KO4BB Wiki ham_radio

ham_radio:brick_oscillators_for_ham_microwave_operation

2013-01-08T19:00:00-04:00

Brick Oscillators For Ham Microwave Operation Brick Oscillators are one of the most common components used to generate the first Local Oscillator frequency for ham microwave transverters. This is typically around 10.224 GHz for a 10.3681 operating frequency (the recommended calling frequency by the ARRL band plan) and a 2m multi-mode transceiver operating at 144.1

ham_radio:calculate_link_margin

2013-01-08T19:00:00-04:00

Link margin calculations (line of sight) Knowing antenna gain, receiver sensitivity and transmit power, calculate the Link Margin Calculate the Path Loss in dB Path Loss (dB) = 37 dB + 20log(f) + 20log(d) with f in MHz and d in miles. Calculate the maximum Received Signal Strength in dBm

ham_radio:choke_ring_antennas

2013-01-08T19:00:00-04:00

Choke Ring Antennas Hello All, Over the past couple of years I have seen several references indicating that the reason all GPS units intended for precision survey applications use a choke-ring antenna is that a properly designed GPS choke ring antenna will cut multi-path reception down very significantly. Other references I have seen indicate that using a choke-ring antenna results in a moderate improvement in GPSDO performance.

ham_radio:circuit_analysis_for_stripline_and_micro-strip

2013-01-08T19:00:00-04:00

Circuit Analysis for Stripline and Microstrip Here was a question about the design of strip lines and micro strips: At 10:16 PM 10/10/2007, Loren Moline WA7SKT wrote: Does anyone know what the impedance of the 1/2 wave legs of a microstrip bandpass filter.

ham_radio:ham_database

2013-01-12T19:00:00-04:00

HamLookup Database (Mysql) This article describes a new Ham Radio Database. The HamLookup database contains mailing addresses and other ham radio related information such as grid square, DXCC country, US county and other which can be used to obtain QSL cards and awards. Several factors set this database apart from the better known ones. This project is purely non-commercial (with an uncluttered presentation). This database offers the capability to store multiple addresses for a given callsign, …

ham_radio:ham_database_mysql

2013-01-12T19:00:00-04:00

ham_radio:how_to_turn_on_an_old_twt_amplifier

2013-01-08T19:00:00-04:00

How to Turn On an Old TWT Amplifier The question “What to do to turn on an old TWT amplifier that has not run in 1-5-10 years” comes up regularly on various mailing lists. I have been designing TWT amplifiers and power supplies for the best part of the last 30 years, so I have a few ideas of my own about it.

ham_radio:impedance_along_matching_line

2013-01-08T19:00:00-04:00

Dear Brian, Jerry & The uw Group, INTRODUCTION -- Brian has asked an interesting and provocative question that gets down to some basics of a peculiar type of transmission line system (full question repeated below), “what is the VSWR and voltage on a 1/4 wave matching transformer that has a four 50 ohm loads?

ham_radio:lightning

2013-01-08T19:00:00-04:00

Lightning, how to protect installations From the Time-Nuts mailing list: From: Jim Lux Subject: Re: [time-nuts] Thunderbolt cabling questions " albertson.chris@gmail.com said: Is there a good book or URL on lightning vs antennas? Again, I'm interested in both the technical issues as well as the local zoning/legal issues.

ham_radio:microwave_equipment_for_the_ham_bands

2013-01-08T19:00:00-04:00

Microwave Equipment for the Ham Bands This page started as a thread on the [Mw] mailing list: Microwave mailing list The question was relative to the best way to get started on the microwave bands when one only has a limited budget. David M. Upton WB1CMG had this to say, feel free to add any useful information you may have (Click the

ham_radio:noise_figure_calculations

2013-01-08T19:00:00-04:00

Noise Figure Calculations Loren Moline WA7SKT wrote: Is it possible to calculate the improved signal to noise ratio between a 1.5db NF LNA and a .6db NF LNA? Loren WA7SKT ---------- Dave Sublette answered: " Loren Somewhere on the Agilent website is a free download of AppCAD. It is a

ham_radio:noise_sources_and_noise_figure_measurements

2013-01-08T19:00:00-04:00

Noise Sources And Noise Figure Measurements There was a lengthy but good thread on the Microwave mailing list about Noise Diodes and Noise Figure meters and procedures. While he probably won't terminate the thread, Jeff had something to say about it (obviously, it was a lot

ham_radio:phase_detectors_for_pll_applications

2013-01-10T19:00:00-04:00

Phase Detectors For PLL Applications -----Original Message----- From: microwave-bounces@echo.valinet.com On Behalf Of Loren Moline WA7SKT ---------- Hello, A while back I asked a question about phase detectectors. Now my question is this. The Macom and other brick PLO's use a different type of phase/frequency detector. Somehow the phase noise is very low on these. All I know is when I listen to a carrier at the IF of my downconverter using one of these PLO's it is a very nice sounding no…

ham_radio:pipe_cap_filters

2013-01-08T19:00:00-04:00

Pipe Cap Filters Pipe Cap Filters are some of the least expensive narrow band filters for the microwave enthusiast. See my page at Didier KO4BB

ham_radio:sdr_using_r820t_based_usb_tv_dongles

2013-01-08T19:00:00-04:00

SDR Using R820T based USB TV Dongles From the Microwave Mailing List at on Jan 5, 2013 I installed the supplied software to take a look but I am out in the boonies so hoping to see a HDTV channel with the indoor antenna supplied was dreaming. But it did serve to check out the hardware was responding.

ham_radio:sealing_coax_cables

2013-01-08T19:00:00-04:00

Sealing Coax Cable Connectors A few observations from Hot, Humid Central Florida. All Cables must be properly installed and WATERPROOFED. I have even used 9913 here for a few runs here in the humidity of central Florida for over 15 years with no water intrusion.

ham_radio:semi_rigid_cable

2013-01-08T19:00:00-04:00

Semi Rigid Cable On Tuesday 29 January 2008 15:07, Richard Gill wrote: A few years ago I bought some Semi-Rigid Coax from out favorite bid site for later use. I am building some Yagi's as described in the Aug 2006 QST article by Jim, W6PQL. The yagi's use a piece of UT-141 Semi Rigid coax as a balun. The coax I have has no ID or number and does not look like the coax in the article. Anyway the coax I have has the follow specs: appears to be made of Copper tube.

ham_radio:simulation_software_for_pll

2013-01-08T19:00:00-04:00

Simulation Software For PLL This was contributed originally by Grant Hodgson, October 1, 2007 on the Microwave mailing list ---------- There are some free PLL simulation tools that allow you to see the effect of any changes on the loop components before you warm up the soldering iron.

ham_radio:tube_manufacturing_codes

2013-01-08T19:00:00-04:00

Tube Manufacturing Codes Hi, It was commonly known that tubes were made by one manufacturer and sold by another. In order to identify which company ACTUALLY made the tube, the ACTUAL manufacturer's EIA code number would be stamped somewhere on the tube. Manufacturers would commonly make tubes for other companies.

ham_radio:varian_cpi_twt_model_numbers

2013-01-08T19:00:00-04:00

Understanding Varian/CPI Model Numbers From the MW Mailing List: " So I am trying to decide what tube to try first for the 10 GHz side Once long ago I saw/had an old Varian DOS program to knew tube numb brrrs. Ideally there must be some good

ham_radio:yagi_antennas

2013-01-08T19:00:00-04:00

Yagi Antennas On Thu, 2008-05-08 at 19:04 -0700, Loren Moline WA7SKT wrote: Hello, Back in the old school yagis were constructed with element spacing of say .15 wavelength and lots of times the elements were all spaced the same distance apart. A length was calculated for the driven element and the reflector was made 5% longer and the first director 5% shorter and if tapered the remaining directors were shortened by 5% progressively.