Making Extension Mast with MORAD Stanchion and Adaptors

[jimh]

On extension masts: I discovered that I could make my own extension mast using components from MORAD. The mast would be composed of three parts:

• a base adaptor, M87 ($40); this threads onto the typical ratchet mount, and mates to a 1-inch stanchion
• a 1-inch stanchion, available in two and five-foot lengths: V2 ($30) and V5 ($50)
• a top adaptor, the M89 ($30), which mounts to the stanchion and then provides a threaded 1 x 14 coupling for antennas with that type base to mount to

The extension mast created would be all metal, and would have a generous opening at the base for the antenna transmission line cable and connector to exit. The assembly of the threaded components could be done before passing the transmission line through the mast, so the tedium of having to turn the coaxial cable in synchronism with the threaded of the mast is eliminated. The total cost is not crazy: A two-foot mast is $102, which is a bit expensive, but a five-foot mast is just $30 more at $122. Those are MSRP prices from MORAD. MORAD is not sold by the usual big marine distributors, so street prices are usually only at a small discount (maybe four-percent) from MSRP.

In contrast the Shakespeare 4008-4 four-foot fiberglass extension mast retails for $195. That is much more expensive, but typically the Shakespeare products are sold at substantial discounts by big marine distributors. The street price for a 4008-4 may be around $85.

The advantage of the MORAD make-your-own extension mast approach:

• all metal thus excellent strength and durability
• excellent connector clearance for transmission line
• wide range of heights available by cutting metal stanchion to custom length

Positioning the antenna transmission line inside the metal extension mast may also help avoid antenna currents from flowing on the transmission line. Antennas currents flowing on the transmission line often cause problems with pattern distortion, interference to other devices whose cables are near the transmission line, and may permit ingress of noise into the antenna and thus into the receiver.

In the event of damage, the extension mast described above made from three separate components would be unlikely to need complete replacement. The stanchion tube might be the only component that would need replacement.

[jimh]

In the five years that have elapsed since posting this topic, the prices involved have increased somewhat. The most recent prices for constructing an extension mast using the MORAD stanchion tubes and adaptors are given below.

M89 is now $37. This mounts to the top of the stanchion pipe and creates the 1 x 14 thread stud for attaching an antenna or antenna mount that needs to thread onto this stud.

Fig. 1. The M89 adaptor that mounts atop the 1-inch stanchion tube, and creates a threaded stud for attaching the antenna.

M89.jpeg (22.72 KiB) Viewed 318 times

V2 and V4 1-inch stanchion tubes are now $45 and $59 respectively. These stanchions fit into sockets on adaptors at each end and are retained by set screws.

Fig. 2. Aluminum stanchion tubes.

stanchionTube.jpg (15.77 KiB) Viewed 318 times

M87 is now $48. This adaptor has a bottom socket that can thread onto a 1 x 14 thread on a typical ratchet tilt-mount. The upper end has a socket to accept the 1-inch stanchion and hold in in place with set screws. This adaptor has a side hole to allow the transmission line to exit.

Fig. 3. The M87 adaptor, threaded onto a typical mount, and with 1-inch stanchion tube installed.

M87.jpeg (27.56 KiB) Viewed 318 times

As a result of the changes in price, to build an extension mast with the 2-foot stanchion tube now will cost $130. To build an extension mast with the 4-foot stanchion tube will now cost $144.

Note that you need to specify the color preference when ordering. Typically the components are available as gold-anodized, white, or black.