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Reviews Categories | Antennas: VHF/UHF+ Omnidirectional: verticals, mobile, etc | Diamond X-300A Help

Reviews Summary for Diamond X-300A
Diamond X-300A Reviews: 18 Average rating: 4.6/5 MSRP: $$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.
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KX5F Rating: 5/5 Mar 3, 2014 15:57 Send this review to a friend
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: 5/5 Jul 5, 2013 16:52 Send this review to a friend
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: 4/5 Jan 11, 2013 16:04 Send this review to a friend
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: 5/5 Jun 23, 2012 17:25 Send this review to a friend
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: 3/5 Jun 3, 2012 00:47 Send this review to a friend
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.
KB3MRU Rating: 3/5 Jun 2, 2012 15:56 Send this review to a friend
Lasted 4 years  Time owned: more than 12 months
Great performance and low SWR across both bands. Easy to mount and appeared to be of good quality.

I have it on a 25 foot, guyed mast. It's been up for just over 4 years. I used very high quality hardware (stainless steel, etc.) because I thought it would be up there for much longer.

I noticed the antenna is now wobbling at the point where the lower fiberglass meets the cast metal base. It still seems to work but I have to take it down before it falls down.

I'm disappointed it didn't last longer. Not sure what I'll get to replace it. Maybe something by Bozak if he makes a dual band omni.
W4HWD Rating: 5/5 May 27, 2012 18:08 Send this review to a friend
Great antenna!  Time owned: 0 to 3 months
After reading some of the reviews, I'm wondering why it was so difficult for some to assemble this antenna. I believe some people couldn't find their own rear-ends with both hands! It took me about 6 minutes to put it together, and another 20 or so to climb on the roof, attach the LMR-400 and clamp it to the top of my 35' mast.

I hadn't been on 2 or 440 for a while and was very impressed with performance that exceeded my expectations. Using this antenna 35' AGL (about 15' above the roof) I was able to work, with a 5W Alinco HT thru 100' of LMR-400, 2M repeaters in the following locations: Abbeville, SC (85 miles away); Elberton, GA (91 miles away); Denver, NC (88 miles away); Marion, NC (43 miles away). All the local machines and machines closer but not necessarily local were all full scale. On 440, there aren't as many repeaters but the furthest one I was able to talk on was in Abbeville, SC (85 miles away). Now granted these are repeaters with high antennas, but the distances are still impressive for an antenna that is still way lower than the trees that surround it on three sides! And with 5W from an HT, I can't wait to see what it does when my new Kenwood V71A shows up later this week!

Only thing I noticed was the SWR is not quite as low or flat as advertised...the SWR on my antenna is 2:1 at the ends of the 2M band and only about 1.7:1 through the middle. That's a non-issue for me because dummy loads are 1:1, and I don't think the SWR really matters, as evidenced by what this antenna is doing on the air! We'll see how it holds up for the long run, I expect no trouble as it's built solid and in no way resembles a poor quality antenna.
W2ZOU Rating: 5/5 Dec 12, 2011 13:38 Send this review to a friend
Outstanding  Time owned: 0 to 3 months
Build quality is superb, excellent performer. I upgraded from a J-Pole, HUGE difference.
KF5LQI Rating: 5/5 Sep 2, 2011 18:26 Send this review to a friend
So far so good  Time owned: 0 to 3 months
Not sure what issues A1oc had. Yes the element for the upper portion was up inside the fiberglass shell. Looked up inside and then saw it was surrouned by a foam insert. A sharp rap on the table and out it popped. Bolted together with no problem from the radials (I did use a little red thread locker) Attached the base to a 10ft section of a 4inch fiberglass "C" channel and painted it camoflage. Used LMR600 cable to run it and hired a tree company to install it at the top of an 80ft pine tree in my yard. Tip of the antenna clears 90ft and I have worked simplex 20 miles and 32 miles thusfar using a 746PRO on 100watts.

I can't speak to the longevity, yet, but so far my expectations have been exceeded. For the money, I would buy again anyday.
AI0C Rating: 3/5 Jan 29, 2011 18:31 Send this review to a friend
A good antenna, but a few product issues  Time owned: 0 to 3 months
After reading the reviews here on I decided the X-300A was the antenna for me. As an antenna it works fine, but getting it up and operational was another matter.

Step 1 has you connecting the lower and upper elements. While the lower element was sticking out of its outershell, there was nothing sticking out of the other outershell.

It's a bit hard to see anything down that long dark tube of outershell, but I finally spotted the element. It took a bit of work to convince the element to make an appearance so that I could connect the two elements together. It would be helpful if the assembly instructions made note of this.

When I got to Step 5 where you attach the radial elements I ran into another problem. I couldn't get any of them to screw in! An examination with a jeweler's loupe of the three threaded holes in the base revealed them to have plated threads! The plating was apparently heavy enough to gum up the threads to the point that I couldn't get the radials to thread into the holes.

A trip to a nearby hardware store to purchase a 5 x 0.8 mm plug tap for $5 so I could chase the threads solved that problem. You wouldn't believe how much plating came out of those holes!

Step 7 was the funniest of them all. It said, "Attach assembled antenna on mast by whole balance into account." That's not a typo. At least not on my part.

I contacted RF Parts Co. (the distributor of Diamond Antennas in the US) and explained my problems with the X-300A. Their response? Silence.

In the end the X-300A is a good antenna but this experience will make me think twice about purchasing a Diamond Anteanna in the future or purchasing from RF Parts Co.
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