[Elecraft] RX antenna & carrier-operated relay

[Don Pomplun]

Didn't I see something about "protectors" built into the K3S antenna 
connectors?  Are they like the transient discharge tubes that protect 
(somewhat) against lightning?  Is there also one on the RX antenna input?

Don   K2BIO


On 03/04/2017 06:05 PM, Jim Brown wrote:
> Fabio,
>
> You've seen my antenna farm -- Beverages run within 20-30 ft of my 
> 160M TX antenna facing NE. Beverages feed a DX Eng preamp before going 
> the sub-RX. I don't do anything special to protect the radio, but it 
> does occasionally protect itself. I also use the Beverages on 80, 40, 
> and 30M, but TX antennas are much farther away (more than 100 ft). 
> This is at 1.5 kW with a Ten Tec tube amp.
>
> BTW -- I just added a pair of VE3DO loops tuned for 160M and aimed to 
> EU.  Each loop is a rectangle 40 ft long and 10 ft vertical, with the 
> bottom wire 2 ft off the ground and fed at the center. Details on 
> OK1RR's website. The two loops are spaced 5/8 wavelength (350 ft). You 
> probably don't have room for two loops, but you might fit one of them.
>
> 73, Jim K9YC
>
> On Sat,3/4/2017 2:11 PM, Fabio IZ4AFW / NZ1W wrote:
>> Hi Dave,
>>     thanks for the suggestion.
>> I tried doing a quick measure using a cross-needle SWR meter today,
>> using the lowest setting.
>> On 40m the power appears to just deflect the needle, well below the 0.5W
>> mark. Probably I could say less than 250mW, maybe 100mW.
>> I usually have an external relay in a box to disconnect the RX antennas
>> while transmitting, but not today.
>> I was thinking why the RX antennas remain connected when transmitting if
>> there's not another use in a typical single-op station.
>>
>> Thanks,
>> Ciao
>> Fabio
>>   IZ4AFW / IO4W / NZ1W
>>
>>
>> Il 04.03.2017 13:12, David Olean ha scritto:
>>> Hello Fabio
>>>
>>>      I have two beverages  that are somewhat close to my TX antenna. 
>>> One
>>> had about 75 mw on it during TX while beverage #2 had about 1 watt! 
>>> This
>>> is enough power to cause damage to preamps, so I made two power 
>>> limiters
>>> and now the inputs are clipped at about 0 dBm. All it took was two
>>> transformers and two diodes in a box. Do you know what the power level
>>> is on your beverage during transmit periods?  Really high power levels
>>> could burn up the transformers.  Disconnecting the antenna is a good
>>> idea too.
>>>
>>> Dave K1WHS
>>>
>>>
>>> On 3/4/2017 9:53 AM, Fabio IZ4AFW / NZ1W wrote:
>>>> Hi guys,
>>>>      I was thinking of a possible firmware improvement related to the
>>>> carrier operated relay.
>>>> I use my radio on a small lot and recently I added a short beverage
>>>> antenna for low-bands receiving. My main activity is single-op
>>>> contesting.
>>>> Because of the interaction between the tx antennas and the 
>>>> beverage, on
>>>> some bands I have the COR (carrier operated relay) activating when 
>>>> I use
>>>> high power.
>>>> I know the good solutions, but my point is different.
>>>> As I have the COR activating only when the RX Ant input is 
>>>> selected, why
>>>> doesn't the K3 firmware disable it when pushing the ptt?
>>>>
>>>> In fact, when I push the ptt I don't need the RX-ant part to be 
>>>> active,
>>>> as I'm transmitting, and -at least in my setup- I have no other
>>>> rigs/devices that need that input (I mean, no in-band receivers and so
>>>> on).
>>>> Instead of using external relays (ptt-activated) that cut out the rx
>>>> input when I am transmitting, why the K3 firmware just doesn't disable
>>>> the RX ant input on its own (and re-enables it if needed when 
>>>> releasing
>>>> the ptt)?
>>>> Maybe I'm missing something here, or that could be a nice improvement
>>>> for a next firmware release.
>>>>
>>>> Thanks for any comment,
>>>> Ciao 73
>>>>    Fabio
>>>>    IZ4AFW / IO4W / NZ1W
>
> ______________________________________________________________
> Elecraft mailing list
> Home: http://mailman.qth.net/mailman/listinfo/elecraft
> Help: http://mailman.qth.net/mmfaq.htm
> Post: mailto:Elecraft at mailman.qth.net
>
> This list hosted by: http://www.qsl.net
> Please help support this email list: http://www.qsl.net/donate.html
> Message delivered to radioprincegeorge at gmail.com