Help Choosing An Amplifier, Power Supply, and Antenna for a HT

[KK4GDX]

I am a new ham and new to the forum. I'm getting an HT radio to use on the 2 m band and I would like to get a small brick amp, power supply, and antenna so that I can hit some of the more distant repeaters in my area. I am considering a Mirage B-34 or B-34-G for an amp, a MFJ-4115 or Astron SS-12 for a power supply, and an Arrow Antenna open stub J-Pole mounted 20 or so feet high outside. I think the B-34 would work fine as I don't need SSB or CW on 2 m but I'm not really sure about the power supply or antenna. The ability of all or part of the kit to be portable for use in the field would be a big plus. What do you all think? I'm not stuck at all on any of the brands or models I have chosen so please feel free to make recommendations.

Thanks for the help.

[KM3F]

Here are the considerations.
What will the radio output levels be?
Select and amplifier that will accept one of the drive levels without overdriving the amplifier but still near it's max so the power capability is not waisted.
Look at the amplifier spec for total current draw at max drive and output and size power supply at least 10% or more above that spec. Note this is based on input power not output power.
Select a vertical antenna with as much gain as you can handle for mounting, space and any portability considerations.
No use settling for a lesser antenna for the purpose your wanting to do.
Antennas are the one item a beginner fails on and only results in replacing it a second time when it should have been the better one the first time.
J poles are ok but not for top performance when you could have a gain antenna.
Remember if an antenna has 3db gain, that's equivelent to doubling 'effective radiated power' (ERP) of any power fed to it.
Good luck.

[KK4GDX]

My radio is 5 watts max. Thank you for all of the info.

[Lafayette]

Using an amplifier with a HT is like trying to put shoes on a cow.
It is not worth the effort.
Especially when combined with a J Pole antenna.

A transceiver - of 40 or 50 watts can be bought, new or used for less then the cost of a amplifier.

The amplifiers only job is to try to modify the output of the radio.
It will not increase the amount of receive power - going back into the radio.

The proper way to use an amplifier is to only use a amplifier when all other options has been exhausted.

Let me explain this to you in terms you can understand.

A long time ago, a company named Collins, who manufactured a quality filter for amateur radios, devised a scheme which is used to this day to measure the received power of a incoming signal.

They determined that as a base, you had X amount of signal present expressed in milliwatts or microwatts to move the needle 1 S Unit.
Each S unit beyond that level was a 6 DB increase in power.
IN the world of communications, once a signal can be heard and understood, it does not matter how loud the signals are - especially when you are dealing with a FM signal and repeaters. The job of the repeater is to receive everyone's signals and retransmit them from a high location which increases the range of the transceiver that transmitted the original signal. That is the reason why we build repeaters on top of mountains or very tall towers and not next to someones house where the owner of the repeater already owns the land, as a matter of convenience.

So you have 5 watts of transmit power.
1 S- unit of power beyond that 5 watts would equal increasing the power 4 times.
5 x 1 = 5
5 x 2 = 10
10 x 2 = 20
20 x 2 = 40

To move the needle one S - Unit, you need to increase Your transmit power to about 40 watts. If the amount of signal needed to break open the squelch of the distant repeater is this amount, then this is all that you need to accomplish your goal.

But one thing to remember is that everything beyond the BNC connector at the top of the handheld radio is expressed as loss. The reason why a Handheld radio works so well with it's rubber duckie antenna is because the antenna is mounted directly to the radio and there is no feed line loss.

Now if you want to move the S meter two S units, you need to increase the transmit power another 4 times.

40 x 1 = 40
40 x 2 = 80
80 x 2 = 160
160 x 2 = 320

That means to increase your transmit power two S units - you need to produce 320 watts of transmit power at the antenna, not at the amplifier.

Or you need to have a antenna with a gain of more then 1.

Your J Pole antenna's gain is Parity - or 1

By using a 8 DB gain antenna, you will not only have increased your transmit power about 1 1/2 times, you will have also increased your receive range by about the same amount. It does you absolutely no good to have a radio that talks but does not listen.

Unfortunately there is not many knowledgeable people left in this world that can understand this and is willing to stick their necks out far enough to tell anyone this - because there are no clubs anymore that teaches how communications works and the magazine editors are paid with advertising dollars which are provided by the radio and amplifier manufacturers.

Back in the day, amateur radio people were all professional people who were all linked one way or another by their educational background or by heredity to someone who was in the radio field and these people already knew this stuff.

Unfortunately today, the educational part is gone and all we have left is people who can regurgitate the answers to a simple test to get their license and that is the reason why we have so many dummies on the radio today.

http://k9erg.tripod.com/theory.htm

[KK4GDX]

Thank you for the lengthy explanation. I see then that you recommend a 40-50W transceiver over adding an amp to a HT. What do you recommend for an antenna?

[Lafayette]

Well - since the antenna does all the work, you need to decide which antenna will work best for your situation.
If you want to talk and listen in all directions equally well, the Diamond X 500 antenna is probably a good choice. If you want to talk locally - 50 miles or less - then the Diamond X 50 would work for you. If you want to work SSB - which can talk 1500 miles on a good day, then some sort of beam would be the answer. I know of some guys who owns M2 beams 9 and or 11 elements that talks the world with 100 watts or less.

I was reading an article in CQ magazine last night and I think they said that the difference between a 100 watt signal and a 5 watt signal was just 16 Db or 2 1/2 S units.
Which means if you had a 16 DB antenna and a 5 watt radio, the loss in the line and the loss in the connector removed, you would still probably have 9 - 12 DB of gain with a 16 Db antenna at 144 or 440 MHz, depending on the amount of loss in the line at X MHz.

[KK4GDX]

Thanks.

Chris

[K7KBN]

More like 13dB. Ten times the logarithm of (Power #2 divided by Power #1)

Power #2 (100) divided by Power #1 (5) = 100/5, or 20.

Logarithm (base 10) of 20 = 13.01....something. But not 16.