Kestrel Calypso Antenna question

[Mudslinger]

I had a go at SWRing the antenna today. I managed to get a good SWR over half of the Mid band and up to channel 40 on UK40, and that was with a bit of cutting.

I don't think it would be possible to get a good SWR on the 80 channels plus the bit in the middle.

Not made any contacts on it yet...

[lambrettadave]

Good luck with the testing

[scanhermit]

Aye, t'will be interesting.

[Hair Bear]

Right then, had a bit of a chance to play.
The set up - Rotel 240 shop standard cb27/81, rg58 coax running to a dv type stud mount through the center of the car roof. The antenna I currently use is one half of an integral spring mounted center loaded 'twin trucker' set, if that makes sense(?). SWR around 1.6 across all 40 channels. Using a known homebase with a loft antenna (make unknown) as a reference gives the homebase a s9+ r5 signal at 5 miles.
Set up the Calypso on the red band, swr just under 3. Set up on the black band, swr 1.8. Couldn't get it any lower as the whip needed to be a little longer than was provided. Call back to the home base from the same point s8 r5. When I find a piece of suitable spare whip I'll try giving it another tune and try again.

[scanhermit]

Is that "the existing mobile antenna gives S9+ R5 to the base antenna at 5 miles and the Calypso gives S8 R5"?

[Hair Bear]

Yes, but at the moment the Calypso has a higher swr due to lack of whip length. And that should read 'swr 1.8 on the black band'! I'll go back and edit that...

[scanhermit]

That doesn't sound a bad result - I can't get S8 at 5 miles to a base antenna with my PNI antenna, which is more than a foot longer than the Calypso.

[Hair Bear]

For a bit of clarity, static mobile at 95m elev., homebase at 70m elev., highest ground on a straight line between 60m elev., and distance nearer 4 not 5 miles (sorry, poor guestimation!).

[Mudslinger]

I had the trim the whip on mine to get a decent SWR. I appreciate setups can be different (I was using a limpet mag mount) but to me it sounds odd that yours was too short.

[Hair Bear]

Not a complaint I've had before...

[scanhermit]

Now now, it's not the length of the antenna, it's what you do with it...

[Hair Bear]

Ahem,
Just in case my figures are wrong (good possibility) I'll revisit this soon and let you know.

[scanhermit]

Thanks, much appreciated. The Calypsos are all sold now but I do like to see real world experiment. I've linked the first of a series of mobile antenna shootouts from small to large below. The TLDR is that shorter antennas loaded higher than the base do well in hilly, undulating terrain whereas the big boys are best for hill topping. The full series is an interesting watch if you have the time.