Just go to http://soldersmoke.com. On that archive page, just click on the blue hyperlinks and your audio player should play that episode.
http://soldersmoke.com
Jac (KA1WI) and I spoke on 40 meters on June 29th. I told him about the BITX -- he said he liked the idea of building something and pledged to start melting solder. This week I got this message and video from him. Good going Jac! That was fast! I think we all know who designed the IF amp: Wes W7ZOI. As for the DS/PLL, I recommend you take a look at the Si5351 with an Arduino microcontroller.
Hi Bill,
I started in July building a receiver with the available parts I had collected over many years. Finally today the receiver is working more or less to my satisfaction. Here is a brief description.
I am using a set of crystall filters from an old Atlas 350XL, 5.595 is the IF frequency and the filters have independent USB and LSB plus CW 500 Hz filter. The radio set is a single conversion type. A DBM at the front end and as product detector. Keeping the BFO signal from leaking is a challenge but I managed by carefully matching the three ports of the DBM used as product detector. Matching the IF filters impedance was another challenge. Following the DBM there is a LNA amplifier using a 2N3866 and I am trying another LNA with a discontinued Siemens BFT66 transistor with a very low noise figure. I have some experience with those and they can be amazingly quite.
The IF amp is a hybrid cascode with three stages and AGC that I found in the internet designed by a well known OM, the design works very well it is easy to make and is very stable despite its nearly 70 dB of wide band gain. The AGC range is close to 100dB . . .
The front end has 6 BPF covering from 1.5 to 30 Mhz all switched by relays. This unit I got from an old German receiver.
The VFO or 1st LO is a DDS unit I had played with years ago. From N3ZI is far from perfection but it does the job when the bands are alive and well. The alternative to the simple DDS are complicated. I wish there were more DDS PLL kits available. It can take a long time to get a full synthesizer satisfactorally working.
The set is made of mechanical parts from a Tektronix main frame instrument, there are many parts of different shapes that can be attached together in a crazy way but certainly very functionally. There is the IF amplifier and the Product Detector BFO enclosed in two brass silver plated boxes, both also recovered from some surplus ages ago. The DDS is one of the sides on the chassis without any shielding.
The IF filters and the front end are going to be attached to the rear of the chassis by just adding brackets etc., you get the idea. I am glad the video is acceptable.
I thought it will interest you know that at age 70 is also possible to roll your own, despite having to check every solder joint since my eye sight is the biggest problem
I have other projects, another receiver with an IF of 9 mHz with SSB and AM filters using another type of high gain IF amp.
Pete Juliano and I were talking on Skype yesterday evening. He was regaling me with tales of the wonders of his new beam antenna. He mentioned that he was working a lot of East Coast stations... Wait a minute, I thought, I'm an East Coast station. And I have a 20 meter rig sitting right in front of me. "Meet me on 14.190 Pete!" It took me a minute or so to get the rig connected to the CCI amplifier and the 20 meter dipole. By the time I got everything fired up, there was a station on the frequency. I thought we'd lost the spot. But no! I realized it was Pete calling me.
This was extremely cool. Pete was using his ZIA rig with the brand new beam. I was on my VFO BITX20. And I was using the CCI amp that Pete had coached me on (he taught me how to tap the holes for the heat sink).
This was the first time I had ever contacted another homebrew SSB station -- and the first time Pete and I had spoken on the air. THE RADIO GODS WANTED THIS ONE TO HAPPEN!
Interested to hear you talking about civility ... My introduction to amateur radio was via a Heathkit GR 64 and Roy, G3PMX. When I finally took my ticket - 1970, and passed, I called him on the phone to tell him - he told me to come on up to his QTH, I did, via an old bike taking about 30 minutes to get up the hill. When I got there, he put me on the mike, the guy the other end was really great, talked about being a part of an international brotherhood and a movement for world peace - just a magical first contact ...
Roy asked me if his call seemed a little odd, it did, it was short, JY1, but I was really slow to cotton on to who I'd just spoken to... What really blows me away to this day was that the King of Jordan sat in his shack and waited for a 16 year old kid to pedal up the hill just to give him a fantastic first contact ... My only regret is that I never got to speak to him again to say "thank you" - when you talk about legacy radios, it isn't the tech that we need to hold on to, though we do, it was what that man did to reach out to a fellow amateur. By all accounts, he was a fantastic guy, he used to sit at Roy's kitchen table drinking coffee and just being one of the guys ... Sadly I was at sea by then hence not meeting him.
Roy knew him because he worked for Marconi & put the antennas on the palace, Hussein just appeared having that Roy was an amateur and they had a long conversation about radio - when he turned to leave, Roy asked his name so that he could stay in touch - Hussein told him to just ask for Hussein the radio guy - never let on that he was King ... Roy said that on several occasions, JY1 travelled to the UK more or less incognito and hired fairly innocuous cars to get about the country simply because he was here as an amateur, not a head of state …
I really do regret that I never got the chance to say “thank you” to him – it was the sort of gesture that I have always thought typifies what you have tried to support and continue, and is indeed carried on by the likes of Joe Taylor who once took the time to respond to an email from me explaining how to set a WSPR system up despite being Nobel Prize winner !! Great example of the spirit of amateur radio transcending all else :-)
Paul Hodges, KA5WPL, didn't have the variable capacitor called for by the Michigan Mighty Mite schematic. So in the true spirit of the International Brotherhood of Electronic Wizards, he rolled his own! He used two empty aluminum cans and some electrical tape. Wow, that's really cool Paul.
You have truly earned you membership in the Color Burst Liberation Army, and for the capacitor I award you the prestigious Brass Figlagee with Bronze Oak Leaf Palm.
"SolderSmoke -- Global Adventures in Wireless Electronics" is now available as an e-book for Amazon's Kindle.
Here's the site:
http://www.amazon.com/dp/B004V9FIVW
Free e-Book version of The ARRL Antenna Book
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