Radio Discussion Community

Just to update you all, My Sirio Silver Megawatt 4000 arrived this morning with the S0239 Roof mount, Just finished the install and woohoo i have an SWR of 1:1 , i think it had something to do with that tank whip, i will order another one but for now im reallly happy with the sirio just made contact and had a super convo with a Guy in Dublin (mobile)

Me thinks these tank whips aint that good!

i am having the exact same problems, even using a huge steel ground plane.

To be honest there is not much that can go wrong with a tank whip?! It is literally just a quarter wave length of steel?

Unless there is no connection between the top and bottom section? Or the overall length of it has changed somehow I cant see what could be causing problems?

Let me know what you find out though because we do sell hundreds of the things and no one has had a problem with one before

Andy

i think it will be fine once i have got a suitable groundplane.

Ill let you know mate.

I bought a new mount and radial groundplane and hooked it all up and connected a 9ft lenght of coax to some steel and put the antenna on that!

my SWR is now gone from red to just over 1.0

Tank whips are BIG so every little helps when it comes to improving groundplane, get a radial from andy.

the ground plane is about the only thing that can go wrong with tank whips

the sirio silver is a great antenna

I have Tank Whips SWR @ 3 accross the 40 UK channels - My short Springer with a Tristar swr in @ 1.1 across the 40 with the same mount.

However, I am using a smallish mag mount - I am wondering if the Problem with Tank Whip - is caused by the small Mag mount not giving enough ground pane?

I am thinking either a bigger Mag Mount or a body mount....

Any opinions welcome??

Already tried the Radial kit ... It didn't make any difference.

Maybe time to get the drill out....

Has anybody had any success (for static use) with a Tank Whip on Triple Mag Mount? (or any kind of mag mount for that matter). Do mag mounts give enough group plan?

yes would work with a triple magmount static

I have had no end of trouble getting the SWR down on my Tank whip to an acceptable level. The biggest Magmount my local CB shop could sell me helped a little....

Then, I tried running more power through it - @ 4w I was getting 2 plus - If I run 10-100 watt through it it drops down to 1.1 Yahoo!

Does this make sense? - Was wondering if its something to do with more wattage causing the mount to give a better groundplane.

If the tank whip is 9ft, it is about 6" too long. After checking that you have continuity between the centre of the PL259 antenna plug and the whip. Infinity (open circuit) between the inner and outer of the coax and continuity between the outside of the antenna plug and the vehicle body (if using a magmount, look for continuity between the outside of the antenna plug and the magmount body).
Once you have done all the above, cut 6" off and check the SWR on Ch 40, Ch 20 and Ch 1. You should see that the best SWR is on Ch 1. Trim the antenna 1/2" at a time, while checking the same 3 channels after each cut. Stop when you get to the point where the lowest VSWR you can get is on Ch20.
If you are using the tank whip on a mast, cut four wire radials cut to about 8'6" and slope them down at 45 degrees. Tie them off with fishing line.
I am running the above set-up but using a 1/4 wave Shakespear antenna on the mast. I have just been talking to somebody in Royston, which is about 25 miles from me.