Kenwood TK-8180 max transmit power

[VladSF]

I finally had time to setup my 8180 as a base station.
While setting up the radio I noticed that at high power its uses 5amps.
So I looked in panel mode and max transmit power set at 60.
Is it safe to raise it to lets say 95 so I am draining 8 apms from power supply? (according to Kenwood at max power should be around 9 amps)
If anyone has this radio would love to know what your max transmit power is set up for.
I have a feeling it was lowered by previous owner.

 

[kayn1n32008]

What is the complete model number? This will determine what you can safely run the radio at.

 

[VladSF]

What is the complete model number? This will determine what you can safely run the radio at.

TK-8180-K2

 

[kayn1n32008]

Your radio is a 25w radio. It should draw 5-7 amps and output no more than 25w.

Just because the slider can move, does not mean it should. Just because the manual says it can draw 7-9A does not mean it should.
If it’s transmitting @ 25w leave it alone.

 

[bruch]

The service manual states that the High Power setting should be adjusted to 28 Watts (+/- 3 Watts) output into a 50 ohm dummy load, not adjusted by the amount of current the radio draws, however it is rated at 30 Watts at no more than 9 amps draw.

 

[VladSF]

I was hoping to avoid purchasing a watt meter, but I guess I will have too.
Its just seemed strange to me that the radio was only taking 5 amps instead of 9 on high power.

 

[N5XPM]

The service manual states that the High Power setting should be adjusted to 28 Watts (+/- 3 Watts) output into a 50 ohm dummy load, not adjusted by the amount of current the radio draws, however it is rated at 30 Watts at no more than 9 amps draw.

I have not aligned TX power on a TK 8180 in awhile, but the adjustment in the radio is not calibrated to watts (which I think is already understood here). Also, as noted you should be transmitting into a dummy load and the service manual usually defines an alignment sequence that specifies a particular frequency to be used for adjusting the transmit power into the dummy load.

The current draw in the specs is usually at a specific voltage as well and analog ammeters on power supplies are not necessarily well calibrated.

Without following the full alignment sequence, I would leave it alone and consider lower loss coax and a higher antenna instead to improve transmit AND receive performance. After that, if more output is needed, just buy a TK 8180 (H) for the 45 watt output.

 

[VladSF]

I have not aligned TX power on a TK 8180 in awhile, but the adjustment in the radio is not calibrated to watts (which I think is already understood here). Also, as noted you should be transmitting into a dummy load and the service manual usually defines an alignment sequence that specifies a particular frequency to be used for adjusting the transmit power into the dummy load.

The current draw in the specs is usually at a specific voltage as well and analog ammeters on power supplies are not necessarily well calibrated.

Without following the full alignment sequence, I would leave it alone and consider lower loss coax and a higher antenna instead to improve transmit AND receive performance. After that, if more output is needed, just buy a TK 8180 (H) for the 45 watt output.

I am pretty happy how radio transmits.
I just have a feeling its transmitting at half power (10-15 watts instead of 30)

 

[mmckenna]

The alignment procedures for those radios requires a number of steps.
Plugging it into a watt meter and a dummy load is only part of it.

The manual calls for putting it on a bench power supply set to 13.8 volts with an ammeter in line. Setting the RF output power involves watching current consumption as part of the process.

If the radio is working for what you need, adjusting the RF power output without following the correct procedures can create more issues. Anway, a few extra watts isn't going to make any noticeable difference on the far end.

 

[VladSF]

The alignment procedures for those radios requires a number of steps.
Plugging it into a watt meter and a dummy load is only part of it.

The manual calls for putting it on a bench power supply set to 13.8 volts with an ammeter in line. Setting the RF output power involves watching current consumption as part of the process.

If the radio is working for what you need, adjusting the RF power output without following the correct procedures can create more issues. Anway, a few extra watts isn't going to make any noticeable difference on the far end.

Kenna,
Thank you for your input.
At the end of the day amateur radio its just a lot of fun and experiments for me.
I think I will get a watt meter, I have built in amps meter and will experiment with this radio.
If things go wrong I can hopefully go back to original settings or if it breaks it was that expensive ether, but will be an interesting learning curve.

 

[cmdrwill]

If things go wrong I can hopefully go back to original settings

Before you make any changes, READ the radio and save that in an archive. BEFORE making ANY adjustments READ the radio's alignment/calibration values and SAVE them to an archive.

 

[VladSF]

Before you make any changes, READ the radio and save that in an archive. BEFORE making ANY adjustments READ the radio's alignment/calibration values and SAVE them to an archive.

Ofcourse, would not do it any other way.

 

[mmckenna]

Per the manual, you want a bench power supply set to 13.6 volts capable of 20 amps (although your radio will only pull 10 or so at the most)
RF watt meter
50Ω load.
Accurate ammeter.


Radio should not pull more than 9 amps.

Depending on the exact frequency used, power level will be anywhere from 21-35 watts.

You really should acquire a service manual for that radio and go through the whole process.

 

[VladSF]

Per the manual, you want a bench power supply set to 13.6 volts capable of 20 amps (although your radio will only pull 10 or so at the most)
RF watt meter
50Ω load.
Accurate ammeter.


Radio should not pull more than 9 amps.

Depending on the exact frequency used, power level will be anywhere from 21-35 watts.

You really should acquire a service manual for that radio and go through the whole process.

Kenna,
If you don't mind me asking what page this info is in the service manual?

 

[VladSF]

Per the manual, you want a bench power supply set to 13.6 volts capable of 20 amps (although your radio will only pull 10 or so at the most)
RF watt meter
50Ω load.
Accurate ammeter.


Radio should not pull more than 9 amps.

Depending on the exact frequency used, power level will be anywhere from 21-35 watts.

You really should acquire a service manual for that radio and go through the whole process.

I think I just found it in p36

 

[mmckenna]

I think I just found it in p36

Yeah, depends on what version you have.

Having the service manual can be handy. Basic test gear like a watt meter, dummy load, ammeter/volt meter will let you make a few adjustments easily.

 

[VladSF]

Yeah, depends on what version you have.

Having the service manual can be handy. Basic test gear like a watt meter, dummy load, ammeter/volt meter will let you make a few adjustments easily.

I have a built in digital amp meter, but I need to get a watt meter, any recommendation on what to get?
I looked at mfj but they have really mixed reviews. I know you get what you pay for but is there anything mid range that is decent?

 

[mmckenna]

I have a built in digital amp meter, but I need to get a watt meter, any recommendation on what to get?
I looked at mfj but they have really mixed reviews. I know you get what you pay for but is there anything mid range that is decent?

Best mid range? yeah, get a used Bird 43 with the proper element for UHF and your wattage.

I bought a used one about 20 years ago and an assortment of slugs to handle everything from a 4 watt CB radio up to 100 watts on UHF.
MFJ is junk and I would not trust it to do any sort of reliable radio alignment at all.

A used Bird 43 will run you in the $100 to $150 range, if you shop around. Don't be concerned about looks, they are very simple devices. A line section, a cable and a meter. As long as it has all three of those, you are good to go. The box it sits in can be spray painted if needed. You can swap out the connectors on the end easily if the one you find doesn't have what you need (Get N connectors, much more useful/universal). Easy to find extra parts for them.

The elements are easy to find, but you'll pay from $30 to $50 each.

More costly than an MFJ meter, but it'll last you a lifetime. There's a good reason they've been around for so long.

 

[WRCM]

I'll second that: get a Bird or a Coax Dynamics. The cheap (and even not so cheap) swr/wattmeters that are marketed to radio hobbyists can be wildly inaccurate. And if you ever need a wattmeter for frequencies much over 500 MHz, you will have to buy a Bird or Coax Dynamics anyway.

 

[WA0CBW]

Old technician trick for a Bird wattmeter. Put an "N" connector on one side and a "UHF" connector on the other side. Make a jumper the same way, an "N" on one end and a "UHF" on the other. Now it will work with either type connector and only one jumper and you don't need any adapters.
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