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Re: [TenTec] OT: Question to the group

To: Discussion of Ten-Tec Equipment <tentec@contesting.com>
Subject: Re: [TenTec] OT: Question to the group
From: Gary J FollettDukes HiFi <dukeshifi@comcast.net>
Reply-to: Discussion of Ten-Tec Equipment <tentec@contesting.com>
Date: Mon, 18 Jul 2016 09:54:31 -0500
List-post: <tentec@contesting.com">mailto:tentec@contesting.com>
Of course, my Siamese cat-tenna will only operate in the “Morris Code” portion 
of the bands.

LOL

Gary



> On Jul 18, 2016, at 9:14 AM, rick@dj0ip.de <Rick@dj0ip.de> wrote:
> 
> Hi Gary,
> 
> I found time to come back in and continue addressing more of the points.
> 
> Nothing is wrong with the resonant antenna.  It is what I have used quite a 
> lot over the years.
> We are on the same page here. However it is wrong to believe that only 
> resonant antennas can be efficient.  Maxwell clearly points that out, as does 
> Cevik.
> 
> I was only saying that people often are forced to use non-resonant antennas 
> due to space limitations and that the JVM (in standard format) is not the 
> best matchbox for that.  
> 
> I was in full concert with you on all points, except ... and maybe it wasn’t 
> even you who said it . . . it was claimed several times that the JVM was the 
> greatest matchbox ever.  It was great in its days, but had weaknesses later 
> as we got more bands and people began to match funny things with them.  At 
> least one company (Annecke) improved on the design and sold them.  It was 
> distinctively better.
> 
> But wait, W6SAI published an article showing how to do that, something like 
> 50 years ago.  That's where I "borrowed" the idea, then applied it to the JVM 
> and improved it and published instructions on how to d-i-y. 
> 
> I went to great length to explain and show people how to remedy this and many 
> people have applied my mod to their JVM.  I continue to get thank you emails 
> for the work from people who have successfully done the mod.
> 
> I am a firm believer in link coupler matchboxes and have a couple of pages on 
> my web showing people how to build their own simple, dirt cheap link coupled 
> matchbox.  But I have altogether 4 different circuits for 4 different 
> applications. 
> Each fits a different set of circumstances where it works, but it fails 
> everywhere else.  It is difficult to put them all in one box and the high 
> power switch would cost a small fortune.  So I make different proposals for 
> people confronted with different tough environmental situations . . .  such 
> as how to get a relatively efficient power transfer into a short 20m (66 ft.) 
> long (or even shorter) dipole on 160m.  
> 
> I love quads and loops much more than dipoles. 
> I began feeding them with open wire back in the 1970s, using the Annecke 
> Symmetrical Coupler, which was the matchbox that is an improvement over the 
> JVM.  Except mine was home-brew using spare parts I purchased directly from 
> Annecke. 
> 
> HOWEVER THE FACT REMAINS:  THERE AREN'T ENOUGH JVM's to go around if everyone 
> wants one.
> Even if you are lucky enough to find one, you often find them "melted" on the 
> inside.
> Therefore some kind of alternative is required.
> 
> A much less quality but very practical solution is to use a good 1:1 Guanella 
> balun between a simple L-Network and the openwire.  That's "1:1, not "4:1".  
> I often use the Model 238 like this.
> Especially with low power (100w or less), this can be a good substitute.  
> 
> In my 45 years of living on this side of the pond, I have never once seen a 
> JVM for sale on the used market.  The ANNECKE I speak of was great, but 
> Alfred Annecke built and sold exactly 20 units.  I built my own.  So there 
> are perhaps 21 units floating around somewhere in the world. Won't find one 
> of those either.  So most people must seek or build something else.
> 
> Now to your two cats and the JVM.
> I built something similar using two galvanized trash cans.
> You can find a picture here: 
> http://www.dj0ip.de/antennas/ 
> Pictured is one version which I fed with a short coax.
> 
> I'll put that up against your Siamese cats any day! (hi)
> 
> Cheers Gary!
> 
> 73
> Rick, DJ0IP
> 
> 
> -----Original Message-----
> From: TenTec [mailto:tentec-bounces@contesting.com] On Behalf Of Gary J 
> FollettDukes HiFi
> Sent: Monday, July 18, 2016 9:42 AM
> To: Discussion of Ten-Tec Equipment
> Subject: Re: [TenTec] OT: Question to the group
> 
> 
> 
>>> Stating individual cases where something worked proves nothing.
> 
> Well, actually it does. As I pointed out, with a RESONANT cubical quad, 
> driven with 470 Ohm Dentron parallel line, I got a perfect match on 20, 15 
> and 10. This was an efficient antenna with efficient feed lines and an 
> efficient (in this application) tuner. It was positioned quite a long 
> distance from the transmitter so the lower loss parallel feeling was of some 
> advantage.
> 
> Better would have been the use low loss ceramic spacers and true parallel 
> ladder line. However, the Johnson matchbox would have worked equally well in 
> that application, whereas the autotuners and most of the T match tuners 
> wouldn’t have worked at all without an external BALUN.
> 
> Since my radio at the time, a Drake TR7, had pretty good low pass filters 
> within, I was not too concerned that the Matchbox offered no such lowpass 
> filtering.
> 
> Even more important than the match is the near-perfect balance of currents on 
> the line (as you mentioned). Two bad things happen when the currents on 
> “parallel” lines are not balanced. Your noise level on receive goes up since 
> the feedline begins to act as part of the antenna and your chances of getting 
> the Worked All Neighbors award in transmit also goes up dramatically as the 
> feed line begins to radiate where you do not want it to radiate.
> 
> Nothing matches everything. Nothing even works well for everything. Devices 
> like this need to be matched to the application. I only sang the praises of 
> the Johnson because it did indeed work with every application in which I used 
> it.
> 
> Nothing else did as well…
> 
> As I said before, improvement is always welcome and what you discuss in terms 
> of such improvements is great. Why does this become contentious?
> 
> A little humor, if that’s allowed:
> 
> I once got a perfect match with a Johnson Matchbox using two cats as an 
> antenna, with alternately polarized mice as spacers for feed line made of old 
> violin strings (catgut).
> 
> Of course, they were Siamese cats… It was, after all, a balanced dipole…
> 
> April fools...
> 
> 
> Beyond that, what is wrong with resonant antennas? Where is the advantage of 
> a non-resonant antenna? Nikola Tesla clearly showed the inherent advantages 
> of resonant loads 120 years ago… They are pretty easy to match too!
> 
> 
>> On Jul 18, 2016, at 1:09 AM, Gary J FollettDukes HiFi 
>> <dukeshifi@comcast.net> wrote:
>> 
>> I’ll just stay with resonant antennas…
>> 
>> Gary
>> 
>> 
>>> On Jul 18, 2016, at 12:48 AM, rick@dj0ip.de <Rick@dj0ip.de> wrote:
>>> 
>>> Stating individual cases where something worked proves nothing.
>>> I've had half a dozen cases where it did not work and other matchboxes did.
>>> 
>>> In order to gain clarity on this, you must try it with all kinds of 
>>> antennas; resonant antennas, long antennas, short antennas, odd sized 
>>> loops, etc.
>>> 
>>> What the Johnson does well is push equal amounts of current into both 
>>> wires of the feedline with relatively high efficience, if and only if 
>>> it finds a match.
>>> What it does poor is match over a very broad matching range.
>>> 
>>> You don't have to trust me; try it as I have and compare it to an 
>>> MFJ-974 or MHF-976.
>>> 
>>> OR... simply read the ARRL test report where the ARRL shows several 
>>> balanced matchboxes and their matching ranges, including the JVM.
>>> 
>>> Now I guess I have to go research the issue it was printed in because 
>>> it's probably too much work for some of the readers.
>>>> "A New Generation of Balanced Antenna Tuners", by Joel Hallas, W1ZR, 
>>>> QST
>>> September 2004. 
>>> 
>>> OR, simply do what I have said her MANY TIMES, go to my web site, 
>>> find the page on MATCHBOX-SHOOTOUT And read the page, plus download 
>>> the file at the bottom of the page.
>>> THERE you will find a nice colorful Excel spreadsheet comparing the 
>>> matching range of the various matchboxes.
>>> THERE you will see that the JVM was indeed limited in matching range.
>>> 
>>> THEN go read my web page on how to fix it.
>>> 
>>> AND THEN YOU WILL HAVE THE BEST MATCHBOX EVER!  ;-)
>>> 
>>> 73
>>> Rick, DJ0IP
>>> 
>>> 
>>> -----Original Message-----
>>> From: TenTec [mailto:tentec-bounces@contesting.com] On Behalf Of 
>>> Carter
>>> Sent: Saturday, July 16, 2016 9:32 PM
>>> To: tentec@contesting.com
>>> Subject: Re: [TenTec] OT: Question to the group
>>> 
>>> On 7/16/2016 10:13 AM, Carter wrote:
>>>> On 7/15/2016 6:59 PM, Jim Allen wrote:
>>>> 
>>>>> I had one of those [135 foot dipole fed with ladder line], not at  
>>>>>> 60', about half that.  CC&Rs and all that.
>>>> 
>>>> The exact setup I've got, also at 30 feet.
>>>> 
>>>>> What is a "well designed truly balanced antenna tuner?"  From what  
>>>>>> I've read, there aren't many.
>>>> 
>>>> Johnson Matchbox, kW or 275 watt version, not "perfection" but 
>>>> certainly very good -- and readily available at a fairly modest price.
>>>> 
>>>> Just my 2 cents...
>>>> 
>>>> Carter   K8VT
>>>> 
>>> 
>>> Sorry, forgot to mention it earlier...
>>> 
>>> Not to say my Johnson kW matchbox is the "best ever"; however, it 
>>> works flawlessly  with my FT1000MP and 135 foot ladder line fed 
>>> dipole on ALL (including WARC) bands. Worst case is 2.1:1 on 30 
>>> meters, all other bands 1:1.
>>> 
>>> Carter   K8VT
>>> 
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