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Looking for SG-Labs mast mounting inspiration

So I have my 1.2Ghz SG-Labs transverter and SG-Labs amplifier and I would like to mast mount the setup as most of the summits I go to have at least some trees.

I am looking for some inspiration on mast mounting the setup. Any ideas folks?

73,
Tom, N2YTF

Hi Tom,
Well you could possibly use the bottom two sections on a telescopic fibreglass mast. You would have to use a locating pin in the ground at the bottom and three guys just under the equipment box. You could until recently buy ex military strong fibreglass mast sections that fitted together. They were advertised in CQ magazine IIRC.

An alternative arrangement would be an Al mast. Maybe in two 1.5 m sections with a dowel to join them. The Al mast would be less prone to crushing than a light weight telescoping fishing pole mast.

Some folk in VK use a camera tripod to carry small dishes and UHF yagi as well as the transverter.

73
Ron
VK3AFW

Some folk in VK use camera tripods. In fact camera tripods are in use by VK1AD, VK1RX, VK1DA, VK1AT and VK1MCW.

Check out my 23cm/13cm blog posts:

Loads of options Tom, just use your imagination and the inspirations & ideas will flow.

73 Andrew VK1AD

Tom,

I’m assuming your IF rig for the transverter is at the base of the mast with you. In which case, be careful about radiating a significant signal on 144MHz from the long IF cable.

73 Andy

Hi Andy,

Hadn’t thought about radiating from the IF-Transverter feed line----I guess I figured that as long as there was a good match I wouldn’t radiate…is this a problem? How do I minimize it? Coil the feed at the transverter end?

73,
Tom

Yes. It’s probable some early 2m DX contacts were actually 10m. i.e. 10m IF to the TVTR leaking and being picked up at the remote end 10m IF. Also I know of one guy who was QRV on 23cms with a high level 2m IF and having a QSO with another local ham (20kms QRB) on the 2m IF. It’s only when one of them said “good to see you have fixed your 23cms station and are back on the band” that the other realised what was happening an clarity was achieved. So It does happen.

For my 13cms I mount the transverter at floor level and have a cable run to the antenna. Either RG400 (about 2db) or an LMR400 UF clone if weight is not an issue (about 0.8db). The simplification in mounting for SOTA operations massively outweighs the loss. And if loss is likely to be a real issue I take the heavier cable.

I don’t think that would help very much - even if the coax is matched well at both ends, there will be some leakage through the braid, rather than “common mode” current flowing along the outside (which could be reduced by coiling etc)

The problem can be minimised by using low loss coax which will have some combination of: close weave braid or double layer of braid or foil as well as braid.

Having said that, I think it is something to be aware of, rather than worry too much about.

On our field day site, I recently set up my SG labs transverter, with a couple of metres of RG58 feeding it from the FT817 at a power level of 0.5 W, to have a dabble on 23cm.

I had a (non scoring) CW contact with our 2m contest station which was about 300 yards away, but the signal level was nothing like enough to cause them a problem - they would have had a quiet word with me if it was :wink:
They were running 400W to a pair of 17 ele yagis, but although they were quite loud at my end (!) their signal didn’t cause me any problems either, beyond a few KHz each side.

Strictly back to topic, I mount my transverters (23 and 13) on the back end of the antenna boom, which makes for a nice short feeder, and also helps to balance the antenna against gravity and windage.
This is 23cm, where the transverter is in a waterproof box, which has enough room inside to coil all the cables for transport. They remain connected to the transverter which makes setup / take down a bit quicker.

This is the 13cm setup, not a great photo, but you can just see one of the transverter SMA connectors (for an external reference, unused) poking up at the near end of the boom. The transverter is attached with some thin rubber bungy cord, and the whole assembly is mounted on a camera tripod at a point between the transverter and the Yagi reflector, using a home brew saddle made of wood and paxolin:

(Beaming north from Long Mynd, lights of Shrewsbury in the distance)

Have fun, Tom,

73
Adrian
G4AZS

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