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Compiled by Mike Morris WA6ILQ
Maintained by Robert Meister WA1MIK
I know nothing about this equipment so please don't ask!

  Contact information:
The land mobile group is a division of RELM Corp. The avionics group is a division of Honeywell Corp.
RELM Wireless
7100 Technology Drive
West Melbourne, FL 32904
BendixKing by Honeywell

Note that if you have any BK aircraft radio (including the KX-99 which is obsolete and largely unsupported), and need parts, you need to contact Bendix King Avionics in Lawrence, KS. Only the land mobile division was sold to RELM.

The BK handhelds are a favorite of the US Forest Service and the people that work with them. The USFS has recently changed the technical requirements, and this email clarifies the situation that affects a lot of folks:

> To: repeater-builder BK page
> Subject: You might want to post this email on the BK page...
Users of BK radios who coordinate with the USFS or BLM should be aware that wideband radios are no longer acceptable for use by wildland firefighting contractors. This means all LPH, EPH and EMH radios will not be usable in USFS operations !!! On top of that, USFS Region 6 which covers California and Washington state is also planning to begin making the switch to P25 digital in 2009.

Testing of the P25 digital mode continues. Results are very favorable for portable radios wherein tests showed the P25 mode more readable all up until the point where the signal became noisy in the analog radio and then the P25 signal was completely lost. It was also found that P25 in mobile applications was very intolerant to "motorboating" caused by multipath reflections and during mobile radio testing, analog rated superior to P25 digital. Based upon these tests, P25 digital may require a repeater infrastructure so that signal levels can remain high and multipath interference can be minimized. The most common comment about P25 is that it either works or it doesn't with little or no warning between the two conditions.

The FCC is also now assigning new analog VHF frequencies in California and elsewhere that require radios capable of operating on a 6.25 kHz channel spacing. Only GPH, DPH and DPHX portables and GMH and DMH mobiles are capable of operating on 6.25 kHz channel spacing assignments. Older LPH, EPH and EMH radios are only capable of operating on channels down to 12.5 kHz channel spacing.

What we're looking for...

An article or two providing an overview of the mobiles, handhelds (EMH, EPH, EPI, EPU, EPV, GPH, LMX, LPH, LPX, LPU, LQH, PRC-127, etc.) and the differences between them.

We're also looking for how to interpret a model number, what makes one model preferred over another(I know to avoid the models that have a ribbon cable inside, but how do you tell one that has a ribbon cable from one that does not?), how to find a used one at a decent price, how to move one from commercial frequencies into the UHF or 2m ham bands, how to program them (yes, I know it can be programmed from the front panel, but if you have an entire radio to reprogram it's easier to use a PC for the first programming), what hardware and software you need to program it from a PC (and how to get it legally), where to get parts, etc.

Since the radios have all gone to surplus, we are looking for the programming software for the EPH-5991K radios. These were specifically made for the Texas Department of Public Safety (their Highway Patrol), and have nothing in common with the regular EPH radios. They require special software that (according to BK) only Texas DPS has, and won't program with the normal BK software. Despite attempts by several people to acquire the EPH-5991K software nothing has turned up.

A step-by-step procedure, with photos, of how to replace / rebuild the PTT switch on a LPH / LPU, EPH or EPU handheld.

If you have any info to donate, just drop an email to donations //at// repeater-builder //dot// com - we'll take care of the rest. If you want to donate an article (which are always welcome, even if you don't want to be identified with it), please drop us an email first.

Information and Modifications

A good source of information and support for BK radios is the Yahoo discussion group "BK_Radio". Note that's an underscore between the BK and the Radio, not a hyphen. Click here: This group has hundreds of members who are BK Radio users and technicians. There is also software and information for programming the various models available in the files section of this group. In fact, a lot of what we have here already - including the programming cable schematics - is from the the Files section from the BK YahooGroup... check out BK_radio at YahooGroups.

With all of the different BK models, many have asked the question about programming cables. The LAA-0725 cable is still the only cable required to program any BK Radio land mobile radio ever made. This cable does require a hardware RS-232 serial port on the programming computer and WILL NOT operate from any USB serial port. The schematic of this cable is further down on this page. Windows XP can also cause some compatibility issues with the software if the "Classic" desktop theme is not selected. Older DOS software like LMR.EXE should be operated in Windows 95 or 98 because there can be timing irregularities in Windows 2000 and XP.

Rich Williamson, W7KI, reports:

To get part numbers, call Bendix-King tech support at 800-422-6281 (then press "2"). Give them the radio model number and a description of the parts you need. Next, call a distributor and give them the Bendix-King part numbers. I personally dealt with "10-4 Communications" at 800-487-9576. I needed a speaker and some fuses. It was only $15 including the shipping, so BK prices are certainly reasonable.

Descriptive tables on BK handhelds:   VHF     UHF     800 MHz / Aircraft / Marine
All three lists, as one file, useful for printing or loading into your Palm Pilot: Entire List

Would anyone like to provide similar information for the mobile radios?

The EPH 5991 models are not on the above list. The EPH 5991A is a high band unit, 210 channels with numeric keypad. The EPH 5991K is a special that was made for the Texas Railroad Department and the Texas Department of Public Safety; instead of multiple 14-channel banks it had one large 64 channel bank, and covered 154-166 MHz.

Here's an LPH series operation and programming guide.

Here's a DPH programming guide. The DPH is a new (as of 2005) 240 channel (15 groups of 16 channels) portable radio capable of both P25 digital and analog operation. The DPHX is an updated version with extended frequency range covering 136-174 MHz; all other info is the same as the DPH. The DPH5102-CMD is another version with both extended frequency range, 300 channels and a larger LCD display that can display more more data. The DPH-CMD has 500 channels, all other info is the same as the DPHX.

Here's a generic BK Portable programming manual.

As of January 2007, the standard GPH analog only radio is obsolete and is to be replaced by the GPH+ although a full set of specifications for this radio have not been released on the RELM website. Here's the GPH-CMD manual.

Speaking of programming, Wayne Rees sent us several collections of software for the ALF, EPH, LPH, and Lxx series of radios. This is all old stuff. Some of it is written in GW-BASIC (that's pre-1990!). It came in two "RAR" files and has been re-compressed into one "ZIP" file. You can download this 413kB archive file here. Repeater-Builder makes no claims as to the usefulness or quality of the contents of this file.

The stock LPH, EPH, GPH and DPH high band portables do not cover the 144-148 MHz amateur spectrum out of the box. They need to be "downbanded" where you sacrifice a little off the top end to gain a little on the bottom end (i.e. move the 148 MHz end to 144 MHz). The LPH series need a change in the EEPROM contents. There is a software program pair called "Ham" and "Eggs" that is for the EPH models where "Ham.exe" would downband the radio and "Eggs.exe" would restore it. Look around for "ham and" The ham and eggs program set was modified for the GPH series and is called, believe it or not, "Green eggs and ham". It was modified again for the early DPH series and is called "Deviled eggs and ham". Please note that nearly all downbanded radios will need a receiver realignment in order to achieve specification sensitivity in the downbanded region. A carefully realignment can also mean that very little (if any) performance is lost on the high end of the operating range. DPHX and DPH5102X-CMD radios have an extended frequency range and do not need to be downbanded.

The BK portable radio knobs are held on by a 0.048" or 0.05 mm bristol spline setscrew. McMaster-Carr, an industrial supplies distributor, has it in their catalog, part number 7048A12 (four-flute) or 7048A13 (six-flute), either for less than $1.00. Or just order an Xcelite part number #99-61 from your favorite tool supplier.

The PRC-127 is the military version of an LPI series high band BK radio first delivered in 1996. It has 14 channels with a channel spacing of 25 kHz, 3 watts of RF power, with a frequency range of 136-160 MHz. The PRC-127(A) is the military version of the EPI3101A radio with a spacing of 12.5 kHz (some documentation states that the (A) model has 28 channels, up to 162 MHz, and can do 12.5 kHz, 15 kHz, 25 kHz or 30 kHz spacing). The 28 channels on the PRC-127(A) are organized into two 14 channel banks, Bank One being preconfigured narrowband and Bank Two being preconfigured as wideband. The current model is the PRC-127(B) with has channel spacing options of 5 kHz, 12.5 kHz, 15 kHz, 25 kHz or 30 kHz spacing. All parameters can be programmed from the front panel keyboard. Battery, charger, and other accessories can be interchanged with other BK models.

PRC-127 radios can be "widened" to a frequency range of 148-170 with slightly reduced power and sensitivity at the extremes. See: this web page.

Craig Coley of The Communications Repair Depot comments that:

"The BK LPH and PRC-127's can be used as tactical repeaters. The radios really work quite well as tactical repeaters because they have tuned, tracking front ends in the receiver as well as a wide dynamic range passive ring mixer. I have used these radios as 2 watt repeaters using flexible antennas and separated by only about 5 feet on the top of a Suburban with good results. There is minor desensitisation of the receiver and the use of PL tones is definitely recommended but the overall results were good. This setup requires only minor modification of existing circuitry within the radios and an interconnecting cable. It can also as a bi-diectional repeater linking two simplex frequencies."

Note that because VHF and UHF radios have fundamentally different designs, you cannot link VHF and UHF with this setup. Click here for Craig's writeup on a quick tactical repeater.

In answer to questions about the upgradeability of various handhelds, Craig also comments that:

"All of the portable radio models except the 'L' series will require a factory only upgrade to increase the number of channels. For 'E' and 'G' series, a 28 channel upgrade costs $50.00 and a 210 channel upgrade costs $150.00. The 'D' series portable radios come standard with at least 240 channels."

"The 'L' series radios require the addition of an accessory board to add an additional 14 channels but this board is obsolete and no longer available from RELM. The LPX is an early 800 MHz analog trunking radio that is obsolete and completely unsupported."


Other PDF Files:

Offsite Links:

The Communications Repair Depot is a RELM authorized Bendix King dealer that has an excellent web site on BK radios. Craig Coley, the owner, has been a BIG help in keeping this page up to date. Unfortunately he and his web page are no longer reachable.

The Relm web site has some downloadable Bendix King software utilities and service bulletins.

Downloadable firmware updates for the current models is available from the RELM web site here.

Updates for the radio programming software are here

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Hand-coded HTML by Mike Morris WA6ILQ
This page originally posted in October 2004

This web page, this web site, the information presented in and on its pages and in these modifications and conversions is © Copyrighted 1995 and (date of last update) by Kevin Custer W3KKC and multiple originating authors. All Rights Reserved, including that of paper and web publication elsewhere.