160 meters on a small lot

[N6YW]

Someone mentioned on my Globe King thread about using an inverted L on my small 90' ft. lot here in the Venice Canals. Perhaps 30' ft. up and 70' ft. long. Make up the difference with an auto coupler I have made by ITT Mackay, the 4030. It's rated at 1KW... not that I would ever run that kind of power through it although the GK-500 has provisions for a 300 watt carrier. I digress.
The 4030 coupler is designed for ship board use, or fixed installations where a random wire or whip would be the radiating element. The caveat seems to be that the element should be rather short, 35' ft. and under down to 16' ft. Much like the RF-604 Harris that I use for my vertical.
The Mackay unit uses a series cap and inductor, and while I would not be auto tuning with it for lack of the control system, it can be manually tuned with momentary switches for L & C.
So, begs the question you conjunctive gurus out here, shall I place these tuning elements in parallel?
The components are seriously rated, 15KV vacuum variable and a 4" edge wound inductor nearly a foot long. My scenario would be to have the coupler ground mounted and bonded to an Earth ground system.
Run a #10awg wire that's as long as I can fit on the lot, up to maybe 40' ft. across approximately 60-70' ft. What would you do? It seems to me that the L can electrically lengthen the radiator while the C cancels the reactance being in parallel. This is my understanding and is this wrong?
Thanks.
73 de Billy N6YW

[Jim, W5JO]

In your quest to do 160 with the King, remember the low impedance match out of that rig is about 300 ohms.  That is as low as it can go.

[WD5JKO]

In your quest to do 160 with the King, remember the low impedance match out of that rig is about 300 ohms.  That is as low as it can go.

  I remember that Jim. Back in the 1980's someone sent me plans to make a ferrite toroid based impedance transformer to better match the king to 50 ohm loads. In Billy's case, why not load that inverted 'L' to be an electrical 3/8 wave, and hook the antenna direct to the King's 300 ohms output? Maybe have a short run of low loss coax going from rig to antenna to better position the antenna feedpoint outside. A short run of good coax on 160 with high SWR won't have much loss.

  It's been a long time since I did anything even mildly serious on 160. I remember when using a 80-40m trap inverted V with Apex at 40', hung on a wooden A-Frame wooden antenna. I cut the coax at the A-Frame base, and resonated the whole antenna with an 'L-Network' mounted to the wooden 2" x 2" base. I added a single 6' ground rod right there too. This was a compromise antenna, but the feed was fairly Hi-Z, so the current maximum was somewhere up higher. With a Globe King, I got out very well all over Texas and beyond.

   Back in the 1970's, in Michigan as WB8PEP, I had a 1/4 wave 160m inverted L. The vertical portion was only 30', but the horizontal section went near a river, so the soil conductivity was good. I remember one December night with 25 watts AM. I could work anything I could hear.

Jim
Wd5JKO

[N6YW]

In your quest to do 160 with the King, remember the low impedance match out of that rig is about 300 ohms.  That is as low as it can go.

  I remember that Jim. Back in the 1980's someone sent me plans to make a ferrite toroid based impedance transformer to better match the king to 50 ohm loads. In Billy's case, why not load that inverted 'L' to be an electrical 3/8 wave, and hook the antenna direct to the King's 300 ohms output? Maybe have a short run of low loss coax going from rig to antenna to better position the antenna feedpoint outside. A short run of good coax on 160 with high SWR won't have much loss.

  It's been a long time since I did anything even mildly serious on 160. I remember when using a 80-40m trap inverted V with Apex at 40', hung on a wooden A-Frame wooden antenna. I cut the coax at the A-Frame base, and resonated the whole antenna with an 'L-Network' mounted to the wooden 2" x 2" base. I added a single 6' ground rod right there too. This was a compromise antenna, but the feed was fairly Hi-Z, so the current maximum was somewhere up higher. With a Globe King, I got out very well all over Texas and beyond.

   Back in the 1970's, in Michigan as WB8PEP, I had a 1/4 wave 160m inverted L. The vertical portion was only 30', but the horizontal section went near a river, so the soil conductivity was good. I remember one December night with 25 watts AM. I could work anything I could hear.

Jim
Wd5JKO

That's a cool story Jim! I bet it worked great.
I want to plan this out so I can make an attempt to use 160 this coming Winter.
I didn't mean to infer that I was going to specifically run the GK-500, but what ever rig I have
that works, Hi. If my GK-500 has a 300 ohm output on 160, it's unbalanced because it's coaxial.
I admit to a little confusion about this but I think you're referring to the fact that the tank circuit
in the 500 is a little inefficient at loading a broad range of loads and doesn't want to see a real low
impedance. Well, the 4030 coupler I have could match about anything given the quality of it's
components. It's a coaxial input unit too, so maybe I need to go old school and devise something
out of the handbook and forget the coupler. What a shame though, this thing is a work of art.
The coil is as good as it gets. 
I'll consult my library of antenna books and see what candidates fit the bill.
Here are some facts pertaining to my property here:
I live in the Venice Canals, which are fed from the Pacific Ocean via Marina Del Rey. The canals are actually little peninsulas and if you google my qth you can see what I mean.
The water table is @ 4' ft. !!! The soil conductivity here is amazing and because it's salt water, I have better than normal ground losses than others.
I had better hit the books.
Thanks,
73 de Billy N6YW

[Jim, W5JO]

I took a different approach.  I added a capacitor to the tune side by putting it on the bandswitch, added a second variable of the same value to the one in place along with some chosen value doorknobs and it will tune into a coax fed antenna of 50 to 600 ohms without anything external or bare wired exposed.

Another thing I did is change all the relays to 24 volts for the coils.  I mounted a small 24 volt transformer then ran the output to a bridge then filtered the daylights out of that.  From there it powers all the relays in the set.  I like that better than running 120 in the decks.

[Jim, W5JO]

Someone delete that second post, I meant to modify

[DMOD]

Hi Billy,

I had an inverted L once about 75 ft long, 20 ft up, 10 ground radials, and made a "T" match for it.

The measured impedance was about 30 + j180, so the R was about 30 ohms and the inductive reactance was about 180 ohms.

These values were for a frequency of 1.9 million CPS for the 160m band.

So below is a schematic of the T network that worked well for me.

Phil - AC0OB

[WB4AIO]

Someone mentioned on my Globe King thread about using an inverted L on my small 90' ft. lot here in the Venice Canals. Perhaps 30' ft. up and 70' ft. long. Make up the difference with an auto coupler I have made by ITT Mackay, the 4030. It's rated at 1KW... not that I would ever run that kind of power through it although the GK-500 has provisions for a 300 watt carrier. I digress.
The 4030 coupler is designed for ship board use, or fixed installations where a random wire or whip would be the radiating element. The caveat seems to be that the element should be rather short, 35' ft. and under down to 16' ft. Much like the RF-604 Harris that I use for my vertical.
The Mackay unit uses a series cap and inductor, and while I would not be auto tuning with it for lack of the control system, it can be manually tuned with momentary switches for L & C.
So, begs the question you conjunctive gurus out here, shall I place these tuning elements in parallel?
The components are seriously rated, 15KV vacuum variable and a 4" edge wound inductor nearly a foot long. My scenario would be to have the coupler ground mounted and bonded to an Earth ground system.
Run a #10awg wire that's as long as I can fit on the lot, up to maybe 40' ft. across approximately 60-70' ft. What would you do? It seems to me that the L can electrically lengthen the radiator while the C cancels the reactance being in parallel. This is my understanding and is this wrong?
Thanks.
73 de Billy N6YW

I would make the vertical portion as long as possible, and the total length also as long as possible. I would make the radials elevated. When they're up six feet or more, a few will do the work of 60 on or under the ground.

At the feedpoint, I'd make an L network to match 50 ohm coax. If you want to use the Globe King, make another simple L match for maximum power transfer from the King's weird output network.

I've had good results with this kind of setup, even with only two elevated radials each 50 feet long. I used 150' of total antenna wire length, which also works very well on 75, 40, and 20.

All the best,

Kevin, WB4AIO.

[W1AEX]

Billy,

It's always fun to mess around and see what can be done to get on 160 meters. When I first moved to my current location I wanted to get something up in the air quickly that I could use to cover 160 meters through 10 meters. The issue was that winter was coming on fast and my lot was full of trees that made long wire runs difficult. At any rate, after pacing out a few places where I could run wires easily I ended up with a horizontally mounted square shaped antenna that was roughly 60 feet long on each side. It was only about 30 to 40 feet in height and fed at the center of one side with a random length of open wire line that ran to a T-Match with a 4:1 balun. Being as low as it was it was a cloud burner antenna on 160 and 75 meters but it worked great for talking to guys out to a couple of hundred miles. The pattern was definitely complex on every band, but it loaded easily and worked fine from 160 through 10 meters. I have plenty of room here and eventually put up something more conventional but I never forgot how well the 240 foot horizontal square antenna actually worked. Before I took it down, I played around with putting a big relay across the insulator that was opposite the feedpoint so that I could use it as a full-wave loop on 75 meters. That actually made it a much more interesting antenna. At any rate, it's a balanced antenna that will easily fit on a city lot and it radiates quite well. It might be an interesting alternative if the end-fed antenna doesn't work out.

73,

Rob W1AEX

[N6YW]

Billy,

It's always fun to mess around and see what can be done to get on 160 meters. When I first moved to my current location I wanted to get something up in the air quickly that I could use to cover 160 meters through 10 meters. The issue was that winter was coming on fast and my lot was full of trees that made long wire runs difficult. At any rate, after pacing out a few places where I could run wires easily I ended up with a horizontally mounted square shaped antenna that was roughly 60 feet long on each side. It was only about 30 to 40 feet in height and fed at the center of one side with a random length of open wire line that ran to a T-Match with a 4:1 balun. Being as low as it was it was a cloud burner antenna on 160 and 75 meters but it worked great for talking to guys out to a couple of hundred miles. The pattern was definitely complex on every band, but it loaded easily and worked fine from 160 through 10 meters. I have plenty of room here and eventually put up something more conventional but I never forgot how well the 240 foot horizontal square antenna actually worked. Before I took it down, I played around with putting a big relay across the insulator that was opposite the feedpoint so that I could use it as a full-wave loop on 75 meters. That actually made it a much more interesting antenna. At any rate, it's a balanced antenna that will easily fit on a city lot and it radiates quite well. It might be an interesting alternative if the end-fed antenna doesn't work out.

73,

Rob W1AEX

Rob, Kevin & all
Thanks for the input. This is giving me some options to consider given my circumstances on this lot.
Attached, you can see the block diagram of the MSR 4030 coupler. It's a beauty and I just sold 2 of them to a guy in Michigan who owns the entire radio system it was designed to be used with.
This is excess to my needs but I figure what the heck, try it out and see how it works.
Here's a link to the manual so you can see the specs:
http://elektrotanya.com/mackay_4030_1_kw_antenna_coupler.pdf/download.html
I am attaching a screenshot of the coupler block diagram to show what it is electrically.
I have some unit-strut I can mount it with at the base of my mast, bond it to an electrode, and run a few radials as best as I can. With the entire canals as my water source and the water table at 4' ft. I should be able to do a little more than cook worms. I can run a wire up the fiberglass mast to the 40 ft. level and then shoot it out over the rest of the property to a support above the house.
This would give me about 100' ft. of wire, so the coupler would have to do the rest.
I could also dog leg an additional length which might help.
K4RT emailed me an idea about a center loaded wire bent as an L with good success at his QTH.
Lot's of great ideas pouring in here.
Thanks!

[Steve - K4HX]

Your original inverted-L idea is probably about as good as it gets. Try the coupler. If you cannot tune to the loading you need, try putting the cap and coil in series. Or short out the cap all together and just us the coil in series. It's likely the Z at the end of the inverted-L will be low and have capacitive reactance.

With all that salt water around, your L should work beautifully.

[N6YW]

Steve, thank you.
Check this guy out, Bob W6SDO. www.w6sdo.com   
He has several interesting ideas for the average city lot with what appears to be excellent results. And talk about a CLEAN installation. I like that. The 160 L antenna system he built is really cool and it's worth checking out.
I am getting quite excited at the prospects of producing a signal on 160, and with some enjoyable work and some luck, I might be able to reach some of you guys on the East coast! Now that would be worth the effort right there. I am guessing the pattern would be omni, possibly skewed due to surrounding housing.
The "L" would be oriented to the South of me, so only propagation and QSO's will tell the tale of how it will work.
Now, here's another idea I have been mulling over. My vertical. The 43' ft. unit I purchased from DX engineering that has been my main antenna for 2 years. I shortened it for using the Harris RF-601A exclusively for 75 meter phone. Now that the Cobra is working so well on 75, Perhaps I could do the following:
Add some top loading wires. Make the ground plane counterpoise out of 450 ohm ladder line that's cut & folded much like Butternut does with 300 ohm twin lead. Use the Harris coupler to tune the sucker and see if it works. This vertical is roof mounted on the 2nd story of our house, in the center.
Check this out: Up 16' ft. vertical height. The roof line is 64' lineal ft. meaning 16' ft. each side. That's a 1/4 wave on 75 meters. I presently use Romex 12/3 w/ground cut so that I have each of the four counterpoise elements at 33' ft. long. I took two of the conductors and bonded them together at the ends giving around 66' ft. each. The remaining conductors (bare ground and red wire) are left at 33' ft. & 16' ft. so it would be useful on 40 & 20 meters. These are arranged so they exit the feedpoint in the middle of the roof to each corner and turned to the right, then secured in place. 4 total.
I say all of this so the reader can visualize what I have here. On 75 & 40, I have worked every continent and at least 100 countries.
I have the rest of the summer and fall to get something working.
73 de Billy N6YW

[N6YW]

As he smacks his hand against his forehead....
I could also tie the ends of my ladder line together and work the Cobra against ground.
Duh.

[Steve - K4HX]

Nailed it. You're done!

As he smacks his hand against his forehead....
I could also tie the ends of my ladder line together and work the Cobra against ground.
Duh.

[DMOD]

Just for general information I found some info from a July 1929 test by a doctoral student at Rensselaer PolyTech for verticals, T tops, and Inverted "Ls."

For an Inverted L with the vertical height equal to its horizontal length, the AVERAGED resistance is (at 300 meters over a well conducting radial field):

1/4 Wave: R = 13.0 ohms,

1/2 Wave: R = 43 ohms.

It was also noted that for a 1/2 wavelength Inverted L, the radiation is practically the same for both elevation and azimuth.


Phil - AC0OB