Re: [BVARC] Mobile antenna tuning question

[Rick Hiller via BVARC]

Since the meter is new to you……put a 50 ohm resistor across the uhf port to see if it measures properly……. to check calibration.    I keep  an assortment of resistors in my MFJ analyzer box to check calibration.  25, 50, 75, 100 and 200.   Used to ensure the darn thing is working, as it is easily affected by stray RF.    Just like the O, S, L calibration on a vna.   Gl. 73.  Rick.  W5RH Sent from my i-Thingamajig On May 28, 2024, at 9:39 PM, Robert Polinski via BVARC <bvarc@bvarc.org> wrote:  Terry, first I would put a swr watt meter (Bird) in line and see what the SWR is. Many of the low price meters do poorly on UHF. Having installed 1000s of UHF ant on commercial vehicles. They like to be in direct contact with a ground plane. If the antenna will detach from its base ( mon or UHF mount) try it on a mag mount on the roof and take another reading. I have a headache rack on my truck and the UHF antennas did poorly on them, I moved them to the roof and all worked great. If you do not have access to a Bird wattmeter I can bring mine to the next meeting. Robert KD5YVQ   From: BVARC <bvarc-boun...@bvarc.org> On Behalf Of terry leatherland via BVARC Sent: Tuesday, May 28, 2024 4:57 PM To: Eddie Runner <eddie.run...@yahoo.com>; BRAZOS VALLEY AMATEUR RADIO CLUB <bvarc@bvarc.org> Cc: terry leatherland <k5...@yahoo.com> Subject: Re: [BVARC] Mobile antenna tuning question   That wasn’t it.  I used the uhf connector port and it’s still swr off the chart.  Sent from Yahoo Mail for iPhone   On Tuesday, May 28, 2024, 10:23 AM, Eddie Runner <eddie.run...@yahoo.com> wrote: I would call COMET and see if this is normal... Eddie (NU5K)   On Monday, May 27, 2024 at 06:34:01 PM CDT, terry leatherland via BVARC <bvarc@bvarc.org> wrote:     I'm sure someone knows about Mobile antennas. Our friends at River Oaks Car Stereo for sure. Anthony? Here is my dilemma , or something I am doing wrong.    I bought this antenna to mount on my new truck. I have a brand new Comet analyzer. The antenna is hood lip mounted with a comet Hood mount.  When I analyze the raw antenna thru its one piece of coax, it is perfect 1.5 or less on 2Meters @ 50ohms.  But when I dial up  to 440 Mhz, the swr and Ohms is off the chart. My radio is my old reliable Kenwood TMV71 of which I have 3 identical.   Shouldn't I be able to just change the band knob to 430 and it read good SWR?  Do I have to find the resonant point of the upper band and start trimming the top length down to 440 good swr? I'm perplexed or doing something dumb.    Terry   <image001.png>   Terry Leatherland, K5PGF 281-455-8090 Sugar Land, Tx   ________________________________________________ Brazos Valley Amateur Radio Club BVARC mailing list BVARC@bvarc.org http://mail.bvarc.org/mailman/listinfo/bvarc_bvarc.org Publicly available archives are available here: https://www.mail-archive.com/bvarc@bvarc.org/ ________________________________________________ Brazos Valley Amateur Radio Club BVARC mailing list BVARC@bvarc.org http://mail.bvarc.org/mailman/listinfo/bvarc_bvarc.org Publicly available archives are available here: https://www.mail-archive.com/bvarc@bvarc.org/

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