AWA 6AQ5 Transmitter

I've gotten the RF portion of my AWA 6AQ5 transmitter ( https://www.antiquewireless.org/homepage/pcb-item-12 ) done and tested on 80, 40 and 30 mtrs. This transmitter sounds nice on 80 and 40 running 8-10 watts out with a single 6AQ5. It doesn't sound quite as good with HC49S crystals on 30 but it is still acceptable. 

The plate tuning and load variable caps are under the chassis. Temporarily I'm running with an external 300 VDC power supply. Eventually I'll add a power supply in the spare space at the rear of the chassis. The PS transformer and rectifier will go on top with the fuse, filter caps and filter choke underneath.

 

The PC Board and parts list from AWA allows for a straightforward semi-kit or homebrew project. My thanks to the AWA for making them available.

 

KC7WXD built one also. See https://www.youtube.com/@kc7wxd

 

Does anyone know when PC Boards started showing up in tube rigs? Were there any before the Knightkit R-100? It used a PCB for most of the components. See its review in the Nov 1958 issue of QST.

 

 

 

Vintage Homebrew

Recently I was asked by the Long Island CW Club to  give a zoom talk about my vintage homebrew projects. The transmitters, receivers and power supplies I discussed covered the late 20s through the mid 50s. My talk, though, wasn't just about recreating some pieces of ham radio history. I also covered the economics, technology and current events that drove ham radio during this period.

My power point charts with my speaker script is at   http://www.wiegandfamily.org/HomeBrewTalk_March25/VintageHomebrew_LICW_31Mar2025.pdf

 

A Siamese Paddle

Recently my local ham radio club asked for members to show off homebrew CW keys. I decided to build something that would fit in with the club show-and-tell and, even better, be usable in my shack.

 

The July 1952 issue of QST describes "The Siamese Paddle". It is two J-38 straight keys mounted on edge and bottom to bottom to form a set of dual lever paddles, great! I didn't have two J-38s but I did find two EF Johnson Speed-X straight keys on my shelf. I could use these for my paddles and still have two original Speed-X keys if I ever decide to disassemble my Siamese Paddles. I also found a couple pieces of aluminum to form the new base and vertical support. 

 

After drilling four mounting holes and creating new finger pieces I now have a new set of paddles.

These paddles aren't a Begali but they are certainly cheaper and my typical CW speed is only around 16 WPM. They work fine for me and fit in well with the rest of my vintage gear.

 

73,

Niel - W0VLZ

 

 

Vinage Radio Homebrew - Handy Links

QST Magazine 1915 – 1969: https://www.worldradiohistory.com/QST.htm 

 

 ARRL Handbooks: https://www.worldradiohistory.com/BOOKSHELF-ARH/Bookshelf_ARRL.htm   

 VE7SL Radio Notebook: https://www.qsl.net/ve7sl/

 

6C4-5763 transmitter by WB8DQT: www.arrl.org/files/file/QST%20Binaries/Jan2012/w1ts_project.pdf  

W0VLZ's Homebrew Gallery

 Over the past many years I've homebrewed many receivers and transmitters along with several accessory pieces.

Go to http://wiegandfamily.org/W0VLZ_Homebrew/W0VLZ_Gallery.htm to see my vintage homebrew projects.

A 1951 Transmitter for the Beginner

 

With summer wrapping up here in MN and moving into fall I looked around my shack for a 80/40 mtr transmitter to use with my  NC-57  (and here). A likely pairing is with my 6AG7 Beginner Transmitter. Both would have appealed to a brand new novice in the early 50s. 

Here's the construction information on my version of this transmitter: http://wiegandfamily.org/6AG7_Xmtr/1951Transmitter.htm

 

A 1941 Simplified Superhet

 

One of my favorite homebrew receivers is the one I built  based on the "Two Tube Superhet Receiver" shown in the 1941 ARRL Handbook. This one has a regenerative detector running at 1700KHz with a tunable convertor stage (covering 80 and 40) and a single stage of audio.

After few minutes of playing with the two tube superhet on 40 meters I decided that a BFO was needed for reasonable CW and SSB reception. The two tube superhet became a three tuber. The regenerative IF remained. It is not typically run into regeneration but just below to improve IF gain and selectivity. As a modern safety measure I RC coupled the headphones into the plate circuit of audio stage rather than directly connecting them. Read about this project here.

I then decided to make a major improvement by adding a crystal filter. This gives this simple receiver almost single signal selectivity. At 6dB down, the bandwidth is only 250Hz. Inserting the crystal into the middle of the regenerative IF stage feedback loop allowed regeneration to make up for crystal insertion loss without adding an extra tube. Also modified from the original was changing the regenerative detector from 1/2 of a 6C8 to a 6J7, adding better bandspread and a front panel BFO adjustment. The attenuator on the antenna input was added after experiencing problems from strong signals overloading the receiver. This version is described here.

The single AF stage really did not drive a speaker very well. As built this is a headphone radio. In addition it needed an external power supply. I built another AF stage (with a speaker) and a power supply into an external box. In addition I added a toggle / Transmit-Receive switch.

I typically use this receiver with my 6J5-6L6 Transmitter.

QRP in the Park

It's 60 degrees and sunny today. After a "Minnesota Nice" winter and playing with Boat Anchors in the Basement it is turning into time to take my KX3 to a local park.

Last night I gave a "QRP in the Park" talk at the meeting of the Rochester Amateur Radio Club. I covered many possible objectives  of portable operating, how these might affect equipment/operating plans and then looked at some of today's options and my specific equipment and antenna choices.

Download a pdf version of my talk here:  http://wiegandfamily.org/QRP/QRPInTheParkTalk_10Apr2024.pdf

See a video showing me setting up my 20 mtr C-Pole vertical here: https://youtu.be/nYn-GnwcSoE

See a video showing how to get an antenna wire over a tree limb here: https://youtu.be/zibrXtaG_Ro

WN6ULH / WA5VLZ / W0VLZ Through the Years

 Here is a look at my stations through the years: http://wiegandfamily.org/shack_tours/shacks.html

 Some entries on this blog link to information on prismnet.com may be broken. If so, try going to https://web.archive.org/web/20220604005204/https://www.prismnet.com/~nielw/wa5vlz.htm