MNQRP NEWS

August 1998 Volume 1 Number 8

Wanted Newsletter Editor and Vice President!

Chris Wilken, KB0DAL has been accepted to Graduate School and has decided he can no longer be the newsletter editor. We all wish to thank Chris for his help and wish him good luck with his studies. I’m looking for someone that has experience with Word and HTML to take on this job. I can help get you set up and going. Please let me know if you can help.

Still need a volunteer for the Vice president job. Come on we need you to help. Email or call me.

Claton Cadmus. KA0GKC

Program for August Meeting

John KA0OSC reports the program for the Saturday August 1^st meeting will be Arnie Kopischke, WA0DFT whose topic will be "My Experiences, Good and Bad, in Homebrewing".

BASIC Programming

How often have you wanted to figure out some equations and do variations? Well if you’re a homebrewer like me it’s every so often. I use a speadsheet and the Hamcalc series of program but sometimes neither are the right tool. Almost every computer comes with some form of BASIC programming language. Even Windows 95, Qbasic is on the CD if it’s not on your machine already. This is a great tool and well worth the effort to learn to do simple programming. Below is a basic program from Bob, WB0POQ it’s a good example of simple programming that can solve a series of equations easily that even with a calculator would be tedious to do. Especially if you decide to make a change. Please let me know if you are interested in learning more about BASIC programming, we could run a series here.

Bandpass Filter Calculation Program

This is a simple gwbasic program that calculates component values for 2 pole Butterworth type L/C filters. It is based on the description and formulae from "Solid State Design for the Radio Amateur" available from the ARRL, or your local library.

The schematic diagram shows the basic layout of the filter. Note that the two coils must have the same value in this design. Also the input and output coupling capacitors must also be the same value. This type of filter can be designed with dissimilar values, but I did not feel like doing the math :-)

I frequently build this type of network using fixed toroidal coils, and install small plastic variables as part of the capacitance. This allows some range of adjustment to get it right.

Pay attention to the fact that the program looks for the inductance to be entered in uH, capacitance in pF, frequency in MHz, and load in Ohms. If you add the terms to the numerical values, the program will crash.

The load resistance is normally the same at both ends of this filter, but it can be designed this way and used with different terminations, with varying affects on the passband.

You will need gwbasic or qbasic to run this program, although it should port to others without too much trouble.

(Use the mouse to select the program text and save it to a file called BWF.BAS-Ed.)

No, this is not a sophisticated program, but it does work, and it comes in handy when you need to design a good bandpass filter quickly. Of course, use at your own risk, do not depend on this program to save your life etc, etc. It is shareware. If you like it, and feel like it, you can send me a couple of bucks. Or, send me a neat skez of some circuit you like.

Bob Liesenfeld, WB0POQ

wb0poq@visi.com

Indoor Transmitting Loop Antenna

Remember last newsletter when I told of the loop antenna I saw at Dayton. Well I’m building my version. It’s a 7 foot PVC pipe cross. I chose this size as being about the biggest you could get in a room. The antenna comes apart for transport but the #10 house wire I used around the perimeter is a bit hard to handle. I think I’ll be changing this to copper braid as used on the antenna at Dayton. Something tells me my predecessor went down this road too! I’ve tried a regular 100pf tuning cap and it receives surprising well, even in the basement. I’m building a "trombone type" tuning cap for it so it can be used for transmitting and to improve the efficiency. For 5 watts output this cap must be rated at about 1.2 kilovolts! I used the Hamcalc series of programs to help design this cap. The small loop program predicts my loop will have about 60% efficiency on 40 meters and better than 95% on twenty and above. I will bring it to the September meeting.

Claton Cadmus KA0GKC

Minutes of the July Meeting

At the June meeting it was decided to have the July Meeting at the Field Day Site on Saturday the 26^th. There were only a few of us there and it was decided to cancel the meeting.

Your Club Officers

PRESIDENT – Claton Cadmus KA0GKC
Duties:
Presides over the meetings and makes the interim club decisions.

VICE PRESIDENT --
Duties:
Takes the Presidents place if absent or unavailable. Acts as counsel to
the President.

FIELD DAY COORDINATOR – Bill Brisley N0BSN
Duties:
Goes nuts for about a week before Field Day, sends in our entry after
Field Day. The rest of the year they have off!

FYBO COORDINATOR – Larry Gaalaas KB0R
Duties:
(Freeze Your Butt Off winter QRP Field Day) About the same as the Field
Day Coordinator but gets colder! I think we really need to make an effort
here. The Arizona Club sponsors this contest. What the hell do THEY know
about winter!

SECRETARY -- David Donaldson WB7DRU
Duties:
Takes or sees that someone else takes minutes at the meetings and maintains
the club business history. Submit the minutes to the Newsletter Editor for
publishing.

TREASURER -- Stan Berkner KA0JWH
Duties:
This person keeps the books and receives and disburses all club funds.
Also maintains the club roster, forwards it to the newsletter editor for
occasional publication.

NEWSLETTER EDITOR – Claton Cadmus KA0GKC
Duties:
Publishes the club periodical, via web page, email and print. Maintains
the subscriber list. The newsletter will contain the meeting minutes, a
current list of contact information, an event calendar, classified ads,
and other articles and advertisements as the editor sees fit.

Newsletter Reporters -- Bob Gobrick N0EB, Claton Cadmus KA0GKC and
EVERYONE ELSE IN THE CLUB!

Newsletter Photographers – Les Bearll N0PPF, Bill Brisley N0BSN

PROGRAM CHAIRMAN -- John Robertsen KA0OSC
Duties:
Locate and coordinate an occasional meeting program. Most of us like the
BS sessions, but a little change would be nice. Many of these programs
can come from our members, we have a lot of talent here.

EDUCATION DIRECTOR -- Bob Gobrick N0EB
Duties:
Doesn't have all the answers, but does know where to find them and can
direct members to resources about QRP, radio construction, CW study and
license upgrades etc. This person is also responsible for our Field Day
site public info table.(100 points!)

PROMOTION DIRECTOR -- Steve Jacobs KI0CL
Duties:
Promotes the Club at Hamfests and the local radio/electronics outlets as a
mechanism to attract new members. Organizes current members to make
announcements on the local nets about our club. Also is responsible for
promoting our Field Day activities to the news media. (100 points!)

Historian – Les Bearll N0PPF
Duties:
Maintain the club history and collect the archival data and momentous.

Club Librarian – Mike Smith N0WDM
Duties:
Maintains the club reference library.

Calendar of Events

Please send in events to the editor.
We can’t show them if we don’t know them!