Date: Tue, 8 Nov 94 04:30:40 PST From: Ham-Homebrew Mailing List and Newsgroup Errors-To: Ham-Homebrew-Errors@UCSD.Edu Reply-To: Ham-Homebrew@UCSD.Edu Precedence: List Subject: Ham-Homebrew Digest V94 #330 To: Ham-Homebrew Ham-Homebrew Digest Tue, 8 Nov 94 Volume 94 : Issue 330 Today's Topics: About the Digest version of this Butterworth: butter.c Colpitts Osc Design Info Filter programs. Help needed with older Kenwood HF model 9R59D Local TV Jamming Looking for schematic for Pulser MB200 Send Replies or notes for publication to: Send subscription requests to: Problems you can't solve otherwise to brian@ucsd.edu. Archives of past issues of the Ham-Homebrew Digest are available (by FTP only) from UCSD.Edu in directory "mailarchives/ham-homebrew". We trust that readers are intelligent enough to realize that all text herein consists of personal comments and does not represent the official policies or positions of any party. Your mileage may vary. So there. ---------------------------------------------------------------------- Date: 7 Nov 94 15:02:52 GMT From: mack@mails.imed.COM Subject: About the Digest version of this It appears that MANY of you receive each message for this group as an individual message. Many others (like myself) receive a big glob of messages once a day. This is the reference to "Digest" in some of my posts. For those wishing to subscribe to the digest version here is the header from the digest: BEGIN QUOTE Send Replies or notes for publication to: Send subscription requests to: Problems you can't solve otherwise to brian@ucsd.edu. Archives of past issues of the Ham-Homebrew Digest are available (by FTP only) from UCSD.Edu in directory "mailarchives/ham-homebrew". We trust that readers are intelligent enough to realize that all text herein consists of personal comments and does not represent the official policies or positions of any party. Your mileage may vary. So there. END QUOTE I hope this helps clear up some of the questions. Ray Mack WD5IFS mack@mails.imed.com ------------------------------ Date: Sun, 6 Nov 1994 17:31:26 GMT From: novatech@eskimo.com (Steven Swift) Subject: Butterworth: butter.c /************************************************ COPYRIGHT 1987 Steven D. Swift Rights to copy are granted provided that the program is neither sold nor used for commercial purposes and that this notice stay with all copies. history: rev 0: november 02, 1987 Steven D. Swift, P.E. Seattle, Washington rev 1: august 31, 1990 updated array initialization modified number of digits in out **************************************************** butter.c this program calculates the component values for nth order butterworth filters. Either low pass or high pass, with either capacitive or inductive inputs. The input and output load are restricted to being the same value and resistive, e.g; 50 ohms. No other restrictions are placed on the values and the program does not check for standard values. Although the output is in a form most appropriate for filters that end up with L's in uH and C's in pF. The formulas used in this program and the examples used to test it came from: Introduction to Radio Frequency Design, W.H. Hayward, Prentice-Hall 1982. Required inputs are: Fc: 3db frequency, in MHz Ro: source and load impedance, in ohms n: order of desired filter hp or lp: type of filter cap or ind: input stage, capacitive or inductive The outputs are: component value, inductor or capacitor indicated by units printed. -------------------------------------------------------------- ***********************************************************/ #include #include float L[25] ; /* inductors */ float C[25] ; /* capacitors */ float g[25]; /* coeficient register */ main() { float pi = 3.141592654; double sin(); /* need sine to calculate coef */ int k = 0; /* counter for coeficients */ float Fc ; /* 3dB cutoff frequency hertz */ float Wc ; /* 3dB cutoff frequency radians */ float Ro = 50.0; /* source and load impedance */ int input; /* alpha for inductive input */ /* alpha for capacitive input */ int n = 3; /* order of filter */ int i = 0; /* dummy counter */ int type; /* type of filter: lp or hp */ float meg = 1000000.0; /* input user chosen variables first */ printf("\n\nBUTTERWORTH FILTER PROGRAM\n\n"); printf("Input the order of the filter (25 max): "); scanf("%d", &n); printf("\n"); if(n>25){ printf("\nOrder too large!\n"); exit(); } init(n); /* initialize arrays to all zeroes */ printf("Input the type of filter (1=hp or 2=lp): "); scanf("%d", &type); printf("\n"); printf("Type of input stage (1=ind or 2=cap): "); scanf("%d", &input); printf("\n"); printf("Input cutoff frequency (MHz): "); scanf("%f",&Fc); Wc = 2*pi*Fc*meg; printf("\n"); printf("Input source and load resistance (ohms): "); scanf("%f",&Ro); printf("\n"); /* calculate normalized filter coeficients and store them in the array g[] */ for(i = 1; i <= n; i++) g[i] = 2*sin( (2*i-1)*pi/(2*n) ); /* test for types of filters and input stage, then perform the appropriate calculations by calling the appropriate function. these functions do not return values, but modify the arrays L[] and C[] directly, getting inputs from the variables typed in by the user and from g[]. */ if ( (type==1) && (input==1) ) for( i = 1; i <= n ; i++) hpind(Wc,g[i],Ro,i); else if ( (type==2) && (input==2) ) for( i = 1; i <= n ; i++) lpcap(Wc,g[i],Ro,i); else if ( (type==1) && (input==2) ) for( i = 1; i <= n ; i++) hpcap(Wc,g[i],Ro,i); else if ( (type==2) && (input==1) ) for( i = 1; i <= n ; i++) lpind(Wc,g[i],Ro,i); else printf("Type of filter incorrect. Please try again.\n\n"); output(n,Fc); /* output results */ } /* all the functions used by main are located starting here */ hpcap(x,y,z,k) /* x is radian freq, y is gk, z is Ro and k is count */ float x,y,z; int k; { if(isodd(k)==1) C[k] = 1.0/(x*y*z); else L[k] = z/(x*y); } hpind(x,y,z,k) /* x is radian freq, y is gk, z is Ro and k is count */ float x,y,z; int k; { if(isodd(k)==0) C[k] = 1.0/(x*y*z); else L[k] = z/(x*y); } lpcap(x,y,z,k) /* x is radian freq, y is gk, z is Ro and k is count */ float x,y,z; int k; { if(isodd(k)==1) C[k] = y/(z*x); else L[k] = (y*z)/x; } lpind(x,y,z,k) /* x is radian freq, y is gk, z is Ro and k is count */ float x,y,z; int k; { if(isodd(k)==0) C[k] = y/(z*x); else L[k] = (z*y)/x; } /* isodd tests if an integer is odd or not, for use in finding whether or not to calculate an L or a C element */ isodd(x) int x; { int i=1; if ( (x % 2) == 0) i=0; /* returns 0 if even, 1 if odd */ return(i); } /* output(): prints out the results of the program */ output(n,f) float f; int n; { int i; printf("\nValues for %d order Butterworth filter @ %.4e MHz",n,f); printf("\n Element Inductors Capacitors\n\n"); for (i=1; i<=n; i++) { if (L[i]>0) printf(" #: %d %.3fuH\n",i,L[i]*1.0e6); if (C[i]>0) printf(" #: %d %.2fpF\n",i,C[i]*1.0e12); } } /* initialize array variables */ init(n) int n; { int i; for (i=0; i<=n; i++) { g[i] = 0.0; L[i] = 0.0; C[i] = 0.0; } } /* that's the end */ -- Steven D. Swift, P.E. ( novatech@eskimo.com ) NOVATECH INSTRUMENTS, INC. 1530 Eastlake Avenue East, Suite 303 ------------------------------ Date: Sun, 6 Nov 1994 15:42:19 GMT From: dshalita@rogue.com (David Shalita) Subject: Colpitts Osc Design Info Does anyone have a reference where I can get some very detailed infomation about how to design Colpitts LC Oscillators? RF Design magazine offers a "Oscillator Design" booklet, but I am not certain this is info for a person with no oscilator design experience. I have several Radio Amateur Handbooks and several QRP series books which never quite offer enough detail in choosing the coupling and the 2 feed back capacitors. 73 and thanks, Dave W6MIK dshalita@rogue.com -- Internet : dshalita@rogue.com AMPR.ORG :lp.w6mik.ampr.org [44.16.0.29] AMPR.ORG :w6mik.ampr.org [44.16.0.26] 7833 Cantaloupe Ave. Van Nuys, CA 91402 ------------------------------ Date: Sun, 6 Nov 1994 17:29:48 GMT From: novatech@eskimo.com (Steven Swift) Subject: Filter programs. I often see requests for filter design programs on this newsgroup. Over the past few years I have slapped together a few programs to calculate the values of L-C filters for Butterworth, Chebychev and Elliptical responses. The elliptical program is just a translation of a basic program I received a while back. I am not a programmer, so the programs aren't clean, but I have checked them against many examples and I have built examples of filters from each program. My big plan is to combine them into one-- if anyone does this, I'd like a copy. The three posting to follow are: Butterworth: butter.c Chebychev: cheb.c Elliptical: elip.c (includes elip.bas) Comments and improvements welcomed. Have fun. -- Steven D. Swift, P.E. ( novatech@eskimo.com ) NOVATECH INSTRUMENTS, INC. 1530 Eastlake Avenue East, Suite 303 ------------------------------ Date: 7 Nov 1994 20:19 -0500 From: hirschj@vax2.concordia.ca (JACK HIRSCHBERG) Subject: Help needed with older Kenwood HF model 9R59D Does anyone have schematics or specs for this unit. I need to know the values of a coil. Please email at: HIRSCHJ@vax2.concordia.ca Thanks, Jack ------------------------------ Date: 7 Nov 94 13:51:00 GMT From: MUENZLERK@uthscsa.EDU (Muenzler, Kevin) Subject: Local TV Jamming Instead of jamming the station (quite complex), why don't you build a notch filter? Or even better, you can buy these things for about $25 for tunable filters and about $40 for fixed channel notches. They are usually around 60+db down, more than enough for even the strongest stations. Usually you can find adds for these things in the back of Popular Electronics and other magazines like that. I think they are available up to about channel 35 or so. They are used by many cable companies to block out premium channels. Good luck.. Kevin Legal stuff: The above opinions are my own and not necessarily those of the staff, faculty, administration, or lab animals (woof!) of The University of Texas Health Science Center at San Antonio or anyone else who is not me. ********************************************************************** Kevin R. Muenzler, WB5RUE The University of Texas Health muenzlerk@uthscsa.edu Science Center at San Antonio, Department of Computing Resources Liberals measure compassion by how many people they are helping. Conservatives measure compassion by how many people no longer need their help. --Jack Kemp ---------------------------------------------------------------------- | I am Voltohm of Borg! | Resistance is E/I! | Power is EI! ********************************************************************** ------------------------------ Date: 6 Nov 1994 22:33:50 -0500 From: mike@io.org (Mike Stramba) Subject: Looking for schematic for Pulser MB200 Anyone familiar with a Pulser MB200? I'd like to get a schematic for it for the purpose of trying to add a bfo to it to receive ssb. Also, I'd appreciate any information on how to do this mod, or if it's even possible. Mike -- ======================================================================= Mike Stramba Email: mike@io.org Toronto,Canada Internex Online - Toronto, Canada (416) 363-3783 ======================================================================= ------------------------------ Date: Sat, 5 Nov 1994 20:16:44 GMT From: jeffrey@kahuna.tmc.edu (Jeffrey Herman) References <395svn$ksa@kelly.teleport.com>, <1994Nov2.015906.8454@ke4zv.atl.ga.us> Reply-To: jeffrey@math.hawaii.edu Subject: Re: THE LITTLE RAZOR BLADE RADIO (UPDATE) I sure hope someone is collecting all these articles and will find an archive site for them. This topic is quite interesting, and reading it is like taking a step back in time. It's almost as if we're seeing radio receivers invented all over again. Now we need some ideas concerning basic transmitters. Jeff NH6IL ------------------------------ Date: Sat, 5 Nov 1994 01:10:08 GMT From: gary@ke4zv.atl.ga.us (Gary Coffman) References<1994Oct25.204901.20098@arrl.org> <1994Oct29.173008.10434@ke4zv.atl.ga.us>, <1994Nov2.150552.5065@arrl.org> Reply-To: gary@ke4zv.atl.ga.us (Gary Coffman) Subject: Re: Where does the power go? In article <1994Nov2.150552.5065@arrl.org> zlau@arrl.org (Zack Lau (KH6CP)) writes: >Gary Coffman (gary@ke4zv.atl.ga.us) wrote: > >: Class AB1 amplifiers routinely achieve 65% efficiency from DC input >: to RF output in VHF TV broadcast service. Tubes certainly aren't >: 100% efficient, but that's not because of some output impedance >: resistor. It's because of contact resistance, back bombardment, >: and plain old I^2R losses in the tube structure. Every attempt >: is made to minimize these losses. Tube contact surfaces are silver >: plated, and made large, tube structure lengths are minimized, and >: suppressor grids are used in some cases. Flowing 12 amps at 8 kV >: can cause a tube, and cavity, to heat, but not 48 kWs worth. > >8000V/12 amps*.35=233 ohms > >Can you further break down these losses--how much is >due to to each factor? I have to admit that I'm surprised >that contact losses would be worth mentioning, particularly >since they involve large, silver plated surfaces. I use >cheap molex connectors with little tin plated contacts, and >they aren't significant in a circuit with involving 2 amps >at 12 volts (12V/2amps=6 ohms). Well, obviously, the largest loss component is the kinetic energy of the electron beam striking the plate. For the tube above, you have about 0.0024 gm of electrons hitting the plate at an appreciable fraction of the speed of light every second ( haven't worked out exactly what the transit time is for that tube, but since it's for VHF service, it's certainly short). That kinetic energy (.5mv^2) has to be dissipated as heat. That's why the tube has anode cooling fins. But the contact resistance contributes enough that fingerstock sometimes unsolders itself, and circulating currents can heat the cavities significantly. I've had tuning plunger fingerstock unsolder itself too. The app notes from the various manufacturers have detailed data on the various thermal loads presented by their particular devices/sockets/cavities. I know that with the 5 hp blowers we use, stack temperature runs about 220-240 F three feet above the tube. I also know I can get that stack temperature with no drive by increasing the static bias current. Most of the heating is not RF heating. The filaments draw 300 amps at 5 volts which is 1500 watts, and that's only a small fraction of the heat load of the system. Gary -- Gary Coffman KE4ZV | You make it, | gatech!wa4mei!ke4zv!gary Destructive Testing Systems | we break it. | emory!kd4nc!ke4zv!gary 534 Shannon Way | Guaranteed! | gary@ke4zv.atl.ga.us Lawrenceville, GA 30244 | | ------------------------------ End of Ham-Homebrew Digest V94 #330 ******************************