SolderSmoke Podcast #176 is available! (And it is GOOD!)
http://soldersmoke.com/soldersmoke176.mp3
16 May 2015
Bench Update:
Pete releases some magic (amplifier) smoke
Pete's new termination-insensitive transceiver makes first contact
Bill goes Yaesu (well, just a filter)
Juliano Mill-Pad boards
Termination Insensitivity is not a personality disorder!
Flip those Bilat Boards! Pete's cool technique for bilat building
Bill's project notebook and stage testing
Installing the W6JFR EMRFD SBL-1 Bal-Mod Mod
AREA 5351: Myths, Urban Legends, and Conspiracy Theories about the Si5351
A Rule of Thumb for Sideband Inversion
Dongle Madness and the Dangers of Dongle Modification
What is a dongle?
24 Mhz to 1.7 GHz right out of the box
Modification for 0-29 MHz
Tapping the IF of a Drake 2-B
Getting another one for VHF-UHF
Dongling Meteors, Satellites and Airplanes
SPRAT cover AD9850 in 1988! Three cheers for SPRAT (and QQ and QST).
Elecraft's new Rig
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
Pete, bill,
ReplyDeletePete,
Sorry to hear about the finals going away. I always add RF feedback to tame them and insure they are stable into radical and reactive loads. The oddity is someday statistically I may blow a big final, but I haven't. I've fried stuff at the 5W and lower level by the pound usually during development. But after that they are bullet proof as possible, even the W5EBY using the infamous IRF510 has been pushed into shorted antenna, no antenna and worse seriously mismatched antenna with no ill effect. I also added feedback to that as well.
Also my antenna switching is two levels. The first switch is dummy/antenna with the antenna side going to the antenna selector. Insures that I do not have to transit many possible wrong positions.
Its amateur radio when no one gets fired for doing that! ;)
SBL-1 is a great part I've done the modulator with balance pot on no less than 4 radios. It just works. FYI the first radio using it is FrankenRadio a 4W 6M SSB rig that is my mobile build back in 2001. I found a 50 ohm pot work well.
Termination insensitive amps. and Bilat amps. I've used many designs and my cheap gene has me use fewest parts. So a finale amp with DPDT, or diode DPDT, or FST switch based DPDT switches to literally turn the amp around. It just works. I've used HyCas that way and also made the switch drive set the gain so I can have AGC on RX fixed set gain for TX. So one Hayward amp and a switches to turn it around is a viable way to go with less parts.
Re Si5351 when you divide by 4 you get the improved phase noise that way AND if you look at the datasheet the phase noise does not degrade with increased frequency so as a percentage of carrier enter frequency it also gets better. The last word on that is for most simple radios its very good. If your doing HBR2000 or Trident both ultimate class radios for high performance then its a concern (not a lockout, but consider what it may mean).
Wisdom, the knowledge to know lore where myth may differ from fact or science.
The other is words as complete sentences forming a full thought are the tool of science and catchy phases are the work of the devil. Never fear them, understand what is being said.
Dongle is a old computer word. Its is the concatination of "dangles" and "legal". The first dongles were copyright locks for software and used the old printer or seriel ports. They often literally hung off a cable from the back of the machine to nearby such as near the keyboard.
REMEMBER if there is more than 1 pin to connect to the others will likely cause great pain! ;-(
Dongles and VHF... They tune everywhere, poorly. Most have terrible dynamic range and not very sensitive. For sat work they need a good preamp. But like all tools they are handy.
AD9850, I did that back then. It was the use of a micro to program it and doing 40 bit math on a 8bit CPU (then common 8751). Free sample in hand and 8085 as the cpu of choice for me I did it still have it and it works well. Much bigger though as the CPU board alone is 4.5x4.5 (now a 18pin dip!).
Every day I hear people moaning about parts availability and from my perspective of more than 50 years this is truly the golden age. Remember 50 years ago a minicomputer was the smallest increment of computer and typically two 6ft racks.
Allison