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Wednesday 22 October 2008

Adding bands to my repaired vertical

A tree at bottom of garden about 6 weeks or so ago a branch came down and took out my vertical. I obtained a new Ali pole and put it in place so the Hustler 6BTV vertical is back up and running again (managed a QRPp 80m qso with G3XBM with it yesterday).

Anyway thinking time I need to add WARC bands 17m and 12m to it.

Saw the add on kits at Dayton FDIM but serious costs involved so this is how I will do it (direct copy from AD5TH):

Parts Required
1. 25ft - Multi strand insulated copper wire (just wired up green house so spare lengths)
2. 2 - ring terminals (crimp or solder)
3. 4 - plexiglass spreader arms (home brew)

One of the home brew "spreader" arms



Spreader Arms

Clive (M5CHH) had given me a small piece of plexiglass a while back. You need a piece 14 inch x 8 inch and about 1/4 inch thick. The alternative is you could use ply wood and paint or varnish it.
1. Cut plexiglass into 14 inch long by 2 inch wide strips (use band saw or score and snap)
2. Drill a single 1 1/4" hole in center on each strip. Drill very carefully.
3. Drill a single 1/8 " hole on center 1 inch from each end of strip. 2 holes per strip (1 on each end)

Vertical Radiators
1. From 25 ft of wire cut 2 lengths 14ft (17M) and 10 ft (12M)
2. Strip one end of each and attach crimp or soldered ring terminal

Assembly

1. Disassemble your Hustler antenna and place a plexiglass spreader over the main tube at the very bottom right above the base and then place a spreader on top of the 10M trap and another on top of the 15M trap. The fourth and final spreader is installed at the bottom of the 20M trap supported by a plastic tie around the antenna tube directly beneath the spreader. Reassemble the antenna and test for proper operation on original 10/15/20/40/80M bands
2. Attach both 12M and 17M wire ring terminals to the main feedpoint.
3. Thread the 12M and 17M wires through the 1/8 inch hole in each spreader. The spreader on top of the 10M trap needs to be slid up the main antenna tube about half way towards the 15M trap and held with a plastic tie. This locates the spreader properly to intersect the upper portion of the 12M vertical radiator
4. Temporarily secure the other end of each wire with a plastic tie or folding the wire over it's top most spreader.
5. Check the VSWR and trim to resonance for 12M and 17M. Secure wires to spreaders with plastic ties.
6. Typically after 12M and 17M are tuned you'll need to re-tune one or two of the other bands of the Hustler BTV

AD5TH 5-BTV 10M and 20M needed a retune. 15M 40M and 80M VSWR was unchanged after the modification.

7. These photos are from AD5TH. I will add mine shortly.




Some notes:
1. I keep meaning to purchase/make a tilt over mount for my 6-BTV, AD5TH said this would have really helped throughout the procedure. It is more cumbersome to complete this modification without the aid of a tilt over mount. An alternative is to enlist the assistance of a helper and a ladder.
2. The wire lengths cited in the instructions are longer than needed by design so simply prudent trimming and testing will achieve resonance. It took AD5TH only 3 trim and test cycles to get both 12M and 17M flat.
3. If your Hustler is ground mounted without any buried radials it is highly recommended that you add at least 25 or 30 ground radials at least 15 ft in length each. Radials in soil need not be "tuned" as "in-the-air" radials must be. At M1KTA QTH I have a lot of random lengths burried around the base of the vertical along with a couple of 4 foot ground rods, the water table is also very high.
4. AD5TH suggested with the 5BTV 20M can be stubborn and needed to be shortened but was already shortened to the max. So with the 6BTV I might have to add a capacitive hat to 20m (I have made one before for use with a buddipole on 160m! which is 3 18" lengths of coat hanger wire at 120 degrees separation perpendicualr to the mast which will raise the resonant frequency). AD5TH was then able to adjust 20m.

As I am doing an antenna 'shoot off' especially as I bought a centre for the HEx beam/cobweb at GQRP rally this will be my 'reference antenna'.

The orginal AD5TH website seems to have gone. These were the original instructions:

Parts Required
25ft - #12 insulated copper wire - (about $4)
ring terminals (crimp or solder) - (about $1)
plexiglass spreader arms (home brew) - (about $5)

Home brew "spreader" drawing

Spreader Arms
Required stock 14 inch x 8 inch 1/4 inch thick plexiglass (about $5 cost)
Cut plexiglass into 14 inch long by 2 inch wide strips (use band saw or score and snap)
Drill a single 1&1/4 inch hole in center on each strip. Use 1 1/4 inch hole saw. Drill very carefully.
Drill a single 1/8 inch hole on center 1 inch from each end of strip. 2 holes per strip (1 on each end)

Vertical Radiators
From 25 ft of #12 wire cut 2 lengths 14ft (17M) and 10 ft (12M)
Strip one end of each and attach crimp or soldered ring terminal

Assembly
Disassemble your Hustler antenna and place a plexiglass spreader over the main tube at the very bottom right above the base and then place a spreader on top of the 10M trap and another on top of the 15M trap. The fourth and final spreader is installed at the bottom of the 20M trap supported by a plastic tie around the antenna tube directly beneath the spreader. Reassemble the antenna and test for proper operation on original 10/15/20/40/80M bands if 5-BTV. Likewise if 4-BTV or 6-BTV check on all original bands for proper operation after reassembly.

Attach both 12M and 17M wire ring terminals to the main feedpoint.
Thread the 12M and 17M wires through the 1/8 inch hole in each spreader. The spreader on top of the 10M trap needs to be slid up the main antenna tube about half way towards the 15M trap and held with a plastic tie. This locates the spreader properly to intersect the upper portion of the12M vertical radiator
Temporarily secure the other end of each wire with a plastic tie or folding the wire over it's top most spreader.
Check the VSWR and trim to resonance for 12M and 17M. Secure wires to spreaders with plastic ties.
Typically after 12M and 17M are tuned you'll need to re-tune one or two of the other bands of the Hustler BTV. On my 5-BTV 10M and 20M needed a retune. 15M 40M and 80M VSWR was unchanged after the modification.

I have a tilt-over mount on my 5-BTV so this really helped throughout the procedure. It is more cumbersome to complete this modification without the aid of a tilt over mount. An alternative is to enlist the assistance of a helper.
The wire lengths cited in the instructions are longer than needed by design so simply prudent trimming and testing will achieve resonance. It took me only 3 trim and test cycles to get both 12M and 17M flat.
If your Hustler is ground mounted without any buried radials it is highly recommended that you add at least 25 or 30 ground radials at least 15 ft in length each. Radials in soil need not be "tuned" as "in-the-air" radials must be.
Today I completed retuning 20M and 10M. Now ALL 7 bands are under 1.3:1. 20M was stubborn and needed to be shortened but was already shortened to the max. I raised the 20M capacitive hat about 1 1/2 " which predictably raised the resonant frequency. I was then able to routinely lengthen the 20M adjustment and the match fell right in.