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Reviews For: AEG Telefunken SE 6861/12

Category: Transmitters: non-amateur adaptable for ham use

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Review Summary For : AEG Telefunken SE 6861/12
Reviews: 1MSRP: 600 euro
Description:
Field Radio Unit Manpack HF LSB/USB CW AFSK Transceiver suitable for for the most severe environmental conditions.
These two radios (AEG 6861 und SP-20) were developed at AEG Telefunken in Ulm in 1970, and the manpack, especially after a simple modification of the RF input on IP2 of 20dBm, can be enhanced abt. 20 dB to 42 dBm ( providing most of the interferences on a bigger antenna- a useful change!) and IP3 could be enhanced 10 dB to 10 dBm from 0 dBm . Still today it belongs to the best radios of the world without RF modems.
Product is not in production
More Info: http://
# last 180 days Avg. Rating last 180 days Total reviews Avg. overall rating
0015
KD7RDZI2 Rating: 2010-01-17
Alluring HF transceiver Time Owned: 3 to 6 months.
ALLURING
I was fascinated by this radio when I first saw it in new conditions at a hamfest. I did not have enough information to buy it, I googled and found the technical manual, I youtubed and listened it! I pretty much liked the sound, bit metallic but crystal clear. Then I decided I had to buy it.

THE PRICE
You can find the very same units at very different prices, currently the average price is about 600 euro (with the battery pack for external 24VDC but the NiCd batteries are not included) for what I have seen but the price mainly depends on demand and supply and I believe this unit could become quite collectible in the near future.

USER FRIENDLY
I think that this radio is ideal also for operators without much experience in the air. The radio was thought to be operated by humans without technical background. It is designed to forgive the operator from mistakes, being protected at the TX output and having a fantastic internal ATU.


SPARTAN BUT WITH THE ATU
For example, there is no S-meter. I think a radio without an S-meter could be a great innovation in amateur radio but I am aware that not everybody would agree. There is no tuning knob. Another great innovation! Contraves are used to change the frequency up to 100Hz. No noise blanker! No notch! No 100 watts (just select 2 or 20 watts) No everything but an internal ATU (at least in my unit) that can tune a rod 3.3 meters high from 1.5 to 30 Mhz and virtually any antenna and longwire.
The radio has two antenna connectors. One is a BNC type, 50 ohms. If the ATU is disabled, the antenna is connected to the BNC. The other output is for a longwire or the vertical antenna made for this radio. If the ATU is enabled I can use either use the BNC antenna output or the longwire/vertical antenna connector.

THE RECEIVER
Performance: the receiver performs very well. I like its architecture: high first IF at about 40Mhz, a roofing filter, and the second if at about 9Mhz.
The receiver, when the ATU is not enabled, does not always handle large signals outside the band when it is connected to a very broadband antenna.
When the ATU is enabled the rx is perfect, but if you operate in CW with the ATU, the first dot transmitted is lost as it tunes the ATU. This is not very convenient, and then in CW I prefer not to use the ATU whenever it is possible.

I use the ATU instead on SSB and digital modes. SSB is a pleasure to listen with the optional 600ohm LS-166 external speaker. Alternatively I use a DSP external unit such as the old JPS NTR-1 or the sound card of the computer. They all sound very well. Another solution is a small audio amplifier with a high imedandace input, or almost any Hi-Fi.

Hi impedance headphones (I use 2000ohm headphones) can be connected to the radio, otherwise I can use low impedance headphone when connected to an audio amplifier or the soundcard.

Of course, noise reduction, audio dsp can be done entirely by the PC or any dedicated unit.


THE TRANSMITTER

The trensmitter is fantastic!
First of all it can transmitt in the whole HF spectrum, from 160m to 10 meters bands.

The transmitter requires a balanced to ground microphone. For what this means, just refer to http://www.heilsound.com/amateur/tips/balanced_to_unbalanced.htm. For what I understand this is the best solution for a microphone input. A VOGAD (Voice Operated Gain Adjusting Device) by Plessey is used at the micrphone input. What does this mean: you can even whisper into the microphone to have a lot of modulation. How it sounds? Depends of course from the microphone, buy it sound perfectly, very natural!!!! Other hams say the same, they are often surprised by my modulation!!!

What special microphone do I use??? Dynamic ones. I was given one for free at a hamfest! And it was a balanced one! Another one I use I paid about 4 USD. It was old new stock! It also works great.
I also tried a homemade condenser type microphones. I didn't connect the condenser micro directly to the radio, but to the soundcard. The free program Voice Shaper does advanced dsp filtering and the audio then goes to the radio after a PSK interface that isolates and attenuates the audio from the soundcard. The power in this way can be adjusted from 0 to 20Watts, and the voice can be modified to a dx kind of modulation.

DIGITAL MODES:
I made a simple homemade PSK interface using an optoisolator, a couple of audio transformers and an audio attenuator to operate digital modes very easily. It works perfectly.



OVERALL IMPRESSION
It is a fantastic radio, really built like a tank, can be operated from -40 up to 70 degrees, can be put into the water (according to the manual) at 1 meter depth for 2 hours, looks very nice, it is extremely easy to operate, there is a technical manual on line, the connectors are a bit difficult to find: these are mil connectors and expensive ones. I paid 12 euro for the DC connector, and to get the audio connector I had to take it from a cheap miltary surplus radio which I paid another 30 euro.