F.A.Q. for Military Application Testing

Question 1:RS103 SusceptibilityDwell Time

We have a contract requirement for thesusceptibility test specifying a minimumdwell time of at least 3 minutes. How longwould it take to test 4 equipment sides inboth polarizations in accordance withMIL-STD 461E, RS103 from 2 MHz to 18GHz?

Answer 1:RS103 SusceptibilityDwell Time

In order to determine the total timerequired for the frequency scan in eachfrequency band called out by RS103, onemust first to determine the number of thefrequency steps for each frequency bandin RS103 table III.

This is done by applying the geometricprogression formula for each member: an = a0 x rn, where an is the “n+1”member, a0 is the first member and r isthe coefficient of the geometricprogression.

The number of steps, n+1 can bedefined by using the formula:

n + 1 = lg10 (an/a0)/lg10(r) + 1

The justification for using the geometricprogression formula in determining thenumber of frequency steps is given below.

If we assume that a0 is the start frequencyF0 and an is the stop frequency Fn; thenthe relation between F0 and Fn is based oneach frequency in the frequency band beingdefined as the sum of the previous frequencyand the multiplication of the previousfrequency by the frequency step size “ ”1

The first frequency of the frequency band, F0,and the second frequency, F1, areconnected by the expression below:

F1 = F0 + F0 x = F0 x (1 + )

The third frequency is connected by thesecond and the first scanned frequencies as:

F2 = F1 + F1 x = F1 x (1 + ) = F0 x(1+ ) x (1+ ) = F0 x (1+ )2

The sequence above could be continued; itdemonstrates that the members of thesequence are connected with the geometricprogression rule and that the coefficient ofthe geometric progression r is connectedwith the frequency step size by theexpression:

r = 1+

Based on the expression given above forthe number of the frequency steps:

n = lg10 (Fn/F0)/lg10(1+ )

“Calculate the transmitter ERP in dBW, based on the receiv-er meter reading V, using the following equation:ERP = V + 20 log R + AF - 135where:V = reading on the measurement receiver in dBuVR = distance between transmitter and receiver antennas inmetersAF = antenna factor of receiver antenna in dB (1/m)”

Answer 5: RE 103 ERP CalculationThe formula is the logarithmic version of the classic far fieldstrength but rearranged so that the ERP is in dBW.

Friis Far field formula = E2= Pt*Gt*30/R2 Eq.1

But E = (V*AF 1/dB) Eq.2

where V is measured by measuring receiver in voltage andAF is antenna factor of the receiving antenna

Substituting Eq. 2 in Eq. 1, we have (V*AF 1/dB)2 =

Pt*Gt*30/R2

Where:V = reading from the measurement receiver in VR = distance between transmitter and receiver antennas inmeters

Gt = Antenna gain

Pt = Transmitter power

But Pt*Gt =ERP

Converting the aforementioned formula into logarithmyields:20 Log V + 20 Log AF = 10 Log ERP + 10 Eq.3Log 30 - 20 Log R rearranging Eq. 3 yield Eq. 4

Spring/Summer 2005

360 Herndon ParkwaySuite 1400Herndon, VA 20170www.rheintech.com

360 Herndon ParkwaySuite 1400

Herndon, VA 20170

Phone 703-471-6441Fax 703-689-2056www.rheintech.com

We have provided typical questions andanswers that represent technical opinionswith justification for MIL-STD testrequirements. The particulars of the testitem must be considered with respect tothe applicability of these questions andanswers. We hope you find our FAQnewsletter valuable and we welcomeyour feedback and questions. Call at703-689-0368 or send email tomultipoint@rheintech.com.

See our website at www.rheintech.comfor MultiPoint archives, a facility virtualtour, and other helpful information.

CONTENTSQ1: RS103 Susceptibility Dwell Time

Q2: RE102 Paragraph 5.16.1

Q3: System Ambient Noise Floor Calculation

Q4: Platform Applicability

Q5: RE103 ERP Calculation

In 2005, US Military spending will top $420 Billion!Is your product ready to sell to the U.S. Military?

Call Rhein Tech for fully accredited Military Standard Testingservices:MIL-STD-461/462, RTCA/DO-160D and more…Call 703-689-0368 or email sales@rheintech.com

www.rheintech.com Spring/Summer 2005

1RS103 requires using equal to 0.01 or 0.005, depending on the investigated frequency band.

Question 3: Calculation of MeasurementSystem Ambient Noise FloorWe have a MIL-STD 461E military application in whichwe must demonstrate RE102 measurement system ambi-ent noise floor in our anechoic room from 1 - 18 GHzat 1 MHz fixed IF bandwidth with no Video/PostDetector enabled, the Video filter must be set to 3 MHzor wider. We require a 20 dBuV/m display limit on ourdata plot using available test equipment. The intendedmeasurement antenna or antennas used for this meas-urement, the preamplifiers, and the cables or wave-guides (if used) should all be connected to the measure-ment path of the receiver or spectrum analyzer.Receiving system sweep times are to be set per MIL-STD461E, Table II. Power to the preamplifier(s) isto be set on when the sweep isperformed. Data plots mustreveal that the displayed ambient& system noise floor is =< 14dBuV/m from 1 to 18 GHz. Howwould we calculate this stringentrequirement?

Answer 3: Calculationof Measurement SystemAmbient Noise FloorThe calculation below is made for the frequency of 18GHz and equipment listed below. If the noise floor spec-ification can be achieved at this frequency, the selectedequipment would meet the desired noise floor require-ments at lower frequencies.

Noise Floor Level (NFL) shall be calculated based onthe formula: NFL = SA DANL@1MHz - A(G) + AF + AMP(NF) + CL,Where SA DANL is spectrum analyzer DynamicAverage Noise Level, A(G) is the Amp Gain, AF isAntenna Factor, AMP(NF) is the Amp Noise Figure andCL is the Cable Loss at 18 GHz.

The values used for the calculations below are fromthe data sheets of the following test equipment:

1. SA: Rhode and Schwarz, Model No. R&S FS 26;Dynamic Average Noise Level (DANL): 0dB attenua-tion, RBW=1 KHz, VBW=2 KHz, 0 span, SWP=5

0ms, trace average@ 20 count normalized to 10 HzRBW. SADAN@1 MHz = - 91 dBm

2. Cable: 4 meters coax SMA type Megaphase RFcable, M/N: F130-S1S1-160, 0.25dB/ft attenuationat 18GHz; Its loss is 3.28 dB

3. Low loss Miteq Amplifiers, model AMF-6F12001800-13-10P. A part of its specification isshown in the Table with the gain level of 45 dB in thefrequency range of 12-18 GHz

4. Antenna: Electro-Metrics Model EM-6961 – double-ridge horn antenna with AF = 47 dB/m at 18 GHz.

Based on the formula and the data above, the NFLwould be equal to: NNFFLL@@1188 GGHHzz == --9911 -- 4477 ++ 3377 ++ 11..33 ++ 33..2288 == --9966..44 ddBBmm

Please note that the DANL specifi-cation for all manufacturers ofSpectrum Analyzers/Receiverscontains some averaging count.Evidence of averaging in theDANL tends to skew the DANLdata by as much as 10 dB, whichmakes it more difficult to meet therequired 14dBuV noise floor.

Question 4: Platform ApplicabilityWe have a unit for military application and would liketo know the requirements needed to satisfy a govern-ment contract.

Answer 4: Platform ApplicabilityIn order to determine the required tests, one must firstdetermine the platform from Table V of the MIL-STD461E standard. Each branch of the service has specif-ic requirement depending on the platform in which theequipment would be installed.

Question 5: RE103 ERP CalculationWe cannot seem to understand the ERP formula in MIL-STD RE103 paragraph 5.17.13.4d(6), kindly explainhow the formula was derived. I have included the per-tinent section of the standard including the ERP equa-tion.

–continued on page 4

Question 2: Paragraph 5.16.1, RE102ApplicabilityWe would like further explanation about RE102paragraph 5.16.1 “This requirement is applicablefor radiated emissions from equipment and subsys-tem enclosures, all interconnecting cables, andantennas designed to be permanently mounted tothe EUTs (receivers and transmitters in standbymode).” We normally test our equipment, a trans-mitter, by operating it in modulation mode into adummy load placed directly on the RF output port.

Answer 2: Paragraph 5.16.1, RE102ApplicabilityThe operative phrase in paragraph 5.16.1 is “andantennas designed to be permanently mounted tothe EUTs.” When an antenna is permanentlymounted, it cannot be disconnected in order to adda dummy load. If it is permanently mounted, thetransmitter should not be transmitting duringRE102 testing unless the antenna can be mountedindependently in another room, e.g. test equip-ment control room. This paragraph specificallyrequires emissions from the EUTs enclosures, sub-system enclosures, interconnecting cables and

emissions that would otherwise radiate from trans-mitters and receivers antennas to be measuredwhen the EUT is not transmitting or receiving if itcontains such modules.

RE103 (test procedure used to verify that radiatedspurious and harmonic emissions fromtransmitters do not exceed the specified require-ments) is applicable when receiver or transmittermodules are installed. These modules would beturned on to radiate any possible harmonic andspurious emissions during RE103 testing.

1

2

3

4

1

30

1000

8000

30

1000

8000

18000

0.01

0.005

0.001

0.0005

1.477121

1.522879

0.90309

0.352183

0.004321

0.002166

0.000434

0.000217

342

703

2081

1623

136.7

281.2

832.2

648.9

1899

BandF0,

MHzFn,

MHzLog(Fn/F0)

Time* requiredfor 4 sides, 2polarization,

(Hours)

Maxstep size, Log(1+ )

Number of steps Nin each band =

Log(Fn/F0) / Log(1+ )

Total time required for the test

The examples in the table below lists the calculated number of the frequency steps based onthe maximum step size within each frequency from 1 MHz to 18 GHz.

*Notes: • The total time required adding the start frequency in each band in order to determine total steps, therefore, plus “one”,

was to account for the required steps.• Total time was calculated based on the 4 EUT sides and 2 polarization.

Note: This table does not account for additional time required for critical equipment operatingfrequencies such as CPU clocks, time for the test setups, etc.

www.rheintech.com Spring/Summer 2005 Spring/Summer 2005 www.rheintech.com

2 3F.A.Q. for Military Application TestingF.A.Q. for Military Application Testing

Question 3: Calculation of MeasurementSystem Ambient Noise FloorWe have a MIL-STD 461E military application in whichwe must demonstrate RE102 measurement system ambi-ent noise floor in our anechoic room from 1 - 18 GHzat 1 MHz fixed IF bandwidth with no Video/PostDetector enabled, the Video filter must be set to 3 MHzor wider. We require a 20 dBuV/m display limit on ourdata plot using available test equipment. The intendedmeasurement antenna or antennas used for this meas-urement, the preamplifiers, and the cables or wave-guides (if used) should all be connected to the measure-ment path of the receiver or spectrum analyzer.Receiving system sweep times are to be set per MIL-STD461E, Table II. Power to the preamplifier(s) isto be set on when the sweep isperformed. Data plots mustreveal that the displayed ambient& system noise floor is =< 14dBuV/m from 1 to 18 GHz. Howwould we calculate this stringentrequirement?

Answer 3: Calculationof Measurement SystemAmbient Noise FloorThe calculation below is made for the frequency of 18GHz and equipment listed below. If the noise floor spec-ification can be achieved at this frequency, the selectedequipment would meet the desired noise floor require-ments at lower frequencies.

Noise Floor Level (NFL) shall be calculated based onthe formula: NFL = SA DANL@1MHz - A(G) + AF + AMP(NF) + CL,Where SA DANL is spectrum analyzer DynamicAverage Noise Level, A(G) is the Amp Gain, AF isAntenna Factor, AMP(NF) is the Amp Noise Figure andCL is the Cable Loss at 18 GHz.

The values used for the calculations below are fromthe data sheets of the following test equipment:

1. SA: Rhode and Schwarz, Model No. R&S FS 26;Dynamic Average Noise Level (DANL): 0dB attenua-tion, RBW=1 KHz, VBW=2 KHz, 0 span, SWP=5

0ms, trace average@ 20 count normalized to 10 HzRBW. SADAN@1 MHz = - 91 dBm

2. Cable: 4 meters coax SMA type Megaphase RFcable, M/N: F130-S1S1-160, 0.25dB/ft attenuationat 18GHz; Its loss is 3.28 dB

3. Low loss Miteq Amplifiers, model AMF-6F12001800-13-10P. A part of its specification isshown in the Table with the gain level of 45 dB in thefrequency range of 12-18 GHz

4. Antenna: Electro-Metrics Model EM-6961 – double-ridge horn antenna with AF = 47 dB/m at 18 GHz.

Based on the formula and the data above, the NFLwould be equal to: NNFFLL@@1188 GGHHzz == --9911 -- 4477 ++ 3377 ++ 11..33 ++ 33..2288 == --9966..44 ddBBmm

Please note that the DANL specifi-cation for all manufacturers ofSpectrum Analyzers/Receiverscontains some averaging count.Evidence of averaging in theDANL tends to skew the DANLdata by as much as 10 dB, whichmakes it more difficult to meet therequired 14dBuV noise floor.

Question 4: Platform ApplicabilityWe have a unit for military application and would liketo know the requirements needed to satisfy a govern-ment contract.

Answer 4: Platform ApplicabilityIn order to determine the required tests, one must firstdetermine the platform from Table V of the MIL-STD461E standard. Each branch of the service has specif-ic requirement depending on the platform in which theequipment would be installed.

Question 5: RE103 ERP CalculationWe cannot seem to understand the ERP formula in MIL-STD RE103 paragraph 5.17.13.4d(6), kindly explainhow the formula was derived. I have included the per-tinent section of the standard including the ERP equa-tion.

–continued on page 4

Question 2: Paragraph 5.16.1, RE102ApplicabilityWe would like further explanation about RE102paragraph 5.16.1 “This requirement is applicablefor radiated emissions from equipment and subsys-tem enclosures, all interconnecting cables, andantennas designed to be permanently mounted tothe EUTs (receivers and transmitters in standbymode).” We normally test our equipment, a trans-mitter, by operating it in modulation mode into adummy load placed directly on the RF output port.

Answer 2: Paragraph 5.16.1, RE102ApplicabilityThe operative phrase in paragraph 5.16.1 is “andantennas designed to be permanently mounted tothe EUTs.” When an antenna is permanentlymounted, it cannot be disconnected in order to adda dummy load. If it is permanently mounted, thetransmitter should not be transmitting duringRE102 testing unless the antenna can be mountedindependently in another room, e.g. test equip-ment control room. This paragraph specificallyrequires emissions from the EUTs enclosures, sub-system enclosures, interconnecting cables and

emissions that would otherwise radiate from trans-mitters and receivers antennas to be measuredwhen the EUT is not transmitting or receiving if itcontains such modules.

RE103 (test procedure used to verify that radiatedspurious and harmonic emissions fromtransmitters do not exceed the specified require-ments) is applicable when receiver or transmittermodules are installed. These modules would beturned on to radiate any possible harmonic andspurious emissions during RE103 testing.

1

2

3

4

1

30

1000

8000

30

1000

8000

18000

0.01

0.005

0.001

0.0005

1.477121

1.522879

0.90309

0.352183

0.004321

0.002166

0.000434

0.000217

342

703

2081

1623

136.7

281.2

832.2

648.9

1899

BandF0,

MHzFn,

MHzLog(Fn/F0)

Time* requiredfor 4 sides, 2polarization,

(Hours)

Maxstep size, Log(1+ )

Number of steps Nin each band =

Log(Fn/F0) / Log(1+ )

Total time required for the test

The examples in the table below lists the calculated number of the frequency steps based onthe maximum step size within each frequency from 1 MHz to 18 GHz.

*Notes: • The total time required adding the start frequency in each band in order to determine total steps, therefore, plus “one”,

was to account for the required steps.• Total time was calculated based on the 4 EUT sides and 2 polarization.

Note: This table does not account for additional time required for critical equipment operatingfrequencies such as CPU clocks, time for the test setups, etc.

www.rheintech.com Spring/Summer 2005 Spring/Summer 2005 www.rheintech.com

2 3F.A.Q. for Military Application TestingF.A.Q. for Military Application Testing

F.A.Q. for Military Application Testing

Question 1:RS103 SusceptibilityDwell Time

We have a contract requirement for thesusceptibility test specifying a minimumdwell time of at least 3 minutes. How longwould it take to test 4 equipment sides inboth polarizations in accordance withMIL-STD 461E, RS103 from 2 MHz to 18GHz?

Answer 1:RS103 SusceptibilityDwell Time

In order to determine the total timerequired for the frequency scan in eachfrequency band called out by RS103, onemust first to determine the number of thefrequency steps for each frequency bandin RS103 table III.

This is done by applying the geometricprogression formula for each member: an = a0 x rn, where an is the “n+1”member, a0 is the first member and r isthe coefficient of the geometricprogression.

The number of steps, n+1 can bedefined by using the formula:

n + 1 = lg10 (an/a0)/lg10(r) + 1

The justification for using the geometricprogression formula in determining thenumber of frequency steps is given below.

If we assume that a0 is the start frequencyF0 and an is the stop frequency Fn; thenthe relation between F0 and Fn is based oneach frequency in the frequency band beingdefined as the sum of the previous frequencyand the multiplication of the previousfrequency by the frequency step size “ ”1

The first frequency of the frequency band, F0,and the second frequency, F1, areconnected by the expression below:

F1 = F0 + F0 x = F0 x (1 + )

The third frequency is connected by thesecond and the first scanned frequencies as:

F2 = F1 + F1 x = F1 x (1 + ) = F0 x(1+ ) x (1+ ) = F0 x (1+ )2

The sequence above could be continued; itdemonstrates that the members of thesequence are connected with the geometricprogression rule and that the coefficient ofthe geometric progression r is connectedwith the frequency step size by theexpression:

r = 1+

Based on the expression given above forthe number of the frequency steps:

n = lg10 (Fn/F0)/lg10(1+ )

“Calculate the transmitter ERP in dBW, based on the receiv-er meter reading V, using the following equation:ERP = V + 20 log R + AF - 135where:V = reading on the measurement receiver in dBuVR = distance between transmitter and receiver antennas inmetersAF = antenna factor of receiver antenna in dB (1/m)”

Answer 5: RE 103 ERP CalculationThe formula is the logarithmic version of the classic far fieldstrength but rearranged so that the ERP is in dBW.

Friis Far field formula = E2= Pt*Gt*30/R2 Eq.1

But E = (V*AF 1/dB) Eq.2

where V is measured by measuring receiver in voltage andAF is antenna factor of the receiving antenna

Substituting Eq. 2 in Eq. 1, we have (V*AF 1/dB)2 =

Pt*Gt*30/R2

Where:V = reading from the measurement receiver in VR = distance between transmitter and receiver antennas inmeters

Gt = Antenna gain

Pt = Transmitter power

But Pt*Gt =ERP

Converting the aforementioned formula into logarithmyields:20 Log V + 20 Log AF = 10 Log ERP + 10 Eq.3Log 30 - 20 Log R rearranging Eq. 3 yield Eq. 4

Spring/Summer 2005

360 Herndon ParkwaySuite 1400Herndon, VA 20170www.rheintech.com

360 Herndon ParkwaySuite 1400

Herndon, VA 20170

Phone 703-471-6441Fax 703-689-2056www.rheintech.com

We have provided typical questions andanswers that represent technical opinionswith justification for MIL-STD testrequirements. The particulars of the testitem must be considered with respect tothe applicability of these questions andanswers. We hope you find our FAQnewsletter valuable and we welcomeyour feedback and questions. Call at703-689-0368 or send email tomultipoint@rheintech.com.

See our website at www.rheintech.comfor MultiPoint archives, a facility virtualtour, and other helpful information.

CONTENTSQ1: RS103 Susceptibility Dwell Time

Q2: RE102 Paragraph 5.16.1

Q3: System Ambient Noise Floor Calculation

Q4: Platform Applicability

Q5: RE103 ERP Calculation

In 2005, US Military spending will top $420 Billion!Is your product ready to sell to the U.S. Military?

Call Rhein Tech for fully accredited Military Standard Testingservices:MIL-STD-461/462, RTCA/DO-160D and more…Call 703-689-0368 or email sales@rheintech.com

www.rheintech.com Spring/Summer 2005

1RS103 requires using equal to 0.01 or 0.005, depending on the investigated frequency band.