Fig. 1 - Single yagi at 16-feet on temp mast
Fig. 2 - Dual yagis stacked horizontal in Vert Pol
Fig. 3 - Dual yagis stacked horizontal in Horz pol
Either Fig. 2 or Fig. 3 will be considered for 2025 installation (Tower installation, delayed).
August 20, 2022 Update:
Brandon-KL7BSC drove down from Anchorage to help me dismantle the broken 6m array and tower, today. We were able to remove the rear
half of the 6m LFA yagis and a section of boom with the 5th element. I had removed the 2m yagis with 8-elements intact (were originally
11-element yagis). 432-18 yagi lost two front elements and front section of boom (might be able to purchae replacemnts from M2).
900 MHz 33-loop yagi and 1296 45-oop yagis survived. Most of the aluminum support structure is bent but a few pieces survived.
Azimuth rotator base bolts came loose and rotator might be bent. Main shaft had to be cut in several places to remove it from tower
top. That tower section might also be bent so pointed top might have to be removed to reuse. Otherwise four sections of Rohn-45g are
intact and reusable. Here is a photo of work underway:
August 8, 2022 Update:
QRT 6m EME!
40-foot Rohn-45 tower collapsed in high winds after guy screw-anchor pulled out. Broke tower leg at concrete base and bent other
two legs so tower is on ground and 6m array is smashed. I mght be able to cut boom at rear half of antenna to make 5-element
antennas (10.65 dBi not enough gain for eme). 30-foot of the tower looks OK but bottom section legs are bent. Will decide next year whether
to consider putting tower back up (36-foot).
December 15, 2021 Update:
Local noise continues to hamper making eme contacts. MR is impossible to operate but MS is often quieter enabling contacts. Also,
elevation actuator fails* at temperatures below 32F (0c) so operation only on horizon which restrics use to either MR or MS.
But am adding contacts; see my 6m eme Log.
*elevation actuatore will be replaced next spring (March/April?).
October 12, 2021 Update:
Repaired 2nd yagi SWR and connected both to 2-way splitter. SWR 1.2 from 50.150-50.350
Now fully QRV for 6m-eme using Q65A or JT65A.
August 29, 2021 Update:
First test on the Moon. Running only one yagi with Q65A-60 second period at 1000w for two hours trying with Drago-S59A.
But no signals seen by either of us. He had to QRT before Moon reached 8-degrees (max ground-gain) so inconclusive.
I was operating in from 266-298 degrees azimuth which has trees in the path. Moon was visible until elevation 10.
I think all my previous 6m eme contacts were near Moon rise in the east, so that might be a factor.
New Meanwell RSP-3000-48 switching PS ran 46V at power peaks; cheap ammeter indicated well over 50A. PS and amp ran cool
so this was a good test. I saw no reflected power with 1000w Bird element (so SWR is low).
I will try again weekend of Sept. 4/5 when degradation is lower on 6m.
August 23, 2021 Update:
Replaced HP PS with new Meanwell RSP-3000-48 switching supply and made a few modifications to wiring the Control Panel.
Tests well with 49.6 vdc (no load). See the new diagram.
Next will test the Harris Amp into a 500w load and then the antenna. Later, when completed, the Harris will be replaced
by a 1200w W6PQL HF/6m amplifier.
August 18, 2021 Update:
Man-lift rented and azimuth rotator repaired by installing new bolts, set nuts, locktite, and 3/8 inch shear bolt
installed. Both LMR-400UF azimuth wrap cables were pulled apart; also the elevation encoder cable. Elevation
actuator power cable is abraded (wrapped with electric tape). SWR problem with one yagi so coax line was installed
to bypass 2-way divider. New elevation encoder cable installed.
QRV with one yagi (12.9 dBi). Probably ground-gain will be required to make eme contacts. Per the EZNEC analysis
(shown below) that will peak at 8.4 degrees elevation with 5-dB added gain; secondary lobe at 25-degrees only about
1-dB improvement over free-space gain so elevating antenna may work as well.
May 4, 2021 Update:
Problem with azimuth rotator holding the mast in wind. I will drill a large hole for 7/16-inch bolt to pin the mast and will add
locking nuts to the eight 10mm mast holddown bolts (with a little Locktite) to prevent loosening in wind caused vibration.
Tested Harris Amplifier into 500w load at 8w drive producing 600w output, so appears functioning OK.
Windmilling of the 6m array apparently has stressed the coax lines wound arround the mast causing high SWR (possibly failure of connectors),
so that will also require repair/replacement of LMR-400UF cables. A 36-inch actuator wiil be substituted for the 24-inch currently installed,
and some other maintenance done using a rented 45-foot man-lift bucket (est. two weeks as weather needs to be calm for use).
August 24, 2020 Update:
Completed removal of T2X rotator and installation of new Alpha-SPID RAK. The digital azimuth encoder was also installed. Coax cables
rerouted so there is adequate slack for rotation and replaced a water-damaged coax jumper in the 2m coax line. Cables dressed and
tywraped to tower leg down to ground level. Thrust bearing was not installed at this time as it needed some refinement in design.
Took about three days using a rented man-lift to access work at 40-foot above ground. Antenna rotates freely
and elevates to 45-degrees (end of travel for the actuator arm) which was a mistake in design as local Moon reaches 58-degrees at max.
Some minor wiring and jumper cables need to be done, plus testing Harris amplifier after long period of disuse, before fuly QRV for
eme and meteor scatter operation.
December 14, 2019 Update:
The azimuth rotator became stuck with array pointed SE (approx. 130-degrees). Attempts adding a couunterweight to reduce friction
were unsucessful, so decision was made to purchase an Alpha-SPID RAK worm-gear drive to replace the T2X "Tail Twister" rotator.
With this it was also decided to add an azimuth digital encoder to use the RazTrack System as the new rotator has no azimuth
potentiometer to read and pulse position readout is considered unreliable for eme.
The T2X was repaired by CATS Rotor Service for $151.00 plus two-way shipping of $135. Four gears and drive shaft were damaged
and replaced. Original cost was $719.95 from DX Engineering plus shipping. My total investment is over $1,000 which I recouped $400
by selling it to an Alaskan ham. MFJ now owns Hygain which makes the T2X
Also a thrust bearing constructed from six roller bearins will be installed.
December 1, 2018 Update:
Dual-Array of G0KSC 7-element LFA yagis with az-el was installed on the 39-foot tower.
G0KSC 2-way divider was coupled to 30-foot of ADA7-50 1-5/8 inch cable down to ground
level which will be connected to 50-foot of LDF5-50 to the ham shack. Preamp and TR
relay connected to ground end of the ADA7-50 cable. Photos soon.
Array lifted to ten foot for tuning Sunset Sept. 7, 2020
Array on ground awaiting Array installed on tower
lift by boom truck
Tests of az and el plus cable connections to ham shack remain before being QRV for eme.
March 16, 2018 Update:
After seeing EXNEC4+ comparison diagrams provided by "Pop", YU7EF, I came to a decision that a better antenna
For 6m EME was desirable. I chose two G0KSC LFA2 HD WOS 7 element LFA yagi with HD 9.5m long boom (12.9 dBi)
Stacking 7.4m horizontal produces 15.75 dBi gain in free space (est 20.72 dBi with ground-gain at 10m AGL).
Central States 2018 Presentation
The yagi will be 32-feet above ground which is close to 10m.
I will sell my two 6M6UW modified KLM 7LP yagis (see my For Sale page).
Aug. 25, 2016 Update:
Completed wiring of control panel to HP 50v switching PS and fabrication of fan assembly for the
Harris amp. Initial testing results using Bird43 meter 5A, 50A*, and 1000A elements; antenna as load:
In Rx mode with voltage applied to the Harris amp: V = 51.2 and current under 1 amp with
fans running. Red LED indicator is on steady.
Mode RF drive V I Power out Indicator
Tx 0w 49v 12a 0w Green
Tx 1w 49v 19a 100w Green
Tx 2w 49v 24a 190w Green
Tx 3w NA 28a 250w Green
Tx 4w NA 31a 340w Green
Tx 5w NA 33a 390w Green
Tx 5w* NA 36a 480w Green
Tx 7w* NA 43a 650w Green
Tx 8w* NA 44a 700w Green
Tx 9w* NA 48a 850w Green
Tx 10w* 48.6v 49a** 900w Green
** HP PS full output is 50 amps. K3 driving Yaesu FL6020 linear amp at 0.7w for 5w output; 1.8w for 10w output.
* Bird 50A shows 0.5w lower reading than 5A element for 5w RF level.
Harmonic filter under construction.
I built the harmonic filter from QST article: "A High Performance, Low Cost 1.8 to 54 MHz Low Pass Filter"
(Bill Jones-K8CU, Nov. 2002 pp 34-38). I'm hoping to get permission to link to the article or obtain reprint file.
I enclosed my filter in a 6-3/4 by 4-3/4 by 2 inch diecast aluminum Hammond Box and used high quality Teflon N
connectors. The five pole filter is constructed with two capacitors made from 0.032 inch brass plate insulated by
1/32 inch Telfon sheet. Three coils of 1/8 inch copper tubing are in series between connectors with two capacitors
to ground. A small adjustable capacitor of brass plate and copper flashing permits tuning for best SWR (1.15) and
injection loss is almost not measurable. I had to short one turn of L3 to bring SWR minimum up from 35 MHz to
51 MHz.
2nd Harmonic rejection is -55 dB at 100.400 MHz (98-MHz is frequency of the max reject >60 dB).
Measurements were done using a HP signal generator at 0dBm and a HP141T/8554L Spectrum Analyzer.
W6PQL Dual Directional Coupler for 50-MHz for 1000w was purchased and installed in 2.75x2.75x2.00 inch
aluminum chassis with N-connectors for RF and ferrite beads and 1000pF feedthru caps for coupling out the
Fwd and Rev dc voltages. These will be fed to a surplus SWR Panel meter and logic made by Telewave.
Adjustable pots will be used for setting appropriate levels to the meter from the directional coupler.
Logic board has shutdown relays for excess reverse power plus audible alarm and LED indicators.
This will replace using the Bird43 power meter for monitoring RF output of the Harris amplifier.
To get a reading on the Telewave meter the 27-dB pi-attenuator was lowered to 24-dB which provides 1.7 vdc
driving the meter to display 90w for 900w. On reflected power 100w displays as 200w with 0.5vdc from
the directional meter. DC output from directional coupler is passed thru two variable resistors to adjust
the display and providing fixed load to the detectors (10K and 3.2K, respectively).
Jan. 2016 Update:
Purchased Elecraft HF/6m Linear Amplifier and sold Mirage A1015G amplifier.
Dec. 2013 Update:
Rohn-45G tower installation (photos):
December 12th the antenna was finally installed. Initial testing shows excellent SWR from 50.110 to 50.260 MHz.
July 2013 Update: One of the 3-element 6m yagis was installed on tower#2 side-mounted at the 22-foot level and pointed in a fixed direction of az=130 to cover SE Alaska and the West Coast of the US. This antenna will be used for monitoring for openings on 6m and for working stations to the south during local nets, photos:
June 2013 Update:
The 6-element yagi sustained damage last winter breaking two center insulators.
It has been taken down along with the push-up mast. A 20-foot Rohn-45 tower will
be installed to replace the mast and be fitted with a Ham-IV rotator.
June 2011 Update:
The 6-element 6m yagi installed, June 21, 2011.
April 2011 Update:
Thanks to a kind donation of a 12w/1100w sspa for 6m, I am proceeding with installation of 6m EME.
For a thorough explanation of conversion of Harris Platinum TV amplifiers to 6m operation go to
http://www.bigskyspaces.com/w7gj/HarrisAmps.htm
Thanks for cash contributions from Kerry, G8VR and Fred, G4BWP which went toward acquiring 75-feet of
LMR-600 feedline and the antenna.
I've ordered a HP 226519-001 50-volt, 50-amp switching power supply from e-bay for $30.98 (including shipping).
KL7FZ has several 44-MHz KLM 7LB log-periodic cell 7-element yagis that can be moved up to 50.2 MHz.
I ordered one from him (they were for a state-run meteor scatter network and he has several
new-in-box antennas). I have two sections of 7/8 Heliax cable to provide a 90-foot feedline
but will need about 50-foot LMR-600 to complete the run. Initially, I am going to mount the 30-foot
long yagi on a guyed Rohn push-up mast at about 22-feet without a rotator. I will provide cords off
both ends of the 30-foot boom for steering. The antenna will be horizontal and fixed elevation on the horizon.
I will try operation with the preamp in the shack but the TR relay and preamp may get moved to the antenna.
I have decided to modify the antenna to a six-element yagi design offered by Mike, K6MYC. This will eliminate
one of the log-periodic driven elements Mike has dubbed the design as 6M6UW. The yagi will exhibit 13.1 dBi
gain with 21-dB F/B ratio on a 30-foot boom. This is close to the performance of the M2 6M7JHV.
This will also be useful for 6m meteor scatter!
2010 Update I have a new Elecraft K3/10 which runs 8w on 6m. An ARR P50VDG 6m Preamp was added for improved Receiving on 6m. July 2010 I bought a Mirage A1015G amplifier which outputs 125w with drive from the K3/10. The lower 6m yagi is not loading so unusable and will be removed. The upper 6m yagi works well. November 25, 2008 Update HF triband yagi, two stacked 6m yagis*, 222 and 432 antennas installed on the extended 50-foot tower. All antennas were installed with the tower layed over to ground, and later raised with a boom-truck. Coax cables were run to the 6m yagis, HF yagi, and 432 yagi. Later plans are to run 7/8-inch Heliax to the 222 and 432 antennas (selected with a coax relay). *Note: the 6m yagis were removed in summer 2012.
January 14, 2007 Update
We decided to temporarly install a 6m yagi, 432 yagi and two 222 yagis on 30-foot of tower. This will be increased
to 50-feet with the HF yagi and second 6m yagi being installed.
