RM KL 505 tested by M1APC @ The Shack

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RM KL 505 tested by M1APC @ The Shack

Рет қаралды 5,744

James Hulme

Күн бұрын

Пікірлер: 24

@mbak7801 3 жыл бұрын

In another youtube channel the 12V tracks around the fuses in these amps is criticised for being too thin. This causes voltage drops and localised heating of the board. His fix (with a fair sprinkling of kapton tape) was to run a 18 gauge wire in parallel to improve 12v current capability. Makes some sense and is reversible and non destructive.

@JoeR203 4 жыл бұрын

I still have my RCI Ranger RG-99 which is the same design, but all black.

@hamradio701 4 жыл бұрын

Four transistor MRF 455 each one 60 watt tot out power 240 watt.....

@xszl 4 жыл бұрын

Only came here cuz i saw an old Pres. Grant in the thumbnail

@SadisticFella 4 жыл бұрын

Same here, had one in late 80's with an old turner desk mic and it sounded beefy.

@grahamefreestone5309 6 жыл бұрын

My zetagi b300p does the same thing on position 1 with 5 watts going in from a Grant 2 to a gainmaster. Positions 2 through to 6 are fine. So i keep it off 1... :-)

@golden-balls-radio 6 жыл бұрын

hi James, pretty sure rm specify 1/10 watts in on all modes rather than 10/20 max on the 405 for example.

@MM1APC 6 жыл бұрын

Edd Rhodes I've yet to come across any CB and that does what it says on the box. Their all crap!

@eknaap8800 4 жыл бұрын

RM specifies for the KL-505: 2-10W AM/FM and 5-15W SSB (PEP). It has a circuit which cuts back the amplification when overdriven (for a short period...).

@harrybatt998 3 жыл бұрын

@@MM1APC Hi James, You evidently know what you're talking about, so I thought I'd ask a question if it's OK? I was going to opt for the KL503, however, I heard they sound dismal on SSB. Instead, I changed my order to the KL505 as you have here. On another forum, I've been told that "stock", they're incapable of working on 11M due to notch filtering at the input. I was told 11M will be blocked to ground. Do you know if this is true, please? Also, do you think I've made the right choice going for the KL505 as opposed to the Mosfet KL503?

@eknaap8800 4 жыл бұрын

When I do the math: 30A @ 13.8V is 414W. Heat dissipation and other losses 50W. Left with 360 odd Watt. I can't get mine over 325W PEP @ 15W input max. It does cover most part of the HF (10 to 80 mtr) band though.

@g0fvt 4 жыл бұрын

You would expect to lose about 60% of the input power reaching the output, so for about 420w dc input you might get about 280w output. You also need to figure in the likely voltage drop in the power cables if you are not checking it at the actual amplifier. Although these amplifiers are usable on other bands they really ought to be followed by a suitable filter for each band. I was given an RM amplifier similar to this, unsure whether to use it or rob the transistors from it.

@eknaap8800 4 жыл бұрын

@@g0fvt UPDATE: I replaced the 3 fuses with a straight wire and fed the 3 diodes also with thick wire (instead of only via the PC board). I measured a voltage dorp of about 3 V over the fuses and diodes. I've put (car) fuses in the feedline (40A each), the type one would fuse their subwoofer amp in a car... Output power is about 350W PEP now on 20 and 40 Mtr and a bit more on 10 Mtr. (Which isn't surprising, because the KL 505 is based on a CB amplifier, I think). 73, PD0PSX

@g0fvt 4 жыл бұрын

E Knaap, definitely a step in the right direction!

@g0fvt 4 жыл бұрын

E Knaap I just noticed the typo ai made 5 months ago....

@eknaap8800 4 жыл бұрын

@@g0fvt One wee little typo in an elaborate comment, isn't much to worry about. As an English teacher in the Netherlands, I often comment on grammar and spelling mistakes. They ususally make those in a one sentence comment, which makes it for me hard to palate... (Especially when English is their first language). 🤦‍♂️