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Reviews Categories | Amplifiers: RF Power - 6M/VHF/UHF+ | Commander VHF-144 Help

Reviews Summary for Commander VHF-144
Commander VHF-144 Reviews: 6 Average rating: 4.5/5 MSRP: $2995.
Description: 144 MHz mono-band amplifier based on a single Eimac 3CX800A7 ceramic metal triode, capable of 1000W PEP SSB.
Product is in production.
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K6AER Rating: 4/5 Feb 17, 2008 21:15 Send this review to a friend
Good bang for the buck  Time owned: 3 to 6 months
I have been using this amplifier for about three months. I like the design much better than the other Command Technologies amplifiers (2500 series) for you can access all the critical areas for service.

Setting the transformer into the unit is easy with top and bottom removal of the covers to access of the faming chassis to bolt the transformer in place. Wiring is via a molex connector.

The single 3CX800A7 grounded grid does an admirable job of producing about 1050 watts PEP with 30 watts drive PEP. CW output is about 860 watts maximum. Second and third harmonics are well below 60 dB. Maximum power readings were taken with a HP8953E spectrum analyzer. Class of operation is Class AB2. This is a high gain tube with operation up to 350 MHz which is made by Eimac. Tube replacement cost is about $600 from Eimac.

Keying is 12 VDC at 55 mA positive to ground via a RCA jack.

I found the blower noise within norms with a noise level of 58 dBa at about 18 from the amplifier front.

Tuning is broad and once you set the amplifier at 144.2 MHz you basically leave the tuning set for +/- 200 KHz. Input tuning is broad and you basically tune for maximum power out which corresponds with minimum input VSWR.

Grid trip is set of 65 mA at 860 watts out CW. Once the grid trips resetting the STBY/OPERATE will allow the amplifier to operate again. Due to meter lag you will see a maximum of 45 mA grid on SSB for peak power output. Do not exceed 30 watts drive in SSB to stay within grid dissipation ratings.

I noticed the output series link pickup coil must not be close to 50 ohms for there is a shorting stub attached to the output connector. The output LC networks might not be designed as well as it could. None the less the output is with norms for this tube and the transformer ratings.

Form fit and finish is very good and for the price is a good dollar value.

The manual is still in need of upgrading with the help of a good technical writer. Schematics are a bit sketchy with a lack of IC pin outs and there are no pictorials in the manual. PC boards do not have component markings and some reverse engineering is necessary when repairing these amplifiers.

Because of the lack of first class documentation and minor design and build philosophy I can only rate the amplifier a 4 out of 5.
KA1CDE Rating: 5/5 Oct 9, 2006 04:51 Send this review to a friend
Excellent amp  Time owned: 3 to 6 months
I purchased the Command II over the internet as being mint. When I received it someone had wired in 13 volts to the output jack of the amp, the plug had a 240V plug on the cord but the transformer was wired for 110V, no manual was included.

I called Command Tech and spoke to Pat S. He told me what to check and explained how the transformer should be wired for 240V. Pat S. gave excellent service, was very helpful and explained what needed to be checked.

After following his lead, I was able to get the amp running. Here is what I experienced.

The blower is a little noisey, not bad bit a little noisey:

The amp was easy to tune, 25 watts gave it about 600 watts out carrier. I was able to lower the grid current with out any problems.
I hooked up a coaxial dynamic PEP meter to it, with 25- 30 watts drive {which is MAX} the amp would peak to about 900 watts out.

THe amp appears to be well built, I am very happy with this 2 meter amp. Pat from Command Tech was extremely helpful. No wonder his reputation is so good.
K5YY Rating: 5/5 Sep 30, 2004 12:06 Send this review to a friend
Excellent  Time owned: more than 12 months
Well, a single 3CX800 is not designed for more than about 700 watts output without taxing the grids and shortening the life. Sorry the other ham put a "3" on this fine amp. BUT, I have had two of these amps, the present one for 10 years, and have worked all the modes on 2 meters that one could hope to operate, EME, tropo, MS, low signal tropo, E skip etc. I hold my on in the pileups with this baby. 492 grids on 144mc attests to being able to get thru the attenuation of this VHF band and beat out a few in the process. Best bang for the buck unless you go homebrew or such. This amp deserves at least a 4.5 in anyone's assessment. Pat will make anything right if you have a problem, even after the warranty in some cases. 73 VHFers, San
N1DZ Rating: 3/5 Oct 26, 2003 00:17 Send this review to a friend
Nicely built amp. Do not like the single 3cx800.  Time owned: more than 12 months
I use this amp for over 5 years now on 2m. It is built very nicely. Once you tune it you never have to touch it. At 650 watts the 3cx800 will last forever but if you push it to 1KW you will slowly kill the tube. The 1KW level can only be used at very low duty modes. I managed to slowly destroy 2 tubes in this amp by using it for EME and HSCW at outputs greater than 650 watts. The blower is very noisy.
New this PA goes for close to $2000.00. For this amount of money you can find other PA's with better tubes than a single 3cx800.
K9KJM Rating: 5/5 Mar 27, 2002 05:00 Send this review to a friend
POWERHOUSE  Time owned: more than 12 months
I purchased my Commander II used several years ago, and have had no problems whatsoever with it. A real powerhouse compared to the "little" brick solid state amps....... This unit works very well on SSB, and have also used it on 2 meter FM simplex with great results! I am running it on 120 VAC, and should really change it over to 220 volt operation....... I does draw lots of amps on 120 volts......
W0LD Rating: 5/5 Feb 14, 2002 08:54 Send this review to a friend
An excellent compact 2 meter amplifier.  Time owned: 0 to 3 months
I have been using the Commander II amplifier for over a month now and it is performing exactly as advertised. It delivers 750 watts on cw and the PEP is probably over 1,000 watts. I do not have a PEP reading meter.

For it's compact size it really delivers! The grid current is very critical to the protection of the 3CX800A7. Tuning the amp takes some practice to keep the grid current under 35 mills. However once I got the technique down it is very stable.

It is essential to run the amp on 220 VAC, it runs cooler and easier.

All in all this is a good value, well constructed and delivers power in a compact package.

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