![Trailer with towers mounted and 70cm EME array](/images/phocagallery/amateur-radio/dxpedition-trailer/thumbs/phoca_thumb_m_20210731_180122.jpg)
The EME DXpedition trailer was born out of necessity for ease of setup with a minimum number of people.
When Frank NC1I and I first started doing EME DXpeditions again our first location was nearby in Connecticut. We used a 10-foot (3m) section of RG-25 tower with a flat top, Alpha SPID BIGRAS/HR AZ/EL rotor and a 2.8m TVRO satellite dish. We assembled all those components together on-site and then four people tilted it up - not an easy task! It was held in place with straps to tent pegs in the ground. It took a while to make it level enough for good tracking and we were always afraid of whether it would withstand high winds.
Trailer Setup v1.0
Bob KA1QFE came up with an idea to use his flat bed trailer with two towers mounted on it - one by the hitch to the vehicle with a winch on the top, which would lift and lower another tower on a hinge base located at the rear of the trailer - that tower would have the AZ/EL rotor and antenna. The trailer also doubled as the hauler for much of the equipment, including cables, generator, etc. This was used for quite a few DXpeditions including one of the Rhode Island trips and New Hampshire.
Trailer Setup v2.0
In July 2018 Frank and I noticed a trailer for sale not too far from his QTH - a new 2018 14-foot (4.3 m) Belmont trailer with solid sides, ramp and a wood deck. It had been used once for a trip from Florida to Connecticut. After some deliberations Frank purchased the trailer. By having a trailer dedicated for DXpeditions we would save KA1QFE from the effort of modifying his trailer with the tower mounts, etc. each time we wanted to do a DXpedition. We'd also be able to use the trailer to store all the pieces that will be used for DXpeditions.
Frank dropped the new trailer off with Bob KA1QFE who started on DXpedition modifications:
- Adding mounts for jack stands on the outside corners of the trailer for leveling
- Installation of a tower mounting plate in the front of the trailer for the winch tower
- Installation of a tilt-over tower mounting plate in the rear of the trailer for the antenna tower
- Tower top mounting plate for the winch with electrical wiring
As things go, we really didn't do too much more with the setup until the fall of 2019 when NC1I and I started working on the antenna mount. Frank had a shop fabricate a gusseted pipe welded to a flat plate that we affixed to the flat top section of tower. The plan was this would support the Alpha SPID BIGRAS/HR AZ/EL motor that we had previously used on DXpeditions.
Unfortunately the SPID AZ/EL motor on Frank's 4.5m dish ended up failing. To keep his 23cm home station on the air we took down the 4.5m dish and replaced the failed SPID rotor with the DXpedition rotor.
Trailer Setup v2.1
We never got on the air with the v2.0 setup due to a variety of factors, including the SPID failure. In the spring of 2021 we embarqued on some minor changes:
- Purchase of a Sub-Lunar dual axis SLS SDD3 Slew Drive for the new DXpedition rotor
- Using a taller tower for the winch system for better lifting angle
- Using a shorter tower for the antenna system
- Installing eye bolts and using steel cable with turnbuckles for tower guying
- Modification of the winch electrical connections making it more waterproof
By the end of July 2021 we had the first test of the system and we were more than pleased with the outcome.
Additional articles:
Slew Drive Setup
70cm Polarity Mount
GHE Controllers in a Box
First test of the Sub-Lunar slew drive with the Green Heron Engineering RT-21 AZ/EL controller and appliance PC running PstRotator.
We have attached the SDD3 Dual Axis Slew Drive to the top plate that will be used on the DXpedition Trailer. Both motors are connected to the GHE RT-21azel rotor controller which natively supports this Slew Drive.
We purchased a fanless Intel based appliance PC running Windows and the PstRotator software for sun and moon tracking. The YouTube video shows our first bench test of this setup in the garage - needless to say, everything went very smoothly!
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