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Reviews For: Diamond SX-20C

Category: SWR & Wattmeters & Dummy Loads

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Review Summary For : Diamond SX-20C
Reviews: 9MSRP: $89.95
The Diamond SX-20C is a compact SWR-power meter featuring cross needle design for measuring SWR and output power simultaneously. The meter's small size makes it ideal for testing mobiles as well as base station installations. The connector type is SO-239 (accepts a PL-259). The SX-20C is rated from 3.5-30, 50-54 and 130-150 MHz with power ranges of 30 and 300 watts.
Product is in production
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# last 180 days Avg. Rating last 180 days Total reviews Avg. overall rating
W0YN Rating: 2016-03-12
Disappointing Time Owned: 0 to 3 months.
New out of the box, very inaccurate both forward and SWR reflective reading. Received a bad unit or in need of complete calibration. No schematic or calibration instructions included and can't be found. Meter looks cheaply made in a molded plastic housing. Returned for refund.
PE1DHI Rating: 2015-01-23
Surprizingly good Time Owned: more than 12 months.
I use several bird-43's for my profession and had trouble with contacts from the plugins. The accuracy is not outstanding.
The SX-20C surpized my. It is accurate in the 300Khz-170Mhz range. And it does realy show 300Khz readings from N.D. beacons (aironautical). It is lightweight, which is importand if you travel every day with a helicopter.
Iám a happy user.
former_WJ7S Rating: 2012-08-31
Needs calibration Time Owned: 0 to 3 months.
I just got the SX-20C a couple of months ago
went to use it and like one of the reviews the
power was off as much as 10w in most cases compared
to my bird 43, I took the back off and there are
adjustments for the low and high power scales but
nothing in the little paper that you get with this
meter so you can calibrate it but how is the next
step still looking any help would be greatly
LA7QZ Rating: 2006-12-31
Does what it says on the box. Time Owned: 3 to 6 months.
Bought this one for my MM HF installation using an SG-230 smarttuner. It works fine and I have also used it for testing marine VHF installations.

I had an alomost identical meter on my last boat, and that one had a light, so I took it for granted when ordering that this one had a light too.

The lack of a light was a disappointment, but otherwise it does what I need which is basically to confirm that the tuner is doing its job.

I have no way of checking the accuracy, but it seems to be pretty close if I can assume that the radios I have used with it are putting out the power they should.


KC2LSU Rating: 2004-02-14
Its better than I orignally thought Time Owned: 6 to 12 months.
Well after some more months to play with this meter, I have discovered that it does work better then I orignally thought.

Earlier 0-star review posted by KC2LSU on 2003-10-04

the one I got is nearly 75% off on VHF (146.520)
I've tried it with two radios that are supposed to put out 50 watts. I have a Jpole with a 1:1 SWR connected by 15 feet of RG-8x to the radios. The power needle wont budge past 38 watts, when the ICOM 706 MKIIG radios is set to high power, and is showing max power in its readout. 38/50 = 76%.. 76% off, not very good.. If only there was a calabration knob :)
W3DCG Rating: 2003-09-14
Simple works good, 2 scales. Time Owned: 6 to 12 months.
It's no Bird. I think even a Bird's typical accuracy is +/- 5% full scale deflection...
Typical ham wattmeters seem to fall in the +/1 10% category at full scale.

This meter has convenient scales, 30W, 300W. No amp here, so this is perfect, I have not an extraneoous scale for a KW which I do not have.
Works close enough. For QRP adjustments it's probably well within plus or minus 1W at 5W, close enough, try hearing the difference between 4W and 6W anyway.

Mainly wanted simple accurate SWR instrument.
Went based on QST Review vs price.
Use it as a base station meter.

Liked not having to deal with being sure the Scale is correct, plus calibrating with a pot.

I have no meaningful way to actually measure the accuracy of the meter except for comparison against the internal meter of a TS850 and Pegasus.

I could borrow a Bird from work, but feel not the need to bother.

Works great for what it is and the price.

If it lasts 3 years and I believe it will, it's a great deal.

If I were going mobile, I'd have some concerns about it's ability to tolerate the beating one might expect in a mobile environment. As it appears to be designed for mobile applications, I therefore give it a 4. But because I use mine for base use, I'll post 5. My best guess is that performance vs cost is excellent.

To me that means plus or minus 10%, it keeps working that way for over 3 years, and the cost is under a hundred bux including shipping.
WR2W Rating: 2003-09-14
Works Good For Me... Time Owned: 3 to 6 months.
I have one of these meters that I use to check SWR and power on my mobile set-up every now and then. I also have a Diamond SX-100, and an MFJ-460 SWR/PWR watt meter. After reading the other reviews on this I checked all three meters on my base set-up, and the only meter that gave me Very Slightly less readings was the MFJ-460. All three meters have a 30 watt scale. I did not get any varied readings when I held the plastic case or touched the plastic display on the SX20C. I'm not fond of Any electronic device that is housed in plastic but I wanted a small meter, and I bought the SX20C. I decided to use the MFJ-460 to check my mobile set-up because it does have a metal case, and is less likely to break if dropped. Also, the Diamond SX20C has no meter lamp, and the MFJ does which is good for night use. I give the SX20C a 4/5 because of these reasons only, not performance.
KB1FZA Rating: 2003-07-24
its OK , not great Time Owned: N.A.
I like the form factor. It's light too.
The accuracy is OK - mine was a little over 10%.
The problem with this meter is the plastic case and the plastic display shield. They are very sensitive to static electricity and even minor touch with your finger on the display glass will cause the needles to jump and they will not stay at zero until you remove the static electricity charge by touching the display with something grounded. And of course the whole reading will be way off under such conditions. I had to spray my unit with anti-static spray for computer monitors and helped just a bit. I am thinking of getting another model!
AK9S Rating: 2003-07-02
Disappointing Performance,,, Time Owned: 0 to 3 months.
This power meter is very inaccurate. Mine was off by as much as 25-30% in both power scales (30W/300W).

To give you an idea between actual power and what the SX-20C read:

Radio 1 (high) - 73 Watts (meter read 50W)
Radio 1 (mid) - 25 Watts (meter read 18W)
Radio 2 (high) - 60 Watts (meter read 40W)
Amplifier - 156 Watts (meter read 121W)

The above actual power numbers are based on:

1) confirmation using my friend's SX-400 meter.
2) comparison to manufacturer published power numbers.

Interestingly enough, the SWR readings on the SX-20C were excellent. I returned the SX-20C, as I wanted a good power meter, not an RF field meter :-)