ALTOIDS PA - CQ Ham Radio - Oct 2009

In the Oct 2009 issue of CQ Ham Radio, JN1GLB, Makoto Kasahara wrote the article of ALTOIDS PA (20w amp for QRP rig in Altoids). It is the same formula with ATS-3B. The article describes that he would make the board with requested people.

The ALTOIDS PA is IRF510 parallel PA with 20w output in HF bands.

KEM-RX3.5 : KEM has been released the 80m receiver.

KEM has released the 80m band receiver (KEM-RX3.5). The receiver is superhetrodyne and IF is 455KHz. It's the same diagram that the 40m band reciever has. The KEM-RX7 for DX orders is $54.87, therefore I assume it will be the same price range.

2W output with 2SC1815 * 4 AMP

JJ1WKN made the 7MHz transceiver and the transmitter generates 2W with four parallel 2SC1815. Here is his blog for 2W transmitter. The schematic diagram of 2W amp is quite simple.

KEM-TRX7-CW video by JQ1BWT

JQ1BWT uploaded the KEM-TRX7-CW video. He compared with his FT-2000d on the video. KEM-TRX has a good performance.

7MHz MicroVert by JA1SCW

This web page describes the MircroVert for the 40m band. The length of the radiator is only 143cm and the length of the coax cable for the counterpoise is 8.3m. You need to attach the 29.4uH coil for the radiator and the choke coil of the FT240-43 between the counterpoise and the coax feed to the transceiver.

The antenna is quite small for 40m band and can install it on the small space. I've made one for my QRP rigs and have a good performance to the domestic CW communication.

Circuit - 7MHz trasmitter - CQ Ham Radio July 2009

You can look at the circuit diagram of 7MHz trasmitter on the July issue of CQ Ham Radio in 2009. The collpits oscillator generates the 7MHz signal and the PA stage increases the RF power to 200mW with 2SC1815GR. The LPF consists of two coils and three capacitors. There is the full break-in capability with 2SA1015GR (PNP transistor) .

The VXO with the 20pF capacitor can move the frequency between 7.000MHz and 7.003MHz.

Parallel 2SC1815GR for 7MHz PA - 500mW

The 7MHz transmitter of the CQ Ham Radio July issue can be upgraded with parallel 2SC1815GR. The orignal PA has only one 2SC1815GR, but JM6QAL has been changed to two 2SC1815GR at PA stage. You can look at the parallel 2SC1815GR which can generate over 430mW although the single one is only 200mW.

I've got one board and made this transmitter with parallel 2SC1815GR. I need to have the receiver that can work with the transmitter.

The 2SC1815 is the typical transistor in Japan. There are sub-alphabet like O, Y, GR, BL for different hfe.

7MHz transmitter - CQ Ham Radio - July 2009

CQ Ham Radio magazine provided the board of 7MHz transmitter at the July 2009 issue. You can get the parts from Marutsu.

Here is the part of 7MHz transmitter that you can buy it here.

The transmitter has 7.000MHz crystal with capacitor, therefore the frequency is shifted to 7.003MHz. The output power is about 200mW. Those two transistors are 2SC1815-BR which are common ones in Japan.

Some of people described that they contacted at the beta version in the magazine. You need to get the receiver to contact. The article shows DE1103 and FT817 for the receiver.

The August 2009 issue shows the 2W amp (2SC2078) for this transmitter.

KEM-RX-HF

The KEM is selling the HF receiver called the KEM-RX-HF for 1.9MH-21MHz. The price is $57.17. The IF frequency is 4MHz and 4-pole crystal filter. The original parts are included for 7MHz/40m band and you can change the frequency with the parts.
Since there is no VFO, you need to get the VFO to generate the signal to convert to IF 4MHz.
I've got the KEM-DDS-VFO to connect the KEM-RX-HF for 7MHz receiver. The price of this VFO is $70.96.

The KEM can accept the DX order on this page. You can pay it via the paypal.

KEM-TRX7-CW

KEM, Kida Engineering Manufacture Inc. has released the 40m transceiver kit the last week. The KEM-TRX7-CW is the 1W CW transceiver with DDS-VFO. The transceiver is super-heterodyne and IF is 4MHz and 400Hz bandwidth with three-pole crystal filter. The price is 11500Yen (about $100). You may buy the 10w linear amp. with two IRF540Ns by KEM.