PORTABLE POWER FOR A KL500 AMP?

[rocket]

As a matter of interest, the KL500's we test will regularly shut down a 40A PSU, the juiciest KL500 I've ever tested drew a whopping 44A.

I know that it should draw a maximum of 36A (according to the RM specs) but reality is different.

Add the current draw of your FT-840 into the equation and you are most likely exceeding the max output of your cars alternator (probably around 45A) hence the Voltage drop.

[rich]

Think it's RF feedback - come to think of it i got a minor rf shock/burn from screw in back of mic on one of the occasions when it reset itself.
I'll try seperate leads as a starting point then ferrites if that doesn't cure it - thanks guys.
Rich.

[jazzsinger]

i assume you've tried it using megawatt 4000,i may be wrong,you didn't make it clear,does same thing happen using i max 2000,its almost definately rf feedback causing problems,if mic is picking it up you could filter the mic's audio wire with a couple of small ferrites like you get on speaker wires,or a resistive/capacitance filter [4.7kohm 1/4 watt resistor in series with audio wire,for extra filtering you can add a.001?F or .01?F ceramic disc capacitor in parrallel between audio wire and shield] ,another good way of reducing rf feedback is too mount antenna by drilling hole and using so239 dv style mount for better grounding[magmounts and high power are a common cause of rf feedback,due to insufficient grounding via mag base].

if amp draws 30-40 amps then best use at least 50 amp dc cable.best with at least 30 amp cable for transceiver or if running both of one cable about 80 amps,ensure cables aren't around 9 ft in length as they will be a pretty efficient 11m 1/4 wave which could also be a way in for rf.ferrites on radios dc wires can also help if rf pickup is via these,ferrites should be added close to transceiver.ensure swr is below 1.5:1 as reflected rf voltages could also be the cause of the problems.ive seen the same thing on a yaesu 2 m set,when the icom 706 was keyed the yaesu processor reset.funnily enough the setup used two magmounts and a megawatt 4000 on the ic 706, with a dual band 2m/70cms whip on the yaesu.

you could also tie the radio chassis to ground too.probably the best solution is too direct ground the antenna rather than use a magmount. if problem is on i max 2000 too, better qualitry coax could be the answer,something like mil spec rg 213/u and a 1:1 rf choke balun would stop reflected rf reaching the radio.

[Northernlights]

If the swr is correct without the amp it will be correct with the amp (Just about) as swr is a ratio so power is not particularly relevant

Hi Rich!
The problem sounds very like a Ampage drain , you should be using separate power leads from the battery , as the higher ampage linear is going to bleed off the power from you rig , also YES keep the engine running even when just using the rig pwr , some Ham rig are very touchy on the amps , yes you will get 100w engine off , but you could find your audio is crap , Icom 706 is very bad for this !

Also when hooking up ANY linear the SWR match between rig and linear must be checked and sorted out , I've found quite a few of the big RM mobile linears to have highish SWR readings out of the box (not a good thing for your rig ! ) also good grounding to the body of vehicle ,both rig and linear helps to elliminate stray RF (ECU's don't like high RF levels much) as well as a handfull of ferite chokes ! here and there .

There's a guy up in my neck of the woods, who hooked up a Auto tuner to a yaesu 857 with separation kit in his car, with no grounding !!
next thing while using full cw keydown to tune the rig,with one hand on the key he touched the head unit with the other hand grounding the RF and blew the microprossesor in the head unit (Ouch ! very expensive !!)

Hope this is of assistance to you .
Scott.

[91dd018]

Running an amp in a car is always problematical. It will show up any weaknesses in your set up. If the antenna is connected to the car as in the case of a mobile whip or magmount more problems.
Grounding and thick cables are the only only solution.
Ground everything and do not rely on the device or antenna mount to do it properly.
Especially important is to ensure the antenna braid is grounded at the antenna.
Connect the power leads to the battery terminals with fuses on both leads close to the battery.
Ground the radio to the chasis
Ground the amp to the chasis with a separate cable to the same point.
Be aware that the RF can get into the cars electrical system and do all sorts of strange things especiall to vehicles with computerized systems.
The RF can not only destroy hi tech radios driving them but also the cars computer.
500w from a mobile set up certainly gets out well as you drive down the road with the wipers coming off and on, the auto door locks activating and the security system warning horn blaring.
Take the portable quad and pole and head for the hills.
Good luck
Dave

[rich]

Guys - was portable today 100ft ASL in 68div.
Used the KL500 with the IMAX2000 running it directly from the vehicles battery on 40amp cables. Ran the FT840 from the same battery but on seperate 25amp cables.
Absolutely no probs - used the amp all day (engine running) with some great signal reports: +10 into central Liverpool, S( into Glasgow, S8 into Glasgoe, S5 into Manchester, S9 into Yorkshire.
Delighted to say the least.
KL500 showed 200W on the meter @ setting no. 1 peaking @ 320w on setting no. 4. Settings 5 & 6 showed no further increase in output. That said happy enough with 320w and nice clean audio reports.
Thanks for all the help. Combination of seperate power leads & IMAX2000 did the trick.
Rich.

[rich]

correction on above - make that 1700ft ASL NOT 100ft ASl!! lol..

[leep59]

Guys - was portable today 100ft ASL in 68div.
Used the KL500 with the IMAX2000 running it directly from the vehicles battery on 40amp cables. Ran the FT840 from the same battery but on seperate 25amp cables.
Absolutely no probs - used the amp all day (engine running) with some great signal reports: +10 into central Liverpool, S( into Glasgow, S8 into Glasgoe, S5 into Manchester, S9 into Yorkshire.
Delighted to say the least.
KL500 showed 200W on the meter @ setting no. 1 peaking @ 320w on setting no. 4. Settings 5 & 6 showed no further increase in output. That said happy enough with 320w and nice clean audio reports.
Thanks for all the help. Combination of seperate power leads & IMAX2000 did the trick.
Rich.

I tried mine today mobile on fm and was driving it with 10w kl500 peaked at 230w on stage 6.40amp cable for boot and seperate for radio.but apparently it can draw upto 55amps on full drive

How does that sound to you guys........