Hustler 4BTV 4-Band HF Vertical Antenna

CAMP HF ANTENNA

We have a remote desert camp that go to when the weather is nice and play with radios.  It is a pretty quiet spot both solitude and radio -wise. ( when the dune buggies are not running around)

Several years, at least a decade ago, On a camping trip here I convinced my nephew Nick there may be gold in the ground at about this spot.  We proceeded to dig a 6 foot-deep hole and when we got to the bottom, I put in the 8 foot pole that is the support for this antenna and put all the sand and rocks back in it. I got the Hustler antenna from a ham club swap meet for $20 years earlier. It had been in service since the late '70s.  Finally we dug some trenches and strung some tuned radials under the sand in all directions. They have been here ever since that day.

I used this antenna for many years.  I never really took it down as this spot is so remote and nobody ever bothered it ...until last summer.

[bent antenna]

Mother nature had some fun one summer afternoon.  I am not sure what kind of storm it was, the desert tends to get some violent thunderstorms in the summer as a monsoonal flow sets up from the warm waters of the Sea of Cortez inside of the Baja peninsula.  In any case this storm left lots of sand sticking to the sides of the buildings poles and trailers so it guess that the force of the wind plus the mass of the rain and sand was too much for this 35-year old antenna.  At least the bottom section.


Fortunately, DXE sells replacement parts "...allow you to keep your Hustler vertical performing at its peak. Whether for maintenance or repair due to unfortunate damage, Hustler offers the replacement antenna parts that you need."  So I bought and replaced the lower mast section (P/N 4087-11) I think with shipping it was twice the cost i paid for the original used antenna but she is standing tall now:

 



The base of the antenna was in pretty good shape considering that it was basically in this desert environment for 11+ years.  When I decided to fix the bent antenna I dismantled the entire antenna and took it back to the Radio Ranch repair labs.  In the process I had to cut the radials to remove it as the bolts were badly rusted. 

ANTENNA RADIALS

The new installation would not  be able to attach the radials ( 2 per band) to the original tie points as they were slightly too short now. There would be no way to pull the radials back to make up for this with out digging them up - not an option with out a Nephew in site. ( he is now all grown up with two kids of his own to dig holes with)  Instead, I fabricated a radial plate out of 4 Stanley angle mending brackets:

I simply formed a square ( 2 under, 2 over ) and fastened with #8 SS hardware. The bracket was bolted to antenna base with a salvaged TV antenna "U" bolt that happened to come complete with a mast clamp ( a second bracket that prevents crushing the square antenna tube:

But instead of preventing crushes, I drilled a couple of well-placed holes near the "top" edge of the clamp and used it as the bracket:

These were fastened with 1/2" and only one nut and lock washer as the space is tight between the mast clamp.  Finally the original radial tie points screws were replaced with stainless screws, washers and nuts. Replacing the original "stack of nuts" that corroded before.  I attached these points, in a bit of overkill, with two ground straps made up of a length of braid salvaged from an old RG-8 cable, they look pretty impressive anyway.


At the end of the day, the bracket is mostly buried in the sand anyway. The first 6" of the insulation of the original radials as you can see - is now long gone due to exposure to the elements, are now safely buried under sand and these small stones.   The connection point and UHF connector are now wrapped in tape and a large tube of heat shrink as well.

THE WORKS.

BTW we made some PSK contacts with 5 watts on 15 and 20 meters and a couple of RTTY and - of course -  CW.  The contacts ranged from Cuba in the east to Japan and Russia in the west.  All bands but 10 meters was tried but i think that band was not too active the day I tested it.

Other Toy and Good Guard Doggie

Stay Tuned!

 

~ ~ ~

DSP-610 ~ PA Build

Slow Power Amp.

I know this is on a slow track but progress is progress.



90% Complete Power Amp

 

 

It has been a while since I posted any progress on this build.  The main build took place, mostly on weekends between 9/1/2013  through 11/09/2013.  The board has a couple of interesting quirks...

TIP:  I used a Red Sharpie marker to mark uninstalled (DNI) components:



Note: C6 and C31 are Marked DNI Parts

TIP: Two soldering irons and a solder gun were also very useful in this build. Use two irons as heat sources  for removing mistakes (caps and resistors) to heat both pads at the same time.  I used the 100W gun to solder to the substantial ground plane.

RF Connection Mods.

First, the antenna jacks and RF layout is a bit difficult to figure out.  I put shorting jumpers on the path to allow one antenna for TX and RX.  This seemed the most straight forward for operations.

 

RF In Connector

Then I had issues with the 0.1" headers for RF connections.  I used an Xacto knife to scrape a couple pads for mounting the jack.  I tinned the pads and flowed a generous fillet of solder to the connector




RF In End-Launch SMA connector...

 

Antenna Connector

The antenna output is a vertical launch SMA.  I could not find a suitable connector. While an end launch location would have been more convenient, but I could not figure out an RF friendly placement.  There is a trace on the left-hand side of the board near the RF coils. 

Instead, I modified  a SMA connector by cutting off the mounting tabs. I then used a file to machine them flush (brass works easily) and used the existing antenna pad for the center pin.  The ground connection was made by scraping the blue solder mask, tinning the copper exposed, and "sweating" a fillet with a generous amount of solder. The ground connection is probably adequate.

The modified SMA connector is seen mounted in this picture.  It is pretty substantial and there is enough room for the connector, which will be a right-angle SMA plug:

New RF Connector near the White AXICOM Relay

If I would have planned ahead a little better, I would have done this before mounting the Relays and potentiometers.  I did not want to remove or melt them by trying to solder the left-hand side, and had to be extra careful not to melt the plastic on the pot. 

The Transformers and Coils...

Winding school. 

Count the turns on the inside of the toroid cores. Scrape and tin the wires.  The instructions are from the Soft Rock 50, plans you need to translate the part designators between the two different boards.

Coils (L7, L8, L9, L10 & L11)

The five  toroid coils were pretty straight forward, 3 with 7 turns of AWG #22 and 2 with 5 turns on T-50-6 (Yellow) cores.  The red enamel stained the cores a little when tinning the wire. NOTE:  L7 is a little tricky to mount, be careful there is a large ground via close to the pads, don't solder to that hole! Here are the winding specs. from the BOM;

L7,L8,L9 T50-6 CORE 7 TURNS #22 ENAMELED WIRE (6") AMIDON T50-6

L10,L11 T50-6 CORE 5 TURNS #22 ENAMELED WIRE (5")

The DSP610 PA Coil - Family Portrait

BP Filters

I did a manual sweep of the two filters.  I am not too happy about the 10 meter filter.  I need to check the values of the caps etc. It seems shifted to favor  12 Meters..

 

12M - 10M Filter Response

The plot of the 50 Meter pass filter looks pretty reasonable. Very much as expected.

6M Filter Response

 

 

Transformers (T1) and (T2)

 

These two were just as described:

"...[T1] on the PA board two loops of #18 wire through a BN43-202 Core. The wires are cut to 3" (75mm) each and stripped so that the insulation is 1 5/8" (65mm) long.'

 (Seen on right side with Red and White #18 wire);

"...[T2] 3" (75mm) length of RG-316, remove the outer jacket from one end and expose 0.75" (20mm) of the shield... Remove the outer jacked from the other end of the wire so that the insulation length is 1.5" (40mm)....Loop the wire through the BN43-202 core, unbraid  the remaining shield wires making sure that the shield on both ends of the wire point in the same direction. Strip the dielectric from the two center conductors. Tin and trim both shields and center conductors."

Seen on left side of the following picture. (basically, just a short length of RG-316 coax thru binocular core):
 

 

T1, T2 and L7 (Note via near L7)

Transformer (T3)

The mounting pad for T3 was not good. I applied a little too much heat and the pad lifted;

 After close examination it appeared that there was no electrical connection to the pad so I attached the rather substantial transformer to the board with a dab of 2 part  epoxy.

Transformer (T4)

The instructions are pretty clear for this transformer:

"Step 1:  Wind 2 windings each using 18" of #30 Kynar wire, (Green) 10 turns, one winding through each hole in a BN43-202 core,  ( I wound in same direction)..

Step 2: Cut 2 pieces of #22 Teflon wire, (I used Red and White) Strip the ends so that the insulation remaining is 7/8” long, the length of the bare wires is not important just so it’s long enough to go through the PCB. Tin the ends:"

T4 on DSP-610 PA

I did not really follow the mounting instructions, I just pulled the wires thru marked and stripped the lengths to match,  For the #22 wires I just measured the insulation and simply bent them to feed the leads thru the circuit board pads.

Transformer (L6) 

The description for L6 was pretty vague... (T1 = L6)

"..[L6] has 2 windings on a FT37-43 toroid: the primary consists of 2 turns of #26 enameled wire, stripped and tinned; the secondary is 13T of #26 enameled wire. It's best to wind the secondary first then wind the primary over the secondary. Try to form the leads to match the pads in the PCB..."

This was the most confusing part on the board  for me.  First a transformer labeled as an inductor? Anyway...The winding instructions are pretty straight forward but not a picture to back up the description.  Here is what I came up with...

 

L6 as Wound

The best way I see is to run "two" turns is to loop it (green wire) so it passes through the torrid twice with the most wire through the toroid, exiting on the mounting side. Forming the leads is also a little tricky. To make it match the schematic, after some careful study of the PCB I ended up with this:

 

L6 with leads Formed

 

The First Part Was...

 

Oh, yeah. the first soldered part on the KD6VKF DSP-610 project was L1 on 9/1/13:

 

 

L1 Installed

The next installments; Transistors, DC Bias adjustments, and compete the testing the board. Please Stay tuned!  (The KD6VKF DSP610 will eventually get done, really ☺)

~ ~ ~

DSP-610 ~ Fabricating the PA Heat Sink

Sinking In..

 Poking around in the local surplus store last weekend, I found this roughly 4" x 6" 16-fin heat sink in a bin called "scrap aluminum"!

With out even measuring the part I put down the $2 and brought it back to the ranch,  As you can see a near perfect fit!  I am not sure this will provide adequate cooling or even how I plan to mount it in the chassis but it is a start to the power amp build for the DSP-610

 

 

 

For Good Measure

It would be too much to ask that any holes on this part would be usable.. and this was the case.  I think this was from a power supply or battery charger of some sort...probably a military device. I used the DSP external PA PCB to mark the locations of the required holes.  The trick was to find free of holes, or not too close anyway.

 

After studying the data sheet it looks as if the pin outs for the board intended the TO-220  transistors, to be mounted under the board.  Which works out that the heat sink (or chassis) will work under the circuit board.



 

This also explains the over sized holes...  The screws holes were drilled an tapped to accept #4-40 hardware.  Access through the holes will allow easy mounting to the sink. 

 

 

 

 

These spacers were only for test fit, the final hardware was #4-40 1/4" hex M-F standoffs, which will reduce the lead length,  The bends for the leads may be  a little tricky as I did not get the mounting holes exactly centered...but it should work out OK.

 



 

A dab of heat sink compound on each, and I think this will work!

 

 

READY TO BUILD...

The board seems to have found a good home!  I hope the mounting in the chassis will be OK and this assembly will dissipate the required heat for the RF  power transistors.