[Nashua Area Radio Society]

Hi Brian…

Is this a new or used amplifier?…sounds like used.  It may have a few quirks to work out.

Low grid current could be…

• input network problem limiting drive to tube
•    bad bandswitch
•    bad input network tuning
• input match to amplifier limiting power output from the transceiver
• excessive ALC limiting transceiver output
• excessive plate load limiting plate voltage swing

What’s going on with the plate current?  It should increase with increasing drive.

What’s going on with the plate tuning?  There should be a distinct dip in the plate current when changing the tuning knob.  Do this test with the plate loading capacitor fully meshed (minimum load).

Grid current is caused by the grid intercepting some of the electrons coming off the filament (cathode).  When the plate voltage is high, the electrons are pulled to the plate and grid current is low.  When the plate voltage is low, the electrons move more slowly and more get intercepted by the grid.

At full load, the plate voltage swings from near zero to near 2X the DC supply voltage.  If it spends too much time near zero, the amplifier is lightly loaded and grid current soars.  If the amplifier is too heavily loaded, the plate voltage can’t develop enough swing, the minimum never gets near zero and the grid does not intercept too many electrons.

jeff, wa1hco

 

[Nashua Area Radio Society]

Fantastic! I could only help a little on the overnight shift, but there was plenty of energy and operators aching to put Qs in the log. The all 7300 effort was a great touch. Congrats to all the volunteers who made this a success!

— Scott (NE1RD)

 

[Nashua Area Radio Society]

Some thought from Dave Michaels (N1RF) based on an email thread

A . Hardware & Stationn set-up

1. Power supplies

2. Voltage/Current station monitors & Power control point

3. Transceivers

4. Amplifiers (if used)

5. Tuners

6. SWR/RF power monitors

7. Coax switching/grounding equipment

8. Coax pass through options

9. Grounding, lightning arrestors, RF switches

B. Station Operating

1. Computer interfacing/control

2. Spotting bulletins (Dx Summit, etc)

3. Propagation software (VOACAP, etc)

4. Logging software

5. Uploading to LOTW, eQSL, etc

6. ARRL awards ( WAS, DXCC, etc)

C. Antennas

1. Wire Antennas; types and ways to string up

2. Basic Directional Gain antennas ( overview of basic types, masting options from low cost to the BIG $$$ towers)

For topics in A & B, I think having an actual operating station in the room would be a must for best value.

[Nashua Area Radio Society]

Here is also a quick summary / synopsis of the talk and summary of our speaker:

This presentation will cover Arduino and Raspberry Pi;  the capabilities of each board and how do they differ; and how you decide if one or the other is more appropriate for a particular application.  A demonstration of Arduino programming and discussion of some radio applications for Arduino and Raspberry Pi will conclude the talk.

Bob Evans, N1BE was first licensed as WN2EZS in 1972.  Since receiving his BS in Computer Science and Engineering, Bob has been employed as an engineer for over 40 years by companies that design and manufacture computers.  At home Bob uses multiple Raspberry Pi’s for controlling lights, running web cameras, as a video recorder and as a file server.  When not pursuing his technical interests, Bob and his wife Anne, N1MPF, enjoy boating, gourmet cooking and wine.  (Bob is also a member of the Minuteman Repeater Association Board of Directors, and trustee of the MMRA 146.790 repeater in Weston, MA.)

[Nashua Area Radio Society]

Mike,

What is the typical polarization on 28.480 Mhz???  Vertical or horizontal?

 

[Nashua Area Radio Society]

Thanks for the reply Fred,

I think you missed the part when I said  “I am not sure that I will always be able to join the CW net or be able to use the chosen frequency.”

I live west of the Pac Monadnock – Temple mountain range so the only way to reach you will be NVIS @ 40m or lower frequencies or voice through the N1IMO repeater system http://www.n1imo-n1imn.us/

I would like to see if I can even hear you on 20m but I am not expecting to be able to.  If you go to 10m then I almost know that I will not be able to join the net.

 

[Nashua Area Radio Society]

One of the houses I lived in had a flat roof.  Using Dr. Krause’s Book, I built a simple W8JK 2-element Flat-Top. I nailed a 4-foot length of 2×4 support plank on each corner of the house and used wire feedline through a Harvey-Wells matchbox to load it on all bands. I worked all over the world with that setup!

 

[Nashua Area Radio Society]

Another interesting e-magazine is called TALKING ELECTRONICS by Colin Mitchell.

http://www.talkingelectronics.com/

Colin created TALKING ELECTRONICS magazine back in the 1980’s Australia to help educate those interested in electronics. The website provides lots of information and circuits for those that wish to learn electronics and gain some insights into practical construction techniques. Just scroll down the left side column on the interactive index page to sample and explore some of the available documentation:

http://www.talkingelectronics.com/te_interactive_index.html

Might be a great way to get the youngsters interested.

[Nashua Area Radio Society]

If you like the DIT file please let me know. You may want to return to the K7QO CD and listen to files: 028.mp3, 011.mp3 and 054.mp3

Any new ideas or suggestions that can help folks learn to recognize some of their trouble characters: F, L, B, V etc. are welcome. What works for you may work for others as well.

Practice, Practice, Practice… the best Practice comes from ON the Air contacts!

[Nashua Area Radio Society]

Orders for the November Tech-Night Kits is now CLOSED.

Brian will be handling the order shortly.

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