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6/24/01

GMRS Web Magazine Reviews
the Vertex 800, UHF Portable Radio


Vertex Standard Website

The Vertex 800 UHF Portable Radio

by Greg Forrest, PE
KAF1291
[email protected]

Radio Cost (new): $500 (includes FVP-25 DTMF Pager/Scrambler option)

Programming cable: CT70, Programming software: VPL-1

Overall Review

This is Vertex's latest alphanumeric portable targeted at industrial and public-safety users. This radio could be a replacement for the popular VX10 portable radio. Although the radio is not front-panel programmable (as far as we know), we purchased a couple anyway since the unit comes with 200 channels and is equipped with an eight-character alphanumeric display. The combination of channel capacity and display reduced the need for front-panel programmability; I could virtually pre-program almost any possible channel I could anticipate needing. The DOS software was so easy and reliable that reprogramming would not be a chore.

The receiver sensitivity of this 450-485 MHz version was excellent to 512 MHz, but dropped quickly below 445 MHz. The unit transmitted reliably down to 437.5 MHz. We hope to investigate if the VX can be tuned to improve receiver performance in the 440-445 MHz portion of the amateur band. Each channel can be individually assigned as wide band or narrow band (25 kHz or 12.5 kHz). A voice companding feature for narrow band mode is not provided.

The radio sports a metal chassis with strong plastic cover and industrial-quality control knobs. Its construction compares with that of the Motorola JT1000 and MT/MTS series radios. Both knobs were designed with quite a bit of friction to prevent inadvertent changes (good feature). This 5-watt radio is extremely lightweight (only slightly heavier than most FRS radios) and can be carried in a shirt pocket with no problem. In fact, I had though I had lost it while shopping recently, only to find it was in my rear pocket as I was sitting in my car (I thought it was my wallet). After using the radio for about a week, I am unlikely go back to a larger and heavier radio!

The VX-800's sound pressure level (volume) is slightly above average (given its small speaker), but I occasionally needed it to be 3-6 dB greater in noisy environments (it was just loud enough to sit on the seat of a noisy car and still be heard 90% of the time). Received audio is too rich in mid-range response, and transmit audio quality was about average. Battery life (using the 1600 mAh battery) was the best yet, and it was not unusual to have it last beyond 72 hours in standby mode (with RX power save on).

The VX-800 permits alphanumeric group labels, flexible button and switch assignments, and other highly flexible software features. Almost all of the important channel-specific parameters can be entered using a simple spreadsheet-like programming screen, and Vertex uses the F (Function) keys sparingly.

I will admit some frustration at several significant (and surprising) firmware flaws. First, it is not mixed-code capable (DCS and CTCSS) on the same channel, and it does not perform cross-coding correctly when in talk-around mode (which would have assigned the programmed RX code to the TX code). Also, when the user changes channels following scan activation, neither the priority (P1) channel nor the transmit channel follow the selected channel.

The radio performs poorly under signal fading conditions; we suspect either the AGC (Automatic Gain Control) circuit and/or the CTCSS/DCS detection is to blame for this. The radio's sensitivity is fine, however. If you tend to operate through a strong local repeater or in very localized area in direct mode this problem would not be noticed.

Display/Control

The eight-character multi-segment alphanumeric display is fully user-definable, and includes ten user-definable group labels. The group labels appear momentarily following a group change. Three small decimal points below the display characters indicate when the channel or group is active in the scan list, and if certain scan options are enabled. When using the standard scan feature, the display reads "SCAN" (unless stopped on a channel) which unfortunately conceals which channel you have selected. This is a common design flaw that many manufacturers continue to make (see review of the Kenwood TK805 and TK830 mobile radios; this was corrected in later models).

The display will also display the decoded DTMF address of a radio that responds to a selective call when this feature is enabled (I ordered the FVP-25 option which provides voice-inversion scrambling and 16 key DTMF encoding & decoding). The display is backlit orange (as well as the DTMF pad) and can be set to activate manually or through channel and button activity, or both. It is automatically extinguished after a fixed time interval. This is an excellent feature since it alerts the user visually of message traffic even when the volume is down (during a meeting, etc.)

Front Panel Programmability and Control

Unfortunately, the VX-800's codes and frequencies cannot be changed through the front panel (please let us know if you know differently!). However, a button can be programmed for "Set" mode, which permits certain global parameter changes via the channel knob. These include:

  • Squelch level (global)
  • User/Dealer list
  • Global beeps (on/off)
  • Bell on/off
  • Light
  • Lock (3 options)
  • Home group
  • Power-on scan enable on/off
  • Talk-around on/off
  • Encryption on/off (selected channel)
  • Min. AF volume
  • Min. beep volume

These controls may be useful for commercial or public safety users, but I would have preferred frequency and code programmability since I change these features more often. There are Commission restrictions on programmability, but most manufactures have been able to use a "dongle" and password arrangement to permit this.

A bright tricolor LED on top of the radio indicates TX, RX, Called and battery status (flashing red).

There are eleven switch and button positions (3-position) toggle, four momentary types in various spots, and the A-D buttons on radios with DTMF option). Their assignment choices are extremely flexible, and a (global) "Key Holding Time" setting is provided to reduce inadvertent operation. Even the traditional channel knob can be reassigned to be a group selector, leaving the channel selection to momentary switches. This feature provides for many flexible options.

Well-designed button guards are provided for most all buttons and switches. However, the A-B-C toggle switch can still be bumped into the C position when changing the volume. This is not unusual due to the radio's size. But the flexible button assignments allowed us to reverse the normal settings, eliminating the problem.

The channel and volume knobs are also worth mentioning. Both are designed with significant friction to prevent mis-adjustment. The channel knob is equipped with deep detents and is spring-loaded; light upward pressure releases it, making it easier to turn. It can also be turned without lifting. The volume knob could be equipped with larger ribs, or be made of rubber to make it easier to rotate since it is the smaller of the two and used more often. The PTT switch location and tactile feedback is excellent. However, the rubber cover seems a bit thin and may require service more often under heavy usage.

A strong plastic battery retention clip is permanently attached to the bottom rear of the radio, and swings up to secure the battery in a very positive manner. It is unlikely that the battery would come off even if the radio were dropped. It can sometimes be difficult to open, and I occasionally used a key on it, resulting in scratches on the battery. There is significant pressure on this clip, and I fear that it may become worn over time. The retention clip on my Motorola JT1000 is part of the battery, and is therefore replaced with each new battery. I would rather throw away a used battery than have to send the radio in for clip repair.

Scan programming and activation is easy. However, in order to enter the selected group or channel into the scan list, the user must hold down momentary switches for about 2 seconds. This is fine for enabling an entire group, but becomes a lengthy process for adding individual channels. I still miss my Bendix/King MPU portable which only required a single quick button press (in any mode; even while scanning).

RSS Programmable Features

Most of the useful features and be enabled or disabled in the spreadsheet-like DOS programming screen provided for each group of (up to) sixteen channels. Uploading and downloading were extremely reliable, and the RSS was not disruptive to Windows or DOS mode. However, you must run it in DOS mode for programming. The high-quality programming cable did not require external power and was a useful length.

Instead of droning on about the features, I have shown various programming screens below and described some of more interesting features. The first is the main screen:

Click to see a slightly larger image.

Each channel can be configured for either Wide band or Narrow band (12.5 kHz). Note, however, that each channel code can only be set for CTCSS or DCS, not a mix of both. A global TX/RX offset can be set in the main menu (i.e., 5 MHz, etc.) which directs the program to auto-complete the RX frequency entry (good feature for UHF).

Operation of the Pwr Sav RX is definable in a sub-screen for automatic (based on recent channel activity - excellent feature), of for specific RX/STNBY ratios. A more unique feature is the Pwr Sav TX. The radio is capable of adjusting its transmit power based on the strength of the last signal it received. The stronger the received signal the more it reduces its transmitted power. The dynamic range of the feature was not documented, but even a 3-dB reduction in power (from 5w to 2.5w) would significantly increase battery life. The included maintenance/alignment software permits calibration of RSSI (Received Signal Strength Indication) for correct operation of this feature. Users should keep in mind that such power control methods can be system-specific - they assume the transmitted power from the other party is equal to that of the portable, making this feature limited to one type of operation (simplex or repeater, not both). Therefore, if the radio is aligned for simplex operation but is operated in a repeater system (with a 50+ watt repeater), the radio will drop it's transmit power and possibly drop out of the repeater (all else being equal). This can be avoided by simply enabling or disabling it on a channel-by-channel basis (simplex versus repeater operation). We assume that the RSSI calibration could be offset to permit operation with repeaters, but we did not try performing this.

The radio has four power levels (H, L3, L2 and L1) corresponding to 5, 2.5, 1 and 0.250 watts. The SC column sets whether the channel is in the user or dealer defined list (user defined channels can be changed by the user).

There are 13 global squelch levels (0-12) in the RSS, and the SQ column is used to indicate offsets from the global setting (+7 to -7). This is useful in the 440-445 MHz range channel where I found a lower noise level (which would cause the squelch to open more frequently).

The radio is capable of encoding (DTMF ANI) and decoding 3-digit DTMF codes. It can also acknowledge reception of a page by responding back with the same digits that were received. I was going to use this feature, but I found that too few timing parameters were provided to make it more intuitive and user friendly. For example, the unmet duration on the decoding radio could not be varied or disabled. Also, the acknowledgment delay could not be set, making it difficult to configure a selective call feature on a network of multiple sites (using additional hardware and switching equipment).

A received call could not be muted (through a reset or other button) to quiet the radio following reception of a call. The radio would simply mute after about five to ten seconds. However, the radio would remain in coded squelch following a call (good feature). The radio would not decode the call unless one of the ten pre-programmed codes was received AND the correct CTCSS/DCS code was transmitted. It is interesting to note that when a channel is set to decode a DTMF call, reception of any one of the ten pre-programmed DTMF codes would activate it. This makes it very flexible for setting up common group call codes.

I ordered the voice inversion encryption option which can be enabled in the ENCR column (encryption cannot be employed in GMRS; I was planning on using it for another radio service). The last two columns are for busy-channel lockout (carrier, or TX on correct code only) and for setting one of ten DTMF paging codes. The radio is capable of two-tone signaling as an option.

A few other important screens are shown below:

Click to see a slightly larger image.

Click to see a slightly larger image.

Below I show some of the various programmable key options. More are available but could not be shown here.

Click to see a slightly larger image.

Frequency Spread and Bandwidth

Most industry offerings lack sufficient frequency spread to cover the entire business/public safety radio band available in some areas (450-512 MHz); the exceptions being the Motorola JT1000, and my previous Bendix/King MPU4421 radio. The VX is no exception.

The VX is available in 450-485 MHz (frequency spread of 35 MHz). Land mobile systems are also assigned a portion of the T-band (Television band) spectrum in San Francisco (482-494 MHz). The VX was able to cover to 494 MHz with good sensitivity, but the transmit power started to drop at 488 MHz. The sensitivity and transmit power performance of my 450-485 MHz version was as follows:

Frequency (MHz) 12 dB SINAD (dBm) 12 dB SINAD (microvolts) TX Power (W)
512.0000 VCO Unlock VCO Unlock None
500.0000 VCO Unlock VCO Unlock None
494.0000 -119 0.25 3.2
491.0000 -119 0.25 3.5
488.0000 -119 0.25 3.7
485.0000 -117 0.25 3.9
467.5000 -119 0.25 4.0
450.000 -119 0.25 4.0
447.5000 -119 .25 3.8
445.0000 -120 .22 3.5
442.5000 -107 1.00 3.4
440.0000 -108 0.89 3.3
437.5000 -106 1.12 3.3
430.0000 -106 1.12 None
425.0000 Unstable Unstable None
421.0000 VCO Unlock VCO Unlock None
420.0000 VCO Unlock VCO Unlock None

The RSS permits entry of out-of-range frequencies from 400 to 512 MHz with no special actions or modifications.

Although radios' receive VCO locks consistently down to 437.5 MHz, its sensitivity dropped quickly below 445 MHz. Intermodulation performance is good-to-excellent, and the radio rarely became overloaded. However, I did hear a few bursts of paging data once when just down the hill from some commercial communications sites, although I never heard any problems while in downtown San Francisco where RF levels are quite high. CTCSS sensitivity is average to poor, which may partially explain its poor fade-resistance. This was especially noticeable during fast, deep fades, where the audio would drop out for about 200-300 milliseconds, and then recover (may also be related to a perceived AGC problem). We believe this dropout is the re-acquisition time for the CTCSS decoder. We did not try the using DCS on receive. The only other anomaly is a transmitted audio transient on unkeying (both mentioned later).

The VX-800 does not provide voice companding that could improve effective range in narrow band mode.

Operational Issues

The radio is not problem-free. I have been a bit harsh here on Vertex, but they have a great product that could be a value-leader if a few problems are resolved. The most notable are as follows:

  1. Cannot accept mixed-code channels. The RSS does not permit the mixing of DCS and CTCSS on the same channel. Conventional repeater systems are increasingly employing digital access codes and cross codes (DCS in/CTCSS out) to increase system security while still allowing reasonably quick decoding performance (CTCSS is usually decoded quicker than DCS).
  2. The RX CTCSS/DCS code is not used as the TX code when radio placed in talk-around mode using a programmable switch or button (this only causes a problem if the specific channel uses a repeater with different input and output codes, i.e., cross or mixed coding).
  3. No squelch-tail elimination on receive. We used this radio in CTCSS decode mode with three different Zetron tone panels, MSR2000 and MASTR III repeaters, a Kenwood TK830 and TK805, JT1000 portable, as well as another VX-800 and all caused squelch tails on the VX's receiver. However, squelch-tail elimination performed flawlessly with DCS (DCS uses an industry-standard turn-off code on unkey).
  4. Priority scanning incorrectly implemented. The radio provides a "follow-me" scan feature that was intended to mimic other manufacturer's "Priority Follows Selected Channel" feature, where P1 is always the currently-selected channel. However, when the channel is changed while scanning, the priority remains on the "scan start" channel (the channel selected when scanning was activated).
  5. Radio can transmit on wrong channel when scanning. If the channel selection is changed while the radio is scanning, depressing the PTT will result in transmission on the Scan Start channel (home channel, or various other less useful options). In order to transmit on the selected channel when scanning, the user must disable scanning, switch channels, and enable scanning again.

There were other less significant issues that are worth mentioning:

  1. No channel copy feature in the RSS. There is no way to copy the channel information from one position to another. As a secondary concern, a channel insert or delete function is also missing (although group size can be increased or decreased on a per-group basis). As a result, the user must plan ahead significantly when programming this radio, and spend quite a bit of time doing it as well.
  2. Receiver and/or CTCSS had inconsistent fading performance. We apologize for being vague, but we just could not place a finger on the cause of this. Fading signals would sometimes drop out of the receiver for up to 300 ms (approximately). We first though this was a coded squelch sensitivity problem, but placing the radio in monitor only slightly reduced this problem. Loosening the squelch resulted in too loose a setting, and the radio would often unmute (see No. 6 below). This could be an AGC attack/decay problem, or excessive squelch hysteresis. Both of our radios exhibited this problem.
  3. Various display/firmware annoyances. When the keypad lock is on, changing the channel using the knob resulted in the display reading "- LOCKED -" for about 1-2 seconds following each step, even though the radio (correctly) permits the channel knob to be used when the keypad lock is activated. The same thing occurred when in talk-around mode (asserted through a switch or button) where the display read "- TA ON -". This obscures the channel label when switching and can really be annoying when you are searching for channel within a group (of sixteen). This became so annoying that we were forced to permanently disable all the radio's buttons that could become inadvertently pressed. Also, small decimals on the display indicate if the selected channel and group is active in the scan list (good feature). However, when a change is made, the display does not update until the channel is changed, or the radio's power is cycled.
  4. CTCSS falsing. In extremely noisy environments (such as around computers) or on channels with large amounts of co-channel radio traffic, the CTCSS would occasionally false. The speaker would open and a 300-400 ms burst of noise or voice would be heard. This limited the usefulness of the BELL function (this function alerts the user with a ring signal and shows "CALLED" on the display when the preprogrammed CTCSS/DCS code is received)
  5. Pop heard on receiving radios when transmitter unkeyed. The VX caused a strong "pop" on all receiving radios when it was unkeyed (when reverse-burst or DCS was enabled), although somewhat less with DCS. It appears that it is transmitting a reverse -burst or turn-off code, so we think the VX must send a DC transient when unkeyed. The radio is also capable of transmitting a "chicken burst" (dropping the transmitted CTCSS before the carrier), but this did not work reliably on other radios except on another VX-800.
  6. Receiver or squelch susceptible to certain types of interference. The radio (possibly the discriminator design) was much more susceptible to digital or computer-generated noise than other radios I have owned. Such noise would be demodulated and would often unsquelch the radio, even under tight squelch settings. If I recall correctly, other Vertex (Yaesu) products I have owned over the years had similar discriminator limitations.
  7. CTCSS modulation deviation sloped. The deviation of low frequency CTCSS codes was significantly less than higher frequency codes. This could cause performance problems on receiving radios under weak signal conditions.

Conclusion

Due to its size, weight and battery life, this radio has become my primary portable. My wife even carries it from time-to-time. The construction of this radio is the best I have seen from Vertex and almost equivalent to the JT1000 (or MT/MTS series) Motorola radios I have used. The exception is the battery clip arrangement that may be susceptible to breakage as it ages.

But don't plan on using many of its various features because, in our opinion, they have been poorly implemented (unless you don't mind developing work-arounds). Fortunately, most of the more problematic issues seem to be related to firmware design as opposed to hardware (with some exceptions), making fixes easier if the manufacturer chooses to do so. The most notable exception being the receiver and/or CTCSS dropout problems during fading conditions. This is not a concern under strong signal conditions.

Vertex technical support got right back to us after we emailed questions about the more significant firmware problems. The person who I was referred to seemed extremely knowledgeable about the firmware design (which was a welcome change from my experience with other companies). It appears that some of the problems were simple flaws or oversights; others were design decisions made during development. However, Vertex never got back to us on any of the issues, so we suspect they still exist in later production models. Furthermore, my supplier would not return the radios when asked. I was not sure if this was Vertex's policy or the supplier's.

If Vertex improves its firmware and smooths out a few rough (hardware) edges, this radio will likely be a true value leader. But for most users, its limitations are not show-stoppers.


 

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Last updated June 24, 2001

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