hey all..
so i have an issue.

I bought a tugicom 300w kit.
http://www.tugicom.com/fm-transmitter-kits/300w.html

It comes with both the 24 and 48w PSU that are needed, but heres the confusing part..
The 300w amp has a power feed for the exciter @ 18v.. the exciter takes up to 24v..

Why would they add the feed when the psu is in the kit, i know the amp needs both, i just dont see why they have gone through the bother..

Anyway, my issue is when i fire it up, its only pushing one watt via the exciter, the amp isnt firing up.. but the exciter is drawing its power from the amp, so there is power there.

Bit confused, ill post some pics if needed..

Any thoughts?

Ofcourse pics are needed...


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will go take pics now, i was in bed at the time.

Its common to find a regulated feed for the exciter on amp boards. At a guess maybe the exciter needs reduced drive to power the input of the amp??

download/file.php?mode=view&id=137

300w amp,
Small red cable coming off top left is the 18v supply for the exciter (tx190)
It was a bit sort so i did a join, soldered it, taped it up and stuck it to the wall out of the way.

Beside it you can see the 24v and 48v power coming in from the respective power supplies.

The blue to the right of it is the ground from the24v psu.

Just below the blue on the right is a red cable, its soldered and locked in place with a screw, its a ground going back to the box.


Midway on the lower part of the board, brown cable (nothing is colour coded, all 2.5 mains cable used.. untidy i know) is the 1w in from the exciter.

to the right of it we have ground, the cable was earth cable now wrapped in electrical tape, its going to the to exciter as well, but halfway along the cable its grounded to the box.

Brown cable bottom right, RF out to Ntype chassis mount.

More pics to come.

download/file.php?mode=view&id=138

In the pic you can see the amp, (top left)
on the right is the 48v psu and the 24v mounted on a piece of wood and glued to the top of it.

Above them on the right of the box is a little power strip i made up.. powered by 240v its distributed to each psu and an outer power supply for the fans (old laptop psu)

bit messy i know, its not the final build, looking for a more suitable case and do a final, clean rebuild.

God damn! Did you use WIRE from amplifier output to Antenna connector??? And from exciter to amp? This is for sure reason you don't get power! Also, with 300w there is serious risk of rf burns! This setup shouldn't be used even for test. You MUST use 50ohm coax with ground soldered on both ends!
Man, please be careful with this stuff...


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:/ yeah i did.

rg213 ok, or a higer spec needed?

Lol, you would be better off buying some decent teflon coax for internal soldering. The teflon insulation resists heat much better than standard coax. If you use standard coax the insulation melts easily and can cause a short between centre conductor and ground (inside the cable)..

The stuff I use for amplifier output to output aerial connector is RG-142B/U, this was fine for 150W, I would imagine you could use it for 300W no problems.

For exciter to amplifier input you dont need as good a cable as above, have a look on Ebay, I bought some high quality ultra thin teflon cable on there was excellent.

What have you got the amplifier terminated into when your powering it up, in your other post your asking about making a 300 watt dummy load.

hey shorty,
i had it going into a 5/8w rated to 500w (now they sell them rated to 2Kw.. https://www.a****f.com/en/5-8-fm-transm ... ntenna.htm) and measured to 105.1.. LMR400 cable.

I want to build the dummy load so i dont have to climb every time i want to test.
500w dummy gives plenty of room to play around.

download/file.php?mode=view&id=139

This looks much better and safer now... You could keep that rg213 as it is rated to 1kw. It would be much easier to use some teflon coax as it is thiner. Exciter to amp could be regular rg58. Heatsink for your dummy load from other post should be about three or four times bigger than this on your amplifier


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Grand stuffs, so other than my stupid mistake with wiring, its all looking above board?
Ill have to go for a climb and test it out tonight..

Im not going to, but given that it has SWR protection, turning it on without an antenna, the amp should fire up and then the SWR make it kick into a loop of restarting yeah?

pjeva, cheers for the heads up on the teflon coax, ill look into getting some for the future.

There are few methods of swr protection. Some turn off amplifier completely, some turn of driver stage too, and some just turn down power to 10 or 20% until swr is back to normal. I am not into Tugicom stuff so i don't know what they use. Maybe someone else could explain better. Anyhow, take care... Cheers!


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http://www.tugicom.com/rf-amplifier/amp300.html

- SWR protection - auto shut down

thanks for the help.

Are those fans the correct way round?
They should be blowing air onto the heatsink, not extracting from the case.

Maximus wrote:Are those fans the correct way round?
They should be blowing air onto the heatsink, not extracting from the case.

In this heatsink position it is not ok to draw from the case. He should mount it horizontaly so there can be air flow from one side of the case, through the heatsink and out through the fans...




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Passing hot air over a fan will shorten its life dramatically.

Turning the fans around would be an improvement, however turning the heatsink by 90°, fitting it in close proximity to the case and fitting the fans on the opposite end so as to "blow" cool air over the heatsink would be better still.

So you're not a fan of his building work then?