There is no simple answer without knowing what you are trying to do, e.g. long stay in tarp or tent vs quick stand-up-and-go activation (Iām mostly doing the latter). Iāve used a Diamond RH770 for many years with it directly mounted to my Yaesu FT1D on 100s of SOTA activations with excellent results. Many others have confirmed my experience using a RH770 over the years on this reflector.
BTW: I also bought 3 cheap Chinese clones which appeared to be electrically good on-air but all were of poor mechanical construction. Two broke mid QSO and the third fell apart whilst taking it (carefully) out of its delivery carton. The number of QSOs per unit cost of the Diamond one is dramatically higher than the Chinese ones.
For summits with a poor VHF take-off or for remote ones, I use a āroll-upā j-pole on a 6m pole; the extra height helps where you need to reach chasers farther away.
Personally I would take the RH770 because I own one and I have direct experience of it outperforming a roll-up j-pole deployed about 3m away.
I do have a couple of suggestions on how to do an evaluation yourself.
Round-up two friends and all three of you do an activation on 2m. Listen to what the chasers say about the three different activator signals.
If you have access to an SSB 2m radio, set it up to do FT8. Then make a few CQ calls using each antenna. A quick look on PSK reporter shows a reasonable number of stations in the UK monitoring 2m FT8, so you will quickly see the area coverage, and get an idea of the S/N values at each station hearing you.
Good Luck, and let us know what you find about the three antennas.
No 1 has an SMA to BNC adapter. I have had trouble with those.
No 2 doesnāt appear to have the right connector on the cable (itās SMA at both ends but the antenna is BNC).
Thank you. My FT65/RH770 combo has got me lots of points too. I love flowerpots and often use one to extend the FT65 and also add in a 30W amp between them, if Iām on a lower/remote summit.
Still want to push you for an answer though! Which one of these three?
Thank you. Have you ever elevated the rh770 from the radio with a feeder / mast ? I made a J pole but Iāve made about 10+ flowerpots over the last two years. I swear by them.
Can I push you for an answer on which you think is the better antenna/feeder setup?
The flowerpot options effectively have their own ground plane that the antenna works against within their design.
Just connecting the RH-770 to a pole and putting it up in the air without a ground plane of say 4 1/4 wavelength (or there abouts) rods mounted underneath it and connected to the coax braid is going to be a bad idea. That antenna needs a ground plane directly under it - normally it is the case of the HT but you have taken that away. By the way the coax with SMA connectors on each end isnāt going to fit the BNC plug on the antenna in any case. At VHF/UHF, itās better to avoid using adapters to go from on connector type to another.
73 Ed DD5LP.
Update - other options for DX FM on 2m - HB9CV or Moxon, either of these mounted in vertical polarisation on a 3-4m high, rotatable mast. (but I note you were asking just between the two designs).
I like my 6m flowerpot, it works great, Pity that 6m doesnāt often work great by the time I detect an opening, drive to and walk up the summit, before the band closes again.
Well spotted. That RG74 antenna was made for another radio and I use the connector to use it on the FT5D. The RH770 feeder connector is not shown on the photo, but I do have one. I make my flowerpots with the connector for the radio it is going on, without any break between the antenna and the feeder. The 3rd one is made for the FT5D and Iāll be making one from RG174 if I decide its the way to go.
Can I push you for an answer to which one you think will work best of these three?
Thanks. I make my antennas without the need for adapters for the radio I plan to use them for. I like to buy the coax with the radio fitting already fitted by SOTABEAMS, this way I cut out points of failure and have professionally fitted connectors (which are much more reliable than me doing it!). Iām in the process of moving over to the FT5D so am using some adapters, which I hate doing. They add weight too!
Can I push you for an answer on which of the three you would carry?
One possible downside of having the SMA connector on the cable is that SMA doesnāt have the plug/unplug lifetime that BNC does so I wonder if there is a risk of wearing out the connector on the HT? If you leave the adapter on the rig most of the time then it wonāt suffer the same wear.
Where is the adapter you use from?
CPC do one for about 7 quid that looks like the one you reference in that other post.
Thanks for feedback about the connectors. I have the connectors to fit everything together but have not built the antennas yet with the connectors to directly connect them to the FT5D. I try to eliminate all connections of the coax, except connections to the radio, to reduce weight and points of failure.
Have tried a HB9CV from WiMo. Beautiful thing, well engineered, collapsible antenna. Found it too faffy on the summits and always had great results from Flowerpots.
Can I push you for a choice of the three? you can assume āperfect connectorsā if you like!
I honestly canāt remember. I have a spare one and havenāt needed to use it yet as the first one is still going strong after years. I just did an Internet search and Iām convinced from the photo that SOTAbeams sells the same type.
Itās the bottom one in the photo. You might be able to get it elsewhere without have to get the top one shown there. Donāt forget to use a fibre washer as I mentioned in the linked message.
I try to make antennas so there are no breaks in the coax, except the connection to the radio, so try to avoid adapter altogether. saves weight and reduces points of failure. The reason that adapter is on that antenna is because the FT65 has a male antenna socket and if it snaps its hard/expensive to fix the radio but easy to change the adapter. The FT5D has a female socket so the feeder/ antenna would be the thing to fix/replace!
I use RG174 on my centre-fed linked HF dipoles, but in general I avoid it at VHF. But as you are talking only about very short lengths, I donāt see a problem. Attenuation of 2.5 - 3m of RG174 at 150MHz is about 0.8 to 1 dB.
That raises a good point! (Pun not really intended)
If the summit is a pointy rock, the height of the antenna above ground will not make much difference.
If it is a large flat soggy plateau, it is advantageous to get the antenna as high as possible.
I used to be most active on 2m FM using a roll up Jpole and about 8m of RG58. As Andy mentions, this allowed me to find a sheltered spot, with the 5m pole higher up.
I recall one good example, working Jim EI9GLB (SK) from one of the South Wales summits. My signal was on the noise, and Jim just couldnāt copy the report I was sending.
By lifting the pole off the ground, and holding the base of it above head height, we completed the contact relatively easily - the Jpole now being about 2m higher AGL.
On a pointy summit, that un-necessary length of coax could just make a very weak signal unreadableā¦.
