Batboard

I know that for VHF, the whip is supposed to be 17", but i cant find any information on cutting it to 450mhz center

To the best of my knowledge (and an old PCTEL catalog), the MAT-MWB is simply the base for the MWB1320 antenna.
http://scm.pctel.com/jetspeed/fileserve ... atalog.pdf (see pages 29 & 106).

I couldn't see the cutting chart on the PCTEL website, but a quick search found this:
http://www.antenna.com/artifacts/MIS-Mu ... 2-RevA.pdf (VHF tuning in the bottom right corner, UHF in the top left).
A whip length of 17" is the example given for 150MHz, so I think your info is correct.

VE3HKB wrote:To the best of my knowledge (and an old PCTEL catalog), the MAT-MWB is simply the base for the MWB1320 antenna.
http://scm.pctel.com/jetspeed/fileserve ... atalog.pdf (see pages 29 & 106).

I couldn't see the cutting chart on the PCTEL website, but a quick search found this:
http://www.antenna.com/artifacts/MIS-Mu ... 2-RevA.pdf (VHF tuning in the bottom right corner, UHF in the top left).
A whip length of 17" is the example given for 150MHz, so I think your info is correct.

Thanks bro

alright I got few of these. two of them are cut at 15" mounted on the spring. the other is 18" without spring. same. coils... what frequency is the spring ones cut at 15"?

Hmm.
I have an identical PCTEL antenna, but the coil is labelled MATQW. Pretty sure that was a quarter wave antenna without the spring. I believe this was from an earlier manufacturer's design, SINCLABS, as the whip could attach to the coil directly, or with an optional shock spring. The spring (not originally attached to the coil) on mine is approximately 3-1/4" in length, so I would assume it would reduce the whip length accordingly.

Traditionally, if faced with an unknown antenna, I would go long, and trim (shorten) using a wattmeter until I reached minimum reflected power.

I'll see if PCTEL has any answers, as I think both the MATQW and MATMWB are the same item.

Well, some information.
PCTEL has confirmed that the MATQW and the MATMWB are the same item, a simple non-loaded (no internal coil) base. It is used on about 50 different antenna variants, so it's hard to say what every possible version was. The catalogs list the bases and whips as replacement parts for the models available in that year.

The spring was standard on some models, and optional on others.
If you look through a PCTEL catalog, if the antenna part number ended in (S) it was available in two versions, one without and one with the spring included.

The MWB1320 had a spring as standard, but was not available without one, hence, no (S).
Since the MWB1320 does not appear to have been sold without a spring (that's not to say that there was some version under a different part number) there's no cutting chart specific to that.

Just going by the cutting chart for the MWB1320 (which used the MATMWB base and spring), a whip length of 15" suggests a working frequency of about 164MHz. If you have a whip 18" in length but no spring, from the same chart the frequency was likely around 170MHz.

Comparing a similar antenna MWV1322HD(S), the cutting chart show a difference of about 4". So if no spring, the whip would be 3-5/8 to 3-3/4" longer, or almost the height of the spring itself.