QRP Operating - Austin, TX

On October 26 I finally had a chance to do some more K1/QRP operating. This time while on a trip to Austin, TX. The weather was great: sunny and about 75. My antenna was again a 67' (full wavelength on 20 mtrs) endfed wire . The operating position was on second floor balcony. I ended up running my antenna up to eaves above me and then sloping down to a fence along side the yard. My clear view was to the east and I was on top of a bluff over looking Lake Travis.

A few minutes before noon I had a QSO started with KC9AWL, Len, in Palm Coast, FL on 14.057. He gave me a 559 but when I noted how deep the QSB/fades were I knew we were in trouble. Len turned it over to me but, evidently, the band went south and he lost me. I never heard him a second time.

Within ten minutes I had another QSO going on 14.057, this time with WA9FZP, Phil, in Racine, WI. This enjoyable QSO lasted about 1/2 hour with 559-569 signals the entire time.

815 Transmitter Postmortem

After weeks of vacation, etc I finally got back to my 815 transmitter. To recap ... the major mods since the original design shown in the ARRL handbook and my blog entry dated March 19, 2007 have been to 1) add a loading capacitor between one side of the output link and ground 2) Replace R4 with an RFC to a 200-300 VDC supply and 3) replace the 815 screen voltage dropping network R5/R6 with an RFC to a 200-300 VDC supply. The final layout is shown in my May 28 blog entry.

Tests on 40 meters have been a little disappointing. The 815 runs at only 35%-40% effeciency into a 50 ohm load. 50 watts input gives only about 20 watts out. (whoops! I checked my Drake watt meter agains a Bird. Turns out that the Drake watt meter is reading way low. The Bird says I'm putting out about 30 watts. This is about the power output I expected.) Also the transmitter is not real forgiving. If misadjusted, it goes into self oscillation or generates a trashy sounding signal.

This one will go to the back of the shelf. (but after discovering the watt meter error, only while it waits for a power supply)

More QRPxpeditions

Over the past week I've enjoyed QRPing from both Milwaukee, WI and White Water State Park in SE Minn aboth times using my K1 feeding a 34' endfed wire on on 14.060. In Milwaukee I worked Butch, KD5RSS, in Haskell, OK and Dick, W0NTA near Loveland, CO. Dick and I were both running 5 watts and we were 599 both ways. His antenna and high QTH makes up for a lot. At White Water State Park near St. Charles, MN I found a point on top of the bluff on the west side of the White Water River valley. Conditions weren't specticular but I did work KB3AAG, Frank, in Delphene, PA and N5GW, Gene in MS.

QRP / K1 Video

Here's a video that I just posted on YouTube. In it I demonstate setting up my QRP station, show some of the features of my K1 and then talk a little about my QRP operating experiences. The video itself was done by John Reed K0KTY (SK) about 2 years ago.

https://youtu.be/GUk99uFMvTI

QRP Operating

Today I finally made it away for some more QRP operating. This time it was to Great River Bluffs State Park (See http://www.dnr.state.mn.us/state_parks/great_river_bluffs/ ). This park is along the bluffs of southeastern Minnesota overlooking the Mississippi River Valley. From my operating position I could see far into Wisconsin and watch the hawks soaring below me. Using my K1 and a 32' endfed wire on 14.060 I worked both K7UP, John, in Elephant Butte, NM and W2BWQ, Gene, in Congers, NY. Conditions were only fair with QSB a problem. I heard only half a dozen stations across 20 mtrs.

On the 815 transmitter front it needs a better regulated suppy for both the 815 screen and the oscillator plate. The dropping resistors have to go.

A working 815 transmitter

I have a working 815 transmitter. Unfortunately I had to "glue" a capacitor on to the side of the chassis to do it. Key to getting the final to work into a variety of loads is some sort of antenna tuner. Adding a capacitor into the grounded side of the output link does just that. The added capacitor does output loading . Tune up now amounts dipping the final with C2 and increasing/decreasing the loading with the added output link capacitor. Typical operation is 50 watts input and 35 watts out.

Eventually the loading capacitor will be hidden behind a front panel.

QRP (and a little homebrew)

After a couple of days of on and off rain with cool weather here in SE Minnesota, today was sunny and temperature about 70 ... great evening for a picnic and a little QRPing from the park. We chose to go to Florence Park in Stewartville, MN. With my K1 and 67' endfed wire in a tree, 20 mtrs sounded pretty dead. An early CQ did raise K9PWK but QSB was bad and we lost each other before we really had much of a QSO (he gave me a 229). Finally at 6:45 Terry, N4IY, in Borden, IN came back to me. We had a nice QSO. His 4 watts was doing a fine 579 job.

On the homebrew 815 transmitter front I've been trying to get the final coil wound so that the transmitter delivers full output to a 50 ohm load. At this point I'm about to add an outboard antenna tuner to my project list.

I've powered my new transmitter up on 40 meters.

For use during this test phase I built an adapter to allow the use of B&W 5 pin JVL transmitter coils instead of winding coils on my National coil forms. I'm also temporarily connecting the bias and voltage dropping resistor networks to the back 12 terminal barrier strip. This way I can easily play with the resistor values to get the right voltages.

The transmitter loads up to 40 watts input and 30 watts output with no sign of self oscillation

I've still problems, though. The 815 screen current won't come down. It appears to draw around 60 mA rather than 15. High screen current causes the screen dissipation to be exceeded, maybe damaging the 815. Right now I'm looking for another 815 to compare readings with.

A mid 30's Three Tube Regen

I aquired another radio last week. This one I "won" through ebay. The pictures posted on ebay showed a fairly ughly set with three mis-matched dials. The layout, though, suggested the "Three Tube Regenerative Receiver of Unusual Performance" by George Grammer and written up in the January 1933 issue of QST.











I bid and the gamble paid off. Underneath the flaking paint front panel and cabinet was a fairly nicely done version of George Grammer's design.







George grammer's original article was more than another construction project. He spent a large part of the article talking about features of good regen receiver design before describing "a practical receiver". This receiver includes a tuned RF stage and general coverage/bandspread tuning. Bandspread tuning is via the drum dial at the left after the detector and RF stage bandset capacitors are set. The receiver showed up in the ARRL handbooks through 1937.

815 Transmitter Coil/L1

L1 of my transmitter calls for ten turns on a 1" coil form spaced over 7/8". I had the form and the wire I needed. Winding spaced turns, though, takes a trick. I first wound the ten turn coil on the form, tightening the wire as much as possible. The turns were not even. It was not pretty. I then wound another "coil" (the red wire) forcing evenything to space out evenly over the 7/8". This I heavily coated with clear fingernail polish. After the fingernail polish had dryed I removed the red spacer coil and recoated with fingernail polish.