January 3, 2025. If this were 1929, then the rigs would be a lot different.

Self-Excited Type 27 Tube Hartley Oscillator (SEHO) Circa 1929

[A problem at Go Daddy who hosts my several websites showed one of my websites as being not Private and redirects you to a Porn Site where you do get to see Private Parts. I removed the link from a recent posting and Go Daddy is trying to fix it. What a way to start the New Year.]

Essentially the Self-Excited Hartley Oscillator is a high-power output VFO that is keyed.

Lots of problems with this topology such as vibration will cause a warble when you pound brass. The fix is to mount the SEHO on a shelf not connected to the operating table and to hold your breath while you key.

Another issue: the movement of your antenna (link coupled) can cause the frequency to vary. You must keep you EFHW taught and out of any breezes.

It drifts like a loose lady of the night way past her prime and the exposed wiring is a safety hazard. Did I mention key clicks and terrible chirp. But hey it was frequency agile, involved few parts and pretty cheap to build.

There is an annual competition using only the SEHO and it is called the Bruce Kelly Award. I guess if on 40M you hear a cluster of key clicks, warbly, chirpy and drifting signals then you found the contest. The link provides build info for the 1929 SEHO. [Check out the power supply in the build info. That is the 1st time I have seen a 450VDC three terminal regulator. This could be a great general-purpose power supply for Thermatron rigs!]

Replicas of the SEHO are selling on eBay in the range of $200-300 dollars and most do not include a power supply. This one uses an 01A tube.

A $235 SEHO

BTW I pay $300 a year to secure my websites and that did not work too well for one of the sites. I haven't changed anything or uploaded anything to that site in a long time and this anomaly is a recent event. Damn Chinese Hackers.

73's

Pete N6QW

January 26, 2024. A simple CW Transceiver/Transmitter

Cruise through the lower part of the ham bands bands and what do you hear? Well, FT-8 and CW. Often you will not hear any SSB stations yet go to the lower part of the bands, and it is a cacophony (I love that word) of bad sounding signals and some high-speed keying. Fast is not so much of the issue as is bad, run together and jerky keying. But none the less our hobby started there. So, you could crank down your ICOM 7300 and watch the waterfall on CW or you could homebrew a radio. Actually, to do CW right you need more thought up front than you do with a SSB transceiver. Often, I will state that a CW Transceiver is much more difficult to build than a simple SSB rig. I published two articles in QRP Quarterly on CW transceivers and all I got was a yawn so maybe history will repeat itself. Yawn! 30M CW Transceiver with RIT! Of interest is that the LO is a Varactor tuned LC oscillator using a NE602. Look closely at the RIT circuit which is only activated on ...

March 31, 2024. Happy Easter to those who celebrate this day.

What a great day to Binge on Chocolate and experience the pain of that filling that has been leaking. I would be in that category with the leaking filling(s) had I not just spent an amount equivalent to one of the fancy new uptown appliance box transceivers on two filling repairs. Well at least I can binge on the Chocolate bunnies without fear of pain. Regrettably everything appears to have jumped in price including the price of parts. Well not so much the parts as the shipping costs. That notably is seen in the eBay treasures. I spotted a nice heathkit DX-20 for about $50 and the shipping was $65. Likely it is a twofer with part being a way to in effect charge a higher price by inflating the shipping and in part by increased shipping costs. Shipping with insurance across the US was about $150 for this jewel and that was three years ago. 6AM on the Left Coast ~ 20M Easter Sunday! My only hope is the cost of Chocolate Bunnies remains steady although a pound of See's Candies f...

August 30, 2024. A PNP 20M SSB Transceiver

Shown below is the Block Diagram for the 20M PNP SSB Transceiver steered in the Transmit Mode . The components shown in the dotted block are relay steered so that the block module is single pass and amplifies in a single direction. The Block diagram show steered in Transmit. Essentially the steering process works so that the IF Module input follows the Balanced Modulator on Transmit and then the input side follows the Receive Mixer on Receive. All done with some relays and a bit of RG174U coax. For those who count things in detail, this block diagram is not unlike what was used for the PSSST Transceiver which can be found on my website . Yes, a warmed over P3ST only using PNP devices. TYGNYBNT. 73's Pete N6QW

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