TRF Receiver

Let's add a tuned RF Amplifier up front and see how the Grid Leak Detector reacts.

[@CNCmachiningisfun]

This brings back memories of how I started out in electronics as a kid. I couldn't afford transistors, but I did have vacuum tubes, so I designed simple radios, in which to use them. With a HT of a mere 9 volts, I was rather pleased with their performance :) .

[@thomasreed325]

Thanks for the video. Is a superhet in the works??

[@davidportch8837]

excellent series Mike... much appreciated

[@MIKROWAVE1]

Thanks for watching the series.

[@ka4dqe606]

Quick thought ... I have one of those Precision (920) tube testers too. It might be interesting to talk about use and getting updated/expanded scrolls, and how to maintain the units - even the test equipment needs help from time to time. Greatly enjoy your channel ... I remember the first Morgan book from early elementary school ... I was already into electronics, but it was a really great find in the school library. Thanks. Cheers

[@Harryset1]

Thx for all your great videos! All the best from Germany - H.

[@MIKROWAVE1]

I wish I was over there in Germany drinking a nice Bavarian Dunk on the upper Danube.

[@Harryset1]

@@MIKROWAVE1 It's a pity that the shortwave-bands do refuse to transport (ice)cold beer -- greets from the river Rhine area --- 73''s

[@JCWise-sf9ww]

Mike I like your series on simple radios. When you add a 5th tube to a 4 tube superheterodyne, its usually a RF stage and performs so much better, or AA5 vers AA6. To me a 4 tube battery or AA5 radio with just a mixer/osc, IF, det/1st AF and AF output are what I would call minimalist radios.

[@Swamp-Fox]

I am enjoying this series & trying to wrap my head around it! Off to watch it again!

[@snarfusmaximus]

When you mentioned the TRF regen, the first thing that popped into my head was the Doerle Signal Gripper which is a regen with a tuned RF amp before it. I considered building one but it would require me to make a set of two plugin coils per band. May try an untuned RF stage instead before a regen and see how that works.

[@MIKROWAVE1]

That line up is classic and if done right in a metal enclosure, it really works great!

[@ellise.2574]

Thank you Mike for a very nice video. My National SW3 has a tuned RF stage, tuned regenerative stage and one stage of audio amplification. It uses plug in coils and it is very sensitive . I have band spread coils for the ham bands and it receives SSB and CW very well. Thanks, Ellis.

[@MIKROWAVE1]

The SW-3 was a fantastic example of doing it all with just a few stages. Great little box!

[@ingussilins6330]

Best sound from TRF circuit - without superhet "birdies" and other noises.

[@MIKROWAVE1]

Yes but without RF gain control or AVC, the thing does overload pretty easily.

[@Homer19521]

👍I always thought I had a keen sense for the obvious, but never thought of connecting 9V batt's that way.

[@ThePeaceableKingdom]

I'm very interested in that little two tube amplifier. Has that been covered in a video? I looked through your channel but couldn't find a video on it. Perhaps it is a part of some other vid that doesn't have amplifier in the title, or maybe I'm just blind. If you haven't covered it, would you consider making a vid about it, and if you have, could you point me to the right vid? I'm interested because I'm making a two tube audio amp now, attempting anyway, and I've not been successful on audio amps in the past. (I'm looking at you, Morgan!) My current project is a 1950 Popular Mechanics circuit. I would love any insights into how it could or should be done.

[@MIKROWAVE1]

Check out my FB page Mikrowave1 Radio Project Resources, which has the schematic and parts list. I will look for the video that covers it.

[@ThePeaceableKingdom]

@@MIKROWAVE1 Thank you very much. I found the schematics and a parts list on your FB page. I really don't do FB, but this time it was worth it! Thanks again. I'll be studying those in my spare time as my own little 2 Tube comes together. It's similar to the one with the interstage transformer but has the volume control on the first stage, the voltage amp tube, rather than the power amp tube. Hope it works! (fingers crossed for luck!) Your pointer to the circuits is much appreciated.

[@maikerumine]

Love your videos, man. :) Inspiring!

[@MIKROWAVE1]

Its your turn to build something on a board!

[@maikerumine]

Oh, I have. :) Still adding to it. :)@@MIKROWAVE1

[@bobwojcik1550]

Please explain how AM detection is accomplished here. I understand about using a diode envelope detector but that is not here. How is the audio extracted ? Thanks very much. Bob

[@MIKROWAVE1]

The same way. As a shunt diode detector Cathode to Plate.

[@SpinStar1956]

Hats-Off Mike! Really great series and appreciate the deep-dives into all the subtleties of each topology--well done! I may have posted this before, but I now use Lithium 9V rechargeable batteries for everything from radios, DMM's, testers and even smoke and CO detectors. The rechargeable lithiums do have lower voltage but I have found that even when used with a device that shows a 'low-battery" warning, that the device functions just fine--plus they don't leak!!! I buy mine off of Amazon as either the EBL-brand (btw: I buy the set that has 4-batteries plus a 4-position charger; or the HiQuick brand; none have failed! Make sure that you get the 600mA version, they cost slightly more but last a bunch longer! Also, I charge to 8.2V, not 8.4V for cell longevity. I have excellent results, and next to no self-discharge; and yes they cost more up front but I have saved hundreds over alkaline DuraLeaks! 73...

[@MIKROWAVE1]

Great approach!

[@trcwm]

Very nice series Mike! Any chance of a comparison between a FET vs. tube regen of the same architecture? 73.

[@MIKROWAVE1]

Yes But... To be equivalent in performance, I would use a dual gate mosfet in the RF stage, a JFET in the Grid Leak or Regen Stage, an audio JFET Preamp and a Mosfet Class A speaker PA.

[@trcwm]

@@MIKROWAVE1 I’d already be happy with just a single stage regen. I assume you want a dual-gate fet to be able to easily change the gain?

[@MIKROWAVE1]

@@trcwm I will put one up in the FB page.

[@johnwest7993]

TRF still works very well for a WWVB receiver. A few cheap transistors and LC's and you're in business. And of course, you don't want to change the WWVB carrier frequency, and a superhet will do just that.

[@MIKROWAVE1]

Even modest amplifiers work great at these frequencies, and ordinary low cost inductors for power supplies can provide the bandpass selectivity. Some of the modern low cost op-amps work to above 30 MHz.

[@sir_urx]

Q-multiplier might be easiest addition to that schematic i guess.

[@davidgrey943]

Hi, can you tell me we're you found the output transformer for your audio transformer so I can built your valve audio amp.

[@MIKROWAVE1]

facebook.com/Mikrowave1

[@y_x2]

Superheterodyne has been build with 4 tubes they simply remove the IF tube. It was intend for local station only.

[@KnightT60]

Homebrew coils are invariably solenoid wound. It seems to me scramble wound is actually a better approach.

[@MIKROWAVE1]

True, but nobody can even wind a solenoid without causing trouble in the house!

[@thomashowe855]

Where can I find a schematic for the amplifier you use for this?

[@MIKROWAVE1]

On my FB support page. facebook.com/Mikrowave1

[@thomashowe855]

@@MIKROWAVE1 thanks

[@sylweksliwka7986]

❤😮Poland

[@Capecodham]

I was going to say something nice but you don't like positive feedback.

[@MIKROWAVE1]

I have been watching your latest videos from 10 years ago. I am too scared to watch my old ones. You were very opinionated and amusing. This is entertaining content.

[@Capecodham]

@@MIKROWAVE1 The difference between yours and mine is you sound like you have a PhD and I sound like an Associate's degree.

[@julianvalenti]

Para consolar, animar, corregir.

[@MIKROWAVE1]

¡Para construir, fallar, recuperar y triunfar!

[@julianvalenti]

@@MIKROWAVE1 😀

[@AdamosDad]

73's🎙KD9OAM🎧📻

[@G7VFY]

First ! G7VFY