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Total 258 documents matching your query.

121. Re: Topband: T-loaded vertical (score: 1)
Author: GEORGE WALLNER <aa7jv@atlanticbb.net>
Date: Wed, 19 Feb 2020 23:39:30 -0500
The T has another advantage: it is better on 80 (and 40) if you can match it. A 160 m inverted L, with a substantial length horizontal wire, makes a poor 80 meter radiator because of high angles. A T
/archives//html/Topband/2020-02/msg00186.html (10,169 bytes)

122. Re: Topband: Hi Z amplifiers for 160m (score: 1)
Author: GEORGE WALLNER <aa7jv@atlanticbb.net>
Date: Wed, 11 Mar 2020 09:28:44 -0400
Chris, Assuming a trans-impedance amplifier, "unity gain" is enough (with reasonable size elements). Noise and IP3 are far more important. Lightning and surge immunity are also important. Also, isola
/archives//html/Topband/2020-03/msg00110.html (8,316 bytes)

123. Re: Topband: Hi Z amplifiers for 160m (score: 1)
Author: GEORGE WALLNER <aa7jv@atlanticbb.net>
Date: Wed, 11 Mar 2020 22:30:09 -0400
Here is an example at Digikey: ACX1545-ND Expensive, but... 73, George Can you point to a place that sells them. I became a 'fan' of F termination, but have recently had second thoughts because of th
/archives//html/Topband/2020-03/msg00124.html (8,849 bytes)

124. Re: Topband: Hi Z amplifiers for 160m (score: 1)
Author: GEORGE WALLNER <aa7jv@atlanticbb.net>
Date: Thu, 12 Mar 2020 13:52:14 -0400
Chris, Good choice. Perhaps one note of caution. With a BJT input like this the input current noise may be more dominant, unless the input impedance is kept low. Would be great to see the final desig
/archives//html/Topband/2020-03/msg00131.html (8,957 bytes)

125. Re: Topband: Restoring the Signal to Noise Ratio (score: 1)
Author: GEORGE WALLNER <aa7jv@atlanticbb.net>
Date: Fri, 13 Mar 2020 13:28:10 -0400
This is only half tongue-in-cheek. With the ambient noise going up, and there being limits to the size and cost of receiving arrays most amateurs can build, the next logical step is to raise the outp
/archives//html/Topband/2020-03/msg00153.html (10,957 bytes)

126. Re: Topband: Misek/Lankford Phaser 2 Project (score: 1)
Author: GEORGE WALLNER <aa7jv@atlanticbb.net>
Date: Sat, 14 Mar 2020 00:25:57 -0400
I have built and tested Langford's Phased Delta Flag Array. It was very good. I have built this antenna on a small, remote island in the Bahamas. I compared it with a DHDL and a single flag (same dim
/archives//html/Topband/2020-03/msg00158.html (12,312 bytes)

127. Re: Topband: Slightly OT - amplifier noise (score: 1)
Author: GEORGE WALLNER <aa7jv@atlanticbb.net>
Date: Sat, 14 Mar 2020 13:12:59 -0400
Steve, The J310 is normally a pretty low noise device. Perhaps you should look at filtering the power supply and any control and feed cables. GL and 73, George, AA7JV I have an RX amp question, relat
/archives//html/Topband/2020-03/msg00166.html (8,743 bytes)

128. Re: Topband: Slightly OT - amplifier noise (score: 1)
Author: GEORGE WALLNER <aa7jv@atlanticbb.net>
Date: Sat, 14 Mar 2020 13:20:42 -0400
Steve, Sorry, I did not directly answer you question. Look at the specs of the IF3602. (But also look at the price!) George AA7JV I have an RX amp question, related but slightly off-topic. I have an
/archives//html/Topband/2020-03/msg00167.html (8,715 bytes)

129. Re: Topband: Ground Conductivity (score: 1)
Author: GEORGE WALLNER <aa7jv@atlanticbb.net>
Date: Tue, 24 Mar 2020 09:21:31 -0400
To some extent the term "ground conductivity" is misleading. It gives us false hope. If we thought of it as ground "resistance" we would gain a better appreciation of what it does to RF currents. In
/archives//html/Topband/2020-03/msg00316.html (9,296 bytes)

130. Re: Topband: (no subject) (score: 1)
Author: GEORGE WALLNER <aa7jv@atlanticbb.net>
Date: Fri, 27 Mar 2020 11:08:20 -0400
During the past week I have been surprised by the good propagation between FL and EU. I have a noisy home QTH and do not have an RX antenna now (rebuilding it). The noise on the TX antenna here is S8
/archives//html/Topband/2020-03/msg00361.html (9,457 bytes)

131. Re: Topband: Amazing conditions into the UK this morning. (score: 1)
Author: GEORGE WALLNER <aa7jv@atlanticbb.net>
Date: Sun, 29 Mar 2020 08:56:56 -0400
I was on a around that time and I only heard a few NA stations calling CQ. Unlike earlier this week, not one EU signal in FL (on a noisy TX antenna). 73, George, AA7JV Turned radio on this morning at
/archives//html/Topband/2020-03/msg00373.html (9,461 bytes)

132. Re: Topband: Inverted V vs inverted L (score: 1)
Author: GEORGE WALLNER <aa7jv@atlanticbb.net>
Date: Sun, 19 Apr 2020 13:02:26 -0400
Peter, It depends on a lot of things: ground characteristics, number of radials, height of radials and the overall height available. Generally, over average-to-good ground and with 32 or more radials
/archives//html/Topband/2020-04/msg00094.html (8,355 bytes)

133. Re: Topband: Rohn 25 Vertical questions. (score: 1)
Author: GEORGE WALLNER <aa7jv@atlanticbb.net>
Date: Fri, 21 Aug 2020 15:27:43 -0400
At C6AGU I have in-band RX on all bands. The rigs are Flex 6000 SDR-s. On 160 m I can hear virtually unimpaired to about 12 kHz off the TX frequency. RX antenna is 4 direction delta loop, about 1000'
/archives//html/Topband/2020-08/msg00042.html (10,519 bytes)

134. Re: Topband: RX Power over Coax (score: 1)
Author: GEORGE WALLNER <aa7jv@atlanticbb.net>
Date: Wed, 07 Oct 2020 10:05:22 -0400
I use a 600 foot long run of CATV coax to power a remote pre-amp at the DHDL-s, delivering +12V/100 mA via the central conductor (return via the shield). Prior to installing the F plugs I spray the c
/archives//html/Topband/2020-10/msg00044.html (9,551 bytes)

135. Re: Topband: Good Conditions, Little Activity (score: 1)
Author: GEORGE WALLNER <aa7jv@atlanticbb.net>
Date: Fri, 09 Oct 2020 09:27:26 -0400
Hans, FT8 did not kill Ham radio; it has changed it. Computer are doing that to many aspects of our lives, some them we like, and some we don't. There are things that you can't do with FT8: you can't
/archives//html/Topband/2020-10/msg00054.html (8,882 bytes)

136. Re: Topband: ARRL 160M and 1830-1835 change (score: 1)
Author: GEORGE WALLNER <aa7jv@atlanticbb.net>
Date: Thu, 22 Oct 2020 21:31:34 -0400
If 1,830 - 1,835 is reserved for "intercontinental contacts", who will should CQ? The DX? He is not a DX on his own continent. These "DX windows" are not practical. 73, George C6AGU/AA7JV On Thu, 22
/archives//html/Topband/2020-10/msg00150.html (9,947 bytes)

137. Re: Topband: ARRL 160M and 1830-1835 change (score: 1)
Author: GEORGE WALLNER <aa7jv@atlanticbb.net>
Date: Thu, 22 Oct 2020 22:30:58 -0400
Tim, You are right. In theory the window could work. But the problem is that those (non-DX) who violate the rules suffer no consequences. Therefore, those with the cheek gain an advantage. But,.. A m
/archives//html/Topband/2020-10/msg00153.html (11,339 bytes)

138. Re: Topband: Cage wire performance (score: 1)
Author: GEORGE WALLNER <aa7jv@atlanticbb.net>
Date: Tue, 05 Jan 2021 09:35:27 -0500
Kenny, For the Baker Island KH1/KH7Z DXpedition I developed a 43 foot "T" antenna with spreader wires (Fat Vertical) with sloping top loading wires. It performed very well. I have been using a 65' ve
/archives//html/Topband/2021-01/msg00088.html (9,965 bytes)

139. Re: Topband: Oscillation in Narrow band tuned antenna. (score: 1)
Author: GEORGE WALLNER <aa7jv@atlanticbb.net>
Date: Wed, 13 Jan 2021 11:38:27 -0500
Rune, "Out of the blue" output transistor failures have been happening in SS PA-s. There are lots of discussions of the possible reasons on the various forums, ranging form overdrive, thermal issues
/archives//html/Topband/2021-01/msg00131.html (10,475 bytes)

140. Re: Topband: The WD8DSB mini-flag antenna (score: 1)
Author: GEORGE WALLNER <aa7jv@atlanticbb.net>
Date: Tue, 23 Feb 2021 20:19:21 -0500
The smaller the flag the lower its gain and its signal output. The limit of usefulness is reached when a weak signal is below the thermal (Johnson) noise of the system (~ loading resistor). Below thi
/archives//html/Topband/2021-02/msg00104.html (13,847 bytes)


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