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| Reviews Summary for HARRIS RF-110A |
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Reviews: 2
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Average rating: 5.0/5
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MSRP: $(missing—add MSRP)
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Description: Amplifier, Radio Frequency
2-30 Mc Freq Range at 1 KW AM-FSK-CW-SSB
[US Government contracts: USN, USAF, USA, DOD,
FEMA].
Requires separate RF-124 220 volt, single phase PS.
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More info: http://
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You can
write your own review of the HARRIS RF-110A.
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W5XE
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Rating: 5/5
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Jul 24, 2006 11:01
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Great amplifier.
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Time owned: more than 12 months
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I agree with Mike W4MDL/W0YR about the RF-110.
I had the use of the RF-110 amp with the Harris
270-5 system which used the RF530 receiver and
the solidstate transceiver to drive the 110's.
Had 3 of them in operation. 1 of the amps had
the 8122 drivers, the other two had the 4cx250b
but all performed excellently. They will run at
the designed 1kw pep output level for day after
day, week after week for months or years.
Expensive if one has to replace the tubes but
they were primarily in government service so
the replacement costs not a factor. I might
add that the RF110/124 system was also a part
of the RF-131 system of which that exciter did
all modes including ISB.
Ray, W5XE
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W0YR
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Rating: 5/5
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Jul 24, 2006 09:01
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BIG POWER LOW DISTORTION
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Time owned: more than 12 months
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I bought my RF-110A (with matching RF-124 power supply) from Toronto Surplus Sales in November of 1998. It cost me $1200. Now they are for sale for over $3,000 ! There must be a reason why.
The reason is -- EASY 1,500 W + OUT WITH 3RD Order IMD products down at least -43dB or more -- the lowest distortion amp around.
I spent about three months familiarizing myself with the amp and its power supply and then went through the considerable trouble of building the wiring harness needed between the amp and the power supply and the control box. I also built a 30 dB pad to go between my transceiver and the amp input. As designed, the amp only requires a maximum of 150 mw. drive (!) for full, legal output (1,500w.).
The amp, primarly designed at Harris by Dave, W2DMR, uses a pair of 4CX1500Bs, driven by a pair of 8122s. The amplifier is a no-tune affair. It will cover from 2.0 through 30.0 mHz by selecting one of 19-frequency range positions either by a rotary switch on the front panel, or through a logic arrangement that drives the band-switch motor. The RF-110A was designed to operate with its own very sophisticated exciter/receiver. Interfacing is quite different than what you might be used to for amateur use. However, the adaptations needed can be made without cosmetically altering the amp and the adaptations don't require irreversable changes.
After operating the amp for several months and getting amazing reports on the quality and narrowness of the signal, I decided to eliminate the driver stage, swamp the 4CX1500B grids and drive them directly with the output of the transceiver. I did this because it seemed silly to crank the transceiver down to it's lowest output (5 w.), then, pad the 5 w. signal down to 100 mw., feed it into the amp and have the amp then boost the signal back up to 1,500 w output.
I discovered it was possible to clip the plate supply lead in the 8122 driver section, remove 8122 drivers (and sell them for $65 each within 10 hours on E-bay,) Then, I moved the input coax connection from one terminal strip to another and that's all.
It now takes about 25 to 35 watts, depending on the band, to drive the amp to full, legal power out. I don't want to sound boastful, but I must tell you that people often comment on the strength and narrowness of the signal. The transceiver is operating in a very linear range (max. 30 w out) and the amp is not being pushed at all. (The military de-rated it to 1 kw. out. Into a dummy load I can get nearly 2800 w from these two tubes in the class B bias position.) I run the amp in AB2 for all modes.
I have written a number of articles about the amp conversion. If you want copies of these, please contact me. Bruce, W3BP, Hanina, 4X4MU and many others have used the articles to get their RF-110As up and running and they have the loudest, cleanest signals imaginable.
73,
Mike Lonneke
W4MDL (ex-W0YR)
w4mdl@aol.com
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