Modify AL-1200 HV power supply

WARNING – LETHAL VOLTAGES!!! DO NOT ATTEMPT WITHOUT PROPER SAFETY PRECAUTIONS!!! I’m not responsible for what you do with this information!

The Ameritron AL-1200 has a 3,600v power supply. Its filter capacitor bank of eight, 270mF 450vDC runs right at the limit of its design (8 x 450 = 3600). A common modification is to add two additional capacitors, along with the needed bleeder resistors, to increase the filter bank capacity to 4,500v. Keep in mind that the transformer still puts out 3,600v, so this modification essentially allows the components in the filter bank to have some overhead capacity.

W8JI and W7RY both offer a replacement PCB designed for 10 capacitors. W1QJ described the way he modified an AL-1200 for W2RE. I choose to adopt the W1QJ method, and will show how I did it here.

The modification involves adding two capacitors in series with the existing capacitor chain, with a bleeder resistor across the terminals of each capacitor. I’ve done this by constructing a small PCB that I’ve added to the amplifier. Then, move two HV wires, cut a HV trace and add a jumper for the metering, and add a jumper to complete the HV series circuit.

Conceptually, this is the modification. I’ve omitted the additional bleeder resistors on the drawing, but they are required! The existing bleeders are desoldered on one end to allow me to test them. The one on the far left had failed completely open, thus causing the capacitor to “tick”. That’s what has led to this modification. I had replaced all the caps and bleeders only five years ago.
Here’s my first test fit of the additional PCB. Note the markings on the board indicating the bleeder resistors, capacitor polarity, jumper to complete the series circuit, and destination for the 2 HV wires to be moved, and the new HV metering jumper.
The completed modification and reassembled amplifier.

Beverage Termination Resistors

I use Mouser part # 660-SPR2CT521R471J or 660-SPR2CT52R471J or 588-ON4715E-R58
Carbon Film Resistors – Through Hole 2W 470 ohm 5%TR
$0.10 to $0.46 each, vs the big retailer selling them at $2.49 each

2019 August NAQP SSB M/2

Call: W5WZ
Operator(s): K5ER KA5M W5LA W5WZ WM5H
Station: W5WZ

Class: M/2 LP
QTH: LA
Operating Time (hrs): 10:53
Location: USA

Summary: Compare Scores
Band QSOs Mults
160: 2 2
80: 57 24
40: 434 48
20: 627 52
15: 0 0
10: 0 0
Total: 1120 131 Total Score 146,720

Five members of the Louisiana Contest Club gathered at W5WZ for a M/2 effort.
Having operated the past three NAQP SSB as a M/2 team, Bobby WM5H and Scott W5WZ, were the anchors, joined by periodic station guests Mark K5ER, Marsh KA5M and Jim W5LA.

For this contest, the SO2R station was split between Run 1 and Run2. Additionally,
for the first time at W5WZ we added an in-band S&P station interlocked with Run 2. This S&P 2 was furnished with its own set of independent antenna: KT-34, 40m dipole and 80m dipole. Bandpass filters and front-end protection was employed on all three tranceivers.

We opened with a 262 QSO first hour; hopes were high! The rate decayed to a second
hour of 159, followed by 140 in the 3rd hour.
W5WZ Max Rates:
2019-08-17 1821Z – 8.0 per minute (1 minute(s)), 480 per hour by W5WZ
2019-08-17 1829Z – 5.1 per minute (10 minute(s)), 306 per hour by KA5M W5WZ
2019-08-17 1904Z – 4.5 per minute (60 minute(s)), 272 per hour by KA5M W5WZ

At 2240z, we heard what every contester dreads on a summer day – booming thunder.
Looking at a real-time lightning strike website, we quickly made the decision to
disconnect and safe the station until the slow-moving storm passed. No rain ever
fell at W5WZ, and the strongest part of the storm passed a few miles to our west.
W5WZ – Off Times >= 30 Minutes
2019-08-17 2253Z – 2019-08-17 2359Z 01:07 (67 mins)

No signals ever heard on 10 or 15. Even though 20m was the QSO total king, the mult
count was low. 40m QSO total was lower than our expectations, but the big
disappointment was 80m. Even with the beverage receive antennas, because of the nearby storms and static crashes, we were sorely disappointed in our 80 meter QSO totals.

Carribean stations were not heard; logged 2 Puerto Rico, 2 British VI, and 1 Barbados.

Beginning around 2130z, QSB on 20m was fast and deep, and it wasn’t much better on 40m.

But, with all that, the station performed flawlessly. Operators new to interlocked
transceivers gained valuable experience that will be most helpful for November SS SSB. We employed N1MM+’s “partner mode” on Run 2 and S&P2, with the partner having a separate computer while listening to the same receiver audio stream as the rig operator.

My elmer, Jim W5LA, is a CW guy. He says he doesn’t like SSB contesting. However,
he remarked during the contest that operating a SSB multi-op contest was one of his
bucket list items. Don’t be going anywhere Jim! We’ll make an SSB op out of you yet!

Without the help and contributions of the team, this couldn’t have happened and been
such a success

My wife, Sharon KW5MOM, tolerating all of us!

Bobby, WM5H, for 2 days of assistance in the sweltering heat to get the outdoor antenna work and other preparations completed. And as always, for ensuring that the team is well-fed (to find out how well-fed, you’ll have to be on the W5WZ team for a contest)!

Jim, W5LA for bringing a few pieces of needed equipment to make the partner mode a
success, and for crossing over to the dark side of SSB contesting! It was great to
operate with my elmer at my side (BTW, it is his fault I’m a ham!).

Mark K5ER, for giving up a valuable Saturday away from his wife and other of life’s
necessary responsibilites and priceless opportunities with family.

Marsh KA5M, for making the longest drive to join us- last time he joined the W5WZ team was 2010 CQ WW SSB- he should come back more often!

Thanks for all the QSOs!

73 from Scott W5WZ

Hams love aluminum!

Hams love aluminum! This arrived for me on Valentines Day!

Force 12 mono-band yagi for 17 meters
5 elements on a 30 foot boom

Super excited to get it assembled and up on a tower!

Jan 2019 NAQP SSB – 10 minute audio clip

Here’s a 10-minute audio clip of W5WZ running 20 meters during the Jan 2019 NAQP SSB. The rate was 264 QSOs per hour, or 4.4 QSOs per minute.  Keep in mind this is a 100-watt maximum power contest.

Here is the audio clip

View the 10 minute period, which pretty much coincides with the audio file.

Recording made using QSORDER by K3IT
https://qsorder.hamradiomap.com/

I use SH5 to generate analytical reports about each contest. Link to reports on yesterday’s NAQP SSB contest:
https://www.w5wz.com/sh5/w5wz/2019/2019-01_naqp-ssb_w5wz/

Pondering other 160m transmit antenna

I have a 160m Inv-L, feed against 40 buried radials 125 long. The vertical component is parallel to my existing tower, tapering from a wide (~15 ft) space at ground level to a narrow (~4 ft) space at 77 feet above ground, then heading away from the tower for another 40 feet.

I have a very tall (~100 ft) pine tree at the edge of my property, north by northeast from the tower at a distance of 175 feet. I’m thinking of using the pine tree to support the vertical component, and going to an elevated radial system.

This is an interesting read about elevated radials:

https://rudys.typepad.com/files/elevated-ground-systems-article-final-version.pdf

What are your thoughts?

North American QSO Party, SSB – January 2019

Call: W5WZ
Operator(s): W5WZ WM5H
Station: W5WZ

Class: M/2 LP
QTH: LA
Operating Time (hrs): 12:00

 Band  QSOs  Mults
——————-
  160:   39    19
   80:  223    47
   40:  586    55
   20:  723    60
   15:    2     1
   10:    0     0
——————-
Total: 1573   183  Total Score = 287,859

Club: Louisiana Contest Club

November Sweepstakes, Fourteen Years Ago

11/24/2004 | W5WZ Our family was on a camping trip to Daisy State Park on Lake Greeson in Arkansas. I had hoped to spend a significant amount of time in the contest. However, as my first solo portable operation, it wasn’t as successful as desired.

W5WZ operating 2004 Nov SS SSB at Lake Daisy State Park in Arkansas (Photo by KW5MOM)

I brought an fan dipole for 80/20, and also a trap dipole for 40/15. But, I didn’t bring any soldering irons or antenna analyzers. The 80/20 antenna was up about 25 feet, on the east side of a steep slope near the edge of the lake. The 40/15 dipole had an unknown problem; it wouldn’t tune up anywhere. So I gave it a shot with only the 80/20 antenna.

My station was an IC-756 ProII, a laptop with NA by K8CC for logging and rig control, with the requisite Heil proset and footswitch, all on the picnic table at the campsite.

My family had other plans for the camping trip; as much rain was expected, during the non-rainy periods I was expected to be with them. The first evening, the temperature was falling quickly ahead of the rain, which soon followed, so I packed up and went to bed  in the RV. With 4 kids under age 7 in the RV, indoor operating was not going to happen on this trip.

The next morning, it was very damp and windy, so I decided to set up in the cab of the truck. With the 756 on the dash, laptop in my lap, the passenger seat was mighty comfortable. The kids provided plenty of interruptions, along with the nature hike and my turn at cooking for the family, so once again operating was not the priority. After all, this was my vacation! I did learn that an automobile bucket seat should be considered for an operating chair.

My operating position had one heck of a great view! And the rest of the trip was beautiful, too! — W5WZ

W0AIH SK after fall from his tower

 From Gerry, W1VE.  More information will follow:

“10/31/2018 – Paul Bittner, W0AIH fell 60 feet from the Strum tower (40m). (It was) a beautiful day and he wanted to get ready for SS SSB. No services information yet obviously and the shock has still hit me.  Please pass the word. Thanks.”

I last saw Paul at Dayton 2017 with my daughter Jordan KF5GDJ.  K8CX took a great photo of us.  He was a kind man, always pleasant to be around. 
–Scott, W5WZ

W0AIH, KF5GDJ, W5WZ at Dayton 2017. Photo by K8CX

 

QSO with W7IFG Yield Unexpected Surprise!

A late Sunday afternoon QSO with W7IFG on 2018-10-08 via 20M USB yielded an unexpected surprise!  I had just completed a previous QSO with intentions to QRT for supper.  W7IFG asked for a quick QSO, and I obliged.

Scott told me (his name is also Scott) that he had a QSL card from W1AW/5 that listed me as an operator during the ARRL Centennial QSO Party, and he also knew that the two QSOs on the card were made with me, because he had asked for my home call sign.  We briefly discussed how much fun the Centennial QSO Party was for all the participants, then signed off.

The following Friday, Oct 12, I received an envelope in the mail from W7IFG.  I was quite surprised to find not only a QSL card for the recent QSO, as well as the original W1AW/5 card!

QSL from W7IFG for QSO with W5WZ on 2018-10-08 20M USB, and QSL from W1AW/5 for QSO with W7IFG on 2014-11-xx on 17m USB, with W5WZ as the W1AW/5 operator. 

Thank you very much W7IFG!

73, Scott W5WZ