You can also get some TO-220 non-inductive resistors of a suitable wattage, and mount those to the heatsink. 10-watt devices should be OK, and 50 ohms is close enough. Those devices aren't cheap, but

Hi all I know that the preferred vendor for BITX20 finals is the Vishay IRF510, and '510s from other manufacturers may be suspect, or else just no darn good. Has anybody else done any experimentation

Also, a reminder about 1206 devices — if you are doing a “dead bug” project and need a passive component across two adjacent pins of a 0.1” spaced DIP IC, a 1206 device fits perfectly. They’re also ea

#ubitxv6

All, please note that Harry Lythall SM0VPO is one of the very few sources on the internet who can be trusted unconditionally to provide accurate information all the time. He also has a very sharp sens

Something from long ago … the first time I installed my shack at this QTH in about 1990, I put up a sky wave loop for 80M. Surprise, the 50kW AM BCB station a couple of miles down the road — on 1300 k

Jerry, There are workarounds for all those except the tubes. For the plate transformer, a diode multiplier on a 1:1 isolation transformer will work. For the HV variable caps, you can use a piece of PC

Because 6146 tubes are NLA commercially except at astronomical prices. Chinese 811As would be a better choice, and a decade ago I spent a lot of time looking at amps like this using either Chinese gla

This came across my monitor this morning. It's work-safe. <https://spectrum.ieee.org/the-institute/ieee-member-news/engineers-iran-open-source-ventilator?utmsource=theinstitutealert&utm_medium=email&u

Roger, China and India have been inches away from nuclear war for decades. I would hope that China would take the high roar with COVID relief for India. I also wish we had responded sooner, but this I

The old concern was -- "FCC certification for commercially sold products." However, the FCC rule for amateur equipment made for personal use was (and is) "You are responsible for the lawful operation

Best to ask MPJA. If you need a particular manufacturer, it's better than that to order from a Tier 1 disti who WILL give you your manufacturer of choice. IIRC, International Rectifier introduced the

Testing on-air? There's a tuning device that was very popular a few decades back, and schematics are still available online. It uses a 555 to generate approx. a 30% duty cycle CW key-down, and you can

I’m in Texas, and a month ago we had a historic winter storm that shut down the whole state for a week. One of the unexpected results was that many petrochemical manufacturers had their plants go offl

Arv, I think he meant that the silver thingy inside the fuse got short ... too short to reach both ends. 73 Jim N6OTQ Sent from my quenched-gap spark transmitter.

As we say in Texas, “Yeah buddy!!” Jim N6OTQ Sent from my quenched-gap spark transmitter.

There's a nifty device made from two 555 timers or one 556 timer called a "pulser tuner." You should be able to find the schematic online. It gives about a 40% duty cycle at something like 120 Hz... f

#ubitx-help #ubitxv6-help

>here are affordable toroid sources in the states, and from just dash 2, 6, 43 and maybe 61 you can make lots of inductors and transformers. See if w8diz partsandkits.com is still in >business. >Curt

#bitx20

So I ordered a bitx kit from HFSignals on Saturday. It was on my doorstep this afternoon. I used DHL -- but just four days from Hyderabad? Amazingly speedy. 73 Jim N6OTQ

I've found that not all hot-melt glue brands are equal. Gorilla brand glue sticks appear to be the best on the American market. They cost more but provide much better long-term adhesion than the cheap

Dean, your 30L-1 likes to see 50 watts or more to start to make good power. While it should amplify the output from a ubitx, it's a kilowatt-class amp with only 10 or 12 dB gain. So with the nominal 1

#ubitx #v5 #linear-amp