[Elecraft] EME Radio - 144mhz Transverter or 2m Module

[Jim Brown]

Excellent comments, Oliver.  I've not done EME (too many tall trees in 
the way), but I do own an XV144, and recently set it up with a vintage 
Mirage 2W in to 150W out brick amp of pre-MFJ vintage. Some thoughts 
based on my experience.

The internal transverter is rated for about 10W, the external unit for 
20W. Both should be carefully cooled and derated for keydown modes, 
which is one reasonI sought out that particular Mirage. The other reason 
is that minimizing temperature rise in either transverter improves 
frequency stability. To minimize heat in the XV144, it should be driven 
from the K3 so that 1 mW generates full rated power. Running the 
transverter at reduced output also helps. Since I need only 2W drive, 
I've set up my XV144 so that 1 mW in yields 10 W out.

For whatever reason, both my XV144, as well as my XV220 that has been on 
long term loan to neighbor K6EU, both have some degree of instability, 
to the extent that both behave differently with top cover on and off. 
One thing I suspect as a cause is poor EMC practice. The antenna 
connector is bonded to the chassis, but BNC connectors for interface to 
the transceiver are insulated from the chassis. My XVs are fairly old -- 
I bought them used in 2005 already built, so perhaps current production 
is better in this regard.  And the XV144 did get a glowing review in QST.

73, Jim K9YC

On Sun,8/31/2014 8:25 AM, Oliver Dröse wrote:
> Hi Rich,
>
> don't know the external one (XV144) myself so cannot comment. The 
> internal one (K144XV) has one drawback: no adequate cooling! Cooling 
> is done only passively using the left side of the enclosure. As JT65 
> on EME is a key-down mode you will see that power drops soon and 
> dramatically, i.e. starting with 10 watts it will drop down to 5-6 
> watts after 2-3 overs already due to missing heat dissipation. So you 
> will want to do some external cooling to lessen that effect (but you 
> will not completely get rid of it from my experience).
>
> Besides this the K144XV is very sensitive, whenever I use mine I 
> switch off the external pre-amp which is needed for all other 
> transceivers overhere. :-) And don't forget to order the K144RFLK to 
> keep the frequency stable.
>
> What you should also consider is which amplifier you want to use. So 
> the XV144 might be the better solution if you need more drive power. 
> If you want to think outside the box you can also check other 
> manufacturers. For serious contesting and EME I'm using the HA1YA 
> transverter ME2HT-PRO with +30 dBm mixer 
> (http://www.ha1ya.hu/htmkepek/me2t_protransverterspec.htm) and 60 
> watts (including adequate cooling) to drive a GS35 amp.
>
> HTH - hope that helps!
>
> 73, Olli - DH8BQA
>
> Contest, DX & radio projects: http://www.dh8bqa.de
>
>
> Am 30.08.2014 14:26, schrieb Richard Thorne:
>> I'm starting to get the bug to try something different and EME has 
>> grabbed my attention.
>>
>> I already have a couple K3's and would like to put one to use for 
>> EME.  Which is the better option the external 144mhz transverter or 
>> the internal 2m option?
>>
>> Thanks
>>
>> Rich - N5ZC
>>
>>
>>
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