Warning: Creating default object from empty value in /homepages/11/d132647312/htdocs/Amfone/mkportal/include/SMF/smf_out.php on line 47
811 bias for Mod




 
The AM Forum
January 16, 2019, 01:53:57 AM *
Welcome, Guest. Please login or register.

Login with username, password and session length
 
   Home   Help Calendar Links Staff List Gallery Login Register  
Pages: 1 ... 4 [5]   Go Down
  Print  
Author Topic: 811 bias for Mod  (Read 2424 times)
0 Members and 1 Guest are viewing this topic.
K1JJ
Contributing
Member
*
Offline Offline

Posts: 7697


"Let's go sailing, Tommy!" - Yaz


« Reply #100 on: January 12, 2019, 06:17:27 PM »

The right angle drives I found are millen 10000 which have a 1:48 turns ratio. Are these the correct parts or will that make the turning painfully slow? i sent a email to Chuck to see if he perhaps has some pics of the underside of that deck pic as well as some for the modulator. His QRZ page only shows the same pic as yours.

John


Hopefully Chuck took some pics from underneath the rig too.  That would give you a lot of good info to study.

500 pF vacuum caps used for HF are slow enough already at 1:1 drive ratio. No need to slow them down further. You will be rowing around the bands enough already at 1:1...  Wink Same with the 1500-2000 pF loading vac caps.  

If you vertically mount one, get a 1:1   90 degree angle 1/4" shaft drive.   You will need a separate  1/4" shaft 1:1 panel mounted turns counter too.   (Most vac variables use 1/4" shafts, but not all.)   Be sure you use an insulated 1/4" shaft to the front panel (and/or an insulated 1/4" flex coupler) because there is often RF induced onto the metal shaft coming out of the vac variable casing. Potential RF burns even though the vacuum cap "rotor " may be grounded thru internal threads and finger stock. That goes for all metal shaft variable caps coming out to the front panel on a QRO KW rig.

T
Logged

“Remember, remember, this is now, and now, and now. Live it, feel it, cling to it. I want to become acutely aware of all I’ve taken for granted.”  -  Sylvia Plath

Favorite Song - Trololo thru the years:  
https://www.youtube.com/watch?v=IVqUecYGnoM
w9jsw
Two shots of Whisky
Member

Offline Offline

Posts: 115



« Reply #101 on: Yesterday at 08:58:10 AM »

Chuck is helping me with parts. Have right angle drives, now he is looking for caps. What a guy!
Logged
K1JJ
Contributing
Member
*
Offline Offline

Posts: 7697


"Let's go sailing, Tommy!" - Yaz


« Reply #102 on: Yesterday at 10:46:32 AM »

Chuck is helping me with parts. Have right angle drives, now he is looking for caps. What a guy!

Yep, Chuck has helped many of us over the years.  (WA1EKV / K1KW)


Some background:

There was a time when I was building a lot of rigs and I needed to call him almost every night for advice. I'll bet we spent 100 hours on the phone and email over the years. He was always easy-going and more than willing to help. He could answer the questions that nobody else knew the answers to... the practical side of homebrewing that was not in the books.   He probably doesn't realize it, but he was my mentor for many years, though my work still doesn't compare to his.  The question is: Is the ham radio world a better place because of you?  In his case, yes, he made a huge difference.

It was back in 1965 when there was a knock on the door and there was 14 year old Chuck standing on the porch with his father. We had an eyeball QSO for the first time. He had his homebrew screen modulated 6146 rig under his arm built into a Bud Shadow cabinet. He pulled the cabinet off and I was amazed that anyone could build a rig, never mind make it look like factory work.  He went on to eventually build a 4-1000A plate modulated by 833As in high school. This young whipper-snapper was louder and sounded better than the old buzzard W1's of the 1960's AM era which probably made them crazy...   Grin

He went on over the next 50 years to build many homebrew rigs, some of which are still on the air in others' hands.  He was always on the "fun" leading edge of Ham technology. His 75M rotary beam in the mid 80s, stacked HF logs, homebrew amplifers, SDR, etc., etc., were a ham's dream. He's an engineer's engineer.  

Many don't know it, but he has another serious hobby -  a 6-bay garage full of 1920's/30's restored cars that he regularly drives to events, etc.  My guess is he has helped many of those hobbyists too.

What can I say? You are in good hands. Ask questions and get the right answers.  Glad you are finding some of the hard to find parts...  Some day you will pay it forward and help others build their rigs too.


T
Logged

“Remember, remember, this is now, and now, and now. Live it, feel it, cling to it. I want to become acutely aware of all I’ve taken for granted.”  -  Sylvia Plath

Favorite Song - Trololo thru the years:  
https://www.youtube.com/watch?v=IVqUecYGnoM
Pages: 1 ... 4 [5]   Go Up
  Print  
 
Jump to:  

AMfone - Dedicated to Amplitude Modulation on the Amateur Radio Bands
 AMfone © 2001-2015
Powered by SMF 1.1.21 | SMF © 2015, Simple Machines
Page created in 0.033 seconds with 19 queries.