Models based on REAL measurements - Canadian TV, Computing and Home Theatre Forums

peano · 2011-10-26, 08:37 PM

I have the following antennas and can give exact measurements to .001" if required of every piece.

91XG
MXU59
CM3023
CM4228HD
CM4228 original

I am seeing NEC models predicting results based upon assumed measurements. I honestly don't trust them. If anyone has the time to model with true measurements, I would be happy to provide them.

300ohm · 2011-10-26, 10:31 PM

Ken Nist had the 91XG and the original CM4228a in front of him when he modeled them, so they should be very accurate.
I think Holl_ands has the actual CM4228HD.
You can easily check the measurements of the NEC files with the steps Ive outlined here: http://www.digitalhome.ca/forum/showthread.php?t=107457

But it would be great to have precise measurements of the MXU59 and the CM3023.

I dont think those have been posted anywhere.

Quote:

measurements to .001" if required of every piece.

You got a digital caliper too ? I love those things, heh.

holl_ands · 2011-10-27, 03:12 AM

I KNOW that there are (at least) two, physically quite different, OFFICIAL versions
of the CM4221 and the YA-1713....and there may be others....

Since there are so many variations of the 91XG available from various overseas
sources, it is possible that they might have physical differences from year to year,
so it's worth double checking against Ken Nist's measurements. In nearly every
model, we also perform an approximation to the ACTUAL shape of the X-Bows, the
shape of the Folded Dipole and other details that "shouldn't" make a difference.

Models for CM4221 posted on http://imageevent.com/holl_ands/multibay/4bayrefl
were based on 1) ACTUAL dimensions from mclapp, which were significantly DIFFERENT
than 2) Ken Nist's cm4221a.ez file posted on http://www.hdtvprimer.com/SIMS/.
Model for CM4221HD was based on actual measurements found in smpowell55's posts.

My posted 4nec2 models for the fol. antennas are based on my actual measurements:
YA-1713, CM4228 and CM4228HD. In each of the other 4nec2 models I've posted,
I noted who provided the actual measurements, when appropriate, as well as who
prepared the original 4nec2 file if it was someone else. I also describe MY various
modifications needed to correct for AGT=1, eliminate/reduce Errors & Warnings
and adding my usual set of FR & RP Cards to avoid "fat finger" entry errors.

There is no need to be any more accurate than 0.1-inch (or 2.5 mm if you prefer)
in element length measurements, since you won't see the difference (under 0.2 dB).
I routinely round off GeoEdit output files to just two decimals (which is still overkill)
so that I can align all of the data columns to better "see" errors or problem areas.

However, for radius measurements, a caliper should be used....or compare to known
wire or drill sizes.

Thus far, we're missing accurate measurements for MXU59, CM-3023 & HD9095P.
I'm also looking for detailed measurements for ANT-2086 4-Bay Bowtie.
In all cases we need detailed PHOTOS of the overall antenna as well as close-in shots
for the more complicated areas, such as the X-Bows and Feedline connections.

==========================================================
PS: If you look at Ken Nist's w9032a.ez model for the PR-9032, you'll see that he "simplified"
the Folded Dipole and surrounding Boom Area....and used two parallel (NOT interconnected)
wires for each Passive Director (I would have connected, at least, the ends and middle).

The small wires in his Folded Dipole & Boom Area may cause problems using the NEC2 Engine,
esp. if using one of the Single-Precision "Nec2dXS*.exe" (large number of segments) versions
that I am forced to use for many antennas (e.g. Screen Grid Reflectors). The default 4nec2
Engine is the Double-Precision "Nec2dX*.exe" Engine. Ken Nist used (Quad-Precision) NEC4 Engine.

peano · 2011-10-27, 09:27 AM

I will provide detailed measurments and photos ot the CM3023 to start.

300ohm · 2011-10-27, 09:30 AM

Yeah, even wire gauge diameter isnt consistent to .001 inches over its length Ive found with my digital caliper.

And theyre not that precise at the antenna factories either. One way to notice the imprecision is to measure from the end of the boom to the exact center of the rivets on the top of the boom and then compare to the measurements from the end of the boom to the exact center of the rivets on the bottom of the boom. Shifts of 1/16" to 1/8" on the same antenna are quite common.

holl_ands · 2011-10-27, 08:45 PM

AWG10 has 0.1019-in and AWG12 has 0.0808-in diameter, a 26-percent difference
that causes a small but obvious difference in Gain and esp. SWR performance.

A 5-percent accuracy (0.005-in in the above case) should be more than enough
and 5-percent accuracy for thicker 3/8-in elements would be about 0.02-in.

Of course if you can simply hold a "known" AWG10 and/or AWG12 wire (or drill)
next to the feedline, it should be obvious which is the correct gauge...and hopefully
no one is using odd-ball gauges....

300ohm · 2011-10-27, 09:09 PM

Quote:

I will provide detailed measurments and photos ot the CM3023 to start.

Is the CM3023 the same as the CM4248 ? Ken Nist has it as CM4228 and then in parenthesis 3023 (after the Net Gain chart).
http://www.hdtvprimer.com/ANTENNAS/comparing.html

If so, we have that model here: (Sorry, didnt catch it earlier)

Code:

CM CM4248 :  Channel Master 4248, converted with 4nec2 on 10-Jul-08 2:25
CM AGT = 1.0 (0 db) at 585 mhz.  Autosegmentation = 21
CE
GW	8	1	7.2	1.125	-0.8	7.35	1.4	-0.8	0.05
GW	9	1	7.35	1.4	-0.8	7.45	1.7	-0.8	0.05
GW	10	3	7.45	1.7	-0.8	7.45	3.15	-1.07	0.05
GW	11	3	7.45	3.15	-1.07	7.45	4.6	-1.33	0.05
GW	12	3	7.45	4.6	-1.33	7.45	5.25	0	0.05
GW	13	3	7.45	5.25	0	7.45	4.6	1.33	0.05
GW	14	3	7.45	4.6	1.33	7.45	3.15	1.07	0.05
GW	15	3	7.45	3.15	1.07	7.45	1.7	0.8	0.05
GW	16	3	7.45	1.7	0.8	7.45	0.88	0.8	0.05
GW	17	1	7.45	0.88	0.8	7.45	0.38	0.8	0.05
GW	18	1	7.2	1.125	-0.8	7.05	1.4	-0.8	0.05
GW	19	1	7.05	1.4	-0.8	6.95	1.7	-0.8	0.05
GW	20	3	6.95	1.7	-0.8	6.95	3.15	-1.07	0.05
GW	21	3	6.95	3.15	-1.07	6.95	4.6	-1.33	0.05
GW	22	3	6.95	4.6	-1.33	6.95	5.25	0	0.05
GW	23	3	6.95	5.25	0	6.95	4.6	1.33	0.05
GW	24	3	6.95	4.6	1.33	6.95	3.15	1.07	0.05
GW	25	3	6.95	3.15	1.07	6.95	1.7	0.8	0.05
GW	26	3	6.95	1.7	0.8	6.95	0.88	0.8	0.05
GW	27	1	6.95	0.88	0.8	6.95	0.38	0.8	0.05
GW	28	1	7.45	1.7	-0.8	6.95	1.7	-0.8	0.05
GW	29	1	7.45	3.15	-1.07	6.95	3.15	-1.07	0.05
GW	30	1	7.45	4.6	-1.33	6.95	4.6	-1.33	0.05
GW	31	1	7.45	5.25	0	6.95	5.25	0	0.05
GW	32	1	7.45	4.6	1.33	6.95	4.6	1.33	0.05
GW	33	1	7.45	3.15	1.07	6.95	3.15	1.07	0.05
GW	34	1	7.45	1.7	0.8	6.95	1.7	0.8	0.05
GW	35	1	7.45	0.88	0.8	6.95	0.88	0.8	0.05
GW	36	1	7.45	0.38	0.8	6.95	0.38	0.8	0.05
GW	37	1	6.95	0.88	0.8	6.25	0.88	0.8	0.05
GW	38	3	6.95	0.38	0.8	5.95	0.38	0.8	0.05
GW	39	1	5.95	0.38	0.8	5.95	0.58	0.8	0.05
GW	40	1	5.95	0.58	0.8	6.25	0.88	0.8	0.05
GW	41	5	5.95	0.38	0.8	4.2	0.38	0.8	0.05
GW	42	5	5.95	0.58	0.8	4.2	0.58	0.8	0.025
GW	43	1	4.2	0.38	0.8	4.2	0.58	0.8	0.025
GW	44	3	4.2	0.38	0.8	2.95	0.38	0.8	0.025
GW	45	3	4.2	0.58	0.8	2.95	0.58	0.8	0.025
GW	46	1	7.2	-1.125	-0.8	7.35	-1.4	-0.8	0.05
GW	47	1	7.35	-1.4	-0.8	7.45	-1.7	-0.8	0.05
GW	48	3	7.45	-1.7	-0.8	7.45	-3.15	-1.07	0.05
GW	49	3	7.45	-3.15	-1.07	7.45	-4.6	-1.33	0.05
GW	50	3	7.45	-4.6	-1.33	7.45	-5.25	0	0.05
GW	51	3	7.45	-5.25	0	7.45	-4.6	1.33	0.05
GW	52	3	7.45	-4.6	1.33	7.45	-3.15	1.07	0.05
GW	53	3	7.45	-3.15	1.07	7.45	-1.7	0.8	0.05
GW	54	3	7.45	-1.7	0.8	7.45	-0.88	0.8	0.05
GW	55	1	7.45	-0.88	0.8	7.45	-0.38	0.8	0.05
GW	56	1	7.2	-1.125	-0.8	7.05	-1.4	-0.8	0.05
GW	57	1	7.05	-1.4	-0.8	6.95	-1.7	-0.8	0.05
GW	58	3	6.95	-1.7	-0.8	6.95	-3.15	-1.07	0.05
GW	59	3	6.95	-3.15	-1.07	6.95	-4.6	-1.33	0.05
GW	60	3	6.95	-4.6	-1.33	6.95	-5.25	0	0.05
GW	61	3	6.95	-5.25	0	6.95	-4.6	1.33	0.05
GW	62	3	6.95	-4.6	1.33	6.95	-3.15	1.07	0.05
GW	63	3	6.95	-3.15	1.07	6.95	-1.7	0.8	0.05
GW	64	3	6.95	-1.7	0.8	6.95	-0.88	0.8	0.05
GW	65	1	6.95	-0.88	0.8	6.95	-0.38	0.8	0.05
GW	66	1	7.45	-1.7	-0.8	6.95	-1.7	-0.8	0.05
GW	67	1	7.45	-3.15	-1.07	6.95	-3.15	-1.07	0.05
GW	68	1	7.45	-4.6	-1.33	6.95	-4.6	-1.33	0.05
GW	69	1	7.45	-5.25	0	6.95	-5.25	0	0.05
GW	70	1	7.45	-4.6	1.33	6.95	-4.6	1.33	0.05
GW	71	1	7.45	-3.15	1.07	6.95	-3.15	1.07	0.05
GW	72	1	7.45	-1.7	0.8	6.95	-1.7	0.8	0.05
GW	73	1	7.45	-0.88	0.8	6.95	-0.88	0.8	0.05
GW	74	1	7.45	-0.38	0.8	6.95	-0.38	0.8	0.05
GW	75	1	6.95	-0.88	0.8	6.25	-0.88	0.8	0.05
GW	76	3	6.95	-0.38	0.8	5.95	-0.38	0.8	0.05
GW	77	1	5.95	-0.38	0.8	5.95	-0.58	0.8	0.05
GW	78	1	5.95	-0.58	0.8	6.25	-0.88	0.8	0.05
GW	79	5	5.95	-0.38	0.8	4.2	-0.38	0.8	0.05
GW	80	5	5.95	-0.58	0.8	4.2	-0.58	0.8	0.025
GW	81	1	4.2	-0.38	0.8	4.2	-0.58	0.8	0.025
GW	82	3	4.2	-0.38	0.8	2.95	-0.38	0.8	0.025
GW	83	3	4.2	-0.58	0.8	2.95	-0.58	0.8	0.025
GW	84	69	1.49	16.65	1.94	1.49	-16.65	1.94	0.125
GW	85	69	3.35	16.65	4.36	3.35	-16.65	4.36	0.125
GW	86	69	5.21	16.65	6.77	5.21	-16.65	6.77	0.125
GW	87	69	7.07	16.65	9.19	7.07	-16.65	9.19	0.125
GW	88	69	9.81	16.65	12.75	9.81	-16.65	12.75	0.125
GW	89	69	12.55	16.65	16.32	12.55	-16.65	16.32	0.125
GW	90	69	15.29	16.65	19.87	15.29	-16.65	19.87	0.125
GW	91	69	1.49	16.65	-1.94	1.49	-16.65	-1.94	0.125
GW	92	69	3.35	16.65	-4.36	3.35	-16.65	-4.36	0.125
GW	93	69	5.21	16.65	-6.77	5.21	-16.65	-6.77	0.125
GW	94	69	7.07	16.65	-9.19	7.07	-16.65	-9.19	0.125
GW	95	69	9.81	16.65	-12.75	9.81	-16.65	-12.75	0.125
GW	96	69	12.55	16.65	-16.32	12.55	-16.65	-16.32	0.125
GW	97	69	15.29	16.65	-19.87	15.29	-16.65	-19.87	0.125
GW	98	13	12.47	2.86	0	12.47	-2.86	0	0.035
GW	99	13	18.04	2.86	0	18.04	-2.86	0	0.035
GW	100	13	23.61	2.86	0	23.61	-2.86	0	0.035
GW	101	13	29.18	2.86	0	29.18	-2.86	0	0.035
GW	102	13	34.75	2.86	0	34.75	-2.86	0	0.035
GW	103	13	40.32	2.86	0	40.32	-2.86	0	0.035
GW	104	13	45.89	2.86	0	45.89	-2.86	0	0.035
GW	105	13	51.46	2.86	0	51.46	-2.86	0	0.035
GW	106	13	57.03	2.86	0	57.03	-2.86	0	0.035
GW	107	13	62.6	2.86	0	62.6	-2.86	0	0.035
GW	108	13	68.17	2.86	0	68.17	-2.86	0	0.035
GW	109	13	73.74	2.86	0	73.74	-2.86	0	0.035
GW	110	13	79.31	2.86	0	79.31	-2.86	0	0.035
GW	111	13	84.88	2.86	0	84.88	-2.86	0	0.035
GW	112	13	12.87	2.86	0	12.87	-2.86	0	0.035
GW	113	13	18.44	2.86	0	18.44	-2.86	0	0.035
GW	114	13	24.01	2.86	0	24.01	-2.86	0	0.035
GW	115	13	29.58	2.86	0	29.58	-2.86	0	0.035
GW	116	13	35.15	2.86	0	35.15	-2.86	0	0.035
GW	117	13	40.72	2.86	0	40.72	-2.86	0	0.035
GW	118	13	46.29	2.86	0	46.29	-2.86	0	0.035
GW	119	13	51.86	2.86	0	51.86	-2.86	0	0.035
GW	120	13	57.43	2.86	0	57.43	-2.86	0	0.035
GW	121	13	63	2.86	0	63	-2.86	0	0.035
GW	122	13	68.57	2.86	0	68.57	-2.86	0	0.035
GW	123	13	74.14	2.86	0	74.14	-2.86	0	0.035
GW	124	13	79.71	2.86	0	79.71	-2.86	0	0.035
GW	125	13	85.28	2.86	0	85.28	-2.86	0	0.035
GW	126	5	7.2	-1.125	-0.8	7.2	1.125	-0.8	0.0216
GS	0	0	0.0254		' All in in.
GE	0
EK
LD	5	0	0	0	2.5e7	0
EX	0	126	3	0	1	0
GN	-1
FR	0	1	0	0	585	0

peano · 2011-10-27, 09:27 PM

Looks like it. Ok MXU59 it is.

300ohm · 2011-10-27, 10:08 PM

Right now, the CM4248 (3023) peaks at channel 62. The corner reflector on it is still an excellent size for the new uhf range as is. And I believe the driven element on it peaks at channel 23 when modeled by itself. To make it peak at say channel 46, all that would be needed is some rescaling of the directors and their spacings.

Heres another site that references the CM4248 and the CM3023 as the same thing.
http://www.interceptradio.com/wiki/index.php/TV_Antenna

be236 · 2011-10-28, 01:49 AM

Do we have side-by-side comparisons of NET gain for these three antennas?

**
Thus far, we're missing accurate measurements for MXU59, CM-3023 & HD9095P.
**

Which of these have the best low UHF net gain (say, RF 32 and lower)?

k6sti · 2011-10-28, 07:01 AM

Quote:

Originally Posted by holl_ands

...and hopefully no one is using odd-ball gauges....

Several years ago I was told that Antennacraft used aluminum wire with a diameter of 0.11" for the phasing lines in their FM log-Yagis. Their engineers called it eleven-wire. I learned this from someone who had Antennacraft manufacture FM antennas for him.

Brian

holl_ands · 2011-10-28, 06:14 PM

That would be AWG9 (d=0.1144-in), a mere 10-percent larger than AWG10.

Yup, d=0.11-in for all three of K6STI's AntennaCraft FM-6, FM-10 & FM-13 models:
http://www.ham-radio.com/k6sti/

I found d=0.11-in (r=1.45-mm) in 300ohm's 4nec2 model for the A-C U8000 UHF 8-Bay Bowtie and
I found d=0.12-in (r=0.06) used in tripelo's 4nec2 model for A-C Y10-7-13 Hi-VHF Dual-Driven Yagi,
which he probably rounded off from the actual r=0.0572-in. [PS: Values vary a bit between wire tables.]

So AntennaCraft appears to be consistently using r=0.0572-in (AWG9) feedlines across
(at least) FM, Hi-VHF and UHF frequency bands.

k6sti · 2011-10-28, 09:39 PM

Quote:

Originally Posted by holl_ands

That would be AWG9 (d=0.1144-in)

Gee, I wonder why the Antennacraft guys referred to it as eleven-wire if it was really AWG 9? But I'll bet you're right. I'd use 0.1144" in my models instead of 0.11" if I were absolutely sure. I wonder if anyone at Antennacraft would answer a question. (I've asked for antenna dimensions on the Winegard forum, and the company won't give them out.)

Incidentally, here is an exact formula to convert American Wire Gauge to wire diameter:

Code:

D = .005 * 92 ^ ((36 - G) / 39)

where D is diameter in inches and G is the gauge number.

Brian

eldgreen · 2011-10-29, 12:36 AM

300 ohm, You said that by "rescaling of the director and their spacings" of a cm3023 that it could be made to peak at a lower channel. Could you give the dimensions to peak at channel 44? Also could the gain be increased by adding more boom with directors and spacings of the same dimensions? Thanks.

300ohm · 2011-10-29, 02:01 AM

Quote:

Could you give the dimensions to peak at channel 44?

OK, Ill try to work on that this weekend.

Quote:

Also could the gain be increased by adding more boom with directors and spacings of the same dimensions? Thanks.

With the rescaled directors, you will already be adding more boom length for the same amount of directors.
Directors follow the laws of marginal utility. That is the first few produce a very good increase in additional gain. The second few, not so much. The third few produce even less. With 14 directors already, youll probably need another 7 with a 3+ ft increase in boom length to produce an additional db in gain. That makes for a long antenna, heh.

2011-10-26, 08:37 PM	#1
peano Veteran Join Date: Dec 2002 Posts: 3,586	Models based on REAL measurements I have the following antennas and can give *exact* measurements to .001" if required of every piece. 91XG MXU59 CM3023 CM4228HD CM4228 original I am seeing NEC models predicting results based upon assumed measurements. I honestly don't trust them. If anyone has the time to model with true measurements, I would be happy to provide them.

2011-10-27, 09:30 AM	#5
300ohm Veteran Join Date: Mar 2008 Location: Somewhere in Delaware on the flat side Posts: 7,008	Yeah, even wire gauge diameter isnt consistent to .001 inches over its length Ive found with my digital caliper. And theyre not that precise at the antenna factories either. One way to notice the imprecision is to measure from the end of the boom to the exact center of the rivets on the top of the boom and then compare to the measurements from the end of the boom to the exact center of the rivets on the bottom of the boom. Shifts of 1/16" to 1/8" on the same antenna are quite common. __________________ My builds/plans (not the latest models) are located here.

2011-10-27, 10:08 PM	#9
300ohm Veteran Join Date: Mar 2008 Location: Somewhere in Delaware on the flat side Posts: 7,008	Right now, the CM4248 (3023) peaks at channel 62. The corner reflector on it is still an excellent size for the new uhf range as is. And I believe the driven element on it peaks at channel 23 when modeled by itself. To make it peak at say channel 46, all that would be needed is some rescaling of the directors and their spacings. Heres another site that references the CM4248 and the CM3023 as the same thing. http://www.interceptradio.com/wiki/index.php/TV_Antenna __________________ My builds/plans (not the latest models) are located here.

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2011-10-27, 03:12 AM	#3
holl_ands Veteran Join Date: Nov 2008 Location: San Diego, CA Posts: 1,595	I KNOW that there are (at least) two, physically quite different, OFFICIAL versions of the CM4221 and the YA-1713....and there may be others.... Since there are so many variations of the 91XG available from various overseas sources, it is possible that they might have physical differences from year to year, so it's worth double checking against Ken Nist's measurements. In nearly every model, we also perform an approximation to the ACTUAL shape of the X-Bows, the shape of the Folded Dipole and other details that "shouldn't" make a difference. Models for CM4221 posted on http://imageevent.com/holl_ands/multibay/4bayrefl were based on 1) ACTUAL dimensions from mclapp, which were significantly DIFFERENT than 2) Ken Nist's cm4221a.ez file posted on http://www.hdtvprimer.com/SIMS/. Model for CM4221HD was based on actual measurements found in smpowell55's posts. My posted 4nec2 models for the fol. antennas are based on my actual measurements: YA-1713, CM4228 and CM4228HD. In each of the other 4nec2 models I've posted, I noted who provided the actual measurements, when appropriate, as well as who prepared the original 4nec2 file if it was someone else. I also describe MY various modifications needed to correct for AGT=1, eliminate/reduce Errors & Warnings and adding my usual set of FR & RP Cards to avoid "fat finger" entry errors. There is no need to be any more accurate than 0.1-inch (or 2.5 mm if you prefer) in element length measurements, since you won't see the difference (under 0.2 dB). I routinely round off GeoEdit output files to just two decimals (which is still overkill) so that I can align all of the data columns to better "see" errors or problem areas. However, for radius measurements, a caliper should be used....or compare to known wire or drill sizes. Thus far, we're missing accurate measurements for MXU59, CM-3023 & HD9095P. I'm also looking for detailed measurements for ANT-2086 4-Bay Bowtie. In all cases we need detailed PHOTOS of the overall antenna as well as close-in shots for the more complicated areas, such as the X-Bows and Feedline connections. ========================================================== PS: If you look at Ken Nist's w9032a.ez model for the PR-9032, you'll see that he "simplified" the Folded Dipole and surrounding Boom Area....and used two parallel (NOT interconnected) wires for each Passive Director (I would have connected, at least, the ends and middle). The small wires in his Folded Dipole & Boom Area may cause problems using the NEC2 Engine, esp. if using one of the Single-Precision "Nec2dXS.exe" (large number of segments) versions that I am forced to use for many antennas (e.g. Screen Grid Reflectors). The default 4nec2 Engine is the Double-Precision "Nec2dX.exe" Engine. Ken Nist used (Quad-Precision) NEC4 Engine.

2011-10-27, 09:27 AM	#4
peano Veteran Join Date: Dec 2002 Posts: 3,586	I will provide detailed measurments and photos ot the CM3023 to start.

2011-10-27, 08:45 PM	#6
holl_ands Veteran Join Date: Nov 2008 Location: San Diego, CA Posts: 1,595	AWG10 has 0.1019-in and AWG12 has 0.0808-in diameter, a 26-percent difference that causes a small but obvious difference in Gain and esp. SWR performance. A 5-percent accuracy (0.005-in in the above case) should be more than enough and 5-percent accuracy for thicker 3/8-in elements would be about 0.02-in. Of course if you can simply hold a "known" AWG10 and/or AWG12 wire (or drill) next to the feedline, it should be obvious which is the correct gauge...and hopefully no one is using odd-ball gauges....

2011-10-27, 09:27 PM	#8
peano Veteran Join Date: Dec 2002 Posts: 3,586	Looks like it. Ok MXU59 it is.

2011-10-28, 01:49 AM	#10
be236 Join Date: Sep 2011 Location: Everett, WA Posts: 406	Do we have side-by-side comparisons of NET gain for these three antennas? Thus far, we're missing accurate measurements for MXU59, CM-3023 & HD9095P. Which of these have the best low UHF net gain (say, RF 32 and lower)?

2011-10-28, 06:14 PM	#12
holl_ands Veteran Join Date: Nov 2008 Location: San Diego, CA Posts: 1,595	That would be AWG9 (d=0.1144-in), a mere 10-percent larger than AWG10. Yup, d=0.11-in for all three of K6STI's AntennaCraft FM-6, FM-10 & FM-13 models: http://www.ham-radio.com/k6sti/ I found d=0.11-in (r=1.45-mm) in 300ohm's 4nec2 model for the A-C U8000 UHF 8-Bay Bowtie and I found d=0.12-in (r=0.06) used in tripelo's 4nec2 model for A-C Y10-7-13 Hi-VHF Dual-Driven Yagi, which he probably rounded off from the actual r=0.0572-in. [PS: Values vary a bit between wire tables.] So AntennaCraft appears to be consistently using r=0.0572-in (AWG9) feedlines across (at least) FM, Hi-VHF and UHF frequency bands.

2011-10-29, 12:36 AM	#14
eldgreen Join Date: Dec 2010 Location: arkansas Posts: 111	300 ohm, You said that by "rescaling of the director and their spacings" of a cm3023 that it could be made to peak at a lower channel. Could you give the dimensions to peak at channel 44? Also could the gain be increased by adding more boom with directors and spacings of the same dimensions? Thanks.