[HBQRP] building a very efficient hf handy ssb+cw 20m transceiver based on a already present ssb qrp rig design called the ILER 20..

[{vu3sxn} - shubham tiwari]

Hi there,

I am requesting for support from HAM radio operators interesting in home brewing to build a very efficient  hf handy ssb+cw 3 to 5 watts of rf output on 20m or 14mhz transceiver based on a already present ssb qrp rig design called the ILER 20..

The reason to build one--

An HF handheld is truly the ultimate backpack radio. The small size, light weight, and make them very attractive for the QRPer on the go or out enjoying nature. Which radio is best for you is a matter of individual taste. Also since with hf radios you can definitely make a contact even dx during a dire need or in an emergency situation, the  Mizuho  series transceivers are my inspiration.

I understand there are other portable options but thats not what im thinking about, you cant hang an ic-706 or ft-897d or even a ft 817  etc  on your belt, and who wants to carry a big ole heavy battery to power the rig. also i realize the antenna wavelength issue but granted, you can base or center load a 7' telescoping whip that will work for local comms. and if you want real distance or possible dx comms, you use the external antenna jack with a dipole, longwire or whatever.

The design that I am following—

I am trying to convert the qrp transceiver ILER – 20  to a more compact and efficient..

The details of ILER -20 transceiver –

GENERAL: 

Frequency Coverage: VXO tuning 25-100KHz segment in 20M band (60-70Khz máx reasonable stability for). Bandwdith range is selected according L6 value in the VXO circuit. 

Frequency control: high stability VXO oscillator. 

Option A: a pair 11.000MHz. (14.276MHz upper limit approx.) 

Option B: a pair 11.046MHz. (14.320MHz upper limit approx.) 

Variable capacitor tuning control (polyvaricon). 

Antenna: 50 ohm 

Power requeriment: 12-14VDC, 35mA. Receive (no signal), 100mA max. receive, 800-900mA on transmit. 

Board-mounted components: 51 resistors, 77 capacitors, 3 resistors trimmers, 1 trimmer capacitor, 1 potentiometer (volume), 9 IC’s, 8 transistors, 7 diodes, 12 inductors-coils, 6 RF transformers, 1 tuning polyvaricon, 7 crystals. 

Front panel controls: tuning, volume. 

Rear controls: Rx Attenuator switch 

External connections: microphone/ptt, phone jack, antenna, DC input. 

Board size: 100x120 mm. 

TRANSMITTER: 

RF Output: 3 – 4 watts (12.5-14V) 

Output 2º harmonic: -45dB 

Other signals spurious: -50dB or better 

Carrier suppression: better than -35dB 

T/R Switching: PTT relay 

Mike preamp & passband 

Mike Type: dynamic 600ohms, CB or similar OK (no included) 

RECEIVER: 

Type: single conversion superheterodyne, balanced mixer 

Sensitivity: 0.200uV minimum discernible signal 

Selectivity: 4 pole crystals ladder filter (2,2KHz nominal bandwidth) 

IF frequency: 3.276Mhz. 

SSB Audio preamp & AGC (AGC mini module included) 

Audio output: 250mW @ 8 ohms



Options needed to be incorporated in the design are—

1.The pcb of transceiver should be as small as possible [maybe the resistors and capacitors can be made surface mount}

2.Instead of a variable capacitor tune for vxo it should be varactor tuned. For best tuning

3.The design should be made as efficient as possible, the receiver is very efficient, but I want the transmitter to be more efficient,

4.The transmit portion draws about 900ma  and rf out put is 4 watts,ie the transceiver takes power = 13v * .9a= 11.7 watts to give an out put of 4 watts,which according to a survival hf handy radio is a lot of power draw,I want the transmit section to be more efficient drawing about 500ma  at 13v or 6.5w  to give  3 to 4 watts  rf out pot …can this be don??

5.Also this design should have a cw option as well..

6.use of a small microcontroller is also appreciated if it can be used to perform work of few stages of the transceiver and if it makes it more small and efficient,even a reduction of 50ma current is considerable ,microcontrollers such as atmel ATtiny can be used easily

THE MAIN AIM IN MAKING THIS SINGLE BANDER RIG SSB+CW IS TO MAKE A CHEAP RADIO WITH EASY TO FIND PARTS WHICH WILL WORK ON AAA,AA,OR ANY OTHER 12V BATTERY AND IS SMALL ENOUGH TO BE CARRIED ON ANY TRIP ..



Also suggestions are welcomed to make this small transceiver as small portable and efficient as possible, 

AGC and a freq counter can be omitted as they are not necessary …



Thanks

Vu3sxn

Email—vu3sxn at gmail.com

The circuit diagram of ILER 20 transceiver and its manual is attached in the email above.. 

Also both the files  manual plus the circuit diagram are available to download from this link—


     http://www.ziddu.com/download/21988074/newprojectonhandheldtransceiverusingiler.zip.html