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Reviews For: Commander VHF-144

Category: Amplifiers: RF Power - 6M/VHF/UHF+

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Review Summary For : Commander VHF-144
Reviews: 7MSRP: 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
More Info: http://www.palstar.com
# last 180 days Avg. Rating last 180 days Total reviews Avg. overall rating
0074.6
W2WRX Rating: 2022-08-07
Excellent 2 meter tube amplifier..... Time Owned: more than 12 months.
I really love this 2 meter tube amplifier,it's so effortless to tune and maintains the tune-up once it is setup properly. The built quality is 2nd to none and it's built with some high quality components as well and also the silver coatings on the tank and other parts. The fan has some noise, but not to where it uncomfortable during long sessions on the radio.

This one came with a trim port ( FAN ) in the rear of the amplifier so that you can slow it down and never hear it,just make sure with your hand that the fan is running or else damage to the tube and components will decrease it life in the amp.I am very happy too that this amp does cool down quickly when I am rag chewing for 1/2 hour to 1 hour of usage and the fan just puts out some high CFM's of flow to the tube.It will put out 1200 watts on all modes,but I would suggest to tame it down to 1K or 800 watts for longevity on the now rare tubes of the Eimac's 3CX800A7's and more rarer Eimac's 3CPX800A7's,if you do find some NOS matched or NOS singles at a good price and you want to preserve your amp in the near future or the life time of owning it,better start looking around and keep some used or NOS around. If you intend on keeping it.....

As long as you take care of tuning the tubes and not staying on the tube when you dip it of grid and plate when tuning you'll be fine. This tubes are very toughly built and it's a must to use the manufactures specifications of max. tolerance of the Eimac's tube.

When I bought this one,it did not come with Eimac Pulse 3CPX800A7,but with a Eimac 3CX800A7 and it did fine on the power and drive from the radio to achieve the wattage that I was looking for with 40 watts of drive to 1.2K PEP output.Normally it requires 30 watts with 600ma of plate or 35ma of grid for 1.0K output of the manufactures requirements.
So the tube in it was very new and stout and in great condition with no burn tarnishing on the coil and tube,very well taken care of and hardly any dust,but I did go in the chassis to inspect and tighten and loose nuts or bolts after it was SAFE to touch in the RF section of the high Voltage and other areas.Be safe than sorry,it can kill you if it is not done right when opening and then touching with bare hands.

I will keep this Commander ii VHF 2M amplifier for a long long time,even with out replacing the tube and it will give me 1K of power to the 2 meters band and including my other Commander VHF 1200 6M from my last Reviews of it.Here's a review on YouTube by BBI......

https://www.youtube.com/watch?v=MGMR_u1OxT8
K6AER Rating: 2008-02-17
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: 2006-10-09
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: 2004-09-30
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: 2003-10-26
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: 2002-03-27
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: 2002-02-14
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.