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Reviews Categories | Transverters | Down East Microwave Inc. 144-28 Help

Reviews Summary for Down East Microwave Inc. 144-28
Down East Microwave Inc.  144-28 Reviews: 14 Average rating: 3.6/5 MSRP: $395 build/ 295 kit
Description: High Dynamic Range 144 MHz Transverter,linear output 25W, 35W on FM/CW. Noise figure 0.8 dB. IF= 28Mhz Including metal enclosure and heatsink.
Product is in production.
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KM3F Rating: 4/5 Jan 8, 2013 20:36 Send this review to a friend
With some attention it's a very good performer.  Time owned: more than 12 months
Since the last review I added a quiet computer fan on the heat sink.
The frequency stability is now solid to the point that key down drive to the full 30 watts output into a 50 ohm load for more than 5 minutes shows no frequency drift on a sampling frequency counter.
The driving radio is a KW480 with the TCXO option.
What a pleasure to be this stable in QSO.
KM3F Rating: 4/5 Dec 12, 2011 15:36 Send this review to a friend
Second later review  Time owned: more than 12 months
....After using this unit a couple years driving a MIRAGE amplifier at about 120 watts, it does a fine job for weak signal work using a 12 element beam for contacts within 350 miles on SSB.
....I installed a small 2" fan in the bottom cover to blow outside air on the crystal and exit out of two rows of holes in the other end of the cover.
....This modification has provided satisfactory frequency stability for normal SSB use even on extended QSO.
....I have a spare unbuilt kit to build as a backup.
....Further experience is at reduced drive input and adjusted to the 7 to 8 watt output level, it can be used on the AM mode for those who want to try that mode. This must be done to prevent overdriving as 4 times 7 watts is 28 watts just below the units max output for peak power, to stay clean.
Great unit.
WA2ODO Rating: 5/5 Oct 17, 2011 06:27 Send this review to a friend
I opps'd  Time owned: more than 12 months
A few years ago I acted out of anger and badly rated the DEMI 144/28 preamp and company. I have tried on many occasions to modify, change and/or delete this review. So far I have been unsuccessful. I have written to staff an asked for help retracting it or at least the ability to modify it. I have not be answered as of yet ( had some email issues), but I sent it again a few days ago and I hope they will let me delete it.

The real review should be. The unit does drift on newer modes like WSJT but is Fantastic on all others. (This has been corrected Fantastically on the new version). The issues with the company were as much if not more my fault. They are a great bunch of people and do a great job helping the MW community. Again ...sorry about my opps.
K3ROJ Rating: 2/5 Oct 16, 2010 14:01 Send this review to a friend
Sensitive but not Stable  Time owned: 6 to 12 months
Frequency stability suffers even in this unit and I often wonder why they can't add a 10 MHz reference input. Most of us have the GPS 10 MHz references such as the Z3801A. Many hams including myself would be willing to pay for an accurate and stable 116 Mhz PLL oscillator driven by a 10 MHz reference. I also own the Elecraft 144 which performs as well, but then again, unstable frequency.
K4TAX Rating: 4/5 May 31, 2009 20:14 Send this review to a friend
Very good performer  Time owned: more than 12 months
I've owned two different ones. I found both to perform quite well and as expected. One took a lightning hit and was totally wiped. I've been able to work several EME stations with the transverter, a 150 watt brick and a single 10 ele yagi using CW mode. The transceiver behind the transverter is a Tentec Omni VII for the 28 MHz IF. Overall, when service or info was needed, I found the folks at DEMI to be good, prompt, and technically very competent and helpful. It is not and item for the appliance operator as it does require one to be able to create and build their own interface if such is desired. They offer a good one for a few dollars. The unknowledgeable user can destroy the unit and not even realize it.
Overall, I would not hesitate to purchase another one or different model if needed. Very good value for the dollars spent.
W1JHR Rating: 5/5 Oct 20, 2007 06:12 Send this review to a friend
Disparity between reviews  Time owned: more than 12 months
I find there is substantial inconsistency between the reviews for the DEM 144-28 and the DEM 222-28. Apart from a few component values they are essentially the same product on the same board. I am not running digital modes or doing anything to evaluate or compare oscillator stability beyond using my ears and a frequency counter. I am using 0 dbm as drive at 28 MHz and have not had a problem with the DEM line from 50 MHz to 222 MHz. except the inability to zero the 50 MHz unit which required a replacement crystal. The units work flawlessly at home as well as in the field. I have built all three units and must say that I found them somewhat difficult to build and get working properly. I am no stranger to kits having built DEMís whole microwave transverter product line from 903 to 10 GHz. I actually find the microwave units easier to build and get working. Perhaps this is because the functions have been split between 3 boards. Things do get easier once you have built a couple of units too. I would recommend factory built units unless you are an experienced builder. I also own the Elecraft XV 50 through 222 transverters.
N5KDA Rating: 0/5 Nov 30, 2006 20:15 Send this review to a friend
Save your money  Time owned: more than 12 months
I've owned the high power transverter since 2003. This is the one made to match the transverter output of the IC-756 Pro II. Since I have owned it, I have lost output FOUR times. I just got this back from DEMI in May of 2006 and it has less than 100 hours use on it since then. I know of others that have very bad frequency stability problems. We call them drift masters. A transverter and nice HF rig is a great way to go but run away from DEMI. I now have a Kenwood TS-790A for a primary rig and will keep the DEMI for a backup. Run Forest run...
N8ERM Rating: 5/5 Oct 22, 2006 11:50 Send this review to a friend
Great product  Time owned: more than 12 months
This unit was purchased from another ham. He ran it in a rover over ROUGH rodes and beat it up pretty badly. He never had it fail. This unit has a hot reliever and is selective. I put it in a new box and it keeps on ticking. A great product.
ON6AB Rating: 0/5 Aug 19, 2005 13:02 Send this review to a friend
Dead (again) and forgotten  Time owned: more than 12 months
Another review about this piece of junk.
Well, not exactly a review, more an in memoriam.
It's dead again. I'm not interested in what's wrong this time since it's not going to the repair man but to the junkyard. I've had it with this clumsy built, poor quality, awfull, ugly piece of misery built in a cheap DIY aluminum housing! Time to buy something decent!

PY2RN Rating: 5/5 Mar 1, 2004 01:42 Send this review to a friend
Vy Satisfied  Time owned: more than 12 months
I'm very satisfied with DEMI transverters, I have 3, 144-28, 430-28 and 1268-144 I'm using them in a very "noisy" region, it beats by far the RX of a TS2000 and FT847 on both 144 and 430MHz. I Higly recommend their transverters, they are not 100% designed for the "appliance operators" you have to know what you're doing. If you are looking for beauty such fancy panels, silk screen, nice meters and lights (usually everything that an appliance op looks for) go to SSB/DB6NT line of products, they are real nice but be prepared for the big, big $$$$$.
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