828 Radio Freq Tuning

[GunfighterSIX]

In the Mi8 I turn the channel selector to the desired channel and push the white button to tune. "НАСТР" (TUNING) light then flashes green.

 

According to Belsimtek's Mi8 manual that white button is for AGC automatic gain control.

 

AGC as described by the TM 1-1520-Mi-17-10:

"The radio receiver is equipped with automatic

gain control (AGC). A noise suppression circuit

(squelch) frees the pilot from listening to noise during

standby reception when there is no signal at the

receiver output."

 

So why am I pushing that button to tune?

 

How to use 828 according to Belsimtek's Mi8 manual

On the R-828 radio set control panel:

– "ПШ" (SQUELCH) switch OFF

– "ГРОМК" (VOLUME) control to maximum

– "КАНАЛ" (CHANNEL) selector to the desired channel. "НАСТР" (TUNING) light should turn on for 1-5 sec.

 

There is nothing about pushing the AGC button to tune in these steps, the TM 1-1520-Mi-17-10 states the same thing.

 

Any thoughts?

 

Note: The KA50 828 radio has a “АСУ (Automatic tuner) button. After you have selected a channel, you will need to press the tuner button to tune the radio to the selected channel." Was this function accidentally copied over to the Mi8 from the KA50?

 

Thanks

Edited March 23, 2016 by GunfighterSIX
added KA50 note

[Looney]

As far as my knowledge on radios goes, being a former communications officer, the AGC is usen in the receiver circuit to allow a constant volume of signal to be heard instead of louder and softer signals, it has nothing to do with tuning.

 

Tuning is performed to match the amplifier output impedance to the antenna impedance. Basically, you're compensating for the length of the antenna by tuning the amplifier via a set of coils to match both impedances which allows for the best tranmitter efficiency. Most (western) tranceivers do this automatically the first time you key-in on the new frequency, the russian counterparts require you to press and hold the tuning button until the system, via its light, tells you tuning had been succesfully completed.

[Martillo1]

I can confirm what Looney says about AGC. I was involved in the AGC circuitry design and testing of the SINCGARS radio in the 90's.

[GunfighterSIX]

I think there is a miss understanding my post. I am not asking what tuning or ACG is or why it is required. I was making a point that they programed the functionality of the radio incorrectly in the Mi8. Unlike the ka50 828 radio, the Mi8 828 radio automatically tunes when you rotate the channel selector. The button on the radio is for AGC automatic gain control, not tuning. This is according to a few manuals including Belsimtek's.

 

"the Russian counterparts require you to press and hold the tuning button until the system, via its light, tells you tuning had been successfully completed."

It does not require you to push a tune button in the actual MiI8 828 radios. As stated in the check list and manuals I posted

 

My point was that they seemed to have copied the KA50 828 radio functionality to the Mi8 828, but the two radios do not function in the same way. I was just trying to bring it to the attention of Belsimtek.

 

Thanks

Edited April 16, 2016 by GunfighterSIX