Wednesday, February 20, 2019

43ft Vertical Is Up

Last weekend I took down the Carolina Windom 80, and up went the 43 ft vertical [Zero-Five] in the back yard with 16 x 30 ft radials, and LDG RT-600 tuner at the base. This comes after much internet searching, reading, and many emails with a friend of mine who knows more than I do about verticals and DX. I've yet to finish the radials, need to add more, at least 30 to 40 and bury them.

Left - Close up of base, radial plate - I'll get some paving stones and gravel to make it nice. Right - The lense in my iPhone makes it look "bent", the tree on the right does not lean, nor does the end of the deck or anything else back there that looks like it's falling over. 

Transmitting WSPR, initial results are promising. Near sunset here in the west, my beacons are spotted from the mid west to the east coast - New York, Connecticut and down to Florida. Overnight on 80m they have been spotted in VK5 and VK7, and Costa Rica so far.

Receiving WSPR with the rig band hopping 160, 80, 60, and 40m on receive at night, I spot a few stations from Australia, Japan, New Zealand, and South Africa. A nice surprise was Indonesia and Papua New Guinea on 60m! Note the "official" WSPR 60m frequency is 5.2872 MHz - this is not one of the permitted 60m channels in the US, so we can only receive here and not transmit!

I plan on using WSPR as a measuring stick to compare changes - since I can leave it running on receive 24/7, and enable transmit when I'm home. Monthly archives in CSV format can be download, I can pull this into Excel/Libre Calc to make some pretty charts.

For a low noise receive antenna after much reading about Pennants, Waller Flags among other things. I decided on the the K9AY loop, direction is remotely switchable, and the well made control boxes can be purchased directly from Gary K9AY. Using known quality makes a good starting/reference point for later experimentation with the loops or other low noise receive antennas.

The K9AY loops need about 30 ft of space. Even with a 1/4 acre lot I'm limited on places to put it out of the way. Emailing with Gary who was very helpful, I learned the loop size can be 60 - 70% of original size and be effective on 80m. Gary is also modifying the filter and preamp for me to allow operation up-to 7MHz / 40m as I'm interested in 60 and 40m DX also. Gary also recommended an INRAD model RX7300, this adds a receive-only antenna jack to the Icom IC-7300. Photos here by K0PIR.

I have ordered the control boxes from Gary, and the rest of the hardware:

  • 13 AWG, 19 strand 40% copper-clad steel wire, polyethylene jacket, (part 531) from The Wireman.
  • 150 ft of LMR-240, INRAD RX7300 and ON4UN's Low Band DXing book from HRO.
  • Diawa antenna switch, RCA manual fit plugs, RCA to PL-259 adapters (easy RX switching between the loop and vertical), 150 ft of cheap CAT5e cable (for the K9AY control cable) from Amazon. 

Next I plan to add a 160 and 80 Meter Matching Network for your 43-foot Vertical [AD5X] for more efficiency on 80m. Ideas for later include adding a movable passive director element [VE1ZAC] for directivity and gain on transmit! And ultimately maybe extend mine to a full 1/4 wave on 80m by getting a wire off the end up into the top of some 65+ ft pine trees I have in the NW corner of my back yard!

Sunday, February 3, 2019

Low Band DX - The Idea Bites!

Tuning around the 80m band a couple mornings ago I hear some big signals out of California on 80m - 3.796MHz - chasing DX stations around, that - unsurprisingly - I could not hear at all with my OCFD at around 40ft.

The guys in Cali, one 800 miles south, the other 400 miles south, then started talking between them selves about ZL contacts, and someone I have known for a long time from ZL was mentioned, who has a nice 80m DX station setup. Something I have admired - a 4-square, which is pretty much the gold standard for 80m DX - nice if you have the space! I fired off an email to Nick to say hello, and that I heard these guys talking. Nick replied and said it would be great to chat on 80 some time. Right, challenge accepted!

What I have:
  • 1/4 acre lot with a 70ft Pine tree in the north west corner. 
  • A high noise floor on 80m, S5 to S9 on a horizontal wire antenna.
  • A general class license that limits me to 3.8-4MHz on SSB/AM voice modes, the DX seems to lurk in the upper end of 3.7MHz.

I researched the inverted L, with plenty of long radials these seem to work well on the low bands for DX.

Using a Delta loop came to mind, each side is about 80ft, I have 80ft between the trees at the back and a shorter tree at the front, but lack of height is a problem, I need about 70ft of height at the top of the triangle. Research also suggested that Delta Loops don't work that well for DX compared to other things.

I then remembered an article by W6NBC - High-Efficiency 40m Vertical Without Radials. These are essentially a 1/2 wave vertical dipole, one side is full length, the other leg is shortened, overall the vertical is around 2/3 of full length. In the hope of avoiding running miles of radials I discussed scaling this to 80m with a couple people who have experience with DX verticals, and none of them seemed very keen on it. However, I'm very interested in trying one of these out to compare.

1/4 wave verticals with a good radial system keep coming up as the best option. Some searching turned up a series of articles published in QEX by N6LF - Series of QEX articles on ground system experiments, I found this very informative and cleared up misconceptions I had about radials and ground planes. I have disliked antenna systems that require dozens of radials, its safe to say my thinking has been changed!

Tricky part, how to get something up into the top of that tree? While discussing my insane idea a couple nights ago on a local repeater, one of the guys suggested they know someone with a drone that can carry 25lb loads, and could get something up there no problem! I'm thinking of putting my 43ft vertical from Zero-Five to use. Attaching a ~20ft wire to the top, and pulling that up into the top of the tree to make it up-to a 1/4 wave on 80m.

How it might look from the street. 43 ft vertical will be phase 1. Phase 2 will be to add the 20 ft extension wire and support line from the top of the tree. Not sure of the effect of a "bent" top, but given the tree locations, and where I can fit the vertical in with reasonably symmetrical radials, choices are limited. Approximate but not to perfect scale. 

The proposed radial layout. Radials shown in yellow. Chainlink fence (galvanized) shown in cyan, this extends for some distance east/west down the street. Green is a wooden fence.

The noise floor is the next problem, noise will be much worse on a vertical!

Things to think about:

The last issue, getting full privileges on 80m so I can transmit in the 3.7MHz segment is solved by getting my extra class license.