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Reviews For: Down East Microwave Inc. 144-28

Category: Transverters

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Review Summary For : Down East Microwave Inc. 144-28
Reviews: 14MSRP: 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
More Info: http://www.downeastmicrowave.com
# last 180 days Avg. Rating last 180 days Total reviews Avg. overall rating
00143.6
SM3LGO Rating: 2020-06-06
Nice transverter for the price. Time Owned: more than 12 months.
I own both the 144-28 and the 432-28 transverters since about 5 years. Both work as advertised. I ordered them ready built from DEM, and my only complaint is that the quality control seems so-so. In the 144-28. there was a loose screw inside the enclosure. Also, there was a short between a line in the circuit board and the shield over the crystal owen which made it intermittently stop working. The 432-28 was incorrectly wired, the wiring to two PINs of the AUX connector had been swaped out of order. Easily fixed though. Setting this aside, both work as advertised.
KM3F Rating: 2013-01-08
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.


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Earlier 4-star review posted by KM3F on 2011-12-12

....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: 2011-10-17
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: 2010-10-16
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: 2009-05-31
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: 2007-10-20
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 DEM’s 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: 2006-11-30
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: 2006-10-22
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: 2005-08-19
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: 2004-03-01
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 $$$$$.