EMRFD Message Archive 8782

Message Date From Subject
8782 2013-07-05 11:03:25 Chris Trask Active Monopole Antenna Amplifier
Four and a half years ago I published an online article on active monopole antenna amplifiers. Lately there has been some renewed interest in the subject, so I pulled out all of the notes I had made since then and revised the article:

http://www.home.earthlink.net/~christrask/Complementar20%Push-Pull20%Amplifiers.pdf

Most of the changes are the result of comments and suggestions by people who have built my amplifiers, and others are a result of ideas gathered from commercial products.

Chris Trask
N7ZWY / WDX3HLB
http://www.home.earthlink.net/~christrask/
8783 2013-07-05 14:01:35 Alberto I2PHD Re: Active Monopole Antenna Amplifier
8784 2013-07-05 14:18:48 Chris Trask Re: Active Monopole Antenna Amplifier
>
>> / Four and a half years ago I published an online article on active monopole antenna amplifiers.//
>> //Lately there has been some renewed interest in the subject, so I pulled out all of the notes//
>> //I had made since then and revised the article:
>>
>> //http://www.home.earthlink.net/~christrask/Complementar20%Push-Pull20%Amplifiers.pdf//
>>
>> /
>That URL is badly malformed, and at least Firefox does not accept it.
>Modifying it in this way made it work :
>
>http://www.home.earthlink.net/~christrask/Complementary%20Push-Pull%20Amplifiers.pdf
>

I typed in the "20%" manually, and it should have been "%20".

>
>Additionally, IMHO, Fig. 3 seems to be upside down,
>

My Tektronix 575 displays PNP devices upside down, and I keep it that way so as to distinguish them from NPN devices.

>
>and in Fig. 12 the markings of T1 and T2 are perhaps swapped.
>

Yes, those are backwards. I'll take care of that shortly.


Chris
8785 2013-07-05 14:43:03 Chris Trask Re: Active Monopole Antenna Amplifier
>
> Four and a half years ago I published an online article on active monopole
>antenna amplifiers. Lately there has been some renewed interest in the subject,
>so I pulled out all of the notes I had made since then and revised the article:
>
>http://www.home.earthlink.net/~christrask/Complementar20%Push-Pull20%Amplifiers.pdf
>
> Most of the changes are the result of comments and suggestions by people who
>have built my amplifiers, and others are a result of ideas gathered from commercial
>products.
>
>Chris Trask
>N7ZWY / WDX3HLB
>http://www.home.earthlink.net/~christrask/
>

Ooops! That URL should have been:

http://www.home.earthlink.net/~christrask/Complementary%20Push-Pull%20Amplifiers.pdf


Chris
8794 2013-07-07 20:21:31 Gene Dorcas Re: Active Monopole Antenna Amplifier
The link wouldn’t work but I went to your web and maybe its all there???



I have for some time now thought that I could do better with a receive only antenna. I either run my 5w qrp rig or my FT-450D into a trap vertical. It seems to work very well when calling a DX station but I’ve often wondered what kind of compromise that trap vertical is for receiving. Do you think an active whip or dipole as a separate receiving antenna would yield any improvement??? I’ve been looking at the active antenna by Clifton labs and then I found your paper(s).



Do u have any suggestions???



Thanks,

Gene, W5DOR

gene@w5dor.com

www.w5dor.com





8795 2013-07-08 06:13:59 Chris Trask Re: Active Monopole Antenna Amplifier
>
>The link wouldn’t work but I went to your web and maybe its all there???
>

It's listed on the web page, but I've attached a copy for you. Seems I can't properly write a URL these days.

>
>I have for some time now thought that I could do better with a receive only antenna. I either run my 5w
>qrp rig or my FT-450D into a trap vertical. It seems to work very well when calling a DX station but
>I’ve often wondered what kind of compromise that trap vertical is for receiving. Do you think an active
>whip or dipole as a separate receiving antenna would yield any improvement??? I’ve been looking at the
>active antenna by Clifton labs and then I found your paper(s).
>
>Do u have any suggestions???
>

There's really no substitute for a full 1/4-wave vertical antenna. Active monopoles are convenient at low frequencies where tall verticals are impractical. They're also convenient in places where antennas are not allowed due to zoning or HOA rules.


Chris

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