No locating marks on Silver Rod antenna

Just had delivery of my 1/2 wave Silver rod and I'm trying to put it together,
there was no Information/instruction leaflet included,
the extending legs have no marks to indicate the length for clamping.

Is there a guide length I should put each leg into the other as a starting point?

There never is. Aim for an overall length of 18ft as a starting point. Then if you measure the SWR and it's higher on Ch1 than Ch40 you need to lengthen it, higher on Ch40 than Ch1 and you need to shorten it.

If the SWR is below 1.6/1.7:1 on all the channels you intend to use just leave it at that, there's little to be gained by trying to hit 1:1.

Thanks NC,

I've put the aerial up.
Before seeing the reply to my question I went with the overall measurement and worked out equal amount to insert into each section, and clamped each rod up with the jubilee clips, the whole antenna was then bolted onto a steel pole, I attached the coax and ran the feed back to my shack, connected to rig via swr meter and powered up the rig.

Boy was I shocked and Happy to see readings from the mid band and UK fm (26.965-27.405 and 27.60125-27.99125) give back readings of 1.2:1 max across all freq's.

All I need now is to get some copys/QSO's to prove it works. I've taken longer than expected to get this far today and have family duties to carry out so maybe tomorrow I'll be on the Air