I was talking to Brian G4ZRP the other day and he told me how he has been spicing up some of his 2m SOTA chasing. He said he’d got a bit fed up chasing using 500mW from his FT290Mk1 and so had been trying the more challenging chasing with 50mW.
Having acquired a box containing assorted inline attenuators he’s been putting them in the feedline and chasing stations. A 10dB attenuator drops the RX’d signal by about 2S points and so hardly affects the signal from most activators. But it does cut down his signal. Anyway that was enough of a challenge as he’s worked a whole bagful of stations with 50mW.
So now he’s onto the 15dB attenuator. Fed with 500mW the TX signal will be around 16mW. He told me he worked Phil G4OBK on Harter Fell LD-028 and got a 53/54 report from Phil whilst Phil was 57. Remember that’s with the attenuator in the TX/RX path! The WX hasn’t been brilliant since then so he’s not tried further but will continue using the 15db pad. After that there’s a 20db and then he’ll try them in series! Nothing in the setup has been calibrated so he’s relying on the claimed attenuation and that his TX is 500mW. The antenna is an X50.
Harter Fell LD-028 is LOS to Brian’s QTH on The Wirral and the path length is around 80miles. Still a 53 report on 2m FM is not bad for just 16mW up the flue and corresponds to a theoretical 5000miles/watt. I’m wondering if there are any better QRPp activation/chaser records lurking?
HG2ECZ Zsolt played with his switchable home-made attenuator last summer. http://hg2ecz.ham.hu/Gyalogradio/toszto.jpg
He was using 1W Pout and a 3 element Yagi (ca. 5-6dBi gain) on 2m.
I was able to hear him from 20km when he switched the attenuator to 70dB! position. My antenna was a 2 element 5/8 collinear (ca. 6dBi gain).
In reply to MM0FMF:
Not quite the same, but I am being heard on WSPR (as I type this) by VK2KRR using 1Watt on 20M. A distance of 16952 miles. I’m qro today, usually make it easily with 500mW. You can do the sum!
73,
Frank
Ah but that’s not FM voice Or put another way, WSPR is many more Watts/HZ than FM voice.
We need to specify the bandwidth for our miles/watt figure. Otherwise we will end up comparing apples with oranges and the answer will be given in grapes/fortnight!
I once cobbled together a collinear for 2m which also worked on 70cm, I tested it with 50mw from my hand held and could easily work the local repeaters as well a mobile for a far few miles.
One day I might just build another as I gave the original away
In reply to MM0FMF:
I agree Andy. Lots of processing power in WSPR. Not really comparing, just observing. As an aside, there was a very strong South African station on 28MHz FM this morning. Remarkably inefficient FM, I prefer semaphore.
73,
Frank
Or put another way, WSPR is many more Watts/HZ than FM voice.