High Frequency Electronics: January 2011

High Frequency Electronics - January 2011There are two articles in the January 2011 issue of High Frequency Electronics that amateur radio operators might find interesting:

  1. The Mathematics of Mixers: Basic Principles. This tutorial walks you through the basics of mixers. Because this article is aimed at engineers, there is math involved, but it’s not overly complicated, and if you stick with it, you’ll gain a better understanding of how the mixer, one of the most basic circuits in amateur radio, works.
  2. Design of Input Matching Networks for Class-E RF Power Amplifiers. The author of this article says, “Little attention is brought to the design of the input matching network and to the device bias conditions, with their effects on the overall circuit performance. This paper attempts to discuss these topics through a systematic design and simulation approach for a typical 5 watt class-E power amplifier operating at 150 MHz.”

Note that the magazine is only available as a single PDF file. To read these articles, you’ll have to download the PDF file first.

Are Wouxoun Radios Illegal?

IC-2ATOn our ham radio club’s mailing list, a new Tech innocently asked what kind of HT he should buy. Since he mentioned that he was going to an upcoming hamfest, he asked about used equipment, and several folks suggested that he look for an ICOM IC-2AT (see right), noting that they were ruggedly built and that many were still in service. They didn’t really not that tuning them involved flipping thumbwheel switches and that to get PL tones you have to purchase a $40 board that you have to mickey-mouse into the radio, but hey, they are built like the proverbial brick outhouse.

Wouxun KG-UVD1Some guys suggested buying one of the new Chinese HTs (see right) now being sold here. They noted that for just a little more than $100, you not only get a dual-band radio, but a boatload of accessories as well.

At this point, Jeff, W8SGZ, our self-proclaimed club curmudgeon wrote:

I’ve been doing a little research.

The US “dealer” is Ed Griffin W4KMA, owner of KMA Antennas in N. Carolina (www.wouxon.us). So at least there is a US presence. The only thing that  concerns me is one little specification : spurious emission is listed as <30dB.

Part 97 says ” For a transmitter having a mean power of 25 W or less, the mean power of any spurious emission supplied to the antenna transmission line must not exceed 25 uW and must be at least 40 dB below the mean power of the fundamental emission, but need not be reduced below the power of 10 uW.” The question is, is their 30dB enough to get down to 10 uW? With only 5 W to start with, maybe it is.

The particular model in question, KG-UVD1P, is FCC “certificated” (I love that word, it’s so nonsensical) under Part 90, so it should be at least of a certain quality level. And at half the price of anything comparable from the Big 3 (or 4 if you count Alinco), it doesn’t sound bad.

Now, according to my calculations, -30 dB, only gets you down to 5 mW. To get down to 10 uW, spurious emissions would have to be -57 dB. When I replied with that information, Jeff said:

This little radio is causing me a lot more work than I like, but once I get my teeth into an investigation, I can’t seem to let it go.

Although the sales literature (what there is of it) states 30dB for spurious emissions, the User Manual states 60 dB. From what I can make out from the test reports submitted to the FCC, the actual attenuation is in the mid 20s (depending on frequency).

And most bizarre of all is this except from a letter from Wouxon to the FCC:

We would like to have the 136-174 MHz frequency range appear on the face of the FCC Grant of Certification for our Part 90 Certification. This frequency range contains frequencies regarded as usual & customary by the United States Federal Government and its various departments, user organizations and the military.

  1. The applicant plans to ensure that USA users, other than those specifically identified in this letter, not operate within bands which are not allowed by the Part 90, as controlled by the users’ FCC station license.
  2. This devise will not be marketed to USA users, other than those identified in the letter, namely the US Government and its various departments & military, for operation in frequency range out of Part 90.
  3. The applicant acknowledges that it is a violation of FCC rules if the device operates on unauthorized frequencies

Is it just me, or does all this sound like W4KMA is in violation of FCC regulations by selling these to US hams? And are US hams who buy and use them in violation as well?

There has to be a loophole somewhere that I am missing. I mean hams are continually retuning commercial (ie Part 90) equipment to use on amateur frequencies. Why would this be any different? The applicant acknowledges that it is a violation of FCC rules if the device operates on unauthorized frequencies.

So, what do you think? It sounds to me as though the Wouxoun radios don’t meet spec and should not be allowed to be sold in the U.S.

The KD8LWR Repeater Guide

“The KD8LWR Repeater Guide” is a database of analog FM repeaters across SE Michigan and parts of SW Ontario that is constantly updated based on my reception.

On a linked repeater system, “Activity” refers to the activity of that particular repeater being transmitted on.

PLs in parentheses mean the repeater sometimes requires the given PL. If you want to key up a repeater on this database with a PL in parentheses, key up the repeater with carrier access first; if that fails, use the given PL.

At the bottom of the post you will see when this repeater database was last updated and the last addition or change of a repeater.  This “change” refers to a frequency, PL, VOIP node, or callsign change as well as if a repeater goes down or back up.

Frequency Input PL Callsign Activity Comments
Ann Arbor area (Washtenaw)
145.150 144.550 100.0 N8DUY Medium  Skywarn/ARES
145.230 144.630 100.0 W8UM Medium Echolink node 301138
146.740 146.140 100.0 WB8UPM Inactive
146.920 146.320 100.0 KT8TD Active  RACES
146.960 146.360  (100.0) WB8TKL Medium  Owned by W8PGW
147.480 147.480 (100.0) KD8LWR Inactive Wide-coverage simplex repeater, at 100 watts ERP from 24 feet
224.340 222.740 W8UHW Medium
224.380 222.780  (100.0) W8PGW Inactive
224.780 223.180 100.0 K8RPT Down/Very inactive
443.050 448.050 107.2 N8LBV Inactive
443.500 448.500 (100.0) W8PGW Inactive
443.650 448.650 100.0 N8AMX Very inactive
444.075 449.075 82.5 WR8DAR Very inactive
444.975 449.975 107.2 WD8DPA Down Linked to 29.640
446.500 441.500 100.0 KD8LWR Testing Medium-coverage repeater, at 15 watts from 24 feet
51.740 51.240 88.5 W2PUT Down Linked to 927.9875 locally, and 444.100 and 927.4875 in Milan, IRLP node 4428
927.9875 902.9875 131.8 (use D025) W2PUT Inactive Linked to 51.740 locally, and 444.100 and 927.4875 in Milan, IRLP node 4428
29.640 29.540 114.8 WD8DPA Down Linked to 444.975
Chelsea area (Washtenaw)
145.450 144.850 100.0 WD8IEL Pretty inactive
146.980 146.380 100.0 WD8IEL Medium Programmed by KD8LWR
224.160 222.560 100.0 WD8IEL Medium
443.575 448.575 100.0 WD8IEL Active CMEN linked repeater system, Echolink node 41083, Allstar node 28236
Howell (Livingston)
145.410 144.810 162.2 K8JBA Very inactive
146.680 146.080 (162.2) W8LRK Active  Skywarn
444.525 449.525 100.0 W8LRK Inactive
Jackson area (Jackson/Ingham)
51.620 51.120 100.0 KA8ZXX Active Wide-coverage repeater, backup repeater programmed by KD8LWR
145.310 144.710 (67.0) K8YQP Inactive Part-time link to 147.360, 224.160, 443.875 and 927.0125, part-time link to 51.620, low-coverage repeater
145.470 144.870 114.8 W8IRA Medium Linked repeater system (linked to Lansing)
146.880 146.280 100.0 W8JXN Medium  Skywarn
147.360 147.960 100.0 KA8HDY Active Linked to 443.875 and 927.0125, Echolink node 644275, remote base, backup repeater programmed by KD8LWR
443.175 448.175 77.0 WD8EEQ Inactive
444.175 449.175 100.0 KA8YRL Inactive
443.875 448.875 100.0 KC8LMI Very active Linked to 147.360 and 927.0125, Echolink node 644275, wide-coverage repeater, remote base
444.950 449.950 KC8LMI Medium Low-coverage repeater, sometimes linked to the other related linked repeaters
446.800 446.800   KC8LMI Down Low-coverage simplex repeater programmed by KD8LWR
927.0125 902.0125 131.8 N8URW Active Linked to 147.360 and 443.875, Echolink node 644275, remote base
Lansing area (Ingham/Eaton)
145.390 144.790 100.0 W8BCI Active
145.470 144.870 107.2/100.0 W8IRA Active Linked repeater system (linked to Jackson)
146.700 146.100 107.2 W8BCI Medium
146.940 146.340 100.0 W8BCI Active
147.080 147.680 103.5 K8CHR Inactive
147.280 147.880 100.0 KB8LCY Active CMEN linked repeater system, Echolink node 41083, Allstar node 28236
224.820 223.220 107.2 W8FSM Down
224.980 223.380 100.0 W8BCI Inactive
442.025 447.025 N8JI Inactive
442.050 447.050 100.0 N9UV Inactive
442.425 447.425 100.0 KD8PA Usually medium
442.525 447.525 107.2 KC8QYW Inactive? CMEN linked repeater system, Echolink node 41083, Allstar node 28236
442.725 447.725 100.0 KB8SXK Medium
442.900 447.900 77.0 W8MSU Very inactive
443.000 448.000 107.2 KD8IFI Inactive CMEN linked repeater system, Echolink node 41083, Allstar node 28236
443.525 448.525 100.0 W8CLI ???
443.625 448.625 100.0 N8HEE Medium
443.700 448.700 WB8RJY Medium Does not identify itself
444.125 449.125 107.2 N8DEF Inactive
444.575 449.575 107.2 N8OBU Pretty active CMEN linked repeater system, Echolink node 41083, Allstar node 28236
444.700 449.700 (DPL 073) KB8FUN Medium
444.850 449.850 141.3 WC8CLI Inactive
51.700 51.200 192.8 WB8RJY Very inactive Wide-coverage repeater
52.960 52.460 KD8PA Down
910.250 439.250 N8OBU ??? ATV repeater (LSB input, AM output)
927.525 902.525 131.8 (use D073?) KB8FUN ???
Flint area (Gennessee)
145.190 144.590 100.0 W8YUC ???
145.410 144.810 91.5 W8YUC Inactive CMEN linked repeater system, Echolink node 41083, Allstar node 28236 (also used in West Branch, but still inactive, and not linked up)
146.780 146.180 (67.0) W8FSM Very active Echolink node 146780
147.060 147.660 100.0 N8NJN Medium
147.100 147.700 100.0 KC8KGZ Active Linked to 224.180
147.260 147.860 100.0 KC8KGZ Very active  Skywarn
147.340 147.940 100.0 W8ACW Medium
147.380 147.980 100.0 N8NE Inactive
224.060 222.460 100.0 N8NJN Inactive
224.180 222.580 88.5 KF8UI Active Linked to 145.310 N8BBR repeater in Bay City (131.8 PL)
224.480 222.880 100.0 KC8KGZ Inactive
224.620 223.020 100.0 W8FSM Inactive
224.960 223.360 W8YUC Down
442.250 447.250 100.0 KA8ZAU Inactive
442.300 447.300 91.5 W8YUC Inactive
442.350 447.350 107.2/88.5 W8FSM Active CMEN linked repeater system, Echolink node 41083, Allstar node 28236
443.925 448.925 151.4 W8FSM Medium
443.975 448.975 67.0 W8VHB Down
444.200 449.200 107.2 W8ACW Inactive?
444.375 449.375 W8JDE Inactive?
444.600 449.600 W8JDE Inactive
444.650 449.650 100.0 KC8KGZ Inactive
1253.250 439.250 KC8KGZ ??? ATV repeater, input on LSB mode, output on AM mode
South Lyon (Oakland)
147.040 147.640 110.9 K8VJ Active
White Lake (Oakland)
145.490 144.890 67.0 N8BIT Usually inactive
Clarkston (Oakland)
146.840 146.240 100.0 K8NWD Medium/active
Detroit area (Wayne/Oakland/Essex, ON)
145.110 144.510 100.0 W8DET Inactive
145.170 144.570 100.0 KA8SPW Inactive Currently still identifies as K8RUR
145.210 144.610 123.0 WW8GM Down
145.270 144.670 100.0 K8UTT Medium Linked to 224.520
145.330 144.730 100.0 WR8DAR Very active  Skywarn
145.350 144.750 100.0 K8UNS Active
145.410 144.810 118.8 VE3EOW Medium
145.430 144.830 100.0 W8JIM Pretty inactive
145.470 144.870 118.8 VE3RRR Medium
146.640 146.040 100.0 W8HP Very active
146.760 146.160 100.0 KE8HR Very active  Skywarn
146.860 146.260 100.0 KK8GC Medium
146.900 146.300 100.0 W8OAK Very active  Skywarn
147.000 147.600 118.8 VE3WIN Active
147.060 147.660 118.8 VE3III Medium
147.080 147.680 100.0 N8LC Active
147.140 147.740 (100.0) N8KD Very active
147.160 147.760 100.0 WR8DAR Active
147.180 147.780 100.0 K8UO Very active
147.240 147.840 WY8DOT Medium
147.330 147.930 151.4 KC8LTS Inactive APCO-P25 repeater, can key up with FM transceivers
224.360 222.960 103.5 KC8LTS Very inactive?
224.420 222.820 77.0 W8JIM Very inactive
224.520 222.920 100.0 K8UTT Very inactive Linked to 145.270
224.700 223.100 100.0 K8PLW Medium
224.740 223.140 100.0 W8PMN Inactive/down
442.175 447.175 123.0 KC8LTS Very active CMEN linked repeater system, Echolink node 41083, Allstar node 28236
442.275 447.275 100.0 W8TX Very inactive
442.475 447.475 88.5 W8JIM Inactive?
442.500 447.500 107.2 WB8NXP Active  IRLP node 4460
442.575 447.575 88.5 K8ZKJ Very inactive
442.775 447.775 107.2 N8BK Very inactive Echolink node 331551
442.800 447.800 107.2 WR8DAR Medium
443.075 448.075 123.0 WW8GM Medium/inactive
443.100 448.100 82.5 WR8DAR Medium
443.125 448.125 107.2 N8DJP Medium
443.225 448.225 107.2 W8HP Inactive/medium
443.275 448.275 107.2 N8ISK Inactive
443.425 448.425 107.2 K8UTT Very inactive
443.475 448.475 88.5 WR8DAR Active
444.000 449.000 100.0 WB8CQP Inactive
444.225 449.225 107.2 N8XN Medium
444.300 449.300 118.8 VE3RRR Inactive
444.325 449.325 107.2 W8OAK Medium
444.350 449.350 100.0 WR8DAR Inactive/medium
444.400 449.400 118.8 VE3UUU Medium
444.425 449.425 118.8 WR8DAR Very inactive
444.600 449.600 118.8 VE3WIN Inactive?
444.800 449.800 110.9 WA8UMT Inactive/medium
445.500 440.500 136.5 KD8NNY Very active Linked to Echolink’s *USA* conference server
927.4875 902.4875 131.8 (use D025?) KC8LTS Inactive? CMEN linked repeater system, Echolink node 41083, Allstar node 28236 (connected to links or not?)
927.6875 902.6875 131.8? (use D025?) K8UH Medium/Active Echolink node 71379, scans other repeaters around the Detroit/Ann Arbor/Toledo/Monroe area
Monroe area (Monroe/Washtenaw)
145.310 144.710 W8YZ Inactive?
146.720 146.120 100.0 K8RPT Very active  Skywarn
442.650 447.650 100.0 K8RPT Inactive?
442.825 447.825 100.0 K8RPT Medium
444.100 449.100 82.5 W2PUT Very active Linked to 927.4875 locally, and 51.740 and 927.9875 in Ann Arbor, IRLP node 4428
444.550 449.550 100.0 N8OSC Inactive
927.4875 902.4875 131.8 (use D025) W2PUT Medium? Linked to 51.740 and 927.9875 in Ann Arbor, and 444.100 locally, IRLP node 4428
Lapeer area (Lapeer)
146.620 146.020 100.0 W8LAP Very active Linked to 443.450, Skywarn
224.800 223.200 100.0 W8LAP Inactive
442.700 447.700 100.0 W8LAP Medium
443.450 448.450 100.0 KG8ID Medium Linked to 146.620

Last updated:
05/31/2013

Last updates:
Removed KD8LWR cross-band repeater and 147.420 simplex repeater (don’t worry, my 147.480 simplex repeater and 446.500 repeater will use Don’s (AE5DW) voice!).

Understand the Unlicensed Services

We share several of our UHF bands with unlicensed services, and from time to time, you’ll encounter those signals on the bands. Another reason to be familiar with them is that there are companies that have their eyes on them.

A recent article on this topic, “Understanding regulations when designing a wireless product in the unlicensed frequency bands,” notes:

The wireless unlicensed frequency bands—especially the industrial, scientific, medical (ISM) bands—are the most appropriate for many new applications and products. They are part of the frequency spectrum that can be used without a license. However, products developed in these bands still are required to be compliant with rules defined by the country’s regulatory bodies before being deployed in the field. This article focuses on the technical design requirements and mandates for the US region.

Could be interesting reading.

AM/FM/2m?

The C. Crane Company has for many years sold radios that they claim have superior AM band performance. They used to advertise a lot on the Coast to Coast AM radio show, touting how the radio was capable of pulling in the show, even if your local station didn’t carry it. They probably still do, for all I know.

There is, of course, a ham radio connection. Art Bell, the longtime host of the show, is W6OBB.

At any rate, C. Crane is now selling the CC-Radio2, which not only touts it’s AM-band performance, but also includes coverage of the 2m ham band. The website says,

The addition of the 2-Meter Ham band may make the CCRadio-2 a life saver during an emergency like hurricane Katrina. 2-Meter Ham operators are early on the scene and they donate their time while handling perhaps 90% of the emergency coordination efforts. The CCRadio-2 can act like a simple radio scanner and search the five memories for ham operator communications. The sensitivity (squelch) can be adjusted for best results.

The C. Crane website has a whole Web page devoted to the 2m band and ham radio in general.

C. Crane sells a whole bunch of stuff that might be of interest to ham radio operators. It’s a site worth checking out.