The AM Forum

Got all motivated on the Noon Time Forum today to get on 160.  Five minutes after the net shut down, I discovered that my Heathkit SA 2040 never heard of 160.

My antenna is an 80 meter dipole fed with 400 ohm ladder line which works pretty well on all HF bands but 160.

Question is, is there some simple way to modify this thing for 160?  Padder Caps?  Is there such a thing as a padder inductor?

js

Do a search on this forum for "K1JJ Tuner", for one that fits your situation.   You may need series instead of parallel tuning depending on your feedline length.

I could double the inductor and capacitor values on your present tuner, but you probably don't have the space for the inductor.

I love the simplicity of the K1JJ tuner but seems like it would be at least 3 feet long if made with 3/8" tubing.  A bit overkill for a couple hundred watts?

js

Try Rich Measures Balanced Balance Line tuner. I know a few guys that built it and are very happy with the results. Click on the URL.

http://www.somis.org/bbat.html (http://www.somis.org/bbat.html)

I've been running a balanced balanced tuner since '83 a few years before measures invented it. You need a pair of matched inductors which is the hardest part. No link so less stuff to mess with.
You can use fixed inductors. I run a pair of broadcast 22 uh variable inductors. I designed mine while sitting in my LA apartment back in '81
It produces the same feeder current as my KW flash box on 75.
ALL in what's in ur junk box.....

I use the balanced link-coupled tuner with split stator capacitor.

To use an 80m dipole on 160, the total length of one leg of the dipole plus the length of the feedline needs to be approximately some multiple of a quarter wavelength,  roughly 130 ft.  Use the handbook formula for the exact length for a given frequency. If that total length is near an odd multiple of a quarter-wave, 130, 390, ect. you need to use series tuning.  If it is near an even multiple, 260, 520, etc, you will need parallel tuning.

You want to avoid any length that is close to an odd eighth wavelength.  That length will be highly reactive and difficult to tune, and once you do get to resonance by tapping down on the coil, chances are the efficiency will be low, and even a wide spaced capacitor may arc over on modulation peaks.  I once had a BC-610 plate capacitor to arc over with only 100 watts carrier output.

The most convenient way to set up series tuning is to split the coil precisely in half, and feed the low-Z load at the break in the coil.  Otherwise you will need two separate capacitors, one on each side of the coil.

If an odd eighth wavelength is unavoidable, you will need a separate tuning  device (series coil or capacitor in each leg of the feedline, balanced pi-network, etc) to tune out the reactance, and then feed that to the balanced tuner.  In mine, I use an extra 60 ft. of feedline strecthed out between two posts to gain the extra length to  make it come out even.  I call it my "tennis net" since that's what it looks like from a distance.  I just switch in the extra feedline if I want to load the 80m dipole on 160.

I wouldn't recommend tying the feeders together and working the antenna against ground as a vertical tee unless the feedline goes almost straight up vertically and you are able to install a good radial ground system. 

The dipole should be at least 60 ft. high to get good results if you feed it as a quarter wave dipole.

My 110' high 80m dipole works well all over north america when fed as a short dipole on 160, but beyond about 100 miles, the quarter wave vertical works better, head and shoulders above it.  But in Nashville, which is about 50 miles away as the crow flies, the short dipole is about 30 dB stronger than the vertical, making enough of a difference whether or not my signal is above the line noise and other urban electromagnetic smog.

JS,

Try adding a manly 45 uH coil in series with the output of the tuner and see if that does the trick.

Also the antenna system may be unbalanced.  Since the tuner is an unbalanced tuner, try the feedline connections both ways.

How long is your transmission line by the way?

I use my SA-2060 on 160 meters all the time with my BC-610. I do however have a full size 160-meter antenna up. I use 450-ohm window line. I had to increase the length of the window line to 265 feet. Originally I had about 100 feet on it but the tuner got hot. Now it is cool as a cucumber at lunchtime. Do you have room to increase the size of your antenna?  It doesn’t arc over like it did with the shorter length of feed line.

I agree with you about a couple hundred watts, but it is a very nice heavy duty tuner with low losses at 160M. Very easy to build too. BUT IF your 80M antenna is already shortened for your property, your have another problem. Do you have space for an inverted "L"?? Hows about a vertical? Cushcraft makes a nice vertical that won't eat you alive$$$$
Fred

Maybe time to reconsider the antenna instead of tuner.

I have acres and acres but the problem is trees and a full sized 80 meter dipole was a real challenge.

An idea of the problem can be seen at:

http://schmidling.com/obs.htm

I am open to ideas of a 160 ant that would fit.

js

Hmmmm a very nice QTH for growing antennas!!!
I had the same situation with thick trees at my last QTH in Maryland. You will have to wait for the leaves to fall from the trees and then you'll see the path for the antenna.
I wanted my antenna up as high as possible so, I had a tree surgeon do some maintenance on the property and with his guys up in the trees, they installed a 3/8 wave dipole fed by open ladder line. It was 90 feet on each side of center, 100 feet high, and would tune with a BLISS tuner 160-10M. The BLISS tuner had developed a bad spot in his patented coil, and the "company " did not make that coil assembly any more, sooooo I built the K1JJ tuner. The days of forking out $600 for things have come to a stop.
I found out I could do just as good as the tree guys by using a sling shot. The tree guys used strong anchors and marine type pulleys to secure the ends. Hurricane force winds and Winter storms never took down any antenna at that QTH.
Fred

If you have 2 tall (65') trees, an inverted L is the best, cheap, fast 160 antenna (IMO).

I just put one up & it works good, much better than the 300'+ doublet it replaced. I made mine 80x80 & feed it in the center as a balanced (no radial) antenna.

I would go with the wrist-rocket and fishing line. At my one QTH, I didn't have quite the configuration for a 160M dipole but I could accomodate a 160M cloud burner. Using the slingshot, I was able to thread wire up and through branch I wouldn't dare try to get to. I had a lot of success with that aerial. Sewing it through tree branches isn't as hard as what you think. Of course, your milage may vary.

Terry,
So the center fed inverted L works. I wonder what you are using for a tuner. Also have you tried it on 75? What is the feed line and how hard is it to resonate. What is the tuner? frank

Until I get some heavy coax run the roughly 300 feet from the vintage gear "shack" in the house to the Hy Tower and 4 element quad in the pasture I am using my 75 meter full wave horizontal loop on 160 by shorting the coax at the transmitter end and feeding it as a T.  I use a homebrew  reversible L network as a tuner so that the loop can be used on all bands.  The tuner is straightforward; the coil is a large roller inductor originally used in a Gates broadcast transmitter and the capacitor is a 1500pf vacuum variable, total cost for all components including the two turns counter dials was under $200 via hamfest shopping.  I use one of the tap switches out of a BC-375 for reversing the L, I mounted another to add fixed capacitance in parallel with the vacuum variable but I have not needed that with the loop on 160.  I have used the tuner with a Drake TR-7A/L-7 on 160 and with my Desk KW and Viking 500 on the other bands and there has never been any problem with heating or arcing.

If you are using an inverted L for 160 the easiest way to tune it is to make it a bit long at the desired frequency and feed it with a capacitor in series at the base of the L to tune out the inductive reactance, a few feet of RG-8 or RG-11 will make a fine capacitor for this purpose just be sure to skin the shield back a little bit on the disconnected end and seal it or you will get some nice fireworks when approaching the legal limit.  I have the Hy Tower set up as an L on 160.  So that I can run the legal limit on 160 instead of using either of the Hy Gain factory options I made a 10 foot  additional stub with a 40 meter trap (also homebrew) in the stub base mounted to the top of the BX tower portion of the Hy Tower.  From this I run the horizontal part of the L to the Rohn 55 supporting the quad.  Again using one of my favorite tap switches (available cheap from Fair Radio) I have 3 "coax capacitors" at the base feed set to select different 160 meter band segments, another tap switch allows selection of 5 different 80/75 meter segments using a coil made of copper tubing feeding the 75 meter element.  At some point soon I will probably replace these tap switches with some "strapping big relays" so that I can remotely select different band segments.

Rodger WQ9E

frank,

Yes it works.

I'm using cheap, store bought ladder line & HB link coupled tuner.

I had to play with the feed line length to get it to load on 75. 40' feed line works out OK.

It loads up on 20, 40, 75 & 160. Seems to work best on 40 but I've gotten good reports on 160 & 75 also. (100 watts) No good for 20 DX.

I may put up a 2nd, shorter one  (40 x 40) for the higher bands.
 

Terry,
Why not post your results in the antenna section. I've read the Cebic article a nunber of times and came away thinking it was cool. Also years ago an old Signal Corps friend suggested the same antenna and claimed the same results.
This could go into Steve's 160 meter antenna section. I would be interested in the tuner settings L,C,Link etc. I wonder if you could hang a couple of them off a common coax. fc

Will do (eventually). Right now I'm getting ready to head South for the winter. Heading out this Sunday so no time to play radio. I'll put my 40 x 40 version up when I get situated in SC & give you a full report. No big trees down there for the 80 x 80.

Terry