Archive for the ‘microwave ham radio’ Tag

October Things To Do – San Diego, CA   Leave a comment

October 3 and 4: Maker Faire® San Diego!

Wayne Yoshida Technical Writer-ExhibitSheet

Maker Faire San Diego is October 3 and 4, 2015, from 10 AM to 6 PM at Balboa Park. Our “Not Your Grandpa’s Ham Radio” theme will feature some new projects as well as some of the old, but popular demonstrations from previous Maker Faire events. Pictured below is a project under construction, I hope to have it completed for this event. It is a homemade 1090 MHz collinear (vertical) antenna that will be part of an air traffic control monitoring station using a software defined radio (SDR).

wayne yoshida KH6WZ tech writer ADS-B antenna



October 15 to 18: Microwave Update (MUD)!

wayne yoshida MUD 2015 Banner

Microwave Update, or MUD, is a yearly technical conference for amateur radio experimenters making, modifying, hacking, building, testing and using the 1,000 MHz and up radio bands. Participants from all over the world gather at these events to share information about operating techniques, radio propagation and radio station equipment. One aspect of this event is the buying, selling and trading of surplus parts and assemblies for these frequency bands, since some items may be difficult to procure in some areas. But perhaps the best thing about MUD is socializing and making new friends from all over the world to discuss common interests and goals.

Preparations for the San Diego MUD are still under way. Last weekend, a few San Bernardino Microwave Society (SBMS) members gathered at Dave’s lab to sort and package some prize and give-away items for the event.

w yoshida MUD San Diego 2015 prize sorting2
w yoshida MUD San Diego 2015 prize sorting1

Left to right: Dave WA6CGR, Rein W6SZ, Pat N6RMJ and Jim KK6MXP sorting and packing some microwave frequency prizes and give-ways.

I hope to see you at any or both of these events!




Maker Faire Bay Area is May 17 and 18!   Leave a comment

Maker Faire 2012-2 010



The big show is coming soon. Last year, over 120,000 people attended this science-art-food-engineering-fun-educational event.

This year, my team (Dennis Kidder W6DQ, Brian Yee W6BY and Marty Woll N6VI) will bring their newest ham radio projects to show. We will continue with my original theme called “Not Your Grandpa’s Ham Radio.”

A group of University of California, Davis (UCD) engineering students will join us to demonstrate their experiments and projects. These new engineers are getting a great head-start by doing hands-on, practical experiments and projects that go beyond their lecture and textbook learning.

Read my LinkedIn post to understand my personal passion about amateur radio, Makers, the Maker Faire and education.



Microwave Contest Locations in Southern Calif   1 comment

Microwave Contest Driving Directions from the Glenn Allen KE6HPZ List (Originally from SBMS Newsletter, January 2004)


This is a copy and paste (with some minor edits) from a post by SBMS member Glenn, KE6HPZ and some additional postings from other members. I have operated from many, but not all of these locations, so verification with new maps or other means might be a good idea. If you have a correction or would like to add a “known good” contest location, please let me know and this list can be updated.

Some pictures will be posted as I find or make them. . . .

Click the link below for a PDF version of this list:

Microwave Contest Driving Directions from the Glenn Allen KE6HPZ List

**Update** Thanks to Dan, K6NKC, here is a link to the KE6HPZ list on the SBMS website.

Goleta State BeachDM04bk — This location has a good shot to the Baja gang. It is DM04bk, and we parked right in the parking lot of the Goleta State Beach. In the Santa Barbara area, take the 217 Highway south from the 101 Highway, about 1.9 miles. Get off the freeway where it says Goleta State Beach, and cross over a bridge and you will be entering into the beach parking lot. Turn right, and go about a ?? of mile down the parking lot till you find a place that has no trees in the way, and shoot over the water. (N34 25′ 0.6″ W119 49′ 58.2″)

Summerland (Santa Barbara) Lookout Park – DM04ek – To get to this location, get off at Evans Street in Summerland, near Santa Barbara. You can try working from the park which is on the south side of the freeway, but there are trees in the park, and we found that parking lot was full. For those that have to work out of the back of their trucks this place didn’t work. So, we found a better spot, still on the South side of the freeway, just .2 miles east of the park. Get on the southbound on-ramp to the 101 freeway, which runs beside the freeway. Right before the on ramp enters the freeway there is a small road the will break off to the right. This is Finney St, and it goes over the railroad tracks and goes into a parking lot. From the parking lot it goes east down the hill. We just pulled of the side of the road, and worked Baja. This spot is DM04ek (N34 25′ 09.1″ W119 35′ 46.1″) I used an 11 element 440 beam to get into Signal peak, or one of the San Diego machines.

Ventura (Grant Memorial Park)DM04ig – To get to this location from North bound 101 get off at California St. There is no South bound off ramp for California St. Get off of the next exit (Harbor blvd, or Seaward Ave) and get back on the North 101 freeway and get off at California. Head up California (N) till you hit Poli Street (California Tee’s into Poli). Turn Left onto Poli, and turn right on the next street, which should be very small street. (Brakey St). It winds through some houses, and climbs up the hill. You will come to a four-way intersection, of small roads on the hill. Take the left or lower road a couple of hundred feet down the road, to a turn out. The location is DM04ig (N34 17′ 05.3″ W119 17′ 41.3″) at 300 ft above Sea Level.

Point Mugu – DM04lc – The operating position of Point Mugu is right next to the very huge rock. On the east side of the Rock there is a parking lot. It is on the south side of the road. So you cannot turn into the parking lot going north bound on the 1. Only the southbound traffic can turn in to the parking area. So if you are going North on the 1, continue past the rock, and turn into the parking lot on the North-west side of the rock, and come out of the parking lot and head south on highway 1 to go around the rock, and go to the other parking lot. The location is DM04lc (N34 05′ 13″ W119 03′ 43″) I have found that this location is blocked to DL29cx, and DM10xl by Catalina Island.

Point Dume – DM04na -Point Dume itself has a bunch of No Parking Tow away signs. So I set up on the South side of the road a couple of miles North-West of Point Dume. There is a large dirt pull off that worked great. Its location is DM04na (N34 02′ 09.8″ W118 51′ 27.4″) I was also able to work people on PV across the tip of Point Dume. Catalina Island gets a little bit in the way when the Baja guys are in DL27.

Las Floras Canyon – Somewhere near Las Floras Canyon Road at Highway 1. Stay in the Floras area. If you go too close to Malibu, you will be below 10 miles to the Point Dume location. If you go too close to Topanga Canyon you will be shooting through PV.

Palos Verdes North and South – DM04ts – The easiest way to get to Palos Verdes is to come in from the 110 Freeway. Get off at PCH (Pacific coast Highway) Highway 1(N33 47′ 26.1 W118 16′ 55.0). Go West 3 miles on PCH, and turn left on to Crenshaw (N33 47′ 31.6″ W118 20′ 00.6″). Go 3.4 mile on Crenshaw up the hill. Turn right on to Crest (N33 46′ 07.4″ W118 21′ 50.1″). Go 1.6 miles on Crest. Go through Hawthorne Blvd, 150 feet. Pull off to the side of the road, and this spot works Frazier and other north locations. Its location is DM04ts (N33 45′ 41.2″ W118 23′ 39.8), and it is 874 ft above Sea level.

PV South – DM04tr – Turn around from the North location, and turn right (South) and go 1 mile down Hawthorn Blvd. The location in on the south side of a divided road, so pass up the location, and make an U-turn at the Salvation Army driveway. Head up the hill to the vista point. There is parking for about 4 cars here. This spot points south to San Diego, and Baja very well. This location is DM04tr (N33 44′ 53.3″ W118 23′ 39.4″). It is 535 FT above Sea Level.

Huntington Beach I – DM03xq – Huntington Beach works well to Baja. During the middle of the day it might be hard to find a parking spot. Pacific Coast Highway (Highway 1) runs along the beach for miles. So if you can get into one of the parking spots, just point out to Baja. Metered parking DM03xq. The Huntington Pier is DM03xp (N33 39′ 17″ W118 00′ 16.2″). Take Beach Blvd south off of the 405 about 5.8 miles to get to PCH.

Huntington Beach II – DM03xq – An alternate DM03xq to number one above is the park that overlooks the Bolsa Chica wetlands. This place is called Overlook Park. This location is accessed via Seapoint, off PCH. Take Seapoint to the east, and at the intersection of Garfield Ave, continue thru the pipe gate, up the hill. Continue to the farthest parking spaces, near the handicap parking slots. There is plenty of parking, and not much visitor QRM, but no restrooms or water fountains. This location gets very windy in the late afternoons. This location is not good to the south to San Diego or to Mexico via a direct path. Marginal signals may be possible via a reflection/refraction off Catalina Island or the oil derricks offshore to the west and over the water. Note – please respect the privacy of the residents there. Complaints may lead to closure of the park to the public. (KH6WZ)

Signal Hill North and South – DM03wt – To get to Signal Hill you have to exit the 405 Freeway at South Cherry exit. Head south on Cherry Ave .8 miles and turn left onto Skyline drive, and head up the hill. When you get to the top of the hill, and you can turn left into the park at the top. You can work east (Heaps) and North (Frazier) and west up the coast to Ventura and beyond. To work San Diego and Baja, you pass by the park and continue to Southward about .3 miles on Skyline, to a dirt field on the right, (N33 47′ 54.7″ W118 09′ 34.1″) DM03wt

Fairview Park, Costa MesaDM13ap – this is where the SBMS Tune-Up Picnic is held. Address is 2501 Placentia Ave. It is near the intersection of Placentia and Adams. Across the street is Goat Hill Junction, a miniature train station. The gravel parking lot may be used if parking at the part is not available. – NOTE this is only 9km away from Huntington Beach (DM03xq) – too close for the ARRL contest, minimum 16km/10 miles.

El Segundo (North side of Hill Top Park) DM03tw – To get to this park, get off of El Segundo Blvd, and head west about 1.4 miles. Turn right on Sepulveda Blvd (Highway 1). Go 0.2 miles and turn left on Grand Ave. Go 0.6 miles to Maryland St, and turn right. Hill Top Park is on the left and go down the street 700 ft to the public parking structure on the left. Go up on the parking structure – there is no roof, so overhead clearance is no problem, except for low-hanging pine tree branches. Go to the parking locations that are marked on the map, and point between the trees. This is the highest point that you can get to in El Segundo at a high altitude of 176 ft, plus the height of the structure. The only thing in the way from this location is piece of PV that is 250 ft high. The location of the structure is N33 55′ 14.7″ W118 24′ 25.1″

Highway 2 Overview (La Canada) – DM04vf – From the 210 Freeway you will exit Highway 2 Angeles Crest Highway. This is National forest area. This area requires daytime headlights, and you will get a ticket for not having them on. Be aware that the rangers will write you up for having a battery out in the open, because of fire danger. So leave the battery in the vehicle, and use something else heavy to keep the tripod from blowing over. To get there, head North up the hill 2.5 miles and you will see a large dirt pull-off on the right. It has an elevation of 2000 ft, and it talks south. But lower Baja locations were weak to this location. You have a large mountain right behind you so you would have to do a bounce shot to get anywhere else. DM04vf (N34 13′ 41.3″ W118 11′ 09.6″)

De Soto and 118 Freeway – DM04qg – It is located just north of the 118 Freeway and get off at De Soto Ave. It has talked to both the closer and farther away Baja locations. Just find a high spot above the freeway DM04qg (N34 16′ 32″ W118 35′ 17″) around 1300 ft elevation.

Secret Site 51 (Loop Canyon) – DM04ti Secret site 51 is a great spot for talking all over the LA Basin and much south. It is located at (N34 21′ 13.4″ W118 24′ 58.4″) DM04ti at an elevation of 3918 feet. It takes about 30-40 minutes to get up there, from the 5 and 14 highway spilt. To get to there, get on the 14 freeway (3.3 miles) and get off at Placerita canyon road. Turn right, and go south-east (5.1 miles) on this road till you hit Sand Canyon Road (N34 22′ 51.8″ W118 24′ 48.4″). Turn right on Sand Canyon road for 2.9 miles up to Bear Divide (N34 21′ 35.1″ W118 23′ 33.1″). Turn right, and go up the road (3N17) (2.9 miles). You will come first to Contractors Point (repeater site). Continue down the road 1 mile to Fire Camp 9. Drive slowly through the camp, and go 0.4 of a mile up the hill, to the repeater site. Park on the side of the road about 100 ft down from the gate at the repeater site. This will give you a clear shot at Mexico, and a clear shot at Frazier. If you have a portable rig, you can walk up to the top of the hill and have a 360-degree view.

Whitaker Peak – Whitaker peak is close to the 5 freeway, and it takes about 10 to 15 minutes to get up there off the freeway. It has a good shot South. It does not have a shot north. You can do a bounce shot to Frazier off one of the hills to the east. It is located at (34′ 56.2″ 118 deg 43′ 08.8″) at 3646 ft. It is between Castaic Lake and Pyramid Lake. To get there going north on the 5 freeway, get off at Templin Highway (N34 34′ 20.8″ W118 41′ 27.6″). Go under the freeway and head north about 2.4 miles on the old road, running beside the freeway. On the left you will see a small one-lane road. It is labeled 6N53 (N34 35′ 05.6″ W118 42′ 56.7″). If you are going south on Highway 5 you can get to the old road, by get off at the Brake Inspection area. Just at the end of the area, were the road is about to get back on the freeway, there is a little road that will turn off to the right (N34 35′ 03.2″ W118 42′ 36.8″) that will take you to the old road, in a few feet. Turn right and you will be at the 6N53 in a ?? of the mile. A few feet up the 6N53 there is a fork in the road. Take the left fork and start heading up the single lane that is a somewhat asphalt road. This road is about 1.8 miles long. You will have a microwave repeater site in front of you, and a gate in front of you. Look behind you on the ridge and you will see a small dirt road running the ridge. Run up the ridge, about a ?? of a mile to a high spot. This is room for about 2 trucks. You will have to do a couple point turn, to turn around, to come back down the hill.

Frazier Peak- DM04ms – (N34 46′ 28.4″ W118 58′ 7.3″) Frazier Peak is 8400 ft mountain that has good shots all directions. There are some trees to the South. It takes 45 minutes to get up there from Highway 5. From Highway 5, get of the Frazier Park exit. Head west on Frazier Mountain Road 6.9 miles. Turn left on Lockwood valley road. Go 0.9 mile down the road. Turn left to into the Ranger Station (8N04) Go through the ranger station, and head up the road about a mile up the road you will go past a campground. Continue up the road about 6 miles to the top of the hill. There will be several forks in the road. There should be a sign that points toward the fire lookout.

Comments and Updates from the SBMS Reflector (old)

PALOS VERDES updates, August 2009

One of the best locations for working north is from the rear parking lot of the Rancho Palos Verdes City Hall.

From: Glenn Allen

A few hundred feet away is a Giant Repeater site, on the back of a church school.



I have operated for a short time for a UHF/VHF contest from the back of the church parking lot.  But the RF noise floor was high. A parking lot to the north of the repeater site is a rest home, and I pulled into the back of that lot for a quick contact, but it was hard to hear the coordination radio.  I was hearing News, weather and sports…

Doug Millar wrote:

This is probably the only turn out on the North side of PV with a good NW SE look. It is 300ft above PCH and sea level and easy to get to:  At the corner of Pacific Coast Highway and Anza Blvd. go south. Anza turns into Vista Montana. Go up the hill to Via Corona and turn right. A short block and you should be at a cul de sac that overlooks the area. I doubt if it is 10 miles from San Pedro, but it is plenty from Signal hill:  33d48′ 23.09″ N 118d21′ 59.09″ W.


Alternative to Mulholland: NIKE PARK – DM04rd

Lat and lon for Nike Park (DM04rd): 34 07 42.25N, 118 30 47.00W. You will need to take the 405 freeway to get to it. Take the Skirball Center Dr/Mulholland exit. There are a couple of turns you need to make in order to get on Mulholland. Do not take Sepulveda unless you want to take a scenic route through some neighborhoods.

Also, do not try to use a gps nav aid or Google maps to get you there. It will try to send you a way that you cannot take. Just follow Mulholland Drive.

This place is a park and according to the signs the gates close at 6pm. That is gate on Mulholland that closes at 6pm.  The road is a bit rough in spots but even in my Honda Civic it is still drivable. You just need to be careful.

Chris n9rin

From Ed, W6OYJ of the San Diego Microwave Group:

Mount Soledad – DM12ju in San Diego

I am writing these notes for anybody to use getting to our famous 822 ft mountain. (More real DX has been worked from here than from Pike’s Peak!) Getting to Mount Soledad in San Diego is easier now, but still confusing. Most maps do not show the following changes. The name of Ardath Road has been changed to La Jolla Parkway. The Hidden Valley Rd intersection has been moved.

1A. If you are arriving on I-5 from the South (Downtown San Diego), take the La Jolla Parkway Exit (It used to be named Ardath Road). Follow it over the summit, stay in the left lane. Turn left at the first signal onto Hidden Valley Rd. Go to Step 2.

1B. If you are arriving on I-5 from the North, Stay on I-5 at the I-5/I-805 junction. After passing Gilman Drive, take the Hwy 52 East (Yes East!) Exit and continue about 3/4 mile on Freeway 52. Take the Regents Road Exit, turn left under the Freeway 52 overpass, and turn left again to get on Freeway 52 WEST. Move into the far left lane and continue as it goes up over I-5 and merges with La Jolla Parkway. Stay in the left lane. Turn left at the first signal onto Hidden Valley Rd. Go to Step 2.

1C. If arriving on I-15 from the North, stay right and take Freeway 163 at the I-15/Fwy 163 split. Then after a few miles take Freeway 52 West. Go several miles, stay on 52. After passing the Regents Road Exit move into the far left lane and it will merge with La Jolla Parkway. Stay in the left lane and turn left at the first signal onto Hidden Valley Road. Go to Step 2.

2. Continue ahead on Hidden Valley Rd. Pass the stop sign. Follow the double yellow lines as it curves while gaining altitude. Eventually you yield and turn right at a Tee-intersection onto Via Capri. This steep road climbs through residential areas until it reaches the roadway summit with a sharp right turn at a yield sign. Stop here at this blind corner, signal a left turn, and wait until the traffic from the right is clear. They do not stop! Turn left into Mt Soledad Park. (Gate here supposed to open at 7 A.M.)

3. On your immediate left is a paved parking lot (overflow parking). The north point of this parking lot is a good spot for working stations to the NW, N, and NE. It is blocked by the higher part of the Park toward the ENE, E, and ESE. From this same parking lot, on the side next to the Park entrance road, you can find a spot with a view to the SE, over Downtown San Diego. This location works for direct shots to Baja. The problem with this location is that you cannot work Arizona or some of the SD locals due to the terrain blockage to the East. There are usually very few tourists here.

4. The main part of the Soledad Park is the area just east and NE of the big Cross at the summit. As you proceed up the park road, stay to the right as it goes counterclockwise around the Cross. There are only four parking places in the first parking area East of the Cross. These are closest to where you want to be, but you have to be lucky to get one. Further around the Cross on the North Side are about 20 parking spaces. This is where most of the tourists congregate, but they will find you in either spot. From these two locations you can attempt to work Arizona. The first spot is best overall, though due to recent concrete “improvements” at the Veterans Memorial surrounding the Cross, you will have to move North a bit to allow direct shots toward Gaviota (304 degrees true).

5. True beacon headings from Soledad: Palos Verdes=314, Frazier=324, Santiago=344.5, Mt San Miguel (San Diego)=119. The grid square here is DM12ju.

6. Bulletproof shielding and filtering is a must for Mt Soledad due to megawatts of TV, FM broadcast, paging, and commercial radio comms.

7. If you want to go home on I-5, you will have to retrace your movements back to Regents Road and again do a U-turn under the 52 Freeway, so you can go west and take the “Los Angeles” ramp to I-5 North.

Closing Note

If you are a licensed ham operator already, and want to try a new challenge, visit the San Bernardino Microwave Society (SBMS). Meetings are held the first Thursday of each month in Corona, Calif. and are broadcast on W6ATN/

For more SBMS information, go to

Harris-Farinon 10 GHz Amplifier for Amateur Radio Use   17 comments

The ARRL 10GHz and Up contests are coming up soon (August 17 to 18 and September 21 to 22), so I thought I’d re-publish my article that originally appeared in The Proceedings of Microwave Update 2005.

The Harris-Farinon Model SD-108175 / 076-108687-001 solid state power amplifier (SSPA) has been seen globally on the surplus market over the last few years. This amplifier is a part of a large rack of equipment running on the traditional 24VDC, positive ground telecom power system bus.

In its original form, the amplifier is very robust and heavy, since it is rated for continuous duty, Class A operation. Figure 1 shows the unit as received. It is mostly heatsink, and the RF unit, where the microwaves are amplified, is the tiny silver box on top.

The SSPA unit (Model SD-108175) measures about 15-1/2 inches wide, 4-1/4 inches high and 10 inches deep, and weighs over 15 pounds. The little silver box (part number 076-108687-001) with SMA isolators at the input and output, is about 3 inches wide, 1 inch high and 2-1/2 inches deep.

Important: Be careful if you see these units for sale, I have seen some inaccurate descriptions of these units – for ham radio use, the only item we want is just the amplifier (076-108687-001) and not the heatsink/chassis assembly or the power supply DC-DC converter.

Farinon10GHz2wSSPA (2)

Figure 1. The Harris-Farinon 10GHz amplifier is very beefy, but it is mostly heatsink. The little silver box is where the RF is amplified.

I took the unit to Dave Glawson’s lab (WA6CGR) to see if we could integrate this SSPA into my X-band rig. It is a 1W unit, but I have several that put out as much as 3W on 10368 MHz. I purchased several of these units at a very reasonable price, and am pleased with their performance on the 10 GHz Amateur Radio band.

The terminals on the amplifier as well as the power supply PCB are marked, simplifying some of the guesswork about what-goes-where. The amplifier includes a “POWER MON” SMA female jack, which should probably be capped with a 50Ohm termination to prevent oscillations or weird things from happening while the amplifier is operating. A “DET OUT” pin is useful to verify amplifier operation.

It may be prudent to read Chuck Houghton’s article, “Above and Beyond, Microwave Stripline Retuning Procedures” on tweaking circuits before any “poking around” is done on any SHF amplifier, to prevent damage. Links to references are at the end of this article.

The first step is to power it up and verify operation in its “as-is” state. With about +17dBm (about 60mW) input, power output is about +35dBm, or a little over 3W at 10368MHz. Current consumption is about 2.6A during standby and about 3A at 10V with RF applied. Dave and I wondered whether or not we could tweak the amplifier to get more power out, so we took a look under the lid of the little silver box, see Figure 2. We decided not to tweak anything inside the tiny box.

Figure 2. A peek inside the SSPA. No tuning is required to get two to three watts output on 10368MHz.

Figure 2. A peek inside the SSPA. No tuning is required to get two to three watts output on 10368MHz.

Since the amplifier passed its first tests, the next step is to re-package the unit so it would be more suitable for portable and roving operations. Certainly, a weight reduction could be done by shrinking the size of the RF module heatsink, and adding a fan or two.

Since the amplifier passed its first tests, the next step is to re-package the unit so it would be more suitable for portable and roving operations. Certainly, a weight reduction could be done by shrinking the size of the RF module heatsink, and adding a fan or two.

The DC-DC Converter
The original power supply board appears in Figure 3. A casual inspection of the unit showed that the 24V input was buck-regulated down to 12V, and then further reduced to minus 2.1V for the bias and +10V for each stage in the amplifier. The DC-DC power supply looks like it can be modified and re-used, by applying 12VDC where the brick converter has its output. However, this modification was not attempted.

Figure 3. The DC-DC supply board. A 24V to 12V brick converter is mounted to a 14-1/4 inch by 7-1/4 inch heatsink under the PCB. The existing DC-DC converter may possibly be modified to make the unit work on 12VDC input. See text.

Figure 3. The DC-DC supply board. A 24V to 12V brick converter is mounted to a 14-1/4 inch by 7-1/4 inch heatsink under the PCB. The existing DC-DC converter may possibly be modified to make the unit work on 12VDC input. See text.

I thought a better, lighter, more modern power supply could be built fairly easily, and the large heatsink for the power supply could be deleted.

With Dave’s help, I made a simple DC-DC converter using a Linear Technology LT-1083 adjustable regulator and a few resistors for the +10V supply. The negative bias supply was made from a surplus 99-cent DC-DC converter. I built the power converters into separate chassis boxes, since I had them on-hand. A single box is also acceptable.

Like all FET power amplifiers, one must make sure that the minus (gate) bias supply is always connected before the supply voltage to prevent damage to the devices. I am sure there are several solutions for power-on sequencing to prevent this from happening, including relay or other switching or timing schemes. However, I chose a very simple route: I simply wired the minus voltage directly to the amplifier bias feed-thru capacitor, with no switching in-between. The plus 10V supply line is switched to the amplifier via a power relay, actuated by the sequencer. This way, whenever the rig is powered up, the minus bias voltage is “automatically” applied (it was never off in the first place), and the plus 10V is applied only when the rig is put into transmit mode.

I had a pair of 24V brushless DC motor fans in the junk box, so I am using these to blow on the heatsink. Since I have both 24V and 12V running around in my rig, I wired up a two-speed fan control using a pair of spare relay contacts. When the radio is in the receive mode, 12V is applied to the fans, reducing the noise. When the rig goes into transmit mode, 24V is applied to the fans, running them at full speed.

The final result is shown below. The amplifier is mounted in one of my 10GHz rigs, “Ms. June.” 3 The SSPA puts out 2W at the antenna port, and now measures about 4 inches by 7 inches by 1-1/2 inches, including the cooling fans. A re-labeled, surplus CB panel meter (1mA movement) connected to the DET OUT pin indicates SSPA operation. (Update: Ms. June was cannibalized for parts. However, many of her parts were used in other radios, including my latest, record-setting 10GHz transverter.)

Figure 5. The Farinon SSPA installed in “Ms. June,” my latest 10GHz rig. Two watts appears at the waveguide port at the antenna relay in transmit. The DC-DC converters are enclosed in separate chassis boxes, and can be seen just to the right of the amplifier. A re-labeled surplus meter monitors amplifier operation.

Figure 4. The Farinon SSPA installed in “Ms. June,” one of my early 10GHz rigs. Two watts appears at the waveguide port at the antenna relay in transmit. The DC-DC converters are enclosed in separate chassis boxes, and can be seen just to the right of the amplifier. A re-labeled surplus meter monitors amplifier operation.


1 – “Above and Beyond, Microwave Stripline Retuning Procedures,” by C. L. Houghton, WB6IGP, San Diego Microwave Group:

2 – The surplus TDK DC-DC converter is described as a “5V in +/-5V DC/DC converter” at MPJA Online, as part number 1042518. This unit is under a “closeout” deal, so supplies may be limited. Go to, and look under “Power Supplies,” “DC-DC Converters.” Their phone number is 800-652-6733, 9AM to 5PM Eastern Time, Monday through Friday. Although probably not necessary, I removed the TO-220 device from the board and re-mounted it to the metal chassis box for heat-sinking.

3 – Most of the SBMS members have names for their rigs, mainly because, as many of you know, microwave radios tend to have personalities of their own. Ms. June is my sixth 10GHz radio re-build. “Morpheus” was my first attempt, see CQ magazine for December 2003 and January 2004 for my dubious start on the microwave bands.