Triax 2120 prime focus aluminium antenna w. polar mount

st1

st1

SMC-dish aficionado
Messages
2,806
My Satellite Setup
Mostly SMC dishes pointing at 28.2E
My Location
Nordsjælland, Denmark
New addition to dish collection: Triax 2120 prime focus w. polar mount.
The little-brother of the 2140, but this time with what seemed to be original feed-horn.

Triax 2140 prime focus aluminium antenna w. polar mount

Was expecting some slight damage (sellers pics didn't give much away, but I sensed that this antenna might have seen some hard handling).

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Picked the dish up today, and indeed it does show some bending damage to parts of the rim, and therefore also to the shape of the reflector.
May try to straighten it, but then again, may not depending on the performance.

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Polar mount is identical to the 2140, but this one is more worn.
The powder coating is peeling, but luckily the mount is also galvanised, so most (but not all) rust is bolts and nuts.

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What to use it for?
TBH, no firm idea right now. I have too many 120 cm dishes to make this one special, particularly now it's a bit hammered and bruised.

But something may come up... new PF/PM dish at the holiday cottage??
 
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st1

st1

SMC-dish aficionado
Messages
2,806
My Satellite Setup
Mostly SMC dishes pointing at 28.2E
My Location
Nordsjælland, Denmark
Just needed to see how the 2120, in the state it's in, does 28.2E.
Took down the 2140, and adjusted the test-bench to fit the 2120, and smacked the dish up.
LNB and adjustments in a short while...

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It is clear from the dents and bruises to the rim that the dish has taken some abuse.
Will be interesting to see if it still gets the job done, as the seller claimed...
 
st1

st1

SMC-dish aficionado
Messages
2,806
My Satellite Setup
Mostly SMC dishes pointing at 28.2E
My Location
Nordsjælland, Denmark
Polar mount: Should call it Rusty or Dusty...

Closer inspection reveals the mount to have been more exposed to the elements than the 2140 mount.
As can be seen in seller's pics above, the dish was mounted just above ground in a flower bed. Lots of dirt has made it's way onto the dish and mount. Surprisingly, it seems a lot of dirt has also made it *into* the dish, as I can hear a lot of debris moving about inside the drum that's bolted to the reflector.

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Also, the mount has been modified at one point to fit over a small pole rather than in the wall-mounting bracket it was designed for.
Three nuts has been welded to the mounting tube, clearly at non-equal distances along the circumference of the tube.
The bolts and the nuts were extremely rusty, and took 15 minutes + WD40 to release when I picked the dish up.

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The extra nuts and bolts makes a mounting of dish more cumbersome.
Still fits in the testbench, though, so something similar must be used in a "real" installation.
 
st1

st1

SMC-dish aficionado
Messages
2,806
My Satellite Setup
Mostly SMC dishes pointing at 28.2E
My Location
Nordsjælland, Denmark
Time to try some reception (fringe, of course).
Fist fitting an LNB. Dug out the Inverto Black Pro Single C120.

In contrast to the 2140, this dish came with what I hoped was the original feed-horn.
This, therefore, is what the LNB mount should look (not like the "40mm-adapted" version on the 2140).
@Spiff can you confirm this is what your LNB mount looks like?

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Tried to figure out how to mount LNB; should the LNB holder plate go in-front or behind of the feed-horn/LNB? Settled for "plate before feedhorn". (This also ties in with pics on the 'net.)
Had to mount the feed-horn upside down, as the cable clashed with the plate and feed support arms.

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Interestingly, the seller had the plate *between* the feed horn and the LNB, which is not ideal as the waveguides then have a gap between them. Nevertheless, he claimed it worked very well.

Dialed 10773H into the meter. Move the dish about a bit (Azimuth) until I got something, then adjust elevation to get proper signal. Tadah - BBC1 London coming in clear and faultless. 10 minutes of optimising brought consistant signal.
Signal strength around 68.5 dBuV, C/N at around 7.8 dB.

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So...
A few thoughts:

1) The dish is clearly warped. But nevertheless delivers 28.5 spor-beam reception north of Copenhagen. Wonder if any "de-warping" would make a significant difference?
2) Polar mount is quite dilapidated. Althogh refurb should be easier than a rusty CM polar mount - perhaps it's not worth it?
3) Yet another 1.2m dish - maybe I would get more mileage out of the others?
 
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