
Not so sure about the Cadillacs...

I owned two Nye Viking MB-VA tuners that were in the &#036;600 price class (each) and rated legal-limit power, and in my operations I was able to successfully let all the smoke out of both of them. They both failed badly when used with a common inverted-L operated off resonance on 160 meters.

Lucky for me, some guys really like these tuners so I sold them for almost as much as I paid for them. No great harm, other than one MB-VA exploding caused me to miss about 30 minutes of the 160 meter contest, once.

WB2WIK/6

N6WK
03-18-2004, 09:40 PM
</span><table border="0" align="center" width="95%" cellpadding="3" cellspacing="1"><tr><td>Quote (WB2WIK @ Mar. 17 2004,00:28)</td></tr><tr><td id="QUOTE">Until the Monimatch circuit was published, hams never had any idea what their SWR was, and simply made contacts all over the world, anyway. #I think I had about 25,000 contacts and 265 countries or so before I owned my first SWR bridge, back in the mid-sixties.

Amazing how what we don&#39;t know can&#39;t hurt us&#33;

Ah, well....[/QUOTE]<span id='postcolor'>
Some say this is #true, but once we know, Things are different from that time forward. Also, &quot;what we don&#39;t know&quot; can in fact sometimes hurt us.
Just think, had you known, you might have made 25,001 contacts and made 266 countries. #http://www.qrz.com/iB_html/non-cgi/emoticons/biggrin.gif

WB2WIK
03-18-2004, 11:42 PM
I think required reading for anyone contemplating buying an antenna tuner, or installing an antenna of any kind, should be Walt Maxwell W2DU&#39;s book, &quot;Reflections.&quot;

Especially its famous chapter entitled, &quot;Too low an SWR can kill you&#33;&quot; That was absolutely great. Not to mention absolutely true.

I think the book is still published, and available from the ARRL Bookstore as well as retail distributors and Amazon.com. Great book.

WB2WIK/6

N6WK
03-19-2004, 04:53 PM
</span><table border="0" align="center" width="95%" cellpadding="3" cellspacing="1"><tr><td>Quote (WB2WIK @ Mar. 19 2004,00:42)</td></tr><tr><td id="QUOTE">I think required reading for anyone contemplating buying an antenna tuner, or installing an antenna of any kind, should be Walt Maxwell W2DU&#39;s book, &quot;Reflections.&quot;

Especially its famous chapter entitled, &quot;Too low an SWR can kill you&#33;&quot; #That was absolutely great. #Not to mention absolutely true.[/QUOTE]<span id='postcolor'>
Thanks, I&#39;ll check it out.

Is there an hidden implication that Hams don&#39;t need SWR meters? Or that we don&#39;t need to know what our SWR is?

My original question was not whether I needed a tuner or not or if I needed to know my SWR.
I prefer to know my SWR. Plain and Simple.
My question was What is the difference between the two types of tuners that I listed in my original post.
http://www.qrz.com/iB_html/non-cgi/emoticons/confused.gif

WB2WIK
03-19-2004, 08:04 PM
N6WK: No sweat, and completely understood. But as always, when a question&#39;s asked, be prepared to get answers that aren&#39;t necessarily related to your question, and screen out whatever information you don&#39;t want.

Especially with the internet&#33;

Yes, personally I would surely imply that SWR bridges/meters have done a world of harm to the amateur radio hobby, in a variety of ways. They are actually fairly recent inventions, in the grand scheme, and have only been available and in popular use for about 40-45 years. Ham radio&#39;s been around for almost 100 years, so there were no SWR bridges for more years than there have been same.

The reason they &quot;hurt&quot; the hobby, in my opinion, is that so many hams, especially newbies who really don&#39;t know any better (and can&#39;t blame them&#33http://www.qrz.com/iB_html/non-cgi/emoticons/wink.gif, will tune and prune antennas to achieve the lowest possible VSWR, despite the fact that the original antenna, prior to tuning, was actually more efficient and a better performer. So, by all their work, they have hurt themselves by now having a weaker signal than they could have had, had they simply ignored SWR.

Worse still, many hams actually believe that SWR and antenna efficiency or performance are somehow related, when of course they&#39;re not. So, I hear people say, &quot;Hey, my new antenna has a 1:1 SWR, and I&#39;m so happy it works just fine,&quot; when they really should be suspicious of such a low SWR. A 1:1 SWR on anything other than a dummy load or an antenna fed with no transmission line is always suspect, because more times than not, something&#39;s wrong that&#39;s creating such a great match. Dissipative loss is the main culprit. If you have a lossy feedline, your SWR will always be perfect, because the reflected signal will be completely dissipated by the line and always measure zero. That doesn&#39;t mean the antenna&#39;s working, or even conducting any current.

If you have an antenna that exhibits a nice, low VSWR across most of the width of an amateur band, other than possibly the 30 meter band (or maybe the new 60 meter &quot;channelized band&quot;), something&#39;s wrong. A very broadband impedance match nearly always indicates power lost, and reduced radiation.

WB2WIK/6

N6WK
03-19-2004, 10:04 PM
</span><table border="0" align="center" width="95%" cellpadding="3" cellspacing="1"><tr><td>Quote (WB2WIK @ Mar. 19 2004,21&#60;&#33;--emo&amp;http://www.qrz.com/iB_html/non-cgi/emoticons/wow.gif)</td></tr><tr><td id="QUOTE">N6WK: #No sweat, and completely understood. #But as always, when a question&#39;s asked, be prepared to get answers that aren&#39;t necessarily related to your question, and screen out whatever information you don&#39;t want.
WB2WIK/6[/QUOTE]<span id='postcolor'>

Thanks Again, I&#39;m learning the filtering process.


</span><table border="0" align="center" width="95%" cellpadding="3" cellspacing="1"><tr><td>Quote </td></tr><tr><td id="QUOTE">If you have an antenna that exhibits a nice, low VSWR across most of the width of an amateur band, other than possibly the 30 meter band (or maybe the new 60 meter &quot;channelized band&quot;), something&#39;s wrong. #A very broadband impedance match nearly always indicates power lost, and reduced radiation.[/QUOTE]<span id='postcolor'>

This would be the reason I am using an antenna Tuner.
Thanks,
#Gordon
N6WK

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