Total Solar Eclipse 2017

The faint lines on the first video are from the support ropes on my hex beam taken from the deck on my house.  The second video is from Illinois.  It was an amazing sight to behold.  The photo below was taken by my son Paul.

The Rage About The New Mode FT8 by Joe Taylor

There has been a lot of talk and activity around the JT mode FT8 by Joe Taylor.  This mode improves throughput in the JT modes by 4X over the various permutations of JT65 (JT9, JT65-A).   The QSO;s go fast.  Transmit times are only 15 seconds where only 12 seconds or so are in key down - similarly for receive times.

Some tips however:

Remember to download the latest version of TQSL version 2.3.1

This is not enough:  update this latest version with the latest Configuration file version 11 which just got released by the ARRL on August 14.  This allows an ADIF file written by the logging program as FT8 to be recognized by LOTW.   ACLog does not have a Pull Down for FT8 and you must enter it manually in the field for mode.

Unfortunately,although there is a lot of activity, I still have a hard time getting any new DXCC entities since all my QSOs seem to be with entities I have digital QSOs before.   I guess patience until more of the rarer entities adopt it.

2017 Amateur Radio Field Day

For this year - I am the Field Day chairperson and so had the job of organizing and mobilizing the many club members of the Greer Amateur Radio Club. Just to recap last year's result - we were in the 2A class (2 transmitter club stations).  Rusty Kirkpatrick WU2T was the chairperson last year.  We ended up 16th nationally in 2A class and 2nd in the Roanoke Division of the ARRL.  We took first place in SC.  Our points total was 7670 last year and this is the score we had to beat this year.

For 2017 - what we did that is the same as last year.
We used the same K3s we used last year - thanks to Dave K4SV
We used the same tribander on the trailer mounted tower - thanks to Dave K4SV
We used the same home brewed hex beam I constructed
We had two transmitters - one dedicated to CW and one dedicated to SSB
We had a Get On The Air or GOTA station.
We had round the clock coverage

What we did differently for 2017
We had dedicated antennas for both transmitters.   The SSB station had 40m and 80m dipoles I constructed in addition to the tower mounted tribander 3 element yagi.  The CW station had the hex beam for 20-15-10 and the CrankIR for 40m and 80m.  Originally I had planned to have Bob ND7Js 80m vertical but unfortunately this did not happen.  This meant reeling the crank on the CrankIR in the middle of the night to convert it to 80m operation and then back to 40m in the morning.
We had a VHF station for 6 meters.

Here is a video put together by Dave Anderson K4SV

Results for 2017
QSOs overall 2300 plus (since it has not been submitted - subject to adjustment
1073 QSOs on SSB, 1185 QSOS on CW
Band CW Phone Dig Total %
---- -- ----- --- ----- ---
   80 143 159 0 302 13
   40 483 51 0 534 24
   20 428 650 0 1,078 48
   15 121 128 0 249 11
    6 10 84 0 94 4
    2 0 1 0 1 0
            -- ----- --- ----- ---
Main Stations Total 1,185 1,073 0 2,258 100

GOTA CW 47 PHONE 85

Grand Total = 1232 CW and 1158 Phone

QSO Points =  2464 CQ and 1158 Phone = 3622 Points x 2 Power Multiplier =7244 Points

Total Contacts by Operator:

Operator Total
-------- ----- ---
K4SV 433 WG4MC 255 AG3R 214  W4RCW 179  WN4AFP 209  NY4G 156 W4FC 155 KE4EA 131  K1IT 101  WU2T 101  KD4S 98  W4EEY 86  ND7J 69  WB4OQL 78  KZ4M 38 K4VOI 7  W4VX 6  KN4EUM 11  KJ4TID 2 K1SBI 37 KM4VJC 24
Total = 21

Total Contacts by Antenna

CrankIR 626 28%
Hexbeam 549 24%
80m Dipole 159 7%
40m Dipole 51 2.2%
Force12 778 34.4%
6m beam 94 4.1%

BONUS POINTS 1030

Emergency Power  200 POINTS
Media Publicity 100 POINTS
Set Up in Public Place  100 POINTS
Information Booth 100 Points
Message to SM 100 POINTS
Educational Activity 100 POINTS
W1AW Field Day Message 100 POINTS
GOTA Bonus 80 POINTS
Electronic Submittal 50 POINTS
Social Media 100 POINTS

OVERALL POINTS - 8274 points

Here are some photos from the operation.



The GOTA screenhouse - I believe that is Ron WB4OQL



A view of Lake Robinson




Inside the GOTA tent - A TS480 set up for digital modes and an ICOM 706 fgor 6 meters

 

Operation now in full swing - Pete AG3R under the watchful eye of Dave K4SV



Last year's captain Rusty WU2T



Carl W4RCW on SSB



Dave K4SV taking a video



Howard K1SBI making QSO's



That is a CrankIR in the foreground near the lake which served as the antenna for the CW ops on 40m and 80m



Matt Case KG4MC standing in front of y home brew hexbeam



There is Dave K4SV/s Force 12 Tribander on a trailer mounted tower



Husband and wife team Vicki KS4VJ and Dave KE4EA



Howard and family.  That is his son Sammy

Getting Things Ready for Field Day

Plans for Field Day

3 antennas for CW station

3 antennas for the SSB station

The CW station will have this hexbeam - with 3 bands on it.   I obtained the weight on a digital luggage scale at 16.5 pounds.  

DX Marathon 2016 Scores - Made Top 10

Formula Class - 5 Watt
Callsign	Countries	Zones	Score
WG5G	225	38	263
IV3AOL	206	34	240
W8QZA	183	36	219
K4AR	179	34	213
ON6QRP	163	36	199
NY4G	165	33	198
DF5WW	154	34	188
IN3UFW	109	24	133
IK4UXA	93	22	115
EB3EPR	90	24	114
KI0G	85	23	108
K8ZT	79	27	106
GU4YBW	82	20	102
YB2ERL	71	27	98
W4ER	65	23	88
G8JQW	44	9	53
PY1CMT	36	14	50
W6OGC	34	11	45
K5ATG	17	11	28
PY4WJ	5	5	10
PU5YSV	2	2	4

Making a Hexbeam Air Dielectric Coaxial Centerpost Feedline from Scratch

Most everybody I know has an NA4RR or K4KIO centerpost - myself included.   I have used a K4KIO centerpost in the past and had been happy with it.  I then decided to build center-post out of PVC pipe with the coax connections inside to prevent water from making contact with the foam core insulation and ruining the dielectric insulation between center conductor and shield.   I used it for about 6 months and decided to make a change to NA4RR's version and this has been on my home station for the better part of 2 years.  I did some research and captured the following equations to construct the equivalent of a 50 ohm (or as close to it) coaxial feedline.

For round coax, make the inside diameter of the outside conductor 2.302 times larger than the diameter of the inside conductor.

If the shield is square, and the inner conductor is still round, make the inside length of one side of the shield 2.134 times larger than the diameter of the inside conductor.

The derivation is as follows:

A coaxial transmission line has some inductance per unit length L$L$, and some capacitance per unit length C$C$. The conductors also have some (very low) resistance R$R$, and the dielectric has some (very low) conductance G$G$. Though it's important to note that these properties are distributed throughout the entire length of the transmission line, lumping them all together we can model a transmission line as:

The characteristic impedance is then:

The characteristic impedance is then:

Z0=R+jωLG+jωC−−−−−−−−√$$Z_0=\sqrt{\frac{R+j\omega L}{G+j\omega C}}$$

where:

• R$R$ is the resistance per unit length, considering the two conductors to be in series,
• L$L$ is the inductance per unit length,
• G$G$ is the conductance of the dielectric per unit length,
• C$C$ is the capacitance per unit length,
• j$j$ is the imaginary unit, and
• ω$\omega$ is the angular frequency.

If we assume a good conductor and dielectric, then R$R$ and G$G$ are negligible¹. The equation then simplifies to:

Z0≈LC−−√$$Z_0\approx \sqrt{\frac{L}{C}}$$

For round coaxial transmission lines, we can calculate C$C$ and L$L$ as:

C=2πϵ0ϵrln(D/d)

L=μ0μr2πln(D/d)$$L=\frac{{\mu }_0{\mu }_r}{2\pi }\ln (D/d)$$

where:

• d$d$ is the diameter of the inner conductor,
• D$D$ is the inside diameter of the outer conductor,
• ϵ0${ϵ}_0$ is the permittivity of free space, approximately 8.854⋅10−12F⋅m−1$8.854\cdot {10}^{-12}F\cdot m^{-1}$
• μ0${\mu }_0$ is the permeability of free space, approximately 1.256⋅10−6H⋅m−1$1.256\cdot {10}^{-6}H\cdot m^{-1}$
• ϵr${ϵ}_r$ is the relative permittivity of the dielectric, and
• μr${\mu }_r$ is the relative permeability of the dielectric.

Putting these together and simplifying we get:

For an air dielectric, ϵr${ϵ}_r$ and μr${\mu }_r$ are so close to 1 than you can further simplify:

Z0≈59.96ln(D/d)$$Z_0\approx 59.96\ln (D/d)$$

You can also see that only the ratio of the diameters of the conductors are relevant, so it doesn't matter what units of length are used, as long as they are the same.

We can solve for D/d$D/d$, and set Z0=50Ω$Z_0=50\mathrm{\Omega }$:

56.40ln(D/d)ln(D/d)D/dD/dD/d≈Z0≈Z059.96≈eZ0/59.96≈e50/59.96≈2.302

So in my case - 0.625" diameter and 1.5" diameter aluminum tubing are available from DX Engineering.  If I use average wall diameter for the outside tube and the OD of the inside tube, the ratio of D/d in this case is 2.3  which is really close. 

My plan is to put fiberglass sleeves around the bolts to insulate it from the outer shield along with nylon washers on the inside and outside.  Here is a scaled picture below