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Some recent kit developments


#1

Hi All,

Geoff M3SFN and myself have recently been playing with some new bits of kit and I thought it might be useful for people to hear of our findings.

First on the agenda is the switch over from SLABs to LiPos. Working to a budget, we managed to get on ebay and purchase two 11.1V 2.4Ah LiPos (designed for model usage) and a pair of chargers for the princely sum of 35GBP inc postage. These batteries don’t seem to have and sort of regulatory circuitry built in, so no QRM, and keeping the 817’s display set to show voltage helps ensure you don’t drag them down to less than 3V per cell. So far, they have done us very well indeed across three activations, only time will tell how they work out in the long run. It certainly is a cheap way to reduce weight (one 2.4A LiPo is ~1/6 the mass of a 1.3A SLA). The batteries on their own work out at 14GBP for a pair!

The second development is the construction of a M0JDK style dipole for 2m SSB. Recently tested by JDK and KPO with the help of chasers, I understand they have performed very well. So far, Geoff and I have had three very successful activations using one and today we built a second one for me to take back up to Bangor. They are quick and easy to make, super quick to set up (a blessing with horizontally polarized antennas and in freezing cold weather) and generally just a rewarding thing to make and use. John has a photo of this beast on Flickr. Best DX so far is Graham G3OCH at ~170 miles from SW-003, 5W under flat conditions.

The third thing is merely an observation that people may already be aware of. I have found that as the internal batteries on the 817 start getting near flat, the displayed SWR graph creeps up when using SSB. The JDK dipole was showing as 3 bars on the flat internals, and no bars when we plugged in a LiPo or used Geoff’s fully charged 817. This does not seem however, to occur when using a continuous carrier mode such as FM.

Thanks goto M0JDK, 2E0KPO and others who gave a little bit of enlightenment regarding dipoles.

73,
Dave, 2E0BYA


#2

In reply to 2E0BYA:
Pleased to work you from GW/SW003 Dave - the dipole was putting a quite a good signal here under average conditions

Will be looking out for you from others - remember to look towards Selby, I’m usually monitoring !

73 Graham G3OHC