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SKCC #14331C FISTS #18176 - SP2SWIHello, my name is Mariusz. I was born in 1967. I have been licensed since 1990.

I'm a big fan of working QRP CW (with 5 Watts or less). Sometimes (when there is poor propagation) I increase the power a little. The station is quite basic. I using simple wire and vertical antennas.

Member of SKCC #14331T and FISTS #18176. I only use a straight key, bug or other mechanical device.

 SP2SWI

Transceivers

- Elecraft K2 (#7565) + all options (excluding SSB option).

Elecraft K2 with K6XX CW Indicator (CW zero beat detector) Elecraft K2 QRP Transceiver and Junker Straight Key

My primary transceiver now. I built K2 in November 2014. It really is the perfect QRP radio. Crystal filter works perfectly! Audio filter (KAF2) also works great.

In addition, I  installed the K6XX CW Tuning Indicator. Very useful.

- Ten-Tec Century 22 - CW TRX (model 579 from 1984) with Crystal Calibrator (model 226). Power levels ranging from a few mW to 5 W out max (I reduced max output power from 20W to QRP 5W by the new ALC level setting). I love transceivers prior decades.

Ten-Tec Century 22 and German Junker straight key Ten-Tec Century 22 Ten-Tec Century 22 (Model 579) Ten-Tec Century 22. New ALC level setting. Max RF power is now 5W out (QRP).

I love this transceiver! Very fast, smooth QSK/full break-in. Perfect 4 pole CW bandpass audio filter (Ten-Tec Century 22 has a direct conversion receivers). Filter is inside the AGC loop and filter action does also impact the AGC action. It works very well! I bought this transceiver in January 2013.

Adjustment and modification of Ten-Tec Century 22 (Model 579)

- OHR 500 - 5 Band QRP CW TRX (kit from Oak Hills Research). I bought this transceiver in August 2013.

Oak Hills Research - OHR 500 5 Band QRP Transceiver OHR 500 OHR 500

I confirm reviews from eham.net. Lovely radio!

- Yaesu FT-450. Its power output ranges from 5 - 100 W.

- Elecraft KX1 - QRP CW TRX with KXAT1 internal antenna tuner (80,40,30,20m; ~3 W out),

- PIXIE 2 (80m) - homebrew QRPp CW TRX with sidetone and BCI filter (80m; ~300 mW out).

SP2SWI Pixie 2 QRP (QRPp) CW transceiver with sidetone and BCI filter - Schematic

- PIXIE 2 (40m) - kit from China. Full QSK QRPp CW Transceiver. TX frequency is fixed at 7.023,04 MHz. 600 Hz frequency shift (adjustable). PWR is 228 mW out @ 9V (360 mW @ 12V; 422 mW @ 13.8V). RX current: 12 mA, TX current: 102 mA @ 9V.

My mod: I added a simple RC lowpass filter at the input of audio amplifier LM386 (R = 10k, C = 22nF, cut-off frequency = 723 Hz). Now Pixie is much more selective. Ears are not overloaded now :).

Audio CW Lowpass Filter mod for Pixie 2 Transceiver

Straight keys and Bugs

I like to use straight keys and bugs.

Most often I use old Soviet Army TK Straight Key:

Soviet Army TK Morse Key

TK and TKF keys were manufactured in Cherkassy, Ukraine, for the Soviet Army. It has silver contacts. Key got the basis of stainless steel. I glued it a double-sided tape to the desk. Now works really well. I like the work of TK.

I use also from time to time the Junker DBGM Straight Key:

Junker DBGM Straight Key

Increasingly (but still a little clumsy) I use Vibroplex 100th Anniversary Original Bug (No. 100A-364):

 Vibroplex 100th Anniversary Original Vibroplex 100th Anniversary semi-automatic bug Vibroplex 100th Anniversary Original Bug

Same movement and parts as Vibroplex Original Standard model, but with "japanned base" (high-gloss black lacquer finish with gold-leaf and stripe pattern). Works very precisely. Good bug.

Antennas

- Homebrew GP for 20m band. Monoband vertical antenna for 20 m band (full size λ/4 ground plane antenna with 7 radials λ/4 sloped down about 35-40°).

SP2SWI Homebrew GP Antenna 20m Band - 1 SP2SWI Homebrew GP Antenna 20m Band - 2 SP2SWI Homebrew GP Antenna 20m Band - 3 SP2SWI Homebrew GP Antenna 20m Band - 4 SP2SWI Homebrew 20m Band Ground Plane Antenna - SWR and impedance Z (Ohm)

Aluminum pipe (from λ/2 CB antenna) ~5.10m long and stranded copper wire 4mm2 (~12 AWG) 5.15m long. SWR: 1.25@14000kHz, 1.18@14240kHz, 1.21@14350kHz.

- Sloping Trap Dipole for 40m and 30m band.  Model: Kelemen DP-4030-H.

Trap Dipole Antenna Kelemen DP-4030-H 30m Trap made from teflon (PTFE) coaxial cable Kelemen Antenna Curren Baun 1:1 2kW Kelemen Sloping Trap Antenna Kelemen for 7Mhz and 10MHz Sloping Kelemen Trap Antenna 30m and 40m

Length: 16.8m. PVC-coated copper wire - cross section: 2.5mm2 (~14AWG). Current balun 1:1. Trap coils made from Teflon cable, have a high Q and therefore low losses. Antenna sloping at an angle of about 20-25 degrees from horizontal (10m up side and 3m down side). SWR: 1.9@7000kHz, 1.4@7100kHz, 1.8@7200kHz, 1.4@10100kHz, 1.35@10125kHz, 1.4@10150kHz.

That's all my stationary antennas. Other bands support the above antennas brutally tuned by my Elecraft K2. :)

QSL Info

I prefer electronic QSL via LoTW, eQSL.cc or QRZ.com Log.

LoTW LogBook  SP2SWI eQSL Authenticity Guaranteed

I use also the SKCC QSL Bureau. Direct is also OK (no SASE, stamps or money required).

Never add /QRP to my callsign.

"SP2SWI" --> Yes | "SP2SWI/QRP" --> No

It's just a source of potential confusion (on LoTW, eQSL and elsewhere).


Adjustment and modification of Ten-Tec Century 22 (Model 579)

Sorry for my English. :)

- Adjusting the "TX OFFSET"

I had to adjust the "TX OFFSET" trimmer potentiometer on the "RX / Control Assembly" because it was badly adjusted.

Procedure:
1. Unscrew the cover (lower part), connect the antenna or dummy load, turn the transceiver on and wait 30 minutes.
2. Set the "DRIVE" (on the front) to a minimum.
3. Set the "OFFSET" (on the front) exactly to "0" (center detent).
4. Connect the frequency meter (high input impedance, low capacitance) to the PTO oscillator output (where the coaxial wires are soldered).

Ten-Tec Century 22: PTO Oscillator Output and TX Offset Trimmer Potentiometer
5. Read frequency (it will be a value in the range of 6.0 to 6.5 MHz), with the precision of at least 10 Hz !!

Ten-Tec Century 22: Frequency of PTO Oscillator
6. Press the "LOCK" (on the front).
7. Adjust the trimmer potentiometer "TX OFFSET" (on RX/Control Assembly), so that the frequency was the same as in step 5.
8. Turn off the "LOCK".
9. Disconnect the frequency counter. Screw the cover.
10. Done.


- Greasing the Ten-Tec Century 22 PTO

I do not know when the PTO was greased, so I decided to dismantle, clean, greased and reassemble again.

To remove the knobs are needed Allen keys (hex keys): .050'' and 1/16''.

Ten-Tec Century 22: To remove the knobs are needed Allen keys

Very helpful in removing the PTO is a guide written by Dave (N5XL, VE5AEA) "PTO Rebuild and Dial Restring for the Ten Tec 579 (Century 22) Transceiver": ttc22pto.pdf. Thanks Dave!

The next steps:

Ten-Tec Century 22: Dial Cord - 1 Ten-Tec Century 22: Dial Cord - 2 Ten-Tec Century 22: Dial Cord - 3 Ten-Tec Century 22: PTO Oscillator - 1 Ten-Tec Century 22: PTO Oscillator - 2 Ten-Tec Century 22: PTO Oscillator - 3

All elements of the PTO should be cleaned with a toothbrush, cotton cloth and isopropyl alcohol.

Ten-Tec Century 22: PTO and Isopropyl Alcohol

I used all-purpose lithium grease "MULTIFAK EP 2" from Texaco, because that I found in my garage :). "MULTIFAK EP is a multipurpose grease family made from refined mineral oils and a lithium soap. MULTIFAK EP greases offer great shear resistance, retain their consistency under adverse service conditions and protect bearings and other metal surfaces from corrosion when exposed to wet conditions. MULTIFAK EP greases are non-corrosive to non-ferrous bearing metals as well as steel. MULTIFAK EP contain extreme pressure additives as well as rust and oxidation inhibitors. MULTIFAK EP are recommended for both automotive and industrial purposes as multipurpose lubricating agents for friction pairs operating." I think it will work well in the PTO.

Multifak EP 2 All Purpose Lithium Grease

PTO lubricated. Now PTO works very smoothly and precisely. I hope that it will be a long time :).

Ten-Tec Century 22: PTO lubricated

It's time to check whether the PTO oscillates at least from 6.0 MHz to 6.5 MHz.

Ten-Tec Century 22: Output frequency range of PTO - 1 Ten-Tec Century 22: Output frequency range of PTO - 2

Done. Everything works fine.


- Modification center frequency of audio filter

I rebuild bandpass audio filter (audio filter between the detector and audio amplifier). Ten-Tec Century 22 has a direct conversion receivers and the audio filter is very important to ensure good selectivity. For me, the center frequency was too low.

Schematic:

Ten-Tec Century 22: CW audio filter schematic

I made the measurement. The center frequency was 510 Hz (bandwidth was about 250 Hz):

Ten-Tec Century 22: center frequency of audio filter: 510 Hz
I decided to change the center frequency to 600 Hz, because this is my listening CW frequency. I replaced capacitors C41 C42, C43, C44, C45, C46, C47, C48 and replaced resistors to resistors with tolerance of 1%. You can use this calculator to choice capacitors and resistors. Example:

Input data for calculations:

  • Center Frequency = 600 Hz;
  • Gain = 1;
  • Q = 2.4 (for bandwidth 250 Hz @ -3 dB, for a single operational amplifier);
  • C41-C48 = 3 nF.

Result of the calculation:

  • R60, R63, R66, R69 = 212.2 kOhm;
  • R62, R65, R68, R71 = 424.4 kOhm;
  • R61, R64, R67, R70 = 20.17 kOhm.

Standard E96 1% tolerance resistors: 210k/1%, 422k/1%, 20k/1%.

The next steps:

Ten-Tec Century 22: RX/Control Assembly - 1 Ten-Tec Century 22: RX/Control Assembly - 2 Ten-Tec Century 22: RX/Control Assembly - 3 Desoldering resistors and capacitors Resistors and capacitors Ten-Tec Century 22: RX/Control Assembly - 4 Ten-Tec Century 22: RX/Control Assembly - 5 Ten-Tec Century 22: RX Control Assembly - 6

Filter test:

Ten-Tec Century 22: center frequency of audio filter: 600 Hz

Done. The center frequency is 600 Hz (bandwidth is about 250 Hz). The filter works well.


- Links


 

8441998 Last modified: 2017-11-09 10:44:30, 64270 bytes

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Grid Squared Award#16743
Granted: 2017-08-19 18:57:51   (SP2SWI)

World Continents Award#12529
Granted: 2016-04-07 20:55:19   (SP2SWI)

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