Base antenna for 446 mhz help needed

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WARLOCK
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Base antenna for 446 mhz help needed

Post by WARLOCK » 27 Oct 2017, 18:25

just bought and received a base antenna for PMR446 Mhz, e/bay item number 302491369589 from stanislavpalo130 when i tested the antenna i find there is a short between the inner section and outer section of the coax cable should this be so ???

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Re: Base antenna for 446 mhz help needed

Post by paulears » 27 Oct 2017, 19:11

I bought one from him too, and it's sitting here and I can confirm it's a DC grounded antenna, so the short is correct. Mine actually works rather well on 433 and 453 too! Mine is 1.17 VSWR at 448.1MHz at it's best on the analyser.

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Re: Base antenna for 446 mhz help needed

Post by gmham » 28 Oct 2017, 12:46

So if it's showing it's lowest vswr on 448.1mhz can I ask what it's showing on it's intended design freq off 446mhz ?
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Re: Base antenna for 446 mhz help needed

Post by paulears » 28 Oct 2017, 14:17

1.2 I spotted these about a year ago and have had a UHF high band one and the 446, and the tuning is quite sharp, it's not got much response at any other frequency, then suddenly takes a dive right down. It's handy for 449MHz too. I tried to make something very similar, and found that inside mm accuracy was critical at UHF, and while with wideband designs it doesn't matter.

EDIT - I've just spotted that I mixed them up. The ones I have are these ones 302501691331 (in 446 and 453 versions)
Which is a half wave design, compared to the 5/8th one this post relates to - mine of course is not tenable, being sealed in the tube, while the ⅝ version is.

He makes decent quality kit, and while I make a few myself, his are neater and surprisingly light!

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Re: Base antenna for 446 mhz help needed

Post by Admiral » 29 Oct 2017, 13:40

"DC ground coil for full static protection"

He put a clue in the listing, you will still need to make sure you ground it though. Plus, it has an N connector, so make sure you get one of those on the end of your coax as adaptors outdoors will invite moisture and could be lossy if they are ten bob Chinese things.
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Re: Base antenna for 446 mhz help needed

Post by Steve B » 29 Oct 2017, 16:18

WARLOCK wrote:just bought and received a base antenna for PMR446 Mhz, e/bay item number 302491369589 from stanislavpalo130 when i tested the antenna i find there is a short between the inner section and outer section of the coax cable should this be so ???
I love that guy's antennas. They are good ****. They work on principles of gamma match magic. Bought a yagi from him a while ago and have made 100+ mile contacts with it.
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