DRAKE MN2700 Manuel d'utilisateur

Antenna Tuners(Antenna Couplers)6/1/2011 Larry Benko, W0QE 1

What do you really want/need?• Matches nearly everything?, Match = 1.0:1 SWR? • Improve SWR bandwidth?, Hardly ever adjusted?•Peak/average power (mf

Matching Network Components• Generally constructed from reactive components.– Exceptions: transmission lines, delta match, resistances such as the 800

DIY Coupler• In approximate order of ascending cost1) Fixed inductor2)Small value fixed capacitor2)Small value fixed capacitor3) Air variable capacito

Types of Tuners• Auto, semi-auto, manual adjust, or fixed.• Variable, switched, and/or fixed components. •Is coupler part of transmitter or antenna?•I

Tying it all together• ReflectionCoefficient:•SWR:ρ+=1SWROLOLZZZ-Z+=Γ()()2L2OLXRR+−=ρ1SWR1-SWR+=ρ10≤≤ρΓ=ρ•SWR:• Return Loss:• Mismatch Loss:6/1/2011 L

SWRρReturnLoss (dB)MismatchLoss (dB)PowerTo Load11.1 0.05 26.44 0.01 100%1.2 0.09 20.83 0.04 99%1.5 0.20 13.98 0.18 96%2 0.33 9.54 0.51 89%6/1/2011 La

Voltages and CurrentsOPIrmsRP2Vpk=××=OSWRPIrmsSWRRP2Vpk×≤×××≤6/1/2011 Larry Benko, W0QE 16ORPIrms=ORSWRPIrms×≤VpkIrms IrmsVpkCoupler R + jXRo

SWR Power Vpk(max)Irms(max)1:1 100W1500W100V387V1.41A5.48A3:1 100W1500W173V671V2.45A9.5A10:1100W316V4.47A10:1100W1500W316V1225V4.47A17.3A20:1 100W1500

Stresses Within the Tuner @ 1500W• All are 20:1 SWRs. Stresses & losses are different.387Vpk5.48A 24.5A86.6VpkCoupler2.5 + j0Ω387Vpk5.48A 17.3A12

“Small” Antenna Examples• Example#1– 1.8MHz using 40m (67.2’) dipole, 50’ high, #12 Cu wire– Z = 1.60 – j2420 (SWR ~73000:1)–Irms= 30.6A (1500W), Vp

What is an Antenna Tuner?• An antenna tuner (coupler is a more correct term) is an impedance matching device which minimizes “mismatch” loss (maximize

What is the Smith Chart• A polar plot of the reflection coefficient including phase.•This results in:•This results in:– Plots of constant SWRs are cir

Smith Chart RegionsL type circuits3/2/2009 Larry Benko, W0QE 21

Example Smith Chart showing SWR circles5:1 = Green10:1 = Red20:1 = Orange6/1/2011 Larry Benko, W0QE 2220:1 = Orange50 + j0 (SWR = 1:1)

Sample Design Goals• Match all SWRs of at least 20:1 from 160m thru 20m with reduced SWRs up thru 6m.•Do the basic design on 40m realizing that 4X mor

Low Pass “L” NetworkType “A”– Shunt “C” on ANT Side– Series “L”–Need >Cmax& <Cmin6/1/2011 Larry Benko, W0QE 24–Need >Cmax& <Cmin50

Low Pass “L” NetworkType “B”– Shunt “C” on TX Side– Series “L”–Need <Lmin& >Cmax6/1/2011 Larry Benko, W0QE 25–Need <Lmin& >CmaxTra

Low Pass “L” Network Results• Cmax ~= 8000pF & Lmax ~= 20uH on 160m• Cmin ~= 5pF & Lmin ~= .02uH on 6m•Pretty ugly component values.•Pretty ug

High Pass “L” NetworkType “C”– Shunt “L” on ANT Side– Series “C”–Need >Lmax(not good)6/1/2011 Larry Benko, W0QE 27–Need >Lmax(not good)Transmitt

High Pass “L” NetworkType “D”– Shunt “L” on TX Side– Series “C”–Need >Cmax(not good)6/1/2011 Larry Benko, W0QE 28–Need >Cmax(not good)Transmitte

High Pass “L” Network Results• Worse component values than Low Pass “L”.• Variable component “L” networks are not commonly used for wide range matchin

Basics: Correct or Incorrect?• An antenna operated at its resonant frequency doesn’t need a coupler.– No, resonance only means the feed point is resis

Adding a 3rdComponent• Does adding a 3rdadjustable component help the matching range?•Could the Low Pass “Pi” could be this network?•Could the Low Pas

Low Pass “Pi” Network– Great matching range– Similar component values to the Low Pass “L” network6/1/2011 Larry Benko, W0QE 31100 -2000pFAntennaTransm

Low Pass “Pi” Network– Great matching range– Notice new scaled component values!6/1/2011 Larry Benko, W0QE 32100 -8000pFAntennaTransmitter0.2-20uH

Low Pass “Pi” Network– Still good matching range6/1/2011 Larry Benko, W0QE 33100 -8000pFAntennaTransmitter0.2-20uH

Low Pass “Pi” Network– Not good matching range– Needs <Cmin and <Lmin6/1/2011 Larry Benko, W0QE 34100 -8000pFAntennaTransmitter0.2-20uH

Low Pass “Pi” Network– Very good matching range– Modified for Cmin which includes stray C to Gnd– Includes stray L on input and output6/1/2011 Larry B

Low Pass “Pi” Network– Very good matching range– Modified for <Cmin which includes stray C to Gnd– Includes stray L on input and output6/1/2011 Lar

High Pass “Tee” Network• Neither the “L” or Low Pass “Pi” networks seems like a good candidate for use as an all band general matching network.general

High Pass “Tee” Network– Pretty easy to see why the high pass “Tee” network is popular– Nice component values6/1/2011 Larry Benko, W0QE 38Transmitter3

High Pass “Tee” Network– Great matching range6/1/2011 Larry Benko, W0QE 39Transmitter30-500pFAntenna0.2-20uH30-500pF

Basics: Correct or Incorrect?, Page 2• The ability to match is more important than efficiency when choosing a coupler.– Yes, if the coupler doesn’t ma

High Pass “Tee” Network– Still great matching range6/1/2011 Larry Benko, W0QE 40Transmitter30-500pFAntenna0.2-20uH30-500pF

High Pass “Tee” Network– Very good matching range6/1/2011 Larry Benko, W0QE 41Transmitter Antenna30 -500pF5uH30 -500pF

High Pass “Tee” Network– Obvious why the High Pass “Tee” is popular6/1/2011 Larry Benko, W0QE 42Transmitter30-500pFAntenna0.2-20uH30-500pF

High Pass “Tee” Network– What if we include the stray Cs & Ls– Still great matching range6/1/2011 Larry Benko, W0QE 43Transmitter Antenna0.2-20uHB

High Pass “Tee” Network– Matching range is poor– Lmin is too large (reactance = +j63 @50MHz)6/1/2011 Larry Benko, W0QE 44Transmitter Antenna0.2-20uHBo

Fixed “L” High Pass “Tee” Network– Fixed “L” can cover 2 bands pretty well.– Inductor easy to make very high Q.– Coupler best @ ~5MHz6/1/2011 Larry Be

Fixed “L” High Pass “Tee” Network– Matches all 5:1 SWRs & 75% of 20:1 SWRs6/1/2011 Larry Benko, W0QE 46Transmitter Antenna30 -500pF5uH30 -500pF

Fixed “L” High Pass “Tee” Network– Matches all 7:1 SWRs, 60% of 10:1 SWRs, & 40% of 20:1 SWRs6/1/2011 Larry Benko, W0QE 47Transmitter Antenna30 -5

Other Network Topologies• Lew McCoy W1ICP, Ultimate Transmatch (1970)Transmitter AntennaNotDiff.• Doug DeMaw W1FB, SPC Transmatch (1980)6/1/2011 Larry

Other Network Topologies• Link Coupled (Johnson Matchbox)– Very good for higher R matches– Link coupling very efficient• High Pass Differential Tee (M

Basics: Correct or Incorrect?, Page 3• The SWR presented by an antenna is minimumat the fundamental resonant frequency.– No, often SWR is minimum but

High Pass Differential “Tee” Network– Based on measurements and component values of the Palstar AT-Auto with last version of inductor6/1/2011 Larry Be

High Pass Differential “Tee” Network– Palstar AT-Auto6/1/2011 Larry Benko, W0QE 510.10uH 0.15uH20pF 20pF0.2-24.2uH440-25-440pFAntennaTransmitter

High Pass Differential “Tee” Network– Palstar AT-Auto6/1/2011 Larry Benko, W0QE 520.10uH 0.15uH20pF 20pF0.2-24.2uH440-25-440pFAntennaTransmitter

High Pass Differential “Tee” Network– Palstar AT-Auto– No longer matches all 5:1 SWRs–Add 4’ of 50Ω.66VF 6/1/2011 Larry Benko, W0QE 53–Add 4’ of 50Ω.6

High Pass Differential “Tee” Network– Palstar AT-Auto– Matching range severely reduced6/1/2011 Larry Benko, W0QE 540.10uH 0.15uH20pF 20pF0.2-24.2uH440

High Pass Differential “Tee” Network– Palstar AT-Auto– Matching range very limited6/1/2011 Larry Benko, W0QE 550.10uH 0.15uH20pF 20pF0.2-24.2uH440-25-

The End!6/1/2011 Larry Benko, W0QE 56

Other Topics• Why might a full sized dipole need matching?• Coupler topologies and stresses.•Converting series to parallel impedances.•Converting seri

Does a Full Sized Dipole Need Matching?6/1/2011 Larry Benko, W0QE 58Chapter 3, ARRL Antenna Book 21stedition

Dipole Matching• 7.0MHz = 88.9 –j13.8 7.1MHz = 93.2 +j8.17.2MHz = 97.7 +j29.9 7.3MHz = 102.2 +j51.5•Match with 99 deg. of 75Ωtransmission line at

Basics: Correct or Incorrect?, Page 4• Does 50Ω coax need to be used between coupler and transmitter?– No, but do not use SWR meter in coupler if not

Z = 20 – j0 (SWR 2.5:1), 28MHz, 1500WType Transmitter Side Antenna SideLP-"L"Cp-LsCp = 139.2pF387Vpk, 6.7ALs = 0.14uH300Vpk, 8.7AHP-"L

Z = 5 – j200 (SWR 157:1), 1.8MHz, 1500WType Transmitter Side Antenna SideLP-"L"Cp-LsCp = 5302pF387Vpk, 16.4ALs = 19.01uH5265Vpk, 17.3AHP-&q

Z = 2000 – j0 (SWR 40:1), 7.0MHz, 1500WType Transmitter Side Antenna SideLP-"L"Ls-CpLs = 7.10uH2148Vpk, 5.5ACp = 71.0pF2449Vpk, 5.4AHP-&quo

Series/Parallel ConversionRsXsRsRp22+=XsXsRsXp22+=6/1/2011 Larry Benko, W0QE 63222XpRpXpRpRs+×=222XpRpXpRpXs+×=Note: If impedance was capacitive in se

80m full size dipole– #12 wire up 40’– No feedline– Pink dot = 1.8MHzWhat can be expected when used at all HF 6/1/2011 Larry Benko, W0QE 64when used a

80m full size dipole– 50’ of .66VF 50Ωlossless coaxVery wide range of impedances!6/1/2011 Larry Benko, W0QE 65Even if loss in real coax is ignored thi

80m full size dipole– 50’ of 600Ω lossless open wire lineNotice how impedances are high at all freq. above 3.5MHz.6/1/2011 Larry Benko, W0QE 66above 3

3/12/2009 Larry Benko, W0QE 67File LosslessReflections-50.ascV(Vin1) under I(R1)V(Vout2) under I(R2)

3/12/2009 Larry Benko, W0QE 68File LosslessReflections-100.ascV(Vin1) under I(R1)No further reflections due to R1

3/12/2009 Larry Benko, W0QE 69File LosslessReflections-25.ascV(Vin1) under I(R1)No further reflections due to R1

Basics: Correct or Incorrect?, Page 5• A multiband coupler will have reduced matching at both the top and bottom of the frequency range.– Yes!•A coupl

Smith Chart• Smith Chart basics– Zo at center, constant SWR = circles– X axis is reflection coefficient (-1 to +1)–Top half is inductive, bottom half

SeriesCapacitor3/12/2009 Larry Benko, W0QE 7110MHz = Green20MHz = Red30MHz = Blue

SeriesInductor3/12/2009 Larry Benko, W0QE 7210MHz = Green20MHz = Red30MHz = Blue

ShuntCapacitor3/12/2009 Larry Benko, W0QE 7310MHz = Green20MHz = Red30MHz = Blue

ShuntInductor3/12/2009 Larry Benko, W0QE 7410MHz = Green20MHz = Red30MHz = Blue

SeriesTransmissionLineΩ)3/12/2009 Larry Benko, W0QE 75(50Ω)10MHz = Green20MHz = Red30MHz = Blue

SeriesTransmissionLineΩ)3/12/2009 Larry Benko, W0QE 76(200Ω)10MHz = Green20MHz = Red30MHz = Blue

2:1 TurnsTransformerStep Up3/12/2009 Larry Benko, W0QE 77Step Up10MHz = Green20MHz = Red30MHz = Blue

OpenStub3/12/2009 Larry Benko, W0QE 7810MHz = Green20MHz = Red30MHz = Blue

ShortedStub3/12/2009 Larry Benko, W0QE 7910MHz = Green20MHz = Red30MHz = Blue

Does Coupler Use = Incompetency?• Chest pounding by some would imply so.– I don’t need a tuner since my antennas are designed properly. Tuners have t

Smith Chart RegionsL type circuits3/12/2009 Larry Benko, W0QE 80

Surge Impedance Again• Zo = per unit length, equivalent circuit no loss• Zo = for round coaxL/C∗IDOD

Choices?• You don’t have antennas to cover all desired frequencies with an acceptable SWR for your equipment.– Do nothing and just don’t operate on so