True balanced line kW tuners for 160-10?

[KG4NEL]

Hey all,

I'm in the planning stages of putting up a "real" HF antenna at my QTH...tired of lousy signal reports from an indoor compromise thing, and missing out on the lower bands.

I'm thinking of a 100' sloping wire from the 2nd-floor window of my shack, tied off to the corner of a rose fence in the yard. The counterpoise will be 100+ feet of wire hidden in the rain gutter around the front 3 sides of the house. Going to be running these to a LadderLoc insulator at the window, and about 25' of Wireman ladder line to the tuner. And there's my question.

Where are all the kW-rated balanced line tuners for 160-10? I've heard good things about the Johnson kW Matchbox, but it doesn't seem to cover 160 without mods. Palstar also makes one, but I haven't really talked to anyone who uses it. B&W made one that looks like a tank, but I know next to nothing about whether it's worth hunting down. Not really interested in the modern MFJ offering.

Are you guys with high-power balanced line setups all using homebrew ones?

Thanks in advance!

Jim
KG4NEL

[flintstone mop]

Hi Jim
One of the better HB tuners some of us have built is called the K1JJ (Tom) tuner.
I posted a picture of mine and the link will get you to the ones others built several years ago.

Can't beat it and simple. Perfect for open ladder line.
A.M. mode and 160M become very demanding on the entire antenna system.

http://amfone.net/Amforum/index.php?topic=10989.0

Good luck

[k4kyv]

Probably better to homebrew a custom tuner for your situation.  The commercial ones, including the Johnson Matchbox, are by necessity compromises.

I prefer to use a separate custom-designed tuner for each band and each antenna. Changing bands and/or antennas is a matter of rotating a selector switch.

[KG4NEL]

That's great, lol.

"All ahead full...oh wait, QSY to 40M"

[KM1H]

Fred, you must be running QRP, that PVC pipe hasnt melted

I got 2 questions..

Whats a tuner and whats balanced line

[ve6pg]

..yup..build the 'jj tuner...i did, and no regrets....copper tubing, good cap, and away you go...make ur own ladder line as well..cheaper, and well worth the effort...

..tim..

..sk..

[stevef]

In the process of building one here - at least the layout and parts gathering phase.  There appears to be some variations of the K1JJ tuner - some use a split-stator cap and others not.  Also, I saw a version where the capacitor connects to the coil ends and the feedline taps toward the middle of the coil, others do the opposite and connect the feedline toward the outer ends of the coil and capacitor more toward the middle turns.

What are the pros/cons of these variations?

[K1JJ]

Steve and Jim,

Here's more info with the schematics for both series and parallel tuning.  What you are probably referring to is the need for a low impedance and a high impedance match. Steve/K4HX  shows (in the first post) schematics on how this is done by tapping nearer the ends or nearer the center of the coil, etc.  You will use parallel config for most work (high impedance matches)  and series config for the remaining needed low impedance matches.

By leaving the whole tuner "tap-able" you will be able to handle most any matching situation on any band using a single open wire fed antenna.

BTW, if possible, try to make your antenna center fed and balanced, for best results.

http://amfone.net/Amforum/index.php?topic=18054.0

Have fun.

Tom, K1JJ

[aa5wg]

Hi Jim:

I ordered the same cores that are used in todays "balanced" antenna couplers.  Homebrew baluns from these cores were tested in the above coupler design(s).  It became evidednt these couplers were not quite balanced.  

At times, some baluns became hot and there was non-balanced current distribution along the tested antenna systems.  At times some of the rollers inductors would arc.  The above negatives did not happen all the time because I was testing both good and poor antenna system layouts.  My power was about 120-85 watts output, 160 - 10 meters.  

Some times off the shelf coupler designs work good but they are not as forgiving as the link coupler when it comes to challenging antenna system lengths.  The Link Antenna Coupler, Universal Link Antenna Coupler or K1JJ tuner eliminate todays antenna coupler design weaknesses as described below.

If you build the link antenna coupler without an antenna swithch, balun, roller inductors and antenna relay then your balanced coupler has eliminated the greatest threats of arcing, heating and non balanced distribution of current.  That is not to say you can't arc one of your capacitors.  That can happen with most coupler designs attempting to work with an antenna system length that is challenging and with capacitor plate spacing to small to handle this antenna system length.  And, it is possible to have non balanced current distribution if your antenna system is built incorrectly, i.e. antenna system is coupling to other objects.  

On the whole, the link antenna coupler offers more bang for the buck.  It is a proven tool.

With link coupling you have a half a dozen or more circuits to choose from.  Off the shelf couplers are usally limited to one or two circuits.  And, Walt, W2DU, found that the differential output capacitor type cirucit, Johnson Matchbox, did not work as addvertised.

Search W2DU within AMFone.com and you can read more about this.

Jim, if you build the link coupler with "traditional" circuits you will have the very best in terms of a balanced antenna coupler.
73,
Chuck

[K5UJ]

A KW Matchbox is FB for a center ladderline fed dipole 80 - 10 m.   the honest truth is that any ham who tries to get one single dipole to perform well 160 to 10 m. is kidding himself.  You simply cannot cover all of HF and 160 well with one antenna.  The laws of physics are against you.   you need two 1/2 wave dipoles at a minimum, one for 80 and 40 and one for 20 to 10.   The KW Matchbox will get you on the WARC bands with these.   What about 160?  Unless you can get a dipole up at a minimum 100 feet on that band, and 140 is better, you are better off working against ground with an inverted L or 1/4 wave hot tower, or something shut fed and use coax and an unbalanced L network tuner and lots of radials.   OTOH if you are one of around 5 AMers in the US with the support(s) for 160, then homebrew a big copper pipe coil K1JJ link tuner and bury everyone's meter.

BTW, those non-link coupled balanced tuners can exhibit problems depending on your location, with out of band RF coming in on them because of the direct continuity between the balanced feed and the coax.

These are the simple honest truths or, you can join the ranks of thousands on 160 who have dipoles at 30 feet and who are both piss weak and in denial.

Rob

[W2VW]

Roller inductors are for kids.

[K3ZS]

Along the line of this topic, I have a question regarding link coupled balanced line tuners.   I have a bunch of the TVL transmitter type output plug in coil assemblies.   Are these suitable for use in a link coupled tuner for their respective bands?

[aa5wg]

Stevef:

When there is a high current loop near the antenna coupler ladder line connection, this is a low impeadance point i.e 200 ohms or much less.

For the above, set your link coupler for series tuning such as:

1. connect your output tank capacitor (one capacitor) in the middle of the output tank coil.  By doing this you mechanically now have two smaller tank coils with the output tank capacitor in series with the left and right sides of this coil.  One half of the ladder line is tapped on the left coil and the other half of the ladder line is tapped on the right coil.  Depending on the band in use determinds the placement of the taps.

2. or, (when using two capacitors and one tank coil) connect one capacitor rotors to the the left side of the tank coil and another capacitor rotors to the right side of the tank coil.  One half of the ladder line is connected to the stator of the first capacitor and the remaining half of the ladder line is connectied to the remaining capcitors stator.

The rotors are tapped to the coil at different locations depending on the band in use. 

These are two means of series tuning a low impedance point on the line with the link coupler.
Some one jump in hear is I got my rotors and stators mixed up.

Parallel tuning is prefered if there is a high impedance point at the coupler ladder line connection point, i.e. 200 ohms or much greater.

73,
Chuck  

[K5UJ]

Along the line of this topic, I have a question regarding link coupled balanced line tuners.   I have a bunch of the TVL transmitter type output plug in coil assemblies.   Are these suitable for use in a link coupled tuner for their respective bands?

It should work--I would connect the swing link to your unbalanced input with it across the center to ground and then the far ends of the TVL to the balanced feeder path (with your cap(s) parallel across the feeders).  I'd connect the inner TVL ends together.  That is the arrangement I'd start to experiment with and have the swing link half meshed.  Once you get close to a match you could move the link in and out to see what that does for you.  

The only problem I see is that I don't think the TVL will handle much power as they were used in < 200 w. rigs if I am not mistaken but maybe you are not running a big maul so it is okay.

rob

[k4kyv]

Another advantage to the TVL and HVL coils is that you can use those inner connections for series tuning, without the need for two separate tuning capacitors.  Just use a split stator as you would for parallel tuning, and connect the OWL between the inner terminals, which are normally strapped together.  I once modified a set so they would be self switching between series and parallel tuning when I switched coils to change bands.

I did find that sometimes the commercial coils have too many turns to get high enough Q to allow the transmitter to load fully. I removed a few turns at each outer end of the coil and it worked perfectly.  You could also short them out if you didn't want to permanently alter the coil.

[Detroit47]

Not wanting to steal the thread but I got to ask. I have 126 ft center fed dipole I'm running one of the true ladder line things. If I build a tuner that will handle it will I be able to talk on 160. My dipole is about 30 feet off the ground. I have no room for a vertical this reads no room for ground radials. I hate when all the fun is on 160 and I’m not.

John N8QPC

[aa5wg]

N8QPC:
For testing I have a short (height) 75 meter center fed inverted V using open wire feeders.  It works well on 160 with the link antnna coupler.  The appex is 40 feet up.  For 160 this particular antenna is effectivly (almost) on the ground.  This antenna system cannot compete with the big antenna farms regarding DX.

Chuck

[flintstone mop]

Fred, you must be running QRP, that PVC pipe hasnt melted

I got 2 questions..

Whats a tuner and whats balanced line

Hey Carl
I run legal limit A.M. and there was more at one time and no problems with any heating whatsoever with the PVC. The coils barley get warm after an ole buzzard

I'm pondering the two questions. They may be traps....oh boy another antenna term.
Fred

[K3ZS]

Tnx Don and Rob on your comments about TVL coils.   I actually have the KW versions along with a huge bread slicer variable that was used with them.   I'll try them out.

[Ralph W3GL]

   The versions of the B&W jack bar mounted variable link, center taped
    coil line were, as I recall, BVL = 75 Watts (5 pin tube style base), TVL =
    150 Watts, DVL = 500 Watts and HDVL = KW...

    These were a group of 5 coils; 160 through 10 meters ( before we were
    given 15 meters). I assume B&W produced a 15 meter unit in their later
    production runs...

     I still have my 80 to 10 meter HDVL's and am using the 80 in a clip lead
     series tuned setup on my CF Zepp on 80 meters.
     
     For some reason the plastic on my set is still in good condition, perhaps
     because I purchased mine in the late 40's when plastics were much
     improved over pre-WW2  stocks
   

[WA1GFZ]

a single antenna will cover all bands with the right tuner BTDT
KB3AHE runs 160M with his folded antenna 66 feet long.

[The Slab Bacon]

a single antenna will cover all bands with the right tuner BTDT
KB3AHE runs 160M with his folded antenna 66 feet long.

For anyone interested, here is a sketch of it.

It works reasonable on 160, but it straps on 75 and 40

[W2VW]

A 120' center fed dipole used on 160 will have a low radiation resistance and some reactance which will need to be matched.

Coupler, feedline and dipole conductor sizes should be made large to keep resistive losses low.

Certain feedline lengths can help transform to easier values for the coupler but it can still be a bit of work to keep the R.F. from turning to heat.

If you land up with 8 ohms -j2000 at the coupler expect feedline current to be at least six times what it is at the 50 ohm port of the coupler.

At  800 watts that figures out to be 24 amperes.

To put it into perspective 14 amperes is what one would expext in a 50 ohm system at 10,000 watts.

[KG4NEL]

Thanks, guys. Just put an order in for 130ish feet of 18awg CCS...I'll try the center-fed approach with the feedpoint at the house. Lowest point of the antenna would be 25', highest would be 60'.

Just a random question - I know the WA1FFL "Ladder Lock" insulator is the "commercial" version, but what else have you guys tried for a ladder line center insulator? Seems harder to find than the SO239 version. Thanks!

 

[aa5wg]

Hi KG4NEL:
Here is a YouTube link on home brew center insulators for home brew ladder line.  Hope this helps.
Chuck
http://www.youtube.com/watch?v=qzFKGB6qkXs