x30 RF power increase?

[KX4KDH]

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Is there any way to increase the RF power to 50w in this radio without an outboard amp? I'm not looking for a lecture on the legality of doing so. I just want to know what it would take.

 

[davidgcet]

you could probably turn it up to 50 if it is a 40W unit, but you will burn out the PA sooner. honestly unless you are talking constantly you should not kill it anytime soon.

unless you gain a MINIMUM of 3db you won't see any difference though. so if you are doing 40W now you need to be in teh 80-100W range to have noticeably more talk out range. you could even turn the radio down to 30W and not see any difference between now and then so long as your antenna is right.

if you need a little more range, the better option would be to go with a higher gain antenna so that it affects TX and RX pretty much equally. there is no sense in being able to be heard 40 miles away if you can only hear the other party 20 miles away!

 

[KX4KDH]

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It is a 35w unit, so I don't know how high it would go. I am playing around with different antennas for now.

 

[davidgcet]

if it is the 830G it is 40W from what i see in the specs. 35W is not uncommon, and not enough difference to matter at all.

 

[KX4KDH]

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Yes, it is the TK-830G. It says 35w on the tag on the rear. However, I have also seen 40w on spec sheets. What do you think the line of sight distance should be with a quarter wave antenna?

 

[KX4KDH]

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Also, with this radio I should be able to hit a repeater from a good distance away, right? I tried the repeater in Cary, NC which has excellent coverage, and didn't do jack. I could open the repeater, but had garbage for audio, if any at all. I am thinking it is this Larsen Transit style antenna. I have a quarter wave on the way, so I will find out.

When in simplex, I have very good audio within a mile, or two as it is now.

 

[davidgcet]

sounds to me like you either have an antenna problem OR your radio is out of spec as far as frequency. a couple Khz off and you start to really notice poor range and crappy audio.

 

[KX4KDH]

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Hmm. I guess I need to put it on a meter somehow. Even though I have the frequencies programmed in, I'm sure it could go out of tune. When the antenna comes in, I will find out.

 

[davidgcet]

yes it can easily be programmed properly but out of tune, happens all the time. i had a couple that worked perfectly for about a month then drifted so far off freq we just replaced them.

 

[KX4KDH]

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Crap. I really hope it is the antenna. Like I said, it has great audio for about 2 miles, and then falls on its face.

 

[mrweather]

Not familiar with the Larsen Transit Antenna. It appears to be electrically similar to a 1/4 wave antenna.

If you need more gain consider a Larsen NMO4503CS which is a 5/8 wave (3 dB gain) or an NMO450C which has a bit more gain.

Where is the antenna currently mounted? A UHF antenna really needs height in order to work the best. Center of the vehicle roof is ideal.

 

[KX4KDH]

I have the antenna on the roof, almost in the dead center.... It's the one next to the blue Sharpie.

 

[davidgcet]

those trab style antennas are crap for range, you would do better with a 6" stinger. if you go with a gain antenna, you MUST tune it. don't just go by the cutting chart, put a meter on it and tune down the SWR. i prefer to start about 1/2-1" long and cut down, it is sort of hard to stretch a too short antenna!

unscrew that antenna and double check the prong/tab and make sure it is actually making contact with teh center tab on the mount.

also if you are looking for a replacement antenna look at laird, they are a lot more rugged than larsen. you drop a larsen, you toss it and put a new one on more often than not.

EDIT: one other thing, you did not accidently connect the wrong antenna to it did you? i see you have a low band(maybe) antenna on the other side and if you are hitting it with UHF it is a wonder it talks at all.

 

[KX4KDH]

The antennas are correct. The low band was installed weeks after the 450-470.

I have Laird quarter waves coming for the UHF, and VHF radios.

The low band will be removed for the time being, and VHF put in its place.

 

[davidgcet]

just checking, i have seen it many times and done it a few times myself. of course you catch it soon as you put the meter on though.

 

[wrightracing]

tuning for best power on a specific Freq range

Talking about power, I was wondering if there is a way to tune the TK-730 to get max power for a specific freq range?

I have bought a bunch of these radios and some transmit at higher watts at 151MHz than 156MHz
And just tonight I got a radio that did 45watts on 155MHz and 25watts on 151MHz.

Can we tune them to do better where we use them the most? And how?

Thanks for any help...

 

[davidgcet]

if you have to ask that question, you are neither qualified nor equipped to do the tuning. with a radio having that wild a power swing it is either that the 151 chans are set for low power mode via programming/switch or that the transmitter is wildly out of tune and requires a complete realignment with specialized equipment. i would double check the programming, then if that ain't it take it to a radio shop.

 

[KX4KDH]

It was the antenna.....

Well, I changed from the Larsen Transit antenna to a simple Laird quarter wave. Did a test run up the highway with my scanner at home logging everything. Now, I can get several miles down the road without it dying out, as opposed to this happening a mile down the road.

All of this because of a stupid antenna......

 

[fineshot1]

Well, I changed from the Larsen Transit antenna to a simple Laird quarter wave. Did a test run up the highway with my scanner at home logging everything. Now, I can get several miles down the road without it dying out, as opposed to this happening a mile down the road.

All of this because of a stupid antenna......

The antenna is perhaps the most important part of your radio system,
far more so than high output power.

Think of your stereo system at home or in the car. Do you install crappy
speakers on a great stereo setup? Hell NO!. You usually go the correct
route and use great speakers on a great stereo system to take full advantage
of the great stereo sound.

Same concept for radio communications gear. Only difference is RF vs AF.
The better the quality the antenna usually = better gain or radiating pattern
of an antenna.

 

[gewecke]

The antenna is perhaps the most important part of your radio system,
far more so than high output power.

Think of your stereo system at home or in the car. Do you install crappy
speakers on a great stereo setup? Hell NO!. You usually go the correct
route and use great speakers on a great stereo system to take full advantage
of the great stereo sound.

Same concept for radio communications gear. Only difference is RF vs AF.
The better the quality the antenna usually = better gain or radiating pattern
of an antenna.

Nice analogy!
n9zas