rufz
RFPWR at aol.com
RFPWR at aol.com
Wed Jul 26 22:02:50 EDT 1995
This RUFZ callsign generator program is great. The approach of constantly
increasing the speed each time a call is copied correctly, or decreasing the
speed as calls are missed, keeps pushing the operator beyond the comfort
level. This is the best way to increase code speed. I gave a copy to my ham
neighbor down the street who is starting in contesting; he can do 20 wpm now,
but only about 13 to 15 wpm with callsigns. I bet he is up to 40 wpm by SS!
If only I had a headphone jack on my computer. The dits are hard to hear at
faster speeds on the dinky computer speaker.
Thanks to all who posted the program on the Internet or BBS's.
73, Chas N8RR rfpwr at aol.com
>From n3rr at cais.cais.com (Bill Hider) Thu Jul 27 03:18:41 1995
From: n3rr at cais.cais.com (Bill Hider) (Bill Hider)
Date: Wed, 26 Jul 1995 22:18:41 -0400
Subject: Filters from In'tl Radio & Computer
Message-ID: <199507270218.WAA28536 at cais.cais.com>
At 02:04 PM 7/26/95 -0700, H. L. Serra wrote:
>Does anyone know how to crack the code with these folks? I FAXed them,
>then called them on the phone and was told by a relatively polite southern
>belle that they were just too busy, they had radios stacked up waiting
>for filter installation, they were having trouble getting filters from
>Japan, maybe try gain in late August, da-dah, da-dah, like that.
>Is there any way to get them to sell and/or install filters?
>Is there any other company in U. S. or elsewhere that sells these good
>filters? Any help will be appreciated. 73 Larry N6AZE
>
I just received an order for filters for my IC-781. No problems. Ordered
them via phone and credit card. Received catalog (as I requested) then
called again to order the filters after a lengthy Q & A (my Qs) w/them
concerning the filters. Filters arrived in a week or so. All this took
place in the last 4 weeks.
Bill, N3RR
>From ni6t at ix.netcom.com (Garry Shapiro ) Thu Jul 27 08:13:14 1995
From: ni6t at ix.netcom.com (Garry Shapiro ) (Garry Shapiro )
Date: Thu, 27 Jul 1995 00:13:14 -0700
Subject: Filters from In'tl Radio & Computer
Message-ID: <199507270713.AAA18320 at ix8.ix.netcom.com>
You wrote:
>
>Does anyone know how to crack the code with these folks? I FAXed them,
>then called them on the phone and was told by a relatively polite
southern
>belle that they were just too busy, they had radios stacked up waiting
>for filter installation, they were having trouble getting filters from
>Japan, maybe try gain in late August, da-dah, da-dah, like that.
>Is there any way to get them to sell and/or install filters?
>Is there any other company in U. S. or elsewhere that sells these good
>filters? Any help will be appreciated. 73 Larry N6AZE
>
>
I have been in the queue for filters since May. I am too old and burned
to believe that filters will be allocated as received according to
order date: obviously they will fill their installation orders first.
They swear the credit card has not been charged and will not be charged
until the order is filled. My view is: my radio works,and if the
filters come, it may work better. I am not going to go ballistic over
it, because--clearly--I know of no way to accelerate the process.
Garry, NI6T
>From ni6t at ix.netcom.com (Garry Shapiro ) Thu Jul 27 08:22:58 1995
From: ni6t at ix.netcom.com (Garry Shapiro ) (Garry Shapiro )
Date: Thu, 27 Jul 1995 00:22:58 -0700
Subject: Filters from In'tl Radio & Computer
Message-ID: <199507270722.AAA19601 at ix8.ix.netcom.com>
You wrote:
>I just received an order for filters for my IC-781. No problems.
Ordered
>them via phone and credit card. Received catalog (as I requested)
then
>called again to order the filters after a lengthy Q & A (my Qs) w/them
>concerning the filters. Filters arrived in a week or so. All this
took
>place in the last 4 weeks.
>
>Bill, N3RR
>
I presume you meant that you received the filters that you ordered for
your IC-781.
My guess--and nothing more than that--is that they had those in stock.
I would think there are a helluva lot fewer IC781's out in hamland then
rigs like TS930S's (like I have).
On the other hand, maybe you are just--as the late Lord Buckley might
have said--the Lord's Boy Today.
Garry, NI6T
>From Larry Schimelpfenig <lschim at mailstorm.dot.gov> Thu Jul 27 11:16:56 1995
From: Larry Schimelpfenig <lschim at mailstorm.dot.gov> (Larry Schimelpfenig)
Date: Thu, 27 Jul 1995 06:16:56 -0400 (EDT)
Subject: Becoming a QRQ Operator
Message-ID: <Pine.3.07.9507270655.A23099-b100000 at mailstorm.dot.gov>
Jim, I have to agree with Bill Fisher's advice to put the pencil down and
start assembling it in your head. I was good for 30-35 when I went to Navy
Radioman school. That was copying with pencil. The military seems to want
one to retain what is copied, so the next trick was copying on a
typewriter. That was easier for me than with a stick (I also knew how to
type). Over the years I became comfortable at 50+ on the mill. Early on I
began to realize that I didn't have to write this stuff down to
underestand it. I think many of us take for granted the fact that with
lots of practice we have gained the ability to copy in our heads. It's
much like another language. If I'm doing paperwork or such in the shack I
normally look for interesting conversation on the bands to entertain
myself. It's about a 50/50 split between cw and fone. I found that copying
someone sending a wee bit faster than I could comfortably copy helped.
As with most things, all that's required is time and practice. I would
assume that as with most other things, that some people have the ability
to learn code faster than others. I'd gladly swap some of my ability to
learn code for greater ability to learn higher mathematics!
73 de Larry K7SV - in Virginia - lschim at mailstorm.dot.gov
Still havin' fun!
>From Ed Gilbert <eyg at hpnjlc.njd.hp.com> Thu Jul 27 13:16:18 1995
From: Ed Gilbert <eyg at hpnjlc.njd.hp.com> (Ed Gilbert)
Date: Thu, 27 Jul 1995 08:16:18 -0400
Subject: Balun Preferences
Message-ID: <199507271214.AA128527295 at hp.com>
Jastaples at aol.com wrote:
> It has generally been my practice to build coax baluns for both monoband and
> triband beams. However, recently I built two Cushcraft 40-2CD monoband yagis
> following the W6QHS guidelines. In both cases I used the W2DU ferrite-bead
> balun supplied by The WIreman, Inc. (Model 827SP). So far, all is well.
>
> I am currently preparing a Cushcraft A3SDX and am considering the use of the
> same balun. I would be interested in the comments and suggestions of any who
> may have had experience or knowledge concering this approach. While I don't
> see it as a critical item,,
> it would be of interest to hear what the prevailing wisdom is on the subject.
Here's something I wrote up a while ago on coaxial balun measurements.
It's a little long, but I think there's enough contesters out there
building these things that it's worth posting.
73,
Ed Gilbert, WA2SRQ
eyg at hpnjlc.njd.hp.com
---------------------------------------------------------------------
Having access to a Hewlett-Packard 4193A vector impedance meter at
work, I have made measurements on a number of baluns, coaxial and
otherwise. For my beams I was particularly interested how many turns
and on what diameter are optimum for air core coaxial baluns, and what
the effect of bunching the turns was (formless). Using the remote
programming capability of the HP4193A along with an instrument
controller, I measured the magnitude and phase of each balun's winding
impedance at 1 MHz intervals from 1 to 35 MHz. For comparison, I also
made measurements on a commercial balun which consists of a number of
ferrite beads slipped over a short length of coax. I've appended some
of these measurements so you can draw your own conclusions.
PVC pipe was used for coil forms. The 4-1/4 inch diameter baluns were
wound on thin-walled PVC labeled "4 inch sewer pipe". This material
makes an excellent balun form. It's very light weight and easy to
work with, and I obtained a 10 foot length at the local Home Depot for
about 3 dollars. The 6-5/8 inch diameter forms are 6 inch schedule 40
PVC pipe which is much thicker, heavier, and more expensive.
Each test choke was close-wound on a form as a single-layer solenoid
using RG-213 and taped to hold the turns in place. The lengths of
cable were cut so there was about 2 inches excess at each end. This
allowed just enough wire at the ends for connections to the HP4193A's
probe tip. After data was collected for each single-layer
configuration, the PVC form was removed, the turns were bunched
together and taped formless, and another set of measurements was
taken. I have only included the "bunched" measurements in the table
for one of the baluns, but the trend was the same in each case. When
compared to the single-layer version of the same diameter and number
of turns, the bunched baluns show a large downward shift in parallel
self-resonance frequency and poor choking reactance at the higher
frequencies.
Interpreting the Measurements
-----------------------------
All the baluns start out looking inductive at low frequencies, as
indicated by the positive phase angles. As the frequency is
increased, a point is reached where the capacitance between the
windings forms a parallel resonance with the coil's inductance. Above
this frequency, the winding reactance is reduced by this capacitance.
The interwinding capacitance increases with the number of turns and
the diameter of the turns, so "more is not always better".
The effects of a large increase in interwinding capacitance is evident
in the measurements on the balun with the bunched turns. This is
probably a result of the first and last turns of the coil being much
closer together than the single-layer coil.
An important requirement of these baluns is that the magnitude of the
winding reactance be much greater than the load impedance. In the
case of a 50 ohm balanced antenna, the balun's winding impedance is
effectively shunted across one half the 50 ohm load impedance, or 25
ohms. A reasonable critera for the balun's winding impedance for
negligible common mode current in the shield is that it be at least 20
times this, or 500 ohms. The measurements show, for example, that 6
turns 4-1/4 inches in diameter meet this criteria from 14 to 35 MHz.
The measurement data also reveals the power loss these baluns will
exhibit. Each of the measurement points can be transformed from the
polar format of the table to a parallel equivalent real and reactive
shunt impedance. The power dissipated in the balun is then the square
of the voltage across it divided by the real parallel equivalent shunt
impedance. While this calculation can be made for each measurement
point, an approximate number can be taken directly from the tables at
the parallel resonance points. At 0 degrees phase angle the magnitude
numbers are pure resistive. I didn't record the exact resonance
points, but it can be seen from the tables that the four single-layer
baluns are all above 15K ohms, while the ferrite bead balun read about
1.4K. These baluns see half the load voltage, so at 1500 watts to a
50 ohm load, the power dissipated in the coaxial baluns will be less
than 1.3 watts, and the ferrite bead balun will dissipate about 13.4
watts (neglecting possible core saturation and other non-linear
effects). These losses are certainly negligible. At 200 ohms load
impedance, the losses are under 5 watts for the coaxial baluns and
53.6 watts for the ferrite beads.
Conclusions
-----------
- A 1:1 coaxial balun with excellent choking reactance for 10 through
20 meters can be made by winding 6 turns of RG-213 on inexpensive 4
inch PVC sewer pipe.
- For 40 or 30 meters, use 12 turns of RG-213 on 4 inch PVC sewer
pipe.
- Don't bunch the turns together. Wind them as a single layer on a
form. Bunching the turns kills the choking effect at higher
frequencies.
- Don't use too many turns. For example, the HyGain manuals for my 10
and 15 meter yagis both recommend 12 turns 6 inches in diameter. At
the very least this is about 3 times as much coax as is needed, and
these dimensions actually give less than the desired choking impedance
on 10 and 15 meters.
Measurements
------------
Magnitude in ohms, phase angle in degrees, as a function of frequency
in Hz, for various baluns.
6 Turns 12 Turns 4 Turns 8 Turns 8 Turns Ferrite
4-1/4 in 4-1/4 in 6-5/8 in 6-5/8 in 6-5/8 in beads
sngl layer sngl layer sngl layer sngl layer bunched (Aztec)
---------- ---------- ---------- ---------- ---------- ----------
Frequency Mag Phase Mag Phase Mag Phase Mag Phase Mag Phase Mag Phase
1.00E+06 26 88.1 65 89.2 26 88.3 74 89.2 94 89.3 416 78.1
2.00E+06 51 88.7 131 89.3 52 88.8 150 89.3 202 89.2 795 56.1
3.00E+06 77 88.9 200 89.4 79 89.1 232 89.3 355 88.9 1046 39.8
4.00E+06 103 89.1 273 89.5 106 89.3 324 89.4 620 88.3 1217 26.6
5.00E+06 131 89.1 356 89.4 136 89.2 436 89.3 1300 86.2 1334 14.7
6.00E+06 160 89.3 451 89.5 167 89.3 576 89.1 8530 59.9 1387 3.6
7.00E+06 190 89.4 561 89.5 201 89.4 759 89.1 2120 -81.9 1404 -5.9
8.00E+06 222 89.4 696 89.6 239 89.4 1033 88.8 1019 -85.7 1369 -15.4
9.00E+06 258 89.4 869 89.5 283 89.4 1514 87.3 681 -86.5 1295 -23.7
1.00E+07 298 89.3 1103 89.3 333 89.2 2300 83.1 518 -86.9 1210 -29.8
1.10E+07 340 89.3 1440 89.1 393 89.2 4700 73.1 418 -87.1 1123 -35.2
1.20E+07 390 89.3 1983 88.7 467 88.9 15840 -5.2 350 -87.2 1043 -39.9
1.30E+07 447 89.2 3010 87.7 556 88.3 4470 -62.6 300 -86.9 954 -42.7
1.40E+07 514 89.3 5850 85.6 675 88.3 2830 -71.6 262 -86.9 901 -45.2
1.50E+07 594 88.9 42000 44.0 834 87.5 1910 -79.9 231 -87.0 847 -48.1
1.60E+07 694 88.8 7210 -81.5 1098 86.9 1375 -84.1 203 -87.2 778 -51.8
1.70E+07 830 88.1 3250 -82.0 1651 81.8 991 -82.4 180 -86.9 684 -54.4
1.80E+07 955 86.0 2720 -76.1 1796 70.3 986 -67.2 164 -84.9 623 -45.9
1.90E+07 1203 85.4 1860 -80.1 3260 44.6 742 -71.0 145 -85.1 568 -51.2
2.00E+07 1419 85.2 1738 -83.8 3710 59.0 1123 -67.7 138 -84.5 654 -34.0
2.10E+07 1955 85.7 1368 -87.2 12940 -31.3 859 -84.3 122 -86.1 696 -49.9
2.20E+07 3010 83.9 1133 -87.8 3620 -77.5 708 -86.1 107 -85.9 631 -54.8
2.30E+07 6380 76.8 955 -88.0 2050 -83.0 613 -86.9 94 -85.5 584 -57.4
2.40E+07 15980 -29.6 807 -86.3 1440 -84.6 535 -86.3 82 -85.0 536 -58.8
2.50E+07 5230 -56.7 754 -82.2 1099 -84.1 466 -84.1 70 -84.3 485 -59.2
2.60E+07 3210 -78.9 682 -86.4 967 -83.4 467 -81.6 60 -82.7 481 -56.2
2.70E+07 2000 -84.4 578 -87.3 809 -86.5 419 -85.5 49 -81.7 463 -60.5
2.80E+07 1426 -85.6 483 -86.5 685 -87.1 364 -86.2 38 -79.6 425 -62.5
2.90E+07 1074 -85.1 383 -84.1 590 -87.3 308 -85.6 28 -75.2 387 -63.8
3.00E+07 840 -83.2 287 -75.0 508 -87.0 244 -82.1 18 -66.3 346 -64.4
3.10E+07 661 -81.7 188 -52.3 442 -85.7 174 -69.9 9 -34.3 305 -64.3
3.20E+07 484 -78.2 258 20.4 385 -83.6 155 -18.0 11 37.2 263 -63.2
3.30E+07 335 -41.4 1162 -13.5 326 -78.2 569 -0.3 21 63.6 212 -58.0
3.40E+07 607 -32.2 839 -45.9 316 -63.4 716 -57.6 32 71.4 183 -40.5
3.50E+07 705 -58.2 564 -56.3 379 -69.5 513 -72.5 46 76.0 235 -29.6
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