LPF - low Pass Filter

Mini Dipole 40m Band

https://www.qrz.com/db/YD8KKR


Loading Coil = Enamel 1,8mm , 90 turn , 1 inch diameter , 18cm length 

Magic Antenna , Just 3m total length open dipole for 40m band.......Ready to DX

Just need small space , you don't need a tower , you ready to DX just 7m high antenna from the earth.....

double bazoka antenna

windom for 40m band antenna

ANTENNA WINDOM - 40M BAND

BALUN 1:4

Antenna Mobil 2 MTR >> HF

ANTENA MOBIL 2 MTR 

CONVERT  KE HF

• Siapkan Antenna VHF 2 mtr. (5/8 lamda), yang sudah di seting di Frek kerja 2 Meter.
• Siapkan PVC 1" 11cm. + 2 dop 1".
• Kawat email 1,5mm .
• Pasang 2 Konektor pada dop PVC, atas untuk Female, bawah tuk Male.
• Lilit Kawat email Untuk : 

- 27Mhz. 9 Lilit. spasi 0,5cm.

- 11 Mhz 28 Lilit. ( rapat ).

- 7 mhz 58 Lilit. ( Rapat ).

• Biarkan untuk Output ( Female) hanya terpasang Iner nya saja. (+). untuk tersambung ke antena Larsen 2 meter.
•  Siapkan Konektor SMA Jack Male & Female.
  
  Gambar :
  

Panjang Kabel Penyalur ( Coex ) 420cm + Braket ( Mount ), for HF ( standar ), Coil atau lilitan dalam keadaan terbuka dan tertutup ada perubahan.

Shortwave Antennas for 40m and 80m

Trying to use the shortwave bands for ham radio usually end up in the need of space for large antennas. Of course, the antenna should be "the larger the better" for these bands but sometimes there is no space available. I have also this problem as I only have a small balcony so I decided in trying to build extremely shortened antennas as this is common for mobile antennas. Here is a sketch of the layout:

I built two antennas, one for 40m and one for 80m and I had access to a professional vector network analyzer. The length of the radiator was choosen arbitraryly, then the parameter N₁ was varied to find the right resonant frequency. After thatm the parameter N₂ was varied to get 50 Ohm. The resonant frequency is independend of the parameter.

Here the results for the antenna for 40 m:
l=854mm
N₁=59
N₂=16
total length: 1.15m

And here the results for the 80 m antenna:
l=1500mm
N₁=98
N₂=18
total length: 2m

I used a PVC wastewater pipe with a diameter of 40mm. The radiator can be either fixed on that pipe too, or it can be installed in a separate pipe (one for electric installations in my case).

Double Bazooka NVIS Antenna Calculator

The measurements below are for building a Double Bazooka Near Vertical Incident Skywave (NVIS) Antenna. The End Wire Size can range from 16 AWG to 12 AWG. The larger the wire, the wider the bandwidth. 300 Ohm Twin Lead with the ends shorted is an option for even greater bandwidth.

The antenna is constructed from a single length of 50 or 75 Ohm coax with a coaxial feed point in the center. The span is opened in the middle to expose the braid from each half. The center conductor and dielectric is not disturbed and the two separated braids are then fed with the Coax Feedline. Each end of the coaxial span has the braid and center conductor shorted and connected to the end wires.

The antenna as designed is a broad band antenna with the coaxial cable's capacitive reactance changing to compensate for changes in inductive reactance across the band of operation. This helps to provide acceptable matches on frequencies other than what the antenna was specifically designed for. The antenna as fed matches reasonably well into a 50 Ohm Coax Cable Feedline and an antenna tuner.

A Ground Reflector can be added to enhance NVIS Propagation at frequencies below 10 MHz where NVIS Propagation is usable. The Ground Reflector can be a single conductor or several in parallel spaced a few feet apart. Hardware cloth or "Poultry Screening" is an option too. Several antenna / reflector elevation options are shown that enhance the NVIS vertical antenna pattern and propagation.

Please note: The calculations are approximate, so some final end wire length adjustment may be necessary. Dimensions will change slightly due to antenna height and ground conductivity variations...and Keep The Antenna Away From Power Lines. They are good at turning you into "The Squirrel in the Substation".

Please note: NVIS Propagation is only useful at frequencies below 10 MHz.

		Double Bazooka Antenna				NVIS Antenna Height				Ref Dipole
		End Wire Length Ft (B)	Coax Element Length (C)	Coaxial Element Center (D)	Total Length Ft (E)	0.1 Wave	1/8 Wave	1/20 Wave	Reflector Length	1/2 Wave Ft
	160 Meters
	1.8	37.50	180.56	90.28	255.56	52.00	65.00	26.00	268.33	260.00
	1.9	35.53	171.05	85.53	242.11	49.26	61.58	24.63	254.21	246.32
	2	33.75	162.50	81.25	230.00	46.80	58.50	23.40	241.50	234.00
	80 Meters
	3.5	19.29	92.86	46.43	131.43	26.74	33.43	13.37	138.00	133.71
	3.6	18.75	90.28	45.14	127.78	26.00	32.50	13.00	134.17	130.00
	3.7	18.24	87.84	43.92	124.32	25.30	31.62	12.65	130.54	126.49
	3.8	17.76	85.53	42.76	121.05	24.63	30.79	12.32	127.11	123.16
	3.9	17.31	83.33	41.67	117.95	24.00	30.00	12.00	123.85	120.00
	4	16.88	81.25	40.63	115.00	23.40	29.25	11.70	120.75	117.00
	60 Meters
5.3305	12.66	60.97	30.48	86.30	17.56	21.95	8.78	92.19	87.80	Ch1
5.3465	12.63	60.79	30.39	86.04	17.51	21.88	8.75	91.91	87.53	Ch2
5.3665	12.58	60.56	30.28	85.72	17.44	21.80	8.72	91.57	87.21	Ch3
5.3715	12.57	60.50	30.25	85.64	17.43	21.78	8.71	91.48	87.13	Ch4
5.4035	12.49	60.15	30.07	85.13	17.32	21.65	8.66	90.94	86.61	Ch5
40 Meters
7	9.64	46.43	23.21	65.71	13.37	16.71	6.69	69.00	66.86
7.1	9.51	45.77	22.89	64.79	13.18	16.48	6.59	68.03	65.92
7.15	9.44	45.45	22.73	64.34	13.09	16.36	6.55	67.55	65.45
7.2	9.38	45.14	22.57	63.89	13.00	16.25	6.50	67.08	65.00
7.3	9.25	44.52	22.26	63.01	12.82	16.03	6.41	66.16	64.11
30 Meters
10.1	6.68	32.18	16.09	45.54	9.27	11.58	4.63	47.82	46.34
10.15	6.65	32.02	16.01	45.32	9.22	11.53	4.61	47.59	46.11
20 Meters
14	4.82	23.21	11.61	32.86	6.69	8.36	3.34	34.50	33.43
14.1	4.79	23.05	11.52	32.62	6.64	8.30	3.32	34.26	33.19
14.2	4.75	22.89	11.44	32.39	6.59	8.24	3.30	34.01	32.96
14.22	4.75	22.86	11.43	32.35	6.58	8.23	3.29	33.97	32.91
14.3	4.72	22.73	11.36	32.17	6.55	8.18	3.27	33.78	32.73
14.31	4.72	22.71	11.35	32.14	6.54	8.17	3.27	33.75	32.70
17 Meters
18.07	3.74	17.99	8.99	25.46	5.18	6.48	2.59	26.73	25.90
18.13	3.72	17.93	8.96	25.37	5.16	6.45	2.58	26.64	25.81
15 Meters
21	3.21	15.48	7.74	21.90	4.46	5.57	2.23	23.00	22.29
21.1	3.20	15.40	7.70	21.80	4.44	5.55	2.22	22.89	22.18
21.2	3.18	15.33	7.67	21.70	4.42	5.52	2.21	22.78	22.08
21.3	3.17	15.26	7.63	21.60	4.39	5.49	2.20	22.68	21.97
12 Meters
24.89	2.71	13.06	6.53	18.48	3.76	4.70	1.88	19.41	18.80
24.95	2.71	13.03	6.51	18.44	3.75	4.69	1.88	19.36	18.76
10 Meters
28	2.41	11.61	5.80	16.43	3.34	4.18	1.67	17.25	16.71
28.5	2.37	11.40	5.70	16.14	3.28	4.11	1.64	16.95	16.42
29	2.33	11.21	5.60	15.86	3.23	4.03	1.61	16.66	16.14
29.5	2.29	11.02	5.51	15.59	3.17	3.97	1.59	16.37	15.86