VHF-20A 622-1879-002

Rockwell Collins - VHF Comm
Part Number :

  • Provides AM voice communication in the frequency range from 117.00-135.975 MHz
  • Optional bandpasses available of +-8 kHz or +-15 kHz (see table below)
  • Solid state transceiver
  • Typically used with either CTL-20 digital control or 313N-5/A series analog controls
  • Composed of subassemblies that mount on a central frame
  • Similar to VHF-20B Comm Transceiver but DOES NOT have extended range to 151.975 MHz
Weight: 5.6 lbs. Dimensions: 3.750"W x 3.50"H x 13.9"L
Related documents: DO-138, Env Category AD/A/JNG/AAAEXXXXX; TSO C37b and C38b, class 1, FCC rules and regulations, parts 15 and 87 Temperature: -65 to +131 C
Altitude: 55000 ft. max. Shock: 6 g for 11 ms, operating
Frequency Range: 118.000 to 135.975 MHz Frequency stability: +-0.0015%
Channel Spacing: 25 kHz Frequency control: 2-out-of-5, in accordance w/ ARINC 410
Channel change time: Less than 50 ms Transmit-receive interval: Less than 50 ms
Radiated rfi: Meets RTCA Paper DO-138, DO-109, DO-110 RF power output: 20 watts nominal; 16 watts minimum
Output impedance: 52 ohms, unbalanced Harmonic Content: 60 dB down from carrier minimum
Spurious content: 90 dB from carrier minimum Modulation capability: 90% amplitude modulation
Modulator input: Carbon mic input 0.125 V adjustable, 150 ohms Sidetone output: 100 milliwatts into 600 ohms with 90% modulation
Duty cycle: 1-minute transmit; 4-minute receive Noise level: 50 dB below 85% modulation at 1000 Hz
Audio response: 6-dB variation from 300 to 2500 Hz Audio distortion: 15% max, 85% modualtion
Receiver Sensitivity: 6 dB (signal + noise)/noise for 3-uV signal; 30 dB (signal + noise)/noise for 100-uV signal Receiver Selectivity: 6 db= +-8 kHz min, 60 db= +-17 kHz max (for -001 unit); 6db= +-15 Khz min, 60 dB= +-35 Khz min (for -002 unit)
AGC range: Maximum 3-dB variation, 5 to 200,000 uV Receiver audio output: 100 mW into 600 ohms, balanced
Receiver audio response: 6-dB variation from 300 to 2500 Hz, 1000-Hz reference Receiver audio distortion: 7% max, 30% modulated signal
Part NumberVHF Communications Transceiver Description:
622-1879-001 117.000-135.975 frequency range with +-8 kHz IF bandpass filtering and is compatible with +-8 kHz offset carrier systems
622-1879-002 117.000-135.975 frequency range with +-15 kHz IF bandpass filtering and is compatible with +-15 kHz offset carrier systems


- VHF Comm

NSN: 5895-00-614-2754

Price Condition Delivery

SEA Repair Capabilities: Yes

- VHF Comm

NSN: 5895-00-614-2734

Price Condition Delivery

SEA Repair Capabilities: Yes

Click on a question below to see the answer. If you have a question about this model that is not answered below, please contact questions@seaerospace.com

This does not pertain to the comm selector channel spacing.

With the evolution and growth of airborne travel and the necessity for more usable frequencies in the VHF communications spectrum, the "channel" spacing became smaller. To avoid interference between channels the bandwidth of the RF stages was decreased from 50khz to 25khz. In doing so, another problem was introduced. If the ground transmitter or the air to air transmitter was not capable of tighter frequency tolerances, it was possible the 25khz RF selectivity would not allow the receive signal to pass and the aircraft crew could miss critical voice communications.

Due to the presence of older, outdated equipment in some countries, some manufacturers (namely Bendix/King and Collins) produced VHF comm radios with the 50khz receiver selectivity. With the recent mandates and technological advancements in Europe and South America, the requirements for the 50khz versions has diminished. If an operator were to use a 50khz version radio in the position of a 25khz, they would potentially have channel crossover and or an increase in background noise.
Southeast Aerospace exchanges are based on the return of an undamaged, economically repairable core unit with identical part number as the unit shipped to the customer. An "economically repairable" core is defined as one where the cost to repair/overhaul (or Repair Cap) does not exceed 80% of the original SV/OH exchange price billed. Should the Repair Cap exceed 80%, the customer will be billed the additional amount. In the event this amount exceeds the Outright Price for the unit, the customer would only be billed the difference between the Outright Price and SV/OH Exchange Price with the core returned as-is to the customer.

Here is an example of such a transaction:

$1000 Exchange Price charged to customer
$1000 x .8 = $800 Maximum Allowable core repair charge or Repair Cap

$2000 Cost to repair core unit
- $800 Less Core repair cap
$1200 Additional billing amount.

2200.00 Total Cost of transaction

Please Note:
SEA offers exchange on new items as well. However, repair cap as indicated above is still based on SV/OH exchange price.

Negotiating the exchange price of a unit only limits the allowable repair cap for the core unit. Southeast Aerospace's exchange transactions are based on the return of economically repairable core unit. Once the core is received and evaluated, the core repair cost incurred by SEA cannot exceed 80% of the original exchange price. That is, it cannot cost SEA more than 80% of the original OH/SV exchange price collected from the customer. Therefore, when and if an SEA exchange price is discounted, there is a risk that additional charges may be assessed once the core is returned and evaluated.

For more information, please refer to these other Exchange FAQs

Collins Proline I began production in the early to mid 1970s and was very common in many business aircraft in the 1970s and early 1980s. The original instruction manuals for most of the units is dated in 1974. Although production of the Proline continued through the 1980s, it can be assumed that a Proline I unit is 20-30 years old on average.

The VHF-21C will directly replace the VHF-20A (i.e. no rack or connector change). However, the original controls for the VHF-20A (ex. 313N-5A, CTL-20) are not capable of 8.33 kHz channeling. Therefore, you must replace the original control with the CTL-22C.

Most of the Collins Proline I components were originally manufactured in the early 1970s. Collins has continued to produce some of the Proline I components by special order over the past 30 years however large scale production stopped many years ago. Most of the Collins Proline I product lines incorporates 1960s and 70s analog technology. Collins has superseded the Proline I product line several times with the Proline II, Proline IV, and Proline 21 lines. As a result, some service parts needed to maintain and repair original Collins Proline I components are no longer available. Therefore, you may experience limited to no warranty available and unreliability for many of the Proline I units.

Southeast Aerospace offers many affordable, upgradeable options that are available for aircraft with Collins Proline I. As avionics integration specialists and premiere Collins dealer, Southeast Aerospace is experienced and knowledgeable on all Collins Proline generations.

If you are interested in upgrading any of your original Collins Proline I systems, please contact us for the most reasonable, optimal choice available.