The
products we have for sale are new items of radiocommunications equipment
and electronic component and accessories supplies. They have been
left "in stock" as result of the closure of our physical
shopfront.
These goods are
being sold on a first-to-order, first-sold basis. Earlier orders
(according to the email date/time stamp) will be processed first
for any items "in demand".
The product list continues to change as products codes and quantities
are confirmed in the physical inventory and as products are sold.
Note : We are no longer accepting credit card
details on-line - we are contacting customers by phone to obtain
these.
Depending on customer availability coupled with our part-time business
hours, shipping of orders may be delayed pending supply of this
information.
Notes
:(1) All prices are subject to change without notice and do include GST
but not freight charges. (2) Minimum web order value is $10.00, minimum
freight charge is $10 (ie. $20 total)
OzGear
Yagi Antennas
During 2006/2007, we manufactured
a range of yagi antennas for the 50, 144 and 432MHz bands but that manufacturing
ceased when we left our shopfront/workshop premises. We ended up with a number
of 2m and 70cm yagis left in stock and these will be available for purchase
on a pickup-only basis. At
this stage, they are being supplied without 4:1 half-wave coaxial baluns (as
the original production versions were) however most amateurs should be capable
of making up a suitable balun (taking into account coax velocity factor for
the coax type selected).
We still have several hundred
metres (yes, "hundred") of 12.5mm thinwall aluminium element tubing
and several hundred metres of boom tube stocks, plus many plastic element mount
mouldings so we have two choices.
1. We now sell antenna
experimenter packs containing enough tubing and mouldings so that there
is enough material to build several 70cm and 2m yagis. You do the hard work
measuring, cutting and assembling antennas to "your dimensions". If
they don't work, that is your problem, end-to-end. No information, no screws,
nuts, pop rivets included - just the tubing and the mouldings. Note that the
tubing is supplied in 5.5 metre lengths and we will not cut to shorter lengths
for you to transport home.
Antenna experimenter packs typically contain 20 moulded "sandwich"
insulators (see below), 40 moulded "wing" insulators (see below),
60 x 12.5mm black plastic element end caps, 3 lengths of boom material (5.5m
each) and 4 lengths of element tube (5.5m each). That's right, almost 40 metres
of aluminium tubing, in total, supplied in this pack - and that's enough for
a few good size yagis for 2m and/or 70cm. (The largest 70cm yagi built to date
is 24 elements on one of the 5.5m booms !) Note that the "plastics" part of the packs are done up by weight,
and not by count, so the final number of mouldings in individual packs can vary.
{ Sorry, we will not just sell the element insulators as these properly match
up with the boom tubing }
2. We can sell completely
tuned yagis for the 2m and 70cm bands (sorry, no more 50MHz versions at
this stage) . Correct lengths, correct spacing and very close to optimised designs
- as per our previous product range. The hard work is done by us and all you
have to do is put together the last couple of screws and rotate a few elements
in their mouldings. Needless to say, these yagis are priced on a size basis
and take into account the quantity of materials required plus some labour factors.
If we supply these yagis with our series of weatherproof baluns, the price goes
up further because the labour content required to accurately fabricate the baluns
is even higher.
Small versions
of these yagis can be simply mounted to a vertical pipe using a standard 100mm
x 8mm u-bolt with 90 degree V-block however we have found that it is easy to
overtighten the u-bolt nuts and flatten the boom tube - thus reducing its tensile
strength. As a result, the yagi can "spin" on the mounting tube as
additional stresses are encountered during high wind, causing more flattening
of the boom tube. The solution to that is to use an adapter mounting plate consisting
of 3mm thick bar plus 4 x 100mm x 8mm u-bolts / v-blocks and this method is
recommended as standard practice on all yagis with boom lengths of 3.0m or greater
.
We are not going
to list these yagis or experimenter packs in our webshop - it is a case of emailing
a request for info about which products we can supply either (a) immediately
or (b) after local manufacture (and inherent construction and tuning delays).
The typical list appears further down this page indicating current stocks and
pricing.
Please note that all available
products in this category will be local pickup only from Brisbane - no couriers
- and that your vehicle must be capable of taking the full length of the antenna
boom (or the 5.5m experimenter packs).
Pickups will be on an "as-arranged"
basis only. Casual "drop-ins" will be turned away.
Element
mountings & tube details:
The boom tubing is
a thin-wall aluminium extrusion, flat top & bottom where the matching
moulded element mounts attach.
(Note that the tube in the photo at left has not been de-burred)
The boom tubing is
supplied in 5.5 metre lengths but wall thickness has never been accurately
measured.
The aluminium element
tubing we supply is 12.5mm thin-wall tubing, also supplied in 5.5 metre
lengths. Again, wall thickness has never been accurately measured.
These "sandwich
brackets" are used to mount insulated dipole elements. Note that
additional thin-gauge shorting aluminium strips must be added and these
feed through the rectangular slot and the element retaining screw feeds
through holes on each side of the moulding. With this process, the screw
is NOT the only contact with the aluminium element tubing, thus ensuring
good long term connections.
These mouldings could
also be utilised to make up log-periodic style antennas for VHF &
UHF, a style that needs all elements insulated from the mounting boom.
The cross-over straps can then be set up to connect from one element mounting
screw diagonally across the boom to the adjacent element protruding mounting
screw.
(Note : The photo
shows 2 (TWO) sandwich mouldings)
These "winged"
element mounting brackets are used to attach typical aluminium tubing
pieces via centrally drilled holes. The slotted wings on each side hold
the aluminium element straight and in the correct position due to mounting
tension. The flat central section mounts to the flat structure of the
matching boom material.
For extra strength
on yagis for the lower end of the range, we usually sleeve the 12.5mm
tube with 16mm tubing and place the sleeve centrally on the element before
drilling the central element mounting hole. Even with the larger effective
tube diameter, these wing mountings still hold the elements in position
properly.
