2 Meter LDMOS Amp Project

Post Script - After the trip I got the idea in my head that having a LDMOS amp for 2 meters that can do up to a full KW would be a fun project. I figured having several more db when out and about putting grids on wouldn't hurt, and adding another Yagi will make me EME capable for a trip to Wyoming next summer.

Here are the photos of the amp project. I'm using a -10db pad on the input so 7 watts drive from the Elecraft K3/internal transverter gives me 550 watts. That's a very comfortable level for for testing.

I did finally swap in a -8db pad for 850 watts out - that was the design power level goal, and about what my generator can source when in the field. The amp draws 25 amps @ 48 vdc. I added a small fan inside to move some air over the output coax and LP filter when doing modes like JT65b.

I set my 9 element Yagi up in the driveway for a few days and made nine EME contacts, so the project seems to have worked out well. :-)

See Jim, W6PQL excellent web site for more info and top quality modules and parts.

The smoke test. 7 watts drive = 550 watts thru a -10 dB pad.

It all fits in a 8x12 chassis. My sequencer controls FET switches for the 48 vdc and 12 vdc supplies.

That is one mighty big heatsink, a 4 inch muffin fan will sit on top too.

Home Ground

We're almost in the driveway after a 10 week jaunt around Saskatchewan, Montana and Wyoming. I put 21 grids on from a variety of interesting and high places. Es season on 6 Meters was kind of punk, but when it did double-hop I tried to be there. It was fun to develop an effective 2 Meter station to take out in the field with the truck for some 1200 - 1300 miles meteor scatter contacts. Two EME contacts were made also.

Thanks to all for the many fine contacts! LoTW is up to date.
Gene, KB7Q

Heading home to familiar mountain ranges under summer skies.

DN54fw - redux and EME #2

I ran back up to DN54 on te Beartooth Plateau last evening for several hours. I had a few sprinkles and some lightning setting up, but then it cleared off nicely. I was able to add ND0B, W7XU, KF7CQ, WA5TKU, KS7S, and N0LWF to the 2M meteor scatter log.

During a lull in my skeds the rising moon was just too tempting a target - so I dipped down to 144.140 MHz aimed at the moon as it was 10 degrees above the horizon and immediately heard a JT65b signal in the speaker. I figured it was someone fairly neary by doing EME. When it decoded it turned out to be I2FAK with a huge moonbounce signal. Realize I'm just using a 9 element Yagi, 200 watts, 50 feet of LMR400, and the just the pre-amp in the TE brick when you look at this:

Mama Mia! Nothing like a random 2 meter EME contact to finish off the DN54 visit.

DN54fw - Beartooth Plateau, Wyoming - A great outing

I worked 11 stations last night on 2M: W7MEM, K6EME, NQ7R, WQ5S, W9JN, WB0ULX, N6ENU, W8BYA, AA7A, K7MAC, and WA7GSK. There were some monster blasts that made me turn the AGC back on in the K3 to keep from killing the speaker. This is a dandy location - a negative horizon in most directions and so quiet.

Tonight I'll go back up for a short session i.e. 8/13 0330z to 0700z, and call CQ on 144.144 MHz anytime I'm between skeds.

Pointed south toward AA7A at sunrise. Lots of rolled over rocks from bears hunting for grubs, so refueling the generator at 3 AM was a "keep looking around" job.

Pilot and Index Peaks out toward K7MAC's way, and Beartooth Butte catching the morning sun to the northwest.


DN54fw - The Perseids Plan

Ah, DN54fw -- we stopped by on the way to the motel to check out the very best place to set up.

I'll be QRV from 11,000 feet on the Beartooth Plateau in Wyoming from 0600z to 1300z August 12 and again on August 13. No Internet up there, so contact me for a sked time slot if you like. I'll post my skeds here when I get a few more lined up.

Random Operation - I'll call "CQ U 4" on 144.140 MHz meaning I expect to hear you on 144.144 MHz. When I do I'll start calling you there so we can move off the calling frequency quickly. If I sense company on 144.144 MHz I'll not use ST, rather your suffix and R26, RRR, and 73.

I'll have Internet back at the motel in Red Lodge, MT and be up on Ping Jockey.

DN46fj - Canyon Ferry Lake

We're on our way to the RV dealership in Helena to get some work done on the trailer. So we overnighted on the shores of Canyon Ferry Reservior. The Perseids made 2M operation go quite well. KB7ME, ND0B, KA9CFD (1165 miles), K0SIX, N0LWF, WB0ULX, and W9JN (1062 miles) were logged.

No pictures! There is so much forest fire smoke there is literally nothing to see, the mountains just across the lake even disappeared, but not before I noted the azimuth of the notch to shoot thru for eastern contacts. The compass built into my hand-held GPS is one of the most important tools on these outings. The meteors were quite good both last night and this morning - I had to quit early so I could get to the repair shop on time.

DN45ts - Sheep Mountain, MT

Later then I had hoped, that's the 2m beam still on the ground. Looking east of course, Indiana is out there somewhere.

Crazy Mountains to the north, I counted nine mountain ranges.

Not much room to turn the truck around - Yellowstone River glinting on the right.
Enough to say W8BYA has a great signal, even 1308 miles out. I was still setting levels.
An interesting morning - I used Google Earth to find my way to the top of Sheep Mountain in the dark. The trail I took up was more of a cow path then a county right of way, 4x4 prevailed. On the way down I missed the turn and drove down the very nice access road use by commercial users of the site on around the other side of the mountain to within 50 feet of a county road - oops a locked gate blocked the way. I back tracked 4 miles and finally found my way out. I need to bring a bag of bread crumbs next time.

Anyhow it was a fun morning and a spectacular sunrise. 2 Meter stations worked: W8BYA (1308 miles), W9JN (1010 miles), WA7HQD, KF7CQ, KS7S (982 miles), K6EME, N6ENU, and N7EA.

DN25/35 Sula Peak

The view from Sula Peak looking at the Bitterroot Range. DN25/35
This morning I rolled out of Missoula early and beat-feet 90 miles down the Bitterroot Valley to Sula Peak, 6175' MSL. As promised I was QRV 2 meters by 12:30z. This was a double-gird as the parking area just in front of the fire lookout sits on the DN25/DN35 line. AA7A, KS7S, W7MEM, KC6ZWT, WA7HQD, K6EME, KR7O, and N0KE were worked fairly easily.

Now that the TE amp is working well it draws 28 amps, it tripped the thermal breaker on my Astron switching supply at one point. I need to re-connect a jumper inside that I installed to make the fan run all the time. I used a separate supply to power the K3. The four inch fan I have on the fins of the amp does a great job keeping things from going past slightly warm to the touch.

As I left a storm was rolling in. Good timing I'd say.

DN25/DN35 Double Header - Tomorrow

I'll head out to Sula Peak early tomorrow morning and shoot for a 1230z start time. This will be 2 meters only. I've been here before and I know that spot-to-squat that gives me the DN25/35 line.
I'll be on 144.144 MHz  first sequence FSK441, I should have Internet access. If Ping Jockey is still down I'll use the ON4KST 144/432 region 2 chat.

DN25/35 I did a 6M op from here two years ago.

I've been to the mountain - putting the W7GJ home station on the air

This morning four of us hamsters met up at Lance, W7GJ's QTH and uncorked his big arrays to work KH8/ZL1RS and KH8/W7GJ on 6 and 2 meter EME. A few challenges along the way, but we "got 'er done" as they say.

I'm thinking of a 2M trip down to Sula Peak for DN25/35 double grid operation. Any interest?

DN76cj Miles City, MT and R&R in Bozeman

We tried a different RV Park in Miles City this time and had a better horizon in most directions. I completed 6M meteor scatter contacts with W7KNT, N0LWF, W7MEM, and K7MAC. On 2M I worked W8BYA, WB0ULX, ND0B, WA7HQD, W9NHE, AI5I, K7ND, and K7MAC. I even had a brief double-hop 6M Es opening and worked 8 folks.

Time to leave eastern Montana, it is going to get hot out here, 95+ degrees temperatures are in the weekend forecast.

The TE Systems 2M amp is fixed.  It was the crappy factory solder job on the SO239 output connector - I'm glad I was able to trouble-shoot it in the field and had brought my soldering station along.

We're back in Bozeman for a few days, then off to Missoula to put the W7GJ home station on the air via EME to try and work Lance and Bob out on the KH8-dxpedition on both 6 and 2 meters. Lance kindly left me a 30 page manual on how to run his station. That's "run", NOT "ruin". LOL.

I'm thinking I'm going to just take the 2M gear with me to western Montana and do a more casual grid operation from there.

LoTW has been updated, and I did all the paper QSL card requests I found in our stack of mail last night, they'll go out today.

A big thanks to Mac, K7MAC for getting me to take 2M gear along - the 2M meteor scatter contacts were a whole bunch of fun, especially when I'd go out and find a really good high spot with the truck. Working W5UN on moonbounce was frosting on the cake.

Here's a visual summary of the trip so far:

DN75ax - Tongue River Road, Montana

DN75ax, aka "The Big Open"

Looking for W8BYA, I worked Gedas in about 3 minutes, nice 1100 miles QSO.
Up and out early for the 30 mile drive south into DN75, I was QRV by 1155z and K7MAC was waiting. DN65xx was just down the road too, but when I looked to see if I could do a double gird thing I had a road-cut blocking my horizon.

The 2M amp continues to be a pain. At one point I whacked it a good one and it started working again so I could complete with NQ7R and WA7HQD. There must be a cold solder join in there somewhere - I'll go looking later today. At least I've isolated the problem now.

Great heads-up on everybody's part when I lost the Internet. It was a super marginal signal and once the day started heating up I lost the path to the cell tower - God only knows where that was. I had just put the list out on PJ so I worked my way through it as best I could, and then called CQ in quadrants.

2M stations worked on meteor scatter: K7MAC, W8BYA, ND0B, KC6ZWT, AA7A, W9RM, KR7O, NQ7R, and WA7HQD. Nine stations for a morning's outing is fine with me.

Post Script - I pulled the bottom cover off the 2M amp this afternoon and the solder joint at the center pin of the output connector sure looked suspect. I re-flowed that, so we'll see if that was the problem.  It does put out an even 200 watts into a dummy load with no oscillation.

Man with a plan - DN75

The 2 Meter  set up gave me fits this morning. I'd work a station out to 1100 miles and then have trouble completing with a power-house like K7MAC at 600 miles. Sheer persistence paid off with 10 contacts. Sometime didn't seem right.

 Turns out the TE Systems amp is oscillating and hanging up at times refusing to go back to receive, and acting generally weird. I tried ferrite clamp-ons on the power leads, different length of coax, and checked the screws on the antennas T match and looked at the SWR etc. trying to fix the problem.

Big clue - Putting the amp into a dummy load fixed the problem, so it looks like just too much RF in and around the trailer - I know the house wiring for the RV runs through the ceiling. No matter how high I get the antenna it still persists.

The good news is that when the amp is happy it still puts out 200 watts. More good news was that I brought enough tools and a dummy load along just in case!

Anyhow I'll try DN75 2M only tomorrow with just the truck. Here's the plan given that I don't expect to have Internet:

I should be on 144.144 MHz around 1200z tomorrow morning. I'll call CQ generally east for 30 minutes, then shift to generally westerly 30 minutes and then south 30 minutes etc. If you hear me say something on Ping Jockey to help folks figure out what I'm doing. Who knows maybe I'll have Internet, but that's pretty "out there" country-side. I will send a 73 tone to help folks know we're complete.

The two times I've used the truck I don't remember having this issues, so that's a good thing.


DN68fl - Nelson Reservoir. MT and EME contact #1

I was ready for W5UN on my moon rise. Haven't made a 2M EME QSO in over 25 years.JT65b rocks.
The last 50 miles to the border was a narrow, rutted road so we chugged along at 35 mph when we could. Got set up here on the reservoir and worked 6M meteor scatter K7MAC, NS7K, and W7KNT. W7MEM logged on 2M. No Es at all.

Working W5UN on EME was a hoot; not bad for 200 watts on the wrong end of 50 feet of coax and a 9 element Yagi. I can hear Dave in the speaker as I type this.

Up at dawn the next morning and lots of 2M MS action: WB0ULX, K0RI, AA7A, WA7HQD, KU7Z, K7MAC, NQ7R. Slipped over to 6M and worked W9RM.

DO60aq - Saskatchewan Landing

Forest fire smoke making a hazy day on the South Saskatchewan River.

It seemed to take us all day to go 170 miles, talk about leisure travel. Probably that stop at Tim Horton donuts had something to do with it. Six meter opened a bit and managed 21 contacts.

Shifting over to 6M meteor scatter after dinner logged K7MAC (2x), N7CW, KF7CQ, VA6SW, KR7O, W7KNT, NS7K, NQ7R, W7OUU, and VE5UF.

Now that is one bad boy  meteor burn from KF7CQ.

DO53td - The Battlefords Provincial Park, SK

Putting things together. I fixed the coax routing on the 6M beam right after this picture.

This particular campsite has almost all the attributes of a great VHF site: a/c power, on a hill top with a  good horizon including a big lake to the south, no neighbors from southeast to southwest, on the outside of the loop, and NO mosquitoes. Did I mention no mosquitoes?! It is missing a key ingredient -  6M Es propagation right now - I'm scanning away waiting.

Nice sustained 6M opening late afternoon/evening. I worked 121 stations - best DX XE2S (MX), AC4TO (FL), and K1TOL (ME). LoTW has been fed.

I'm QRV 6&2 meters and meteor scatter will work too. One night here and on we roll farther south to DO60 I think.

Where does Waldo go next?

Where's Waldo - We're out in town basking in fast Internet and fast food and a Tim Horton donuts. It looks like DO53 Thursday, and DO60 Friday and back to the States Saturday to do some grids around Fort Peck Reservoir.

DO73ar - Anglin Lake, Saskatchewan

We're in the boreal forest lands and lakes now. Plenty of mosquitoes too.
Yesterday was a great day for 6M. The band was hopping, and my pile-up was like a 20 meter contest run. Love it. I worked 130 stations from VE7DAY (BC) to AC4TO (FL) to XE2OB/M. The solar flux is 200 right now so who knows what might happen today.

This morning worked 6M meteor scatter and logged W7MEM, W9JN, KF7CQ, K7MAC, KE7X, and N7BYD. My second contact of 600 miles with k7MAC was while he was on his halo omni antenna. :-)

Some nice pings from KE7X this morning.

DO61 - Blackstrap Provincial Park

It was worth going to a vantage point to work W8BYA @ 1260 miles.

What do you think a pawn shop would give me for this mess. The truck shack.
I'm getting pretty far north, but on 6M meteor scatter W7MEM, K0RI, and KF7CQ worked. 2M accounted for K0RI, K7MAC, KF7CQ, and W8BYA (1260 miles).

DN76 - Making a mountain out of a mole hill, then DN78

DN76ck - No horizon from 100 to 175 degrees azimuth - I sure know how to pick 'em.

Good 2M session again last night from DN76, Mile City. K0KUK, K7MAC, W7MEM, and N7NW logged. This morning we managed KB7ME, KF7CQ, N0KE, NQ7R, KC6ZWT, KR7O, KS7S, and ND0B again on 2 meters before we had to scoot. Lots of wind so no way to put both Yagis up at the same time without disaster.

I did have the 6M Yagi up for a bit and worked five stations.

In spite of my location, KS7S came blasting in from Arizona. Nothing like a 12 db burn to move things along.
 It was about a 225 mile travel day northward to Scobey, MT on the Canadian border. We're here in DN78gt camped right in the middle of town, but not too much line noise and fairly good horizons in all directions, those grain silos are out to the northeast and VE4-land.

The wind died! Both Yagis are up and I'm ready for a beer. The bar is just 50 yards away. Bonus!

DN65 a big 2 Meter morning

Just off Route 212 on my high perch at sunrise. A fantastic horizon in all quadrants.
A very nice 2 meter meteor scatter session this morning. I packed the truck the night before and left for this spot before sunrise. I was all set up and ready to go by 5:45 AM local. Logged were W8BYA (IN), WQ5S (TX), ND0B (ND), K5WE (OK), K7ND (WA), AA5AM (TX), NQ7R (AZ), WB0ULX (SD), KR7O (CA), KU7Z (UT), and N0KE (CO). As it was a travel day I had to stop with stations still to work.A fine morning's work  for 200 watts, 9 element Yagi, K3 and a generator.

The hills behind the truck are part of the Little Big Horn Battlefield, troops under Reno and Benteen fought there way up and managed to hold off the Cheyenne and Sioux warriors. Custer? Not so much - Last Stand Hill is about 2 miles to the right.

Windy and rainy most of the way up to Miles City (DN76ck). Nap time for me!

If I leave the part of the 5th wheel hitch off then I can bolt the base of the mast in..

DN65 Garryowen, Montana

Looking west over the top of the trailer.
 Nice day after nasty weather yesterday.
Fairly tight quarters here in the RV Park.
Six meter Es was non-existant yesterday so down with the 6M Yagi and up with the 2M version at sunset. 2M meteor scatter yielded KB7ME, KC6ZWT, AA7A, W7MEM, K7MAC, KS7S, WA7HQD, W9JN, and KE7NR. Six meter scatter added KD7DCR, N7EA, and N0LWF.

Off to see the Custer Battlefield for a bit, then back to see if 6M wants to open up.

Nice 6M opening after dinner, 50 stations worked.

Tomorrow on to DN76 at Mile City.

Delayed in Bozeman

We'll head to DN65 on Saturday, June 28th and be there by mid-afternoon. We'll spend two days there before heading on to DN76. A few things have kept us in Bozeman longer then expected..

The good news is that I received the new PL lock board from Elecraft for the internal 2 meter  transverter in the K3. It works as advertised.

VHF to HF for W1AW/7

We stuffed the trailer into storage this morning and headed for the hills to do our part as W1AW/7 "The Montana Edition". VHF action resumes June 25th from DN65.

W1AW/7 alpine style - a 130' Doublet, 500 watts, and a tuner; mostly CW/RTTY for the next several days.

DN48kh to DN46fj travel day

Up early to run 2M meteor scatter skeds with N7NW, W7MEM, K6EME, K7ND, and NQ7R. It was blustery enough to have to tie the antenna down at each new azimuth position. We just beat the rain packing up and the 11 miles of dirt road out to the hardtop held up fine. No Montana gumbo-mud for us!

Fred, KE7X put me onto the PJclient program that enhances the Ping Jockey web site - what a neat piece of software, it will sure help me stay organized, and on top of things.

235 miles south and we're now back in DM46 on the way into Bozeman to get ready for my part in the W1AW/7 operation. We're going up to a cabin just north of Yellowstone Park for that. I'll be mostly HF CW and RTTY.

Tonight during the contest I worked a bunch of stations on 6M out of 5-land.

Tomorrow on into Bozeman and we'll give VHF a rest for a week or so. All QSOs this week should be up on LoTW and I'll grab my mail and answer QSL card requests too.

DN48kh (Tiber Reservoir) in the rain

We have Internet, but with the heavy rain at times it was spotty as the extra absorption took out the signal; I ended up putting the Mi-Fi card up on the roof of the trailer under a radome (my wife's plastic bowl). Nothing like having to DX the cell tower to get to Ping Jockey.

I worked 13 stations in this morning's session - a credit to the discipline of folks on the list and being right there when their turn came. Thanks!

A great morning for meteor scatter from this very quiet location. 6 Meter Contacts: N8JX, KE7X, KE7NR, KD7DCR, K7ULS. 2 Meter contacts: W9JN, N0KE, KE7NR, KR7O, KC6ZWT, AA7A, KF7CQ, and K7ULS.

Es was slow last evening just three or four logged on 6M, K5YAA was best DX. Mid-day today is very good into CA and AZ single hop, I'm just running 100 watts to save some gasoline and logging a bunch. Raining again, and thunder-boomers all around.
DN48 is Big Sky country.
The list/log sounds orderly, but here's the real deal. Thankful for LoTW.

The one that got away! K6EME had terrible local noise, but I was sure getting him on 2 meters.

DN47 finish up and on to DN48kh

This morning was more 2 Meter meteor scatter action from DN47 with W9RM, N5JEH, K6EME, and K7MAC worked.

We packed up and are now about 50 miles farther north at the Tiber Dam south of Chester, MT in DN48.  We lucked out and have the highest camp site in the park with a clear shot 360 degrees. This a free campground that is an oasis in the midst of the high plains - one of our favorite spots for early season camping (way too hot in late July).

I have sked for 2M MS in the morning and of course the 6M CW machine is going!
Level, plum, and square.

2M Meteor Scatter DN47fp and 6M double-hop

A great 2M meteor session this morning started by working WQ5S at 1030 miles. W9JN, WB0ULX, KF7CQ, KS7S, KE7NR, N7NW were also logged. Nine element Yagi, 200 watts, and LMR600 feedline - it seems to be working.

Now that is a 2 meter ping! W9JN at 1067 miles.

Not a bad sunrise!

Off to town (Great Falls) for some bike riding along the Missouri River and a visit to the CM Russell Museum.

We got back in time for several multi-hop contacts into New England on 6 meters as well as VE2 and VE3. Nice!

DN46 to DN47fp

Finished up DN46 with a nice run of FSK441 meteor scatter contacts on 2 meters this morning. Stations worked: W9RM, KC6ZWT, WA7HQD, K7MAC, KE7NR, KS7S, AA7A, K6EME, and W0VB.

Yesterday's problem is fixed - I even copied CX2SC off a rising moon yesterday evening on JT65b. Wowser!

On to DN47fp - It was about a 150 mile drive today up thru the mountains above Helena, MT, past Great Fall, down six miles of gravel road, and past a loaded missle silo and we're here. Here is Matt, K7BG's barn yard - I even found an a/c power outlet in the shed so we're all fat and sassy with some weather coming in. We're perched up on the high plains so it should be a great location. Just no propagation right now.
On the high plains of Montana, but you can see the Rockies 50 miles to the west - It is going to get stormy.

DN46gh continues

Disappointing morning try to get the 2M gear going. I ran five MS skeds with no joy. I have other gear to try thanks to K7MAC's generosity, so we'll see.

EUREKA! It turns out I was transmitting 4.71 KHz low on 2M this morning. My "Fancy Dan" PLL Lock board isn't working, so my offset compensation is back to the stock factory value i.e. +4.71 KHz. The PLL lock board will have to go back to Elecraft at some point. I may drift around a bit, but at least I'll be in the right place!

KO9A , N5RZ and about 15 others worked on 6M so far. Lots of beacons in too.

Today's wildlife.

DN46gh Canyon Ferry Lake June 8, 2014

On the shores of Canyon Ferry Reservoir.

We're just a 100 miles from home, but a great place to hang out for a few days and work the kinks out of the 2 meter gear which is all new to me. I'll be anxious to see how that all plays tomorrow morning on FSK441 meteors scatter. 200 watts and a nine element Yagi fed with LMR600 on 2M.

The rent here is right! Five dollars a day. As you can see I have shot over five miles of lake out to the east and southeast from here.

On 6M this afternoon W9RM, K0GU, KE7V, and K5WE were worked on a combination of scatter and meteors so far. The K3/KPA500 combo seems to work fine. Later in the day there were some short Es openings - best DX was AC4TO.
Gearing Up

Joyce and I are gearing up for another trot around Montana with the trailer putting grids on. I left the blog entries for the last trip (2012) as a reference. This will be a longer time out and about. This summer I'll add 2 Meter capability and head up to Saskatchewan for a visit to keep it interesting. Later we'll slowly head to the cooler mountains of western Montana. It is hard to tell exactly what grid I'll be in more then two weeks out, but I will keep things up-to-date here so you're in the loop.
Home right after the Perseids. I'm thinking it would be fun to do the Perseids from Beartooth Pass in DN54 Wyoming.

Lost of gear to get working together and herd into the trailer. If you need a grid on 6 or 2 meters in Montana be sure to let me know.