[Lowfer] 2200m problem found

[hvanesce at comcast.net]

Hello Dave,

Did you tend to use the Yasuda relay at current and voltage near its rating?
I noticed 10A, 800V in your photo. 

I like using relays and contactors in part because they have been
interesting electrochemistry/metallurgy projects in themselves, including
HV, vacuum and/or RF relays, and other types. In many or most cases,
reliability was best when the relays were operated regularly at current and
voltage near the rated values (not much more and not much less voltage and
current), with nominal frequency sometimes also a significant consideration.
Brian's application seems interesting in that regard because voltage/current
for different bands might be quite different, such that a relay might not be
operated regularly at current and voltage near the rated values (might for
instance corrode/stick if operated at too low of a current or voltage, or if
operated infrequently, and might become pitted if operated at too high of a
voltage/current without snubbing). In a case like this would you recommend
any additional measures like snubbers or preventive (electrical/manual)
conditioning for sealed/unsealed contacts?

73,

Jim AA5BW 

-----Original Message-----
From: lowfer-bounces at mailman.qth.net [mailto:lowfer-bounces at mailman.qth.net]
On Behalf Of Dave ZL3FJ
Sent: Tuesday, April 3, 2018 7:31 PM
To: 'Discussion of the Lowfer (US, European, & UK) and MedFer bands'
Subject: Re: [Lowfer] 2200m problem found

One of these would be an alternative
http://homepages.ihug.co.nz/~tractorb/relay.jpg
 It's a latching  DPDT relay used for openwire line switching. This one
needs a bit of TLC.
I used to have several but this one is the last and a 'keeper' for now.
 These might be found in the MF broadcasting industry if you have any
contacts there.
73
 Dave, ZL3FJ


-----Original Message-----
From: lowfer-bounces at mailman.qth.net [mailto:lowfer-bounces at mailman.qth.net]
On Behalf Of JD
Sent: Wednesday, April 04, 2018 13:38
To: Discussion of the Lowfer (US, European, & UK) and MedFer bands
Subject: Re: [Lowfer] 2200m problem found

On Tue, April 3, 2018 8:52 pm, Brian, WA1ZMS wrote:
> I'm not so sure a set of vacuum relays would be up to the task, but 
> maybe. I need to go look at some specs. I'm open to other ideas if 
> anyone has any.
>

One alternative might be to locate the LF and MF loading coils (or the major
part of them) outside, after the vulnerable contactors, so that lower
voltages would prevail.  Might be physically awkward, but it'd be safer for
the house and could probably be configured so as not to affect HF
performance.


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