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Reviews For: Diamond M285 Monoband (144-172Mhz) mobile antenna

Category: Antennas: VHF/UHF+ Omnidirectional: verticals, mobile, etc

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Review Summary For : Diamond M285 Monoband (144-172Mhz) mobile antenna
Reviews: 5MSRP: 31.95
Description:
Monoband antenna with PL-259 (UHF) connector. Length uncut is 52.4". Can be cut for any frequency between 144 and 172 Mhz. 3.4 dbi gain, 200 watts, 5/8 wave.
Product is in production
More Info: http://www.rfparts.com/diamond/m285.html
# last 180 days Avg. Rating last 180 days Total reviews Avg. overall rating
1454.2
K7MAP Rating: 2022-11-25
Bonus Band Time Owned: 0 to 3 months.
Yes, this is a M285 review, I will get there.

I am a Larson/Pulse fan. If given the choice between a Larson and anything else, I would take the Larson any day. However, I was in the market for a 6M NMO antenna to go with my new Alinco DR-06TA. Went to look one line. Holy inflation Batman, $70+ for a Larson. I don't love Larson that much. Anyways, I went to see what other companies made 6M NMO mobile whips. Hum, Diamond M685SNMO. $35.00 from a major Ham Radio dealer. Ok, that is a more realistic price. Ordered. It arrives. I pull it out of the box and find a M285SNMO. Crud, they sent me the 2-meter version.
Thank gosh I read a bunch of reviews of the M685SNMO. One nice internet person said that the M285 and the M685 were the same antenna, just with different marketing. RIGHT. Well, while I am waiting for my RMA to return the wrong product, I might as well go set it up on my car, sweep it with my NanoVNA and see if that one internet person was blowing smoke. OMG no. Just as the antenna came from the factory, it had a nice 1.08 to 1 dip at 49.9mhz, then another dip at 143mhz. The antenna tuned the entire 6M band from 50 to 54 with an SWR of about 1.1 at 50 and up to 1.65 at 54mhz. No return required! So, for $35.00 +tax+ shipping, I have a dual band antenna.

The unit seems well built and solid. The whip seems to be a little thicker than a Larson Kool Rod whip.
No clue if the internals are up to Larson standards however. I will update this review in a year or so with how the antenna has weathered Southern Arizona Summers.

This M285 hears well on 6M too. I have a "local" 6M repeater that I cannot hear at my house while using a Uniden scanner and its built in 18" whip. I put the 285 out in the yard on a mag mount base on a cookie sheet, on the ground, and plugged the coax into the scanner. I can hear the repeater. That M285 is no 50 ohm dummy load on 6M. It hears.

WD8KDG Rating: 2019-05-12
Lost in translation Time Owned: more than 12 months.
The M285S works, sort of. I now own two and used them a decade or more. Both did arrive with an instruction sheet and a cutting chart for the whip.

Lost in translation item #1: Grounding
The comments after are, Required for optimum performance. A phone call to the manufacturer cleared up the translation. "A ground plane is required for optimum performance. Don't bother grounding the mount!

Lost in translation item #2: Length
The comments after are, 50" (before cutting)
Same phone call cleared up this issue. The whip is not 50 inches in length. Most of us only cut the whip, I hope.

With two different vehicles, the whip needs to be 50" before cutting. As it arrives from the factory SWR is 2:1 on any transmitting frequency at 144.***. At 145MHz and above there is hope.
AI4HO Rating: 2009-06-13
First Impressions Time Owned: 0 to 3 months.
This is strictly a first impressions type of review, having only had this antenna on my vehicle 2 weeks now. To kinda sorta set the stage here, let me first say that this is the first time using a not only a mono band antenna, but using an NMO style antenna and mount.


Before this, my antennas used to be the typical dual/tri/quad band antennas on typically a large 3 magnet mount. Well this last trip to Dayton saw me on the return trip with the Tar Heel 40A which is considerably larger than the Little Tar Heel II that I went up with. I figured I would have some interference issues, but when the locals say you are weak and scratchy into the repeater, then you know there are issues.


So enter the Diamond M285SNMO mono band antenna, and the Diamond K400C NMO mount. This antenna so far has done well on the local repeater, plus several of the other area repeaters. As previously stated it has only been 2 weeks and I haven't completed my testing. One thing that I had read, one of the other poster made mention of the fact that there had been no cut chart for tuning the antenna. In the packaging was a cut chart for tuning the antenna. Speaking of tuning, thought I was going to have to cut this antenna to get it tuned properly, not so, right out of the package onto the mount, and onto my SWR analyzer.


I check my SWR at its lowest, also at the low end then at the high end. From 144-148MHz the SWR is at 1.2:1, now then at 138.5 the SWR is 2.0:1 and at 153.8 the SWR is 2.0:1, all this means is I could conceivably Xmit on these frequencies, receive on the other hand, is all good, aircraft, public services, weather, etc. can all be heard. Now then, off to check out how well this antenna works on 2 meter SSB. A more thorough review in a few months.



73 de Mark
W3LZK
K4JC Rating: 2007-02-22
Works like a champ! Time Owned: 3 to 6 months.
Excellent 2 meter 5/8-wave mobile antenna. I have mine trunk mounted with a Diamond K600 mount and this combination has proven extremely efficient.

The M285S (really, any 5/8-wave 2 meter antenna) has the added advantage of being a 1/4-wave 6 meter antenna. (You can also buy the M685S sold as a 6 meter 1/4-wave, but it's really the same antenna! Go figure...) SWR after proper tuning is 1.1:1 at 146 MHz, and 1.2:1 at 52.5 MHz. Also very good for reception of public service and 162 MHz WX bands. Construction is pretty solid. Comes in a UHF or NMO mount version.

If you're looking for a good antenna with a bit of gain, this one will fill the bill.
N2LJ Rating: 2006-03-01
Good antenna, does the trick. Time Owned: more than 12 months.
If you have any need for a monoband antenna for a frequency outside of the Amateur 2 meter band, you could do worse than this Diamond. It comes uncut, and you cut it to the length needed.

My application was for the Marine VHF-FM Band, as I am a Land Mobile Radio Operator with the US Coast Guard Auxiliary. I cut the antenna for about 157.125 Mhz. Works well in conjunction with a Diamond K412C mount on the rear door.

Only one issue was that the antenna didn't come with the cut chart, and when I called Diamond, the tech initially told me it was cut for the frequency it is supposed to be used for! I had to explain to him what his product was, and finally, a cut chart came in the mail. They now have the chart on the web page. I verified my cut with an MFJ 259B, and all is well.

Even cut for 157 Mhz, it was a darn sight better than my Diamond NR770HB when it's coil went the way many of them seem to do!

Good antenna, if you can use it!