Review of Kenwood TR-751E

Kenwood TR-751E is still a relatively widespread TCVR among VHF systems. Today, it can be bought second-hand on stock exchanges or for advertising. What this device with similar dimensions as the 706 can do? Let's take a look….

It is a 25W allmode TCVR at 2m. It is produced in two versions, namely: TR-751A a TR-751E, which hardly differ in parameters, but in the equipment. The TR-851E is a similar looking TCVR to 70 cm. In addition to the TCVR, the box contains the MC-42S handheld microphone, power cord with fuses, car mounting jaws MB-10 and manual.

After unpacking, you will lose little space on the table – TCVR has very acceptable dimensions. You will need a 13.8V / 6A power supply and a 2m antenna to power it. TCVR is switched on by pushing the VOLUME potentiometer. If all is well, The TCVR beeps, the display lights up (on the green) and the set mode also lights up.

The front panel is dominated by a rubberized tuning knob, which gently raps when tuning. To the left is the volume control, SQ, RF GAIN and switchable RIT. There are several buttons above them: channel switching (or jump in MHz), VOICE/TONE (voice module activation or tone 1750 Hz), FUNC, WITH, LOW (performance reduction), NB a RIT.

To the right of the tuning knob are ten buttons, which switch modes, bounce, tuning step, SCAN, memory, VFO A/B. Pressing each button is also announced by a beep, which is different for each function. In some cases, it is necessary to press more than one button at a time. On the far right is the microphone connector and modem control buttons (version TR-751A).

The back panel is relatively poor: SO-239 on the antenna, jack for connecting an external speaker, jack for connecting a telegraph key, power cord and connector labeled AUX, which connects the TCVR to the PA. There are four legs and a speaker on the bottom panel.

If we look inside, we notice a nicely fitted TCVR main board. Even the board with the processor will not remain hidden from our sight, but the PA is covered properly. A look at the diagram suggests, that the TR-751E is not an adversary for “stronger elbows” – behind the preamplifier with 3SK129 is a simple mixer with 3SK74. It is followed by a pair of FM filters on 10,695 MHz. Conversion to is still used for FM reception 455 kHz, in the case of other modes, the signal passes through the SSB filter at the frequency 10,695 MHz.

SSB signal is obtained in the balance modulator, FM using the reactance method on 10,695 MHz. The TX mixer is balanced, fitted 2x3SK73. The driver is equipped with 2SC2538. PA je s hybridom Mitsubishi M57727, which gives 25W.

Basic operations with the TR-751E will seduce everyone. But it's worse with SCAN and memory settings, there is already a manual needed. The supplied microphone has UP / DOWN and PTT buttons.

When you come to all “tricks”, You will definitely like the TR-751E. But the TR-751E has one weakness – at least the NF processor is missing. But this will definitely not be a problem for a skilled designer. I rate it one minus.

Parameter TR-751E

Frequency range	144 – 146 MHz
Fashion	FM, USB, LSB, CW
Antenna impedance	50 ohm
Supply voltage	13,8V +/-15%
Consumption	0,8A RX a 6A TX
Frequency stability	better than +/-15.10 on -6
Dimensions (š,in,h)	180x63x213 mm
Weight	2,2 kg
HF power	HI 25 / LO 5-25W
Unwanted radiation	less than -60 dB
SSB suppression	more than 40 dB
Suppression of unwanted SSB banding	better than 40 dB
Maximum FM stroke	+/- 5 kHz
SSB / CW sensitivity	better than 0.13uV
FM sensitivity (12 dB SINAD)	better than 0.2uV
Selektivita SSB/CW (-6/-60 dB)	2,2/4,8 kHz
FM selectivity (-6/-60 dB)	12/24 kHz
Scope of RIT	+/- 1,2 kHz
LF power	more than 2W at 8 ohm