Low Setting Kenwood Trc-70

I've looked at dozens and dozens of 95a certified radios over the last couple weeks, and I'm having trouble finding what I need. Anyway, I'm looking at the Kenwood tk-880, but I don't know if it has a 5 watt setting for use on the interstitial channels. Anyone care to help me out on this one. Probando un trc 70 kenwood en banda de 40 metros 7.085.0. EQUIPO WOUXUN PORTATIL HF VIA REMOTA, CA6FAO VALDIVIA Este sistema permite con buenas instalaciones recibir y transmitir hasta unos 20 km. Solo con la antena del portatil.

Originally published: Aug 2, 2010

What if youwent to your favorite local restaurant, ordered a meal and the waiter served you 1/2 the portion but charged youfull price? Would you feel cheated? Believe it or not,a good deal of home theaterenthusiasts are spending good money on the latest and greatest A/V receiverfrom their favorite manufacturer and serving the same half-portion to theirspeakers. I can't tell you how manytimes I've run into threads on our forums or on AVS Forum where users eitherwere utterly confused about how to set the impedance selector switch on theirnew A/V receiver or they decided to set it to the low setting because theirspeakers were rated below 8-ohms and the user manual saidto do this, or Joe the Plumber set his this way and we all want to be likeJoe. Some even set the switch to the lowsetting while still running 8-ohm speakers, thinking it willbe better.
This article explores why the impedance switch exists and its intendedpurpose. Because of liability and thelitigious society we live in, I can't tell you to ALWAYS set the impedanceswitch to the high setting for 4 ohm loads, but I can show you the facts onwhat this switch does along with supportive data for you to make your owneducated decision.

If you call themanufacturer, they will tell you to ALWAYS set the switch to the low settingwhen using 4-ohm rated speakers mostly due to liability. UL/CSA labs may instruct yousimilarly. It’s a damned conspiracy! Well, not really. I know it sounds crazy to go against themanufacturer's recommendation, but hear me out before you shoot the messenger.

How Should You Set the Impedance Selector Switch on Your AV Receiver? MUST WATCH!

The Basics

Let's back up a bit and define a few basic terms to gain a better understandingof the topic at hand.

• Voltage – Is electromotive force. This is defined as apotential electrical pressure difference between two points in acircuit measured in volts (V).
• Current - flow of electrons in a circuit measured in amperes(A).
  
• AC (Alternating Current) – The electrons move to andfro in the circuit in alternating direction.
• DC (Direct current) – The electrons move in a single direction inthe circuit.
• Resistance – The measure which is the inverse of electricalconductance to direct current. This also can be considered as the ratio ofelectromotive force (Volts) divided by the flow of current (Amperes).
• Impedance – is a complex measurement of opposition to currentflow in an (AC) circuit. With AC, or alternating current(alternating at any frequency higher than Zero Hertz, which is Direct Current)impedance can be represented as the complex combination of Resistance(DCR) and Reactance (“Resistance” to AC current flow). AC ”Resistance”, technically calledImpedance is a frequency dependent, complex measurement including both amagnitude and phase component. Thiscomplex quantity is often represented as the letter “Z”.
• Power - is equal tothe product of Current and Voltage times a power factor, resulting from thephase difference (if any) between the flow of the current, and thepresence of electromotive force (Volts). This product is measured in watts (W). (In DC circuits, or even AC circuitswhere the load is purely resistive, the phase is zero, and the powerfactor is one, so the equation is simple Watts = Volts * Amperes)

WhatAbout Loudspeaker Impedance?

Loudspeaker Impedance is oftenstated as a single rating in ohms. Thisis done for the sake of simplicity, as few ,if any, real loudspeakers present aconstant load to their amplifiers. Typically, the magnitude of the loudspeaker impedance can range from afew ohms to many hundreds of ohms. Loudspeakers are electro-mechanicaltransducers that operate with AC signal input. They will also operate at DC, but only long enough for the VC to go onedirection and jump out of the magnetic gap. As a result, specifying a loudspeaker by its DC impedance or voice coilresistance is a little bit like trying to guess how much horsepower theengine produces based on the number of doors on a car. At and near the resonant frequency of the loudspeaker, its impedanceoften rises to more than 100 ohms. Thenominal impedance is basically a conservative notion of how low the speakersimpedance will go over the range of frequencies it is operating over, so thatmusical spectrum in that range will not cause the amplifier to be overloaded ifthe amount of current drawn by the loudspeaker is too high. As we can see fromthe impedance magnitude curves (bold blue) and phase (light blue) for themeasurements below, the absolute value of the speaker's Impedance variesenormously, and it is the area on the curve where the magnitude is lowest thatposes the greatest current demands on the amplifier. This is especially truewhen this low flat region corresponds to that range of frequencies where muchmusical information lies. It is theimpedance in this low region that was typically used to define the loudspeakers“nominal” impedance. Based on our definitions above, and measurements below,it's easy to see that a loudspeakers impedance is NOT constant but instead afunction of frequency which can also vary drastically from the minimum or “nominal”impedance of the loudspeaker.

Impedance/Phase of two competing speakers (Left Pic: SPK A; Right Pic: SPK B)

Both of these speakers are rated at 8-ohms by their respective manufacturers. Yet when you look more closely at the curves, they look drasticallydifferent not only from each other, but from the straight horizontal line thatwould represent a purely resistive impedance. You can see Speaker A (left pic) never dips below 8-ohms at any frequency. In this casethe manufacturer rated the speaker very conservatively. Speaker B exhibits several dips into the 6-ohm region measuring lower than 5-ohms below 20Hz. This particular loudspeakerlacks a high-pass section for its midrange speaker, so at low frequencies thosemidrange speakers are in parallel with the woofer, creating a high currentdemand on the amplifier, which can cause it to shut down. This happened to me personally when thisspeaker was driven with extremely low frequency content at high output levelsusing a very beefy Marantz Integrated amplifier rated at 200wpc. Despite thefact that there is little musical content near or below 20Hz, the amplifierstill sees that speaker as a dangerous load when driving it. If this system is using a turntable, and ifthere is a slight warp to the record, the combination of phono cartridge andRIAA equalization curve may be producing a demand for output at 15Hz from theamplifier/loudspeaker combination that could be larger in magnitude than theentire audible musical spectrum! The RIAA curve made for LP's and phonocartridges uses far higher gain at the lowest frequencies than the highest. Those of us not old enough to remember whenour music was sold on LP records may have never witnessed this. Suffice it to say, those who favor LP's overdigital media must be proud owners of high order subsonic filters as part oftheir electronic arsenal. The effect ofeven a modest amount of low frequency energy in the subsonic range can causethe loudspeaker, especially vented designs, to move wildly causing grossdistortions under extremely high excursions they were never designed for.

There is no universally adhered-to standard for how consumer loudspeakermanufacturers rate loudspeaker impedance! The EIA published a standard which has for many years been the defactostandard for determining nominal loudspeaker driver impedance. That standard stated the impedance would bemeasured at 400Hz, and the voice coil resistance should not be below 6.4-ohms for an 8-ohms speaker, or twice thatfor a 16-ohm speaker. That standard has becomeless and less common in the business as the race for sales created a pressurefor manufacturers to use ever lower DC Resistance's (DCR's) on their voicecoils to increase the apparent efficiency by drawing more power (lowerimpedance loads draw more power than higher impedance ones when attached toamplifiers) than the competition. Forequally efficient systems, the 4 ohm speaker should be 3db higher than the 8ohm speaker having identical efficiency!

Realizing the fact that impedanceis a complex and greatly variable quantity, don't get hung up on an absolutenumber for impedance. It's important tolook at the loudspeaker's impedance curve and efficiency to understand how itwill play with the amplifier it is coupled with. Impedance dips at low to middle frequencieswhere much of the power is present in music can be far more stressful on linearclass A/B amplifiers than dips in impedance magnitude at high frequencies,where demands for power are relatively small. The opposite is true for Class D amplifiers, some of which choke whenpresented with low impedance dips at high frequencies because of potentialinteractions with their output filter.

SignaLink Jumper Settings & Wiring Information
For Base & Mobile Radios

Warning:Tigertronics has not verified the accuracy of all of the radio wiring information that is provided here.This information is provided for reference only and is NOT intended to replace our detailed jumper installation procedure.It is essential that you double-check this information against your radio's manual before doing the actual installation. While it is fairly simple to install the SignaLink, it is possible to DAMAGE YOUR RADIO or the SignaLink by incorrectly installing it!

Updated: April 5, 2020

IMPORTANT NOTES

• SignaLink USB Users - The SignaLink USB is always powered by the computer's USB jack. When installing the jumpers for the SignaLink USB using the settings shown here and in our other documentation, please disregard the PWR jumper (do NOT install it!). All other jumper settings are the same. Note that if you mistakenly install the PWR jumper, it will make no difference in the operation of the unit as this pin is not internally connected.

• Select The Correct Diagram - When viewing the jumper settings below, BE CERTAIN THAT YOU ARE LOOKING AT THE CORRECT DIAGRAM for the radio connector that you will be using. For any given radio, there are likely to be a different jumper settings for the Mic, Data and Accessory Port connectors.

• Jumper Wire Color - The jumper wires in the diagrams below are shown in color for illustrative purposes only. The color of the wires means nothing - they're just easier to see! The actual jumper wires that are included with the SignaLink are all the same color and can be used to jumper any signal.

• RJ-45 Mic Connectors - There is a lack of standardization in the way that radio manufacturers number their RJ-45 Mic connectors. We have numbered our connector according to the dominant industry standard (as shown below), and all jumper settings shown in our documentation reflect this standard. Icom and Radio Shack follow this standard, but Kenwood, Yaesu and some others do not. All of the jumper settings show below have been corrected as necessary to account for any reversed pin numbering. If your radio is not shown below and you need to figure out your own jumper settings, then you will need to carefully determine how your mic connector is numbered to avoid reversing the connections!
  

SignaLink™, Industry Standard Kenwood, Yaesu, Some Others

• PTT - You should verify in your radio manual that the radio PTT requirements do not exceed the specifications of the SignaLink keying circuit (please refer to the SignaLink manual) and that the PTT line is “Grounded” to make the radio transmit. If your radio exceeds the specifications listed or requires some other keying arrangement, then please contact our Technical Support Staff for suggestions.

• POWER - The SignaLink SL-1 and SL-1+ can usually be powered by the Accessory Voltage found on the Mic and Accessory Port connectors of most radios. If power is not shown in the jumper settings for your radio, then consult your radio manual to see if it is available. The SignaLink SL-1 and SL-1+ requires 6.75 to 15 VDC at 13ma (nominal). If this power is not available from your radio, then you will need to power the SignaLink SL-1 or SL-1+ externally (see the SignaLink manual for details).
  Note that the SignaLink USB is always powered by the computer, so you can disregard the PWR jumper when installing this unit.

• RECEIVE AUDIO / SPEAKER AUDIO - Receive Audio is available on the Mic, Data, and Accessory Port connectors of most radios. If Receive Audio is not shown in the jumper settings for your radio, then consult your radio manual to see if it is available. If it is not, then you will need to connect an audio cable between your radio's External Speaker or headphone jack, and the 'Speaker' jack on the back of the SignaLink. See the SignaLink Installation Manual for details.

SELECT A MANUFACTURER

NOTE: Please read the 'Important Notes' above BEFORE you select your jumper settings. This will save time and may help prevent you from making a mistake that could possibly damage the SignaLink or your radio. Note that the SignaLink USB does NOT use the PWR jumper wire, so you can disregard this jumper during installation. All other jumper settings are the same.

ADI

8-Pin Round Mic Connector (use SLUSB8R, SL1+8R, or SLCAB8R)

ALINCO

8-Pin Round Mic Connector (use SLUSB8R, SL1+8R, or SLCAB8R)

RJ-45 Mic Connector (use SLUSBRJ4, SL1+RJ45, or SLCABRJ4)

6-pin Mini-DIN Data Port (use SLUSB6PM, SL1+6PM, or SLCAB6PM)

AZDEN

8-Pin Round Mic Connector (use SLUSB8R, SL1+8R, or SLCAB8R)

DRAKE

4-Pin Round Mic Connector (use SLUSB4R, SL1+4R, SL1-4R or SLCAB4R)

Elecraft

8-Pin Round Mic Connector (use SLUSB8R, SL1+8R, SL1-8R or SLCAB8R)

Elecraft K3 rear panel Audio In, Audio Out and PTT connectors (use SLUSBK3, SL1+K3, or SLCABK3)

Elecraft KX2 and KX3 Mic connector (use SLUSBKX3, SL1+KX3, or SLCABKX3)

NOTE: The new Elecraft KX2 uses the same radio cable and jumper module as the Elecraft KX3.

ICOM

4-Pin Round Mic Connector (use SLUSB4R, SL1+4R, SL1-4R or SLCAB4R)

8-Pin Round MIC Connector (use SLUSB8R, SL1+8R, SL1-8R or SLCAB8R)

IMPORTANT: This diagram is for the MIC JACK only. If the SignaLink is attached to your radio's 8-pin Accessory Port, then please see the diagram below under '8-pin DIN Accessory Port Connector'.

RJ-45 Mic Connector (use SLUSBRJ4, SL1+RJ45, SL1-RJ45 or SLCABRJ4)

6-pin Mini DIN Data Port Connector (use SLUSB6PM, SL1+6PMD or SLCAB6PM)

8-pin DIN Accessory Port Connector (use SLUSB8PD, SL1+8PD or SLCAB8PD)

IMPORTANT: This diagram is for the ACCY PORT only. If the SignaLink is attached to your radio's 8-pin Round Mic Jack, then please see the diagram above under '8-Pin Round MIC Connector'.

13-pin DIN Accessory Port Connector (use SLUSB13I, SL1+13PI or SLCAB13I)

NOTE: The IC-275, IC-475 and IC-970 CANNOT be used with our SLCAB13I cable due to it's non-standard pin-out.
On these radios you will need to attach the SignaLink to the mic jack or to a different ACC port if available.

24-pin DIN Accessory Port Connector - Tigertronics does not manufacture a cable for the ICOM 24-pin Accessory Port connector, but you can easily build one using our un-terminated radio cable (p/n SLCABNC). To build your cable, simply wire it straight-through for pin numbers 1-8 (Pin #1 to Pin #1, Pin #2 to Pin #2, etc.). Note that your cable MUST wired straight-through or the jumper settings shown below will NOT work, and you might DAMAGE YOUR RADIO OR THE SIGNALINK!

Japan Radio Company

8-Pin Round Mic Connector (use SLUSB8R, SL1+8R, SL1-8R or SLCAB8R)