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Reviews For: Ameritron ALS-500M

Category: Amplifiers: RF Power - HF & HF+6M

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Review Summary For : Ameritron ALS-500M
Reviews: 54MSRP: 799.00
Description:
500W Output Mobile Solid State Amplifier on 12VDC for US
Product is in production
More Info: http://www.ameritron.com/Product.php?productid=ALS-500MR
# last 180 days Avg. Rating last 180 days Total reviews Avg. overall rating
00543.9
DK3QN Rating: 2000-07-24
Nice little AMP Time Owned: 6 to 12 months.
I used an ALS-500 in my shack for about 9 months. It's a nice little amplifier pushing out about 400 to 500 watts RF.

PSU for fixed installation:

As I used it only in a fixed location, I was in a need of an appropriate PSU. So I installed 2 identical 13.8 volt PSU's each providing about 35 Amps, as the cost for those PSUs manufactured in China were quite reasonable and the PSUs used commonly available parts in case of repair. Each of the PSU was providing the power to one of the two
RF modules inside the ALS-500. This is an easy job to implement as the ALS-500 offers two DC supply lines coming out from each amplifier module. Before firing up the set I adjusted both PSUs to the same DC voltage in 'idle' state. It is somewhat key to use 2 identical PSUs to make sure that the 'dynamics' of the PSUs are identical as well when you drive them into the 20 to 30 amps range. If the PSUs behave much different under load conditions you will be faced with an unbalanced power distribution of the 2 ALS-500 RF modules.

Modifications:

The built-in change-over relay is quite noisy. I substituted it with 2 small Matsushita relays.
For this job you most likely have to cut off the original relay's solder connectors in order to be able to remove the relay and then unsolder and remove the remaining 'legs'.
Then I installed the 2 new relays upside down and wired them to the PCB.
The change-over relay noise now was much more quiet plus - as a welcome benefit - much faster (7 mS spec). The reason for installing two relays was the fact that the Matsushita
relays only offered 2 switching contacts per relay and you need 3 for the ALS-500.

Additionally I substituted the fan with a more quiet one providing the identical dimensions.

Conclusion:

This amp is quite ok for SSB operation (w/o Processor) where it puts out the desired 500 Watts easily. It is not designed for key-down modes like RTTY or SSTV at power output levels higher than about 200 to 250 watts. This limitation is caused by the size and implementation of the heat sink which is relatively small for an amp in that power category and it is inside the box. So you cannot do much about it.

It's ok for mobile use. If you want to use it in a fixed location exclusively, I would more recommend the purchase of an ALS-600 instead.

Klaus, DK3QN

(email: DK3QN@gmx.de)

WA4CNG Rating: 2000-07-16
First Class Hi-Power Mobile Time Owned: 3 to 6 months.
Bought one in February (awaiting upgrade on 4-15-2000) used on 10 meters at 200 watts out into 10 Mtr Ham-Stick. (You have to run Hi-Power mobile antennas with 500 watts output). Ran #4 Megacable from battery to unit in rear of 98 Explorer. Ground connections (5) are self tapping sheet metal into rear compartment, plus ground lug on rear of radio. 1 volt loss on +14VDC from battery with 75 watts into amp from FT-100, output is 550-600 Watts on all bands (after 4-15-2000). Now use it fixed with 15VDC 75amp DC supply. Runs cool mobile or fixed. Good output protection ckt for high VSWR. Make sure your antennas are tuned for resonane, it does not like my MFJ 949E Tuner on WARC Bands fixed. Planning on purchasing Ameritron AL-80B later this year for new "Shack" now under construction.
WA4EX Rating: 2000-06-16
Good Amp Time Owned: 0 to 3 months.
I purchased my als-500 amp at the Orlando hamfest back in February and have had very good luck and great reports on my mobile signal.
I would recommend the amp.
73s De Sonny-wa4ex
K6VB Rating: 1999-10-28
Excellent AMP! Time Owned: unknown months.
I have used this amplifier mobile for about 1 1/2 years. It have been used successfully with many different antenna configurations. If the SWR or impedance falls out of range, the amp will shut down to protect the transister finals. This has helped me diagnose mobile antenna and grounding problems. I am currently using it with the SGC 235 Smart Tuner (in QMS package) and am very happy with the performance (10 thru 80 meters). (I have had no occasion to operate 160 meters mobile "yet"). I highly recommend the amp to anyone who if serious about operating 500 watts mobile. Don't forget to purchase the 10/12 meter module (must provide copy of valid amateur radio license). It is very easy to install.

73,
Jim (K6VB)