Consistent Performance with the new PNP CW Transmitter

Let me put in a context easily understood... You get dates with good looking YLs all the time not just one time with one good looking YL.

More data as I just took a look with the RBN at 6AM on April 3, transmitting on 7013 kHz. I was heard in the 400-to-900-mile range running 300 milliwatts. That tells me two things as the PNP CW transmitter can yield consistent contacts and the need for a solid design with appropriate harmonic filters. Low power out of ham band signals can be heard at great distances.

I have run QRP for many years but at the watt level not milliwatts. The solid acid test of course is real contacts not the RBN. But the Reverse Beacon Network is a strong indicator of performance especially if it is consistent. 

The two crystals (7030 and 7055 kHz) I have coming are frequencies considered as watering holes and lots of activity and so that should set us up for the real acid test. (I really splurged and paid $10 including shipping for the two rocks. I stole money from my grocery budget.)

I will stop posting on this subject in deference to those who do not do home grown radios. Guess this being a holiday weekend the bands will be choked with contests and POTA/SOTA crap. So maybe a good time to work on the T/R sequencer.

Them that know, survive. I had a near cardiac arrest experience yesterday when I bought 6 gallons of gas and that took two $20 bills. I have a 20-year-old car and get about 23 mpg. So that comes to 23 * 6 = 138 mile range. That means two weeks of visits to the cemetery to visit the XYL (60 miles) and a doctor visit on Monday (28 miles) and three trips for groceries, banking and miscellaneous (30 miles). That leaves me 20 miles for a buffer. Thank You, Donald Trump for starting a war!

73's

Pete N6QW

PNP CW QRP Rig now on 40M

 

The home-grown rig has been moved to 40M on 7013 kHz and gets 12 Volts PTP out of the W3NQN LPF. That is 360 milliwatts. At 7 AM my signal was heard in the 600-to-800-mile range. 

I have ordered "rocks" for 7030 and 7055 kHz. (The original MC1496 DCR was built for 40M.) The additional power output can be traced to the crystal itself and that the circuit components in the driver stage favor 40M versus 20M. The emitter bypass cap in the driver plays a big part in the frequency spread.

Them that know, survive. Of note do you believe only a couple of more weeks in the Iran war. Reminds me of when I went to Vietnam... like 10 years. Survival depends on trusting your gut and the actions you personally take.

73's

Pete N6QW

PNP Transistor CW Transmitter... SUCCESS!

Productive day yesterday as I came up with a good Colpitts type Oscillator circuit and with some more biasing adjustments we are getting 9.4 Volts PTP at the output side of the W3NQN Filter.

New oscillator board, the Amp and Keyer Board plus LPF 

Thus our 9.4 Volts PTP translates to (9.4^2) * 2.5 = 221 Milliwatts which is a good start (from 50 milliwatts). All Devices are 2N2905's and PNP.

[JIC... Vrms = 0.35355 * Vptp or Vrms = 0.35355 * 9.4 or 3.32337 Vrms. Vrms^2/50 = power in WATTS. 3.32337^2/50 = 0.220895763 Watts or 221 Milliwatts. Or using my short cut Vptp^2 * 2.5 = power output in milliwatts. QED]

221 Milliwatts @ 14.060 MHz. Clean Pattern

The next step is to see if it is heard on the Reverse Beacon Network. That should prove interesting. For a pair of Ears in the final lash up, I am going to use my MC1496 Direct Conversion Receiver. The sweet smell of success!

Imagine that... my 221 milliwatts heard by DX at 2523 Miles

With 221 Milliwatts I was heard out to 2500 Miles which is about 11.3 miles per milliwatt. Good Show OM.

This home-grown stuff can be real fun stuff and for me better than 5X9, Park 12345. This little project is a throwback to when hams were hams. I engineered this rig and not something the average ham today can do! That is OK as the ham radio tent is large and those that can home grow a rig is almost infinitesimal. So, the 1% is an aberration but still a part of the hobby.  We are a beacon to those who feel guilty they can only do contests, operate or watch you tube videos of YL's calling CQ POTA.

Time to think about integrating the Transmitter and DCR into a homogenous rig. The MC1496 DCR BTW has a PNP RF amplifier stage. I thought may be an Arduino to handle the switching. Sort of something old something new.

Them that know, survive. Will you survive?

73's

Pete N6QW