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Reviews For: Diamond X-300A

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

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Review Summary For : Diamond X-300A
Reviews: 23MSRP: $139 HRO
Description:
X300A Dualband Base/Repeater Antenna

Band: 2m/70cm

Max Power Rating: 200
Wind Rating: 112 MPH (no ice)
Height (feet): 10
Connector: UHF
Element Phasing: 2-5/8, 5-5/8
Product is in production
More Info: http://www.rfparts.com/diamond/x300a.html
# last 180 days Avg. Rating last 180 days Total reviews Avg. overall rating
00234.6
EI7II Rating: 2021-10-20
Hits and Tips for your Diamond Vertical X300N or X510N Time Owned: 6 to 12 months.
I've owned my new Diamond X-300 now for about 6 months. ( Owned another one before that for over 14+ years). (it survived a 107MPH Storm). So far... So good. As with all antennas, of whatever shape/form or size, the end result often depends on the care and effort you put in during the assembly. (Barring a manufacturing defect).
An extra 20 mins during the assembly can save you a trip onto the roof, or yr tower.
WATERPROOF EVERYTHING !!! Do not trust the joints to stay waterproof, forever and a day. Do not trust the set screws or fasteners to stay tight forever... a little Loctite will do no harm at all. While there are lots and lots of products to water proof stuff.... for years on end I have used CoaxSeal tape. Advantage is that it provides a watertight seal AND can be removed if so needed. Where you screw the 3 radials into the base mounting, apply a bit of grease to the ends before you screw them in. Tighten the lock-nut and then apply a bit of Loctite and cover the joint with a wrap of Coaxseal. Trust me... NO water will ever get into that joint.

Where the internal brass elements go into each other, make sure that they are fully mated and again Loctite them !
A crucially important step is to waterproof the 2 half's of the fiberglass Tube, where they screw into each other. ( If you are installing the Diamond 510, you have TWO of these). This is the most important point to prevent water ingress. Take your time here... this joint is critical. Make sure you follow the instructions here carefully as to where the rubber ring should be placed !!! Coat the coupler threads with flexible silicone.. and once screwed together... cover the whole joint with a adequate layer of CoaxSeal. (After 20 + years of using Coaxseal.. I still swear by it. (I have seen a post here where one Ham wrapped the whole joint in fiberglass tape, but that will make it impossible to get it apart).

Now.... another very very important point. Ensure the 3 ground radial are ABOVE the TOP of yr mast or mounting pole. Unless you do this you will have a high SWR.
Once you screw you N type connector into place on its antenna mounted socket..... again.. (yes you ill be sick of me by now) wrap the connector carefully with a layer of Coaxseal. If you do not have Coaxseal... use whatever waterproofing you wish... BUT whatever you do >>>>WATERPROOF (these) joints !!! ONE VERY IMPORTANT TIP. NEXT to your N connector is a small drain hole. DO NOT block this when wrapping the connector in your waterproofing tape. It is the ONLY way moisture can get out of the antenna!
Now on a final point.... you've gone to all that trouble, made a brilliant job of it.... and now.. please don't spoil it all by feeding the antenna with a bit of "leftover" RG 8. Buy/use the best Coax you can.... LMR400 or better.
Here is a link to the Coax cable I use.
https://messi.it/en/catalogue/50-ohm-rf-coaxial-cable.htm
I use the HYPERFLEX 13 from them.... short of Hardline, just about the best you can get. Their site is a goldmine of info on cables and connectors.
All in All? I am completely satisfied with this antenna and can recommend it without reservations.

Good luck and many good contacts !
73 de Albert
N4UED Rating: 2017-03-21
Used for over 6 Years now . Time Owned: more than 12 months.
Hi I am Chuck N4UED . I have been using the X-300 for just over 6 years . I really enjoy it . It has changed colors due to our local paper mill . I would suggest at least LMR-400 Coax for enjoyable use . I have mine at 35 feet and have used it for my fill in wide 1-1 APRS digipeater . I have the 70cm side in service as a D-star hotspot . I would suggest anyone interested in one to take the plunge . Mine has the N connector . It has survived Hurricane Irene in 2011 and Hurricane Matthew in 2016 . Good Luck , Chuck n4ued@arrl.net
K6MMS Rating: 2016-10-24
DO NOT BUY Time Owned: 0 to 3 months.
Just got this antenna and schedule help to install it on my 30' high roof peak. Followed instructions but did not see a way to tighten the two elements together since the element in teh top section was 4' up inside teh tube. I did manage to get the bottom element inside the bracket, but again, since it's so high up there was no way to tighten the the screw. We read the instructions thoroughly and there is no mention that you are supposed to fiddle with teh upper element and pull it down (learned about this installation step via eham). Thinking we did everything correctly, we finished the install. Now, I have an inoperable antenna that I need to take down and re-install. This is not how a professional company should operate. FIX YOUR DAMN INSTRUCTIONS!!!!
KM4GGD Rating: 2016-05-27
Good Antenna Time Owned: more than 12 months.
After 1.5 years of service I have -0- issues with this antenna. Easy to assemble, well made, good directions.
K5NAP Rating: 2016-05-14
results w / 710 and Baofeng Time Owned: 0 to 3 months.
I believe when it comes to antennas it is all about location, location, location. That stated my X300NA is mounted in my attic about 24 feet AGL, fed with a 65 foot run of LMR400.

The radios used are a Kenwood 710 and a Baofeng HT. Low power on the Kenwood is 5 watts and 1 watt on the Baofeng. I can hit simplex to a friend in town with 1w from the Baofeng he is 15 miles from my location and his home-brew yagi which is pointing N when I am NE of him. Staying on the Baofeng I can hit specific repeaters from 13-60+ miles still on 1w and their listed coverage is 30-50 miles. However that is location, location, location. Some closer I have to use the high power setting of 5 watts at a much shorter distance.

With the Kenwood I have hit other repeaters on low so far out to 76+ miles though some as close as 43 miles may take 50W. Location, location, location. So far it has been a very quite antenna and APRS loves it which the J-pole I had up didn't and wasn't compared to the X300NA.
So, construction is good. We have at times 100+mph winds but again my X300 is in the attic. A friend has a X50 above his house and it has been there for years and has been subjected to rain storms, high winds, ice storms and we get plenty of golf ball or larger hail in our area (OK) and it has faired very well with no issues that he has spoken of. He also swears by its performance.

Ease of mounting - to damn easy and I mounted it by myself without falling through the ceiling. Speaking of mounting it is about @10' in front of my Alpha DX-EE Fan Diople and centered. Tops are about level or as best as my Mark one Eyeball can determine.

Over all impression - it is a great antenna. Considering mounting limitations, my results give cause to feel young again hi hi.

Why didn't I get a X50 instead of a X300. Price was close and the X300 fits in the attic. A friend who is getting into HAM will need a QTH dual band antenna for he lives even further out of town than I. He can mount the J-pole i will give him up and outside. If that doesn't work I told him to get the X50 and if that doesn't work for him I will buy it from him for portable use.
That is how much I am impressed with the Diamond X series.

Why not recommend the X300 to my friend? Cost smaller attic,and the winds. I feel for what I wanted and needed to talk simplex into town the X50 is the ticket but looking at the cost I went bigger with the X300NA. I am not in the least bit regrettable about spending about 30 dollars more with the performance I am getting out of the X300NA nor the bragging rights especially with the Baofeng on 1w.

Couple of last thoughts.
1-Use good low loss coax for 440Mhz and get the N version. Thus order your coax with the N connector on one end.
2-Buy it you will not be sorry.

Note: advertised 5 watts out of the Kenwood is much stronger than 5 watts out of the Baofeng so the Kenwood does more on 5 watts than the Baofeng does. The Baofeng also is connected via a 3' jumper to the LMR400.

Remember get your antenna up as high as possible and use good coax. Then worry about gain numbers.
Everything I have is a compromise but works well because I follow the above.

73 to all
K5NAP-Jerry
KX5F Rating: 2014-03-03
Outstanding Time Owned: 0 to 3 months.
Have had this antenna several weeks, previously had a cushcraft AR- 270B, and Comet Gp-15 up and this antenna outpreforms both of them, same mast, height,coax and radio..I picked this one over a Gp-6 and am glad I did. Patrick
KC7MF Rating: 2013-07-05
You can't go wrong with this antenna Time Owned: more than 12 months.
I have had this up for about a year and find it to be an excellent antenna. It is up about 20' just clearing my roofline. With it, for example, just the other day I was able to carry on a simplex QSO with a mobile over 30 miles away. It can hit every major repeater in my area including many over 30 miles away. This on as little as 5 watts fed by nearly 100' of RG-8U.

I painted the fiberglass with camouflage paint and it is very discrete. I got mine from the nice folks at HRO in Phoenix and had no trouble at all assembling it just a few minutes. This is a good workman like antenna. The price is good and the antenna seems quite durable. You can't go wrong with it if you want a vertical.
KF7VXA Rating: 2013-01-11
Decent Antenna Time Owned: 3 to 6 months.
I had a OPEK UV-300 that worked excellent till I dropped it trying to get it up higher.
I replaced it with the Diamond 300A.
I have found the Diamond to be a good antenna with decent range, but despite raising it higher by 10 feet and cutting off 15 feet of LMR 400 by re routing it, the two repeaters that are the ones that are the most distant, I cannot hit anymore. I bought a Yaesu 2900A, with another 25 watts, I still cannot hit the repeaters. SWR, the meter hardly moves, the coax checked good with a MJF analyzer as did SWR.
So, I called OPEK to buy replacement parts, more than a few broke or bent and the top piece of fiberglass cracked which killed my SWR when the Caps got wet from several hard rains. Opek would not let me pay for the parts and I had them in less than one week, fantastic service, best I've had.

The OPEK for whatever reason may not have the best name, but I found the internals to be great. I replaced the parts and replaced the 300A. I can now hit the repeaters again and the OPEK was $40.00 less when I bought it a year ago, $100.00 vs. $200.00 for Diamonds version of the same antenna.

All in all, the 300A is a great antenna, it does have aprox. 1.7 DBi less gain than the OPEK which is a factor.
If I had to watch my space, the 10.5' 300A would be my choice, at slightly over 16' the other is rather tall.

If the 300A fits the bill for you, it's a quality antenna which has got me many solid contacts. You do pay more for the name and slightly better quality. It's a better antenna than the Diamond X50 for just slightly more money.
K7TCE Rating: 2012-06-23
Excellent antenna Time Owned: 3 to 6 months.
I started with a DBJ2 homebrew 144/440 J-Pole. The X50A ran circles around it, and the X300A was a noticeable improvement over the X50A. As other have reported, I had poor SWR at first - be advised that top half of the antenna is actually two pieces. I dutifully tapped the upper half of the radome to get the element down, but only the lower half of the "upper half" came down. I pulled it from the radome and asked myself "why such a long radome section for such a short element." Duh. When I got the rest of the antenna element down and coupled I had excellent SWR on both 144 and 440.
GM1FLQ Rating: 2012-06-03
Looks like a weak point Time Owned: more than 12 months.
Have the Watson branded version of this antenna - good performance but same mechanical problem as previous reviewer whereby antenna has broken where fibreglass meets the steel mounting section. Mine is also wobbling around (and yes the mounting bolts were all tightened correctly and are still tight) - something has broken inside the steel mounting tube. Looks like cheap manufacturing is the root cause, my friend had an old Jaybeam of around the same length as the X300 and it was up higher than my antenna for 10 plus years, my antenna lasted 2 years.