#5 Valve QRP - Building a Paraset

The scratch build of a customised Paraset Spy Radio in just a few simple steps from schematic to completion. The 6V6 delivers +36dBm (4W) into a conventional 50 Ohm antenna and the lively regenerative receiver handled its first QSO with Hub, F5JYS who was running a K2 at 5W on a very noisy, crowded band. Great fun!

[@adzbasslines268]

Thank you, Graham (Silent Key), for your helpful tips building the Paraset all those years ago. You motivated me to build my own! . .

[@MIKROWAVE1]

Graham, beautiful video! I built mine about 12 years ago and have enjoyed using it. My best QSO was on 80M 3505 kHz across the pond to Germany with it which was on a random CQ. But the German ham was actually a WW2 Wehrmacht radio van man who hunted these! He sent a and QSL. My only changes were bandspreading. WU2D

[@AnthonyJones-vk6xq]

I realise this video is a few years old, but its quite frankly outstanding, your attention to detail and quality is remarkable, i had a qso this evening with a G4 station running a paraset on 40m........an easy qso between France and the UK ! Thankyou.

[@14404145]

Excellent video as I was an interceptor in the Army Signal I found this information extremely interesting. Thank you, William/W2WC

[@NexxuSix]

Nice! I really like the idea of the paraset, and its history... I hope to build one as well. 73!

[@laseraddict777]

Great job, Graham. Really enjoyed your presentation and great workmanship on your paraset! What a neat rig you turned out. The hanks for sharing. I'm one of those who built the American transistorized version of the Bayou Jumper. Enjoy using it. Looking forward to your next video/project. 73's de Rick, W B 3 B I Q.

[@g4vuxqrp210]

Dear Rick, Many thanks for your comment. It great to hear from someone who is using the Bayou Jumper. I've seen your one on KZbin and it looks like a brilliant rig. There's a certain beauty about using regenerative receivers in the 21st century. Very best 73 and keep on keying! Graham de G4VUX

[@GrumpyOldGit74]

Graham, many thanks for your invaluable help and advice when I built mine, looking forward to a Paraset to Paraset QSO in the future Martin g4zxn

[@g4vuxqrp210]

It was a pleasure Martin, it's a beautiful example and I love your new video! Vy 73 Graham

[@adzbasslines268]

Beautiful valve rig! I built the transistorized 4SQRP Group Bayou Jumper kit. Fantastic little rig with a switchable built in 200Hz CW filter, added mute receive during transmit, fine tuning control and side tone generator.

[@g4vuxqrp210]

Hello Adzbasslines, Thanks for your comment, it's great to hear from you. The Bayou Jumper sounds fantastic ! I hope you make lots of contacts with it. 72 / 73 es gud dx. Graham de G4VUX

[@adzbasslines13]

Hi Graham, how's the MkVII going? I've had fun with the Bayou Jumper, but now building a Whaddon MkVII. I managed to acquire the hard-to-get 6V6 metal tubes. I am getting the chassis made by your contact.

[@bill-2018]

That's a good job Graham, it looks very nice. It puts fun into radio instead of operating a fancy bought set all the time. I love building stuff. I built a transmitter using a 61BT valve I had, for 5.262 MHz, 7.030 MHz and 10.106 MHz.

[@bill-2018]

Bill, G4GHB.

[@g4vuxqrp210]

@@bill-2018- Hello Bill - Many thanks for getting in touch. I often get on 5262kHz and I hope you enjoy your homebrew 61BT Tx. I will listen for you and maybe we will manage a 2 way valve QSO sometime. vy 73 Graham de G4VUX

[@fra366p4]

Thanks Graham for sharing your Parset with us. I have most of the parts for mine just need to order the caps, resistors, etc. and the transmit/receiver switch. I did build the solid state kit that you speak of and it is called the Bayou Jumper. Great little kit and it has given me hours of fun already. Very much interested in the SOE and the Paraset radio. Once again many Thanks for sharing. Mark KA8ONW

[@g4vuxqrp210]

Hi Mark, Great to hear from you. Thanks for the info on the Bayou Jumper, it looks like a brilliant kit. I wish you luck with the valve version. Note that neither the original schematic nor the SM7UCZ version have a bleed resistor in circuit when the rig set to Transmit. This is bad practice as it can leave a charge on the 0.002uF capacitor and the anode circuit of the 6V6 when the power is removed! Very best 73, Graham de G4VUX

[@cameronfrancey1718]

Hi, really nice job Graham! I enjoyed watching your video of this project. The video happened to come up in my recommended by youtube list, quite timely too as I've almost finished reading the book "The Secret Wireless War" written by Geoffrey Pidgeon, who worked in the workshops building sets. 73, and gud luck with the radio, probably wont get to hear you on air with it from over here on the West Coast in Oregon, but maybe some time when I eventually come back home. Cameron, GM7LQR/AF7DK

[@g4vuxqrp210]

Hi Cameron, Many thanks for your comment. Let's hope we can manage a QSO one day if you come back to the UK. I have never managed to reach the West Coast with any radio / antenna! Best 73, Graham de G4VUX

[@adelarsen9776]

Excellent book, I have also own a copy and recommend it. I also recommend the DVD which goes with the book, The Secret Wireless War. It's quite cheap. Grindelwald Productions - www.grindelwald.co.uk 7 3 de VK4SOE/P Clan Radio

[@johnshellythomas7695]

Graham, thank you for this very interesting video! Though I've been a ham since my teen years in the late 1960's, I'd never heard of the Paraset. But I remember well the various transmitter and receiver projects (already old-fashioned even then) in QST and CQ magazines, which used the 6V6 and 6SK7. :) Again, all the best, hope we can meet on the air at some time. 73 de ae3m John

[@g4vuxqrp210]

Hello John - Great to hear from you ! There is a good chance of us meeting on air when conditions improve. Meanwhile, thanks for your comment and best 73 from the UK. Graham de G4VUX

[@adelarsen9776]

Most excellent. Top shelf. Thank you Sir for sharing. 7 3 de VK4SOE/P Clan Radio.

[@g4vuxqrp210]

Ade Larsen, Thank you for your comment. It's a pleasure to hear from you. 73, Graham de G4VUX

[@forthy62]

Incredible good job! 73s de Stephan DF6PA

[@g4vuxqrp210]

Stephan, many thanks for your comment, it's great to hear from you. Vy 73 and gud DX ! - Graham de G4VUX

[@matthalsey387]

thanks for the video. I am just embarking on a Paraset project myself. I note that you dont offer any build plans etc but would you be willing to make your parts list available? Matt

[@grahamcousins795]

Hi - be interested to know where they got 360v dc working in the field - Graham M0GTC

[@f5nfb480]

Where can i find the schema and the list of components please ? I'd like to build one...

[@brucecasey4252]

Great video where can I find parts list? 73

[@Ricky2167]

Good job!!! I started the construction of the box and to find the various components. Where can I find the 36H inductance?

[@g4vuxqrp210]

Dear Riccardo - Any small filament transformer will work, the exact value of 36H is not important. I used this one from eBay www.ebay.co.uk/itm/220V-50Hz-6V-Input-Output-Mounting-Vertical-Single-Phase-EI-Power-Transfor-W2I3/382639713768?epid=17015766552&hash=item59171aade8:g:85cAAOSwabRb9aMz:rk:1:pf:0 The filament winding provides a low impedance headphone output for modern 'phones. 73 Graham de G4VUX

[@robwilliams40]

Thanks for posting this video. 73 Rob G0PEB

[@g4vuxqrp210]

Hi Rob, Thanks for your comment. 73 Graham de G4VUX

[@SpinStar1956]

Really like your Paraset however, it's been 3 years now and I still don't see a the solid-state version you said you'd be designing. When will you be releasing it?

[@cthoadmin7458]

Hi Graham, nice job! An idea for a future video: a whistle stop tour of you lab and test equipment, some of it looks very interesting! De VK4QP

[@g4vuxqrp210]

ctho admin - Many thanks for your comment, it's always great to hear from VK land ! 73 Graham de G4VUX

[@kevinjones2145]

Great

[@RadioPrepper]

Hello, do you have a link to the chassis making company?

[@g4vuxqrp210]

Radio Prepper - Thanks for your comment. The chassis and dial were purchased from eBay member ham-sun. He has just emailed me to confirm that they are still available . A search for 'Paraset' will find it. Kind Regards, Graham de G4VUX

[@RadioPrepper]

Thank you!

[@2E0FNG]

What's the key you're using? I ask because I picked up the same one and I've been trying to find out the maker and the details of it! - I'm referring to the solid brass one with bearings. I can't see it in the video, but it's on the thumbnail

[@g4vuxqrp210]

M0ZAI - Thanks for your comment. The key in the thumbnail is the Kent KT1. They are still available from Kent Morse Keys. Kind Regards, Graham de G4VUX

[@adzbasslines13]

Hi Graham, I noticed your modified schematic showing the addition of a Shendk Filament transformer for audio coupling and your later explanation. Great idea. I'm employing that in mine. How low of an impedance did you get on the output? 72 De VK8feet

[@g4vuxqrp210]

Adz Basslines - Thanks for your comment, it's good to hear from you. The turns ratio is about 40:1 so a parallel pair of 8 Ohm headphones will present an impedance of about 1.6k x 4 = 6.4k to the audio valve. In this case, there is plenty of volume. I sometimes use small active speakers which have a much higher impedance and they are fine too. Kind regards, Graham de G4VUX

[@scharkalvin]

I'm not sure why they used 6SK7 tubes (valves). These were supercontrol or remote cutoff types. Usually the sharp cutoff 6SJ7 would have been used as a detector and audio amplifier. Perhaps at the time the 6SK7 was easier to source. If building a replica, I'd try both types and see which worked better. Also the type 6AG7 power pentode could be used in the transmitter instead of the type 6V6. I have a few of those and none of the 6V6 metal types in my junk box.

[@charlieb.4273]

Very nice project and video, well done. Could you share some details on your power supply? 73 Charlie KM4ZZ

[@g4vuxqrp210]

Dear Charlie, Thanks for your comment. I'm afraid I can't offer any information on the power supply but I'm sure you'll find safety guidelines and construction details in ARRL Handbooks from the 1960s / 1970s. Very best 73, Graham de G4VUX

[@stephenwalters9891]

Do you think switching out the lamps would increase power output by a significant amount? Plus, a 12v Inverter PSU would be a nice companion for portable use. G7VFY.