Breaking a Two-Way 10GHz Distance Record

XE2 to W6 in the 2007 ARRL 10GHz and Up Contest

San Carlos, Mexico to Central California: 900-Plus Miles

Presented by Wayne Yoshida, KH6WZ

Frank Kelly, WB6CWN/4C2WH

Gary Lauterbach, AD6FP

Chip Angle, N6CA

Wayne Yoshida, KH6WZ

Steve Miller, W6QIW

Microwave Update 2007

Busting the North American X-Band Record

KH6WZ / San Bernardino Microwave Society / http://www.ham-radio.com/sbms / 14

Busting the North American X-Band Record

During the first half of the 2007 10GHz and Up contest, the North

American distance record for terrestrial X-Band contacts was broken and

re-broken 5 times.

This milestone for ham radio X-Band operations was made possible by a

one-man DXpedition by Frank Kelly, WB6CWN/4C2WH in DL34wt.

The average contact distance was 1,178km (732mi) and the

accumulated score on just two of Frank’s log pages was over 65k points!

Here are some notes on the story. . . .


Where is DL34wt?

XE

Baja California, Mexico

DL34wt

Operation in Mexico is advantageous because there is a long over water path between Southern California and numerous points along the western shores of the Baja Peninsula. This path is a host to the weather that produces coastal ducting, a principal propagation mode.


The Duct

The 900mi shots to AD6FP, N6CA and KH6WZ required

large antenna gains and high power to extend signals

beyond the duct and inland another 100+ miles and over 6000' mountains and up the

California Central Valley.

Coastal ducting is caused by an abrupt change in the moisture and temperature of the atmosphere at the boundary between the relatively cool wet layer of air hugging the ocean and the dry warm air above it. This boundary zone acts like a lens for radio and optical signals which then follow the curvature of the earth for great distances.


The Broken Records

Frank made 53 10GHz contacts from DL34wt on the first weekend.The NA 10GHz DX record was broken five times, first by W6QIW in DM04am at 1315km (817 mi). Steve’s record lasted approx. 7 minutes

Then N6CA and KH6WZ worked Frank from CM94xm (1320km/820 mi), then CM95qi (1426km/886 mi) and again from DM05ax (1448km/899 mi)

Finally, on 8/19/2007 at 0845, AD6FP completed a contact with Frank at CM96wa, a record-breaking distance of 1460km (907.2mi)

The 10GHz Frazier beacon was copied in DL34wt at 1286km - a new DX record for 10GHz beacon DX


Frank’s system includes 2 10MHz references, 2 IF rigs, 3 waveguide relays and 3 amplifier/power levels. The design goals were to minimize power consumption and RF losses.

The DX Station: Frank Kelly, 4C2WH


The AD6FP rig is a dual-bander, with 10GHz and 24GHz capability. The IF is 144MHz for both bands, and all LOs are locked to a single Rubidium source.

Dual-band feed on the AD6FP rig

The Rest of Us: Gary Lauterbach, AD6FP


Chip’s rig includes a Verticom synthesizer and 10W SSPA. The Elecraft K2 is modified for IF-rig-only use (28MHz IF). He uses a straight key and turns the sidetone off when operating.

The Rest of Us: Chip Angle, N6CA


The revised KH6WZ rig, with transverter system on the ground and IF radio placed on the antenna deck. The 30-in. dish is supported with an N6CA folding support structure made with aluminum tubing.

This is the DB6NT-based rig before exchanging the 24-inch M/A-COM dish with the new 30-inch offset-feed dish.

The Rest of Us: Wayne Yoshida, KH6WZ


Everything is mounted at the antenna feedpoint on W6QIW’s rig. The RF runs are short, so waveguide is avoided. A steel offset 30" dish was selected to keep the weight down.

The Rest of Us: Steve Miller, W6QIW


Summary and Observations: Equipment

• The X-Band rigs used can be duplicated; typical performance can be

built with ham techniques and resources

–RX performance: 1dB NF, 25dB gain

• For terrestrial work, there is little improvement below a 2dB system

NF due to ground noise (about 150K). No need to spend $300 on

an EME preamp!

– TX performance: 10W range

–Antenna: 30-in. plus dish

• Bigger antennas are better – But are they practical and

transportable?

• Offset feed dishes have higher efficiency, and are becoming more

popular. Other dishes (prime-focus) are a low side-lobe design and

not designed for efficiency


What Can New Ops Do to Compete?

• A list of goals for new ops

–Know The Code

– 2' offset feed dish minimum

–RX: 2dB system NF

–TX: 1W minimum

–Frequency stability, or at least, make it “predictable”

– This will work 99% of the stations and be affordable

–Bigger stations are better, of course, but not dramatically so

–Make the rig “modular” so improvements can be made in steps

–Partner with another experienced and successful operator


Seeds Planted: Future X-Band XE Contacts

• The next point “down range” near the tip of Baja is over 1000 miles

• XE2HWB and XE2HWH in La Paz, Baja, Mexico now have their own

2W 10GHz radios built by WB6CWN

The record can definitely be extended on the Northern side


References and Resources

MUD

Proceedings of Microwave Update 2001

“A Flip-Switch 10/24 GHz Dual Band Radio”

Proceedings of Microwave Update 2005

“Tripod Stretching for More Stability”

“N6CA Fold-Up 30 Inch Offset Dish Mount”

WebsitesN6CA

http://n6ca.comSan Bernardino Microwave Society

http://www.ham-radio.com/sbms50MHz and Up Group of Northern CA

http://www.50mhzandup.org/

Breaking a Two-Way 10GHz Distance Record

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