[Lowfer] New QRSS beacon KE on in NC

[jrusgrove at comcast.net]

Kasey

Haven't seen pix of your setup ... please post here or send direct.  Also, not sure where you are on the LF learning curve so if you're already familiar with the following feel free to ignore it ;-) .

While a VSWR indicator is an appropriate tool for the higher bands it's not all that useful at LF... an rf ammeter between the loading coil/variometer and the vertical antenna wire will tell you just about everything you need to know about your antenna. Resonance, or nulling out the antenna reactance while adjusting the variometer, will appear as a peak in antenna current. A sharp peak indicates high Q (desirable) and a shallow peak low Q (undesirable). The measured antenna current and transmitter power can be used to calculate antenna R. One should strive for the highest possible antenna current while maintaining the legal 1 watt input power. Higher antenna current is brought about by lower antenna losses. Improvements in the ground system are likely to make the most difference. Larger diameter wire in the loading coil is another improvement but rarely is it as important as a better ground system. 

A top hat adds capacitance to the antenna reducing the required inductance of the loading coil for resonance ... there's less loss with a smaller coil. The capacitance hat also raises the current 'density' further up the vertical wire which increases effectiveness.

Since the transmitter final amplifier is located directly at the antenna, the tap on the loading coil does not necessarily need to be adjusted for 50 ohms. The only requirement for the tap position is to provide reasonable voltage and current levels of the final amplifier when producing 1 watt. 

>From your picture on QRZ.com you look pretty young (compared to most of us 'oldtimers') so we're overjoyed to have you join this group! I'd be happy to send you a suitable rf ammeter for your project if you can't find one locally ... just say the word.

Don't hesitate to ask a lot of questions. We'll all be watching for your signal! 

Jay W1VD  
  

----- Original Message -----
From: KA4SEY <ka4sey at gmail.com>
Reply-To: Discussion of the Lowfer (US, European, & UK) and MedFer bands <lowfer at mailman.qth.net>
To: Discussion of the Lowfer (US, European, & UK) and MedFer bands <lowfer at mailman.qth.net>
Sent: 11/19/2020 5:41:15 PM
Subject: Re: [Lowfer] New QRSS beacon KE on in NC
________________________________________________________________________________

I'm not sure on the resonance, I dont have anything that can measure the SWR at that frequency. Only putting out about 450mw with only one transistor. (Must be high swr if my finals keep blowing). But where its tapped at now shows the strongest signal back at the house.KA4SEY, KaseySent from my Verizon, Samsung Galaxy smartphone
-------- Original message --------From: jrusgrove at comcast.net Date: 11/19/20  5:19 PM  (GMT-05:00) To: "Discussion of the Lowfer (US, European, & UK) and MedFer bands" <lowfer at mailman.qth.net> Subject: Re: [Lowfer] New QRSS beacon KE on in NC What is your antenna current at 1 watt? How sharp is the peak at resonance?Jay W1VD______________________________________________________________Lowfer mailing listHome: http://mailman.qth.net/mailman/listinfo/lowferHelp: http://mailman.qth.net/mmfaq.htmPost: mailto:Lowfer at mailman.qth.netPost must be less than 50KB total for message plus attachment!This list hosted by: http://www.qsl.netPlease help support this email list: http://www.qsl.net/donate.html
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