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Friday, July 29, 2011

Amateur radio at PAR (W4OP)

An e-mail exchange on QRP-L this morning about using ceramic resonators in 455 kHz filter circuits (great idea Grayson!) led me to the ham radio corner of the PAR electronics web site. PAR is the company run by Dale Parfitt, W4OP.
http://www.parelectronics.com/par-amateur-radio.php.
That's a nice looking 2-B Dale! Please send us the serial number! Even more impressive is Dale's award-wining homebrew solid state version of the 2-B (on the far right). Visit his web site for more info (on his site you can hover your mouse above the pieces of gear for more info).


I'm proud to say that I have a piece of gear in my shack that was built by Dale Par
fitt. The story is told in SolderSmoke The Book: I'd built my own version of Doug DeMaw's Barebones Superhet and had liked it a lot. When I saw another one (this one built on a FAR circuits board) for sale on e-bay, I bought it. It stayed on the shelf for a while. Years later when I started working on it, I turned to QRP-L for help and this fellow named Dale Parfitt came to my rescue. It was only after a long series of e-mail exchanges did we realize that the receiver we were discussing had been built (and sold to me) by... Dale Parfitt.

Our book: "SolderSmoke -- Global Adventures in Wireless Electronics"http://soldersmoke.com/book.htmOur coffee mugs, T-Shirts, bumper stickers: http://www.cafepress.com/SolderSmokeOur Book Store: http://astore.amazon.com/contracross-20

Wednesday, July 27, 2011

Walford Electronics' "QRP In the Country"

A stiff wind and occasional drizzle did not put off the large attendance of QRP and home building enthusiasts who attended QRP in the Country on July 17th. Hundreds of people from all over England and Holland found their way to Upton Bridge Farm, Somerset where the farm barns provided cover. About 25 stalls and displays showed off or sold everything from components to large construction projects. Apart from a few traders selling components, most displays were from Clubs publicising their activities or of ancient domestic and wartime radios, with a few individuals selling items to make space for new projects! There were also practical construction projects to be seen as ‘students’ built their Cary RXs with occasional help from the Bath Buildathon team led by Steve G0FUW. The catering team led by Tony G0GFL cooked a prodigious amount of special local burgers and sausages from the host Tim G3PCJ’s farm served in rolls baked locally that very morning, and washed down by village beer and cider, under the careful eye of Robert PA9RZ!

A raffle raised £200 for those suffering in East Africa; the main prize being a year’s subscription to PW kindly donated by Rob G3XFD which was won by Graham G4DPH. George G3RJV was asked to select a couple of displays that ‘appealed’ to him for two other prizes. The GQRP Club had kindly donated a special edition of Drew VK3XU’s latest project book which was also won by G4DPH for his PW Sprat project; a Walford Electronics Radlet CW TCVR kit went to Colin G3YHU for his valved superhet. A years subscription to BYLARA was won by SWL Mike Jones who is about to take his Foundation licence course.

After the event Tim G3PCJ said he was said delighted with the increased attendance and wished to thank everybody whose hard work had made the event so successful. He urged all Clubs within reasonable distance to plan their displays for next year! Watch the press for announcements of the date!


Any questions to:-
Tim Walford G3PCJ
walfor@globalnet.co.uk
WALFORD ELECTRONICS
www.users.globalnet.co.uk/~walfor


Designers & suppliers of kits for radio enthusiasts

Proprietor Tim Walford BSc MIEE CEng G3PCJ

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Our book: "SolderSmoke -- Global Adventures in Wireless Electronics"http://soldersmoke.com/book.htmOur coffee mugs, T-Shirts, bumper stickers: http://www.cafepress.com/SolderSmokeOur Book Store: http://astore.amazon.com/contracross-20

Tuesday, July 26, 2011

How Curiosity Will Land on Mars



Our book: "SolderSmoke -- Global Adventures in Wireless Electronics"http://soldersmoke.com/book.htmOur coffee mugs, T-Shirts, bumper stickers: http://www.cafepress.com/SolderSmokeOur Book Store: http://astore.amazon.com/contracross-20

Regens: A Complex Relationship; AA7EE's WBR


Bill -
I've been following your blog for a while now and am moved to let you know of my recent experience with regens, a subject that I know is dear to your heart or perhaps, more accurately, the basis of a complex relationship!
Anyway, the last time I built and owned a regen was as a teenager in the UK in the late 1970's when I had a one-tube HAC Model DX one tube regen. Recently I've been looking for a fairly simple receiver to build that would
receive CW and SSB on 40M, as well as AM. I'm developing an interest in AM on 40, a rather impractical mode in some ways, but one that I have an attachment to. A regen seemed an obvious choice, so after seeing the
reprint in "More QRP Power" of the QST article describing N1BYT's WBR regen, I decided to have a go at it.
In short, I'm so glad this was the first regen of my adult life. It is sensitive, suffers no hand-capacitance effects, has very little radiation from the antenna port due to the oscillator tank circuit being in a Wheatstone Bridge arrangement,
no microphony and to make things even better, is very stable in frequency. I can set it to a net or long-winded CW QSO and it stays there with no easily discernible drift (after a short warm-up period of course).
I know you're probably aware of this receiver, but have you tried building one? I think you'd be pleasantly surprised.
The blog post about my version of this great little receiver is here:
Yours,
Dave Richards
AA7EE

Our book: "SolderSmoke -- Global Adventures in Wireless Electronics"
http://soldersmoke.com/book.htm
Our coffee mugs, T-Shirts, bumper stickers: http://www.cafepress.com/SolderSmoke
Our Book Store: http://astore.amazon.com/contracross-20

Saturday, July 23, 2011

The Dish

Our man in Dayton, Bob Crane, W8SX, sent us a really beautiful picture of my favorite antenna (not the one above). Check it out: http://apod.nasa.gov/apod/ap110721.html

We talk about "The Dish" from time to time on SolderSmoke. That's the name of the movie about the role of this antenna in the reception of the TV signals for the Apollo 11 moon landing. This is -- without a doubt -- the best movie ever made about an antenna.

You can get the movie at the Gadgeteer Book Store:
http://astore.amazon.com/contracross-20?_encoding=UTF8&node=8

Check out "SolderSmoke -- Global Adventures in Wireless Electronics"
http://soldersmoke.com/book.htm

Friday, July 22, 2011

Steve "Snort Rosin" Smith: Silver-Tongued Devil! Dual-band "Vlad the Inhaler" RX

You'll see in the comments attached to my last blog post that our man on the left coast, Steve Smith, gave that cute little Doug DeMaw/Vlad Polyakov receiver a name that might set American-Russian ham relations back a bit: He called it "Vlad The Inhaler." Good one Steve! (But you might want to stay out of the diplo game!)

It occurred to me that with the installation of one little switch in the diode part of the circuit, we could turn this into a dual-band RX. Take a look here:

http://soldersmoke.blogspot.com/2010/03/polyakov-plus-dual-band-receiver-with.html

Check out "SolderSmoke -- Global Adventures in Wireless Electronics"
http://soldersmoke.com/book.htm

Wednesday, July 20, 2011

Doug Demaw and Vlad Polyakov

I was looking through W1FB's Design Notebook the other day and I came across the above schematic for a direct conversion receiver (page 111). Note the Polyakov detector. One strange thing though: Doug was running the oscillator at the operating frequency. I thought the big advantage of the Polyakov design was that you ran the oscillator at half the operating frequency (that's why it is sometimes called a "subharmonic" detector). Any ideas on why Doug did it this way?

Check out "SolderSmoke -- Global Adventures in Wireless Electronics"
http://soldersmoke.com/book.htm
Designer: Douglas Bowman | Dimodifikasi oleh Abdul Munir Original Posting Rounders 3 Column