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Reviews Categories | Transverters | Down East Microwave 144-28 ( New 2010 Version ) Help

Reviews Summary for Down East Microwave 144-28 ( New 2010 Version )
Down East Microwave 144-28 ( New 2010 Version ) Reviews: 4 Average rating: 5.0/5 MSRP: $359 Kit or Assembled $479
Description: 144 MHz transverter, 25W out, <1.0 DB NF receive, 28Mhz IF
( 60 watt version also available )
Product is in production.
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AH6LE Rating: 5/5 May 8, 2016 11:25 Send this review to a friend
Very satisfied  Time owned: 0 to 3 months
I recently built one from the kit and I am quite satisfied with the performance after 1 or 2 minor stumbles (my bad not theirs). Thanks to Ed for being so helpful via email too!

The kit was ridiculously easy to build (if one isn't afraid of SMD) and well worth the savings to spend the 4 hours of spare time it took me.

I'm using it with a Flex1500 for EME/JT65B and am very happy with the performance after a week or two of use. It replaced my TS2000 as my main EME radio. About the only criticism I might have is that DEMI should be a little more informative as to using an external 10 mHz reference with it, IMHO
KL7UW Rating: 5/5 Jan 26, 2014 11:31 Send this review to a friend
Very Satisfied  Time owned: more than 12 months
My L144-28HP DRX model is a custom-built for me by DEMI. It has two receive converters for dual polarity eme operation. But the transmit side is standard with 50w RF module.

I run JT65B on eme so freq. stability is a prime requirement. After warm-up of 15-min the heated xtal oscillator is only +5 Hz from being on 116.000,000 MHz. I ran full 50w on JT65 One min keydown/one min Rx for 30-mintutes and drift was only 6Hz higher (+11 total). This is excellent for a non-locked oscillator. I got 54w full saturated power output when new. Ran easy at 30w drive needed for my 150w amp and easily drives my 8877 to 1400w.

Since then I have started a business building kits for other hams:

I now have DEMI transverters for 144/222/432/1296/10,368

N6VMO Rating: 5/5 Feb 26, 2011 12:03 Send this review to a friend
Looking good...  Time owned: 0 to 3 months

This is my third DEMI product. I currenlty have the 902-28 and 2304-144, both were factory built.

This 144-28CK was my first kit from DEMI. It was placed on order with DEMI in July 2010 and arrived in Feb. 2011.

The kit instructions are clear and I found few minor issues putting this kit together and testing it.
One issue was that DEMI forgot to replace a cap after it had been removed in a preceeding step. A quick call to DEMI was all that was needed to fix that one.
The next two were issues from the builder not following instructions. Re-reading the instructions remedied both situations and the kit came to life without a problem.

The 144-28 has been running full power tests for several days without a glitch.

Since many of the issues with the older model 144-28 had to do with excessive LO drift, I took the time to test and document LO drift on this new model. I am impressed with the oven-ized LO crystal design. But, I will purchase and install the referenced LO modification when DEMI releases the product.

You can download the LO drift test data using the link below. 144-28/
N9LB Rating: 5/5 Dec 23, 2010 12:17 Send this review to a friend
Great Performance, Reasonable Price!  Time owned: 3 to 6 months
I have one of the first of the "2010 Version" Down East Microwave Incorporated ( DEMI ) model 144-28 transverters. I purchased the assembled version.

I'm a VHF/UHF weak signal operator. In the past I have used an Icom IC-820 and a Yaesu FT-897 for 2m SSB work. Both of those rigs worked well, but I noticed that I was not hearing the weaker/ more distant stations that others were hearing. Also, I wanted the panoramic-waterfall aka pana-falls display available with a SDR.

So I decided to start using transverters with my FLEX-Radio HF transceiver rather than a separate radio for VHF long distance work.

The DEMI 144-28 transverter's receive sensitivity significantly exceeds that of the above stand-alone rigs. On transmit, When drive is set to produce 25 watts output, then modulated with a two-tone audio source, the detected output as viewed on a scope is clean with no compression or flat-topping. The RF is spectrally clean as viewed on my Avcom spectrum analyzer.

My QTH has more than a dozen high power FM broadcast stations with-in a few miles. The closest is a 50KW FM broadcast station, WMGN, which is line of site from my QTH. The WMGN signal is so strong that my frequency counter reads their carrier frequency with no antenna attached. Also my HF antenna analyzer is QRM'd by that same FM station. Nothing technically wrong with the broadcast station, just 50KW of RF. I can detect no interference at all to the DEMI 144-28 transverter from WMGN or the other high power broadcast signals in this area.

On-Air reports have all been very positive. I attribute this to the transparency of the new DEMI transverter and the fine audio quality associated with the FLEX-Radio HF transceiver.

The new version DEMI transverters have several improvements from the older model transverters:
- Better front end filtering and better high level signal handling
- A 4-step sequencer is included
- ALC feedback to the HF rig is available - if needed - as an option
- Sharper looking cabinet
- Eight-pin auxiliary connector for interfacing to other devices in the shack, such as: Internal sequencer to external pre-amps and/or external power-amps
External or Remote control - if desired
External or Remote metering - if desired

A 10 MHz reference oscillator input option is in the works for this transverter, but is not yet available.

I like this new version DEMI transverter so much that I have placed an order for a DEMI transverter for the 432 band.

When ordering any transverter, make sure you clearly communicate the type of HF transceiver that you will be using with it and the method of inter-connection and control.


Lloyd N9LB EN52

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