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Reviews Categories | Amplifiers: RF Power - HF & HF+6M | Explorer ll 1200 Watt linear with step start Help

Reviews Summary for Explorer ll 1200 Watt linear with step start
Explorer ll 1200 Watt linear with step start Reviews: 2 Average rating: 1.5/5 MSRP: $1595GBP (around 2250 Dollars)
Description: British built 1200 Watt linear with 1.2KVA toroidal transformer and 2 x 3-500ZGg tubes
Note: Photo shows the later model "Ranger", externally otherwise similar
Product is in production.
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G8ITB Rating: 0/5 Mar 31, 2008 16:06 Send this review to a friend
Walk Away!  Time owned: months
Having just used an Explorer HF linear in contest mode - for a while anyway! Till it stopped working after a very few hours use!

A detailed examination revealed extremely poor quality construction practices by the manufacturer; i.e.
Using a "BOLT" fixed to the range switch arm to contact a HV capacitor on one band.
Voltage doubler circuit for HV.
No Co-Axial antenna relay - just two holes punched in a relay case and the small diameter wires to/from the RF in/out SO239's soldered directly onto the relay leaves using wires going through the relay casing.
A low throughput 'muffin' fan pulling air out past the output valves - no way was this set-up capable of cooling the linear - air intake was minimal and further restricted if the case placed on a hard surface - the intakes are punched holes in the base.
No cooling in the toroid mains transformer area.
Components are working on limits.
"Soft Start" - just look at the schematic; then the construction [stop laughing, please].

Linear Amp UK was the 'successor' to Heatherlite - and all their products have a reputation in the UK as 'nasty' and this one confirmed it as correct.

Linear Amp UK has ceased trading as of March 2008 and production has been taken over by Elite Interfaces Ltd, Reading, Berks, RG1 8JP.
Lets hope they can do better!

In the meantime if you are offered a Linear Amp UK amplifier [even free] - just walk away!

Richard P.
GW3NCT Rating: 3/5 Jul 21, 2002 13:30 Send this review to a friend
A curate's egg - good in parts  Time owned: 0 to 3 months
I have had it only 3 weeks. Bought secondhand. Almost 6 years old and the valves ( 2 x 3-500ZG's) are possibly past their best. I find the tuning very vague on 80 and little better on 40. Definitely needs an external power meter to tune up effectively on 80 and 40 and probably also on the other bands. Does include all WARC bands. No QSK. Pre-tuned input circuit, so no adjustment required as is the modern way. Apart from the 5 second step-start after switch-on, is instantly ready. Blower not too noisy, except late at night does intrude somewhat.

Not impressed at the innards. Uses 1 Amp diodes in the usual voltage doubler with high value bleeders. Smoothing is insubstantial in my opinion. Philips consumer grade electrolytics arranged in two banks of 4, rated just 385 volts each, giving a total working rating of just 3,080 volts. Not much headroom. Has a front panel adjustable AFC, but unlikely to be needed with the usual 100 Watt drive. Has a confusing "RF-Out" control which shows increasing deflection on the meter, but does not affect the displayed power out on an external power meter, but it DOES affect the reports back from other stations. In my case needs to be set to just over half way.

I like good build quality. I would not have bought the unit had I known of its inferior build quality, not even second hand. I will sell it on. I have already ordered a new QRO HF2500DX. I will report on the QRO after receipt.

I am saddened to have to report so negatively as I am British myself (look at my callsign). However, I feel it could have been so much better had a little more thought gone into it and a little less caring about cutting costs to the bone.

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